sino norwegian project sound management hazardous for co-processing of afrs and... ·...

Sino‐Norwegian Project 2006‐2009

Environmentally Sound Management of Hazardous and Industrial Wastes in Cement Kilns in China

Guidelines for co‐processing of alternative fuels and raw materials and treatment of organic hazardous

wastes in cement kilns

Draft 25 March 2008

Dr. Kåre Helge Karstensen [email protected]

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Table of content

Table of content ........................................................................................................................... 2

Acronyms and abbreviations - General ...................................................................................... 5

Glossary ........................................................................................................................... 9

1. Introduction ......................................................................................................................... 11 1.1 Objective ........................................................................................................................ 11

1.2 A hybrid ......................................................................................................................... 12

1.3 Policy elements .............................................................................................................. 12

1.4 Limitations of the guidelines.......................................................................................... 16

1.5 General requirements and prerequisites ......................................................................... 16

2. General considerations........................................................................................................ 19 2.1 Compliance with regulations.......................................................................................... 19

2.2 Location, health and safety aspects................................................................................ 19

2.3 Training ......................................................................................................................... 20

2.4 Involvement and communication................................................................................... 21

2.5 Reporting performance................................................................................................... 21

2.6 Environmentally sound management ............................................................................. 22

2.7 Environmental management system .............................................................................. 23

3. Initial waste and impact evaluation by the cement plant................................................. 25 3.1 Waste evaluation ............................................................................................................ 25

3.2 Assessment of possible impacts ..................................................................................... 26

3.3 Commonly restricted wastes .......................................................................................... 29

3.3.1 Risky wastes.................................................................................................... 30 3.4 Check list for acceptance control ................................................................................... 30

4. Waste collection and transport........................................................................................... 33 4.1 Waste collection and handling ....................................................................................... 33

4.2 Waste transport............................................................................................................... 34

5. Waste reception and handling ............................................................................................ 36 5.1.1 Management for non-compliant deliveries ..................................................... 36

5.2 Checking, sampling and testing incoming wastes – general considerations.................. 37

5.2.1 Assess incoming wastes .................................................................................. 38 5.2.2 Techniques for checking ................................................................................. 38


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5.2.3 Inspection ........................................................................................................ 39 5.2.4 Detectors for radioactive materials ................................................................. 39

5.3 Reception and handling.................................................................................................. 40

5.3.1 Labelling ......................................................................................................... 40

6. Waste pre-processing........................................................................................................... 42 6.1 Alternative fuels ............................................................................................................. 42

6.2 Pre-processing and mixing of alternative fuels.............................................................. 43

6.3 Segregation of waste types for safe processing.............................................................. 45

6.4 General design considerations........................................................................................ 47

6.4.1 Design for reception and storage of hazardous wastes ................................... 48 6.4.2 Housekeeping.................................................................................................. 49

7. Waste storage ....................................................................................................................... 51 7.1 Liquid and solid wastes.................................................................................................. 51

7.2 Storage time ................................................................................................................... 53

7.3 Storage of solid waste .................................................................................................... 53

7.3.1 Storage of pumpable waste ............................................................................. 54 7.4 Storage for containers and tank containers .................................................................... 56

7.5 Safety aspects of storage ................................................................................................ 56

7.5.1 The use of fire detection and control systems................................................. 57

8. Best available techniques and best environmental practise (BAT/BEP)........................ 59 8.1 BAT/BEP for cement production................................................................................... 59

8.2 BAT/BEP for controlling emissions of PCDD/PCDFs.................................................. 60

8.3 Conventional fuels ......................................................................................................... 60

9. Co-processing of alternative fuels ...................................................................................... 63 9.1 Input control – general rules .......................................................................................... 63

9.2 Selection of feed point ................................................................................................... 64

9.3 Operations and process control ...................................................................................... 68

9.3.1 Kiln operation and feeding of wastes.............................................................. 70 9.4 Laboratory and quality control....................................................................................... 72

10. Cement quality ..................................................................................................................... 74

11. Emission monitoring............................................................................................................ 75 11.1 Emission limit values for cement kilns in Europe ......................................................... 75

11.2 Continuous emission measurements .............................................................................. 76

11.3 Regular monitoring ........................................................................................................ 76

11.4 Occasional monitoring ................................................................................................... 77

11.5 Additional measures for exit gas cleaning ..................................................................... 78


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12. Test burn and performance verification............................................................................ 79

13. On-site security and safety.................................................................................................. 80 13.1 Personal protective and emergency equipment.............................................................. 81

14. Content of a co-processing permit/licence......................................................................... 84 14.1 Plant organisation and components................................................................................ 84

14.2 Application documents................................................................................................... 85

14.3 Plant data........................................................................................................................ 86

14.4 AFR / hazardous wastes acceptance .............................................................................. 87

14.5 Monitoring and control of combustion .......................................................................... 89

14.6 Air pollution control....................................................................................................... 90

14.7 Monitoring of emissions ................................................................................................ 90

14.8 Qualified laboratories..................................................................................................... 91

14.9 Excerpts of the Directive 2000/76/EC on the incineration of waste in the European

Union - Article 4 - Application and permit ........................................................................... 91

15. References and bibliography .............................................................................................. 94

Annex 1 AFR criteria guidelines for co-processing in cement kilns....................................... 98

Annex 2 Test burn with toxic insecticides in Vietnam........................................................... 101


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Acronyms and abbreviations - General

AFR Alternative fuel and raw material

APCD Air pollution control device

AWFCO Automatic waste feed cut-off

BAT Best available techniques

BEP Best environmental practise

BHF Bag house filter

Btu British thermal unit oC Degree Celsius

CAA Clean Air Act

CEMBUREAU European Cement Association

CEMS Continuous emissions monitoring system

CEN European Standardisation Organisation

CKD Cement kiln dust

Cl2 Molecular chlorine

CSI Cement Sustainability Initiative

DL Detection limit

CO Carbon monoxide

CO2 Carbon dioxide

DE Destruction efficiency

Dioxins A term/abbreviation for polychlorinated dibenzodioxins and

polychlorinated dibenzofurans (see also PCDD/Fs)

DRE Destruction and removal efficiency

Dscm Dry standard cubic meter

EC European Commission

EF Emission factor

e.g. For example

EPA Environmental Protection Agency

EPER European Pollutant Emission Register

ESP Electro static precipitator

EU European Union


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FF Fabric filter

g Gram

GC-ECD Gas chromatography with electron capture detector

GC-MS Gas chromatography with mass spectrometry

HAPs Hazardous air pollutants

HCB Hexachlorobenzene

HCI Hydrogen chloride

HF Hydrofluoric acid

HW Hazardous wastes (the definition of hazardous waste varies among countries

and international institutions, e.g. the Basel Convention mention explicitly 18

main categories of wastes and 26 constituents which are regarded hazardous.

Most regulations regard the following characteristics to be hazardous:

Explosive, flammable, oxidizing, acute poisonous and infectious, corrosive,

liberation of toxic gases, toxic and ecotoxic.

i.e. That is

IPPC Integrated Pollution Prevention and Control

I-TEF International Toxicity Equivalency Factor

I-TEQ International Toxic Equivalent

J Joules

K (Degree) Kelvin

kcal Kilocalorie (1 kcal = 4.19 kJ)

kg Kilogramme (1 kg = 1000 g)

kJ Kilojoules (1 kJ = 0.24 kcal)

kPa Kilo Pascal (= one thousand Pascal)

L Litre

lb Pound

LCA Life cycle analysis

LOD Limit of detection

LOl Loss of ignition

LOQ Limits of quantification

m3 Cubic meter (typically under operating conditions without

normalization to, e.g., temperature, pressure, humidity)

MACT Maximum Achievable Control Technology

MJ Mega joule (l MJ= 1000 kJ)


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mg/kg Milligrams per kilogram

MS Mass spectrometry

mol Mole (Unit of Substance)

Na Sodium

NA Not applicable

ND Not determined/no data (in other words: so far, no measurements available)

NESHAP National Emission Standards for Hazardous Air Pollutants

ng Nanogram (1 ng = 10-9 gram)

Nm3 Normal cubic metre (101.3 kPa, 273 K)

NH3 Ammonia

NOx Nitrogen oxides (NO+NO2)

NR Not reported

OECD Organisation for Economic Co-operation and Development

O2 Oxygen

PAH Polycyclic aromatic hydrocarbons

PCB Polychlorinated biphenyls

PCDDs Polychlorinated dibenzodioxins

PCDFs Polychlorinated dibenzofurans

PCDD/PCDFs Informal term used in this document for PCDDs and PCDFs

PIC Product of incomplete combustion

Pre-processing facility See under Glossary

pg Picogram (1 pg = 10-12 gram)

PM Particulate matter

POHC Principal organic hazardous constituent

POP Persistent organic pollutants

ppb Parts per billion

ppm Parts per million

ppmv Parts per million (volume basis)

ppq Parts per quadrillion

ppt Parts per trillion

ppt/v Parts per trillion (volume basis)

ppm Parts per million

QA/QC Quality assurance/quality control

QL Quantification limit


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RCRA Resource Conservation and Recovery Act

RDF Refuse derived fuel

RT Residence time

sec Second

SINTEF Foundation for Industrial and Scientific Research of Norway

SNCR Selective non catalytic reduction

SiO2 Silicon dioxide

SCR Selective catalytic reduction

SO2 Sulfur dioxide

SO3 Sulfur trioxide

SOx Sulfur oxides

SQL Sample quantification limit

SRE System removal efficiency

t Tonne (metric)

TCDD Abbreviation for 2,3,7,8-tetrachlorobidenzo-p-dioxin

TCDF Abbreviation for 2,3,7,8-tetrachlorobidenzofuran

TEF Toxicity Equivalency Factor

TEQ Toxic Equivalent (I-TEQ, N-TEQ or WHO-TEQ)

TEQ/yr Toxic Equivalents per year

THC Total hydrocarbons

TOC Total organic carbon

tpa Tonnes per annum (year)

TSCA Toxics Substances Control Act

UK United Kingdom

US United States of America

US EPA United States Environmental Protection Agency

VOC Volatile organic compounds

VSK Vertical shaft kilns

WBCSD World Business Council for Sustainable Development

WHO World Health Organization

y Year

% v/v Percentage by volume

µg/m3 Micrograms per cubic meter

µg Microgram


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Glossary

AFR Alternative fuel and raw materials, often wastes or secondary products

from other industries, used to substitute conventional fossil fuel and

conventional raw materials.

Cementitious Materials behaving like cement, i.e. reactive in the presence of

water; also compatible with cement.

Co-processing Utilisation of alternative fuel and raw materials in the purpose

of energy and resource recovery.

Dioxins Together with PCDD/Fs used as term/abbreviation for

Polychlorinated dibenzodioxins and Polychlorinated

dibenzofurans in this document

DRE/DE Destruction and Removal Efficiency/Destruction Efficiency.

The efficiency of organic compounds destruction under

Combustion in the kiln.

Kiln inlet/outlet Were the raw meal enters the kiln system and the clinker leaves

the kiln system.

Pozzolana Pozzolanas are materials that, though not cementitious in themselves,

contain silica (and alumina) in a reactive form able to combine with

lime in the presence of water to form compounds with cementitious

properties. Natural pozzolana is composed mainly of a fine, reddish

volcanic earth. An artificial pozzolana has been developed that

combines a fly ash and water-quenched boiler slag.

Pre-processing AFRs usually needs to be pre-processed and prepared before fed to a

cement process to ensure a homogeneous and stable composition and


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stable combustion conditions. Pre-processing can include drying,

shredding, grinding or mixing depending on the type of waste. Pre-

processing is often done in a purpose made facility, which may be

located outside or inside the cement plant. If the AFR is prepared

outside the cement plant, they only need to be stored at the cement plant

and then proportioned for feeding them to the cement kiln.

Treatment Organic hazardous wastes can be destroyed by exposing them to high

temperatures and oxidising conditions. In lack of available treatment

options and urgent needs, a feasible cement kiln can be used for

treatment of organic hazardous wastes and constituents if this is done

under strict control and Government guidance. Such activities must

have a special permit.


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1. Introduction

Cement kilns have been used for more than three decades to co-process alternative

fuels and raw materials (AFRs) and to treat organic hazardous wastes in a number of

countries. This practise normally combines energy and resource recovery and savings with

effective waste management, and can be extremely attractive and cost-efficient, especially for

emerging economies having insufficient waste treatment capacity. Disposal and treatment of

organic hazardous wastes is however controversial among some stakeholders, claiming that

the cement industry, especially in developing countries, have inadequate technology and

competence of doing this safe and sound.

The absence of uniform operation and performance standards for cement kilns

contributes to this perception and has lead some cement companies to develop their own

internal guidelines in an effort to raise the performance level as well as the acceptance for

such practise (GTZ-Holcim, 2006). Other guidelines are available, but the objective and

coverage varies (World Business Council for Sustainable Development, 2006; Basel

Convention, 2007; Stockholm Convention, 2007).

1.1 Objective

The overall objective of these guidelines is to constitute a benchmark and standard for

cement plants co-processing AFRs and treating hazardous wastes. These guidelines describe

international recommendations and generally applicable principles based on lessons learned,

today’s best practises and state of the art. The final co-processing practise at the plant level

will however be determined by the local circumstances, such as regulation, raw material

chemistry, availability of AFRs and waste materials locally, infrastructure and production

process, co-processing ability, and site specific health, safety and environmental issues. The

detailed and final description of the pre-processing and co-processing practise must be

embedded in the local permit, following the recommendations of these guidelines. This will


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ensure that complying cement plants will be feasible, qualified and be operating according to

internationally recognised environmentally sound management principles.

The fundamental and overarching principle of these guidelines is to prevent that

inappropriate wastes are used and/or that emissions increases. These guidelines recommend

external auditing, transparent information disclosure of performance and the implementation

of a continuous improvement system.

1.2 A hybrid

These guidelines are based on and integrating elements of: 1) the Stockholm

Convention BAT/BEP Guidelines for Cement Kilns Firing Hazardous Wastes (2007); 2) the

Basel Convention Technical Guidelines for the Environmentally Sound Management of POPs

(2007); 3) the Integrated Pollution Prevention and Control Reference Document on the Best

Available Techniques for Waste Incineration (2006); 4) the Organization for Economic

Cooperation and Development recommendation on the Environmentally Sound Management

(ESM) of Wastes (2004); 5) the GTZ-Holcim Guidelines on Co-processing Waste Materials

in Cement Production (2006); 6) the World Business Council for Sustainable Development

Guidelines for the Selection and Use of Fuels and Raw Materials in the Cement

Manufacturing Process (2006); 7) and the Directive 2000/76/EC on the incineration of waste

in the European Union, as well as other lessons learned (Karstensen, 1994; 2001; 2008;

Karstensen et al., 2006). It must however be emphasised that local permits and regulatory

requirements can vary and will take precedence over these guidelines if stricter.

1.3 Policy elements

The guidelines recommends that a national policy on waste management is in place to

ensure that the development, implementation of strategies, legislation, guidelines, plans,

treatment options and other elements of waste management will be exercised in accordance

with the following guiding principles:


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A. Hazardous wastes are a major environmental problem and priority should be given to

prevention of dangerous impacts on human, the environment and the ecosystem;

B. The prevention and reduction of hazardous waste generation is the most beneficial

approach to hazardous waste management and should be given priority;

C. Choice of waste management options should be based on the following

hierarchy/priority:

1. Avoidance, prevention and minimisation;

2. Reuse and recycling to the highest degree possible;

3. Recovery of energy and resources;

4. Disposal, treatment and destruction;

5. Final environmental sound and safe treatment;

Figure 1. Examples of guidelines used in this document


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D. A hazardous waste minimisation strategy comprising waste prevention, cleaner

production, reuse and recovery of materials and energy should be established;

E. Cement kilns shall primarily be used for recovering energy and materials, i.e. for co-

processing alternative fuels and raw materials, which can substitute parts of the fossil

fuel and/or virgin raw materials;

Figure 2. Cement manufacture and conventional fuels used, i.e. coal, pet-

coke, natural gas or fuel oil (WBCSD, 2006).

F. In lack of available treatment options and urgent needs, a feasible cement kiln can be

used for treatment of organic hazardous constituents if this is done under strict control

and Government guidance. Such activities must have a special permit and must

comply with these guidelines;


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G. The national policy should aim for sustainable resource and energy consumption as

well as integrating all relevant elements of and complying with the Montreal Protocol

aimed at eliminating ozone-depleting substances (1987), the Basel Convention on the

Control of Transboundary Movements of hazardous Wastes and their Disposal (1989),

the Convention on Biological Diversity (1992), the Aarhus Protocol on Persistent

Organic Pollutants (1998), the Rotterdam Convention on the Prior Informed Consent

Procedures for Certain hazardous Chemicals and Pesticides in International Trade

(1998) and the Stockholm Convention on Persistent Organic Pollutants (POPs) (2004).

Figure 3. Examples of alternative fuels and raw materials (WBCSD, 2006).


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1.4 Limitations of the guidelines

Common concerns of co-processing of AFRs and the treatment of hazardous wastes in

cement kilns are dealt with in these guidelines. The potential risks involved with this practise

are first of all connected to possible accidents, spills and exposure during collection and

transport to the pre-processing and/or the cement plant; with handling/pre-processing,

preparation and feeding; with possible emissions to air; and with contamination of the

product.

These guidelines cover “all” aspects of co-processing of AFRs and treatment of

hazardous wastes in cement kilns by describing international recommendations and

environmentally sound management principles. These principles must however be adapted to

local circumstances, i.e. regulation, waste types and characteristics, pre-processing facility,

and the co-processing at the local cement plant. The final co-processing and treatment at the

cement plant will be determined by the local raw material and fuel chemistry, by the

availability of AFRs and waste materials, by the infrastructure and the cement production

process, by the availability of equipment for controlling, handling and feeding the waste

materials, and finally by site specific health, safety and environmental issues. Most of these

aspects are to a certain degree site specific and will vary from plant to plant, that is why only

general principles and international recommendations are applicable.

The final details of the pre-processing and co-processing practise must therefore be

described in the local permit/licence; the recommended content of such a co-processing

permit/licence is outlined in chapter 14. The recommendations of these guidelines should

however be integrated in the permit.

1.5 General requirements and prerequisites

The following requirements and prerequisites should be in place to prevent and reduce

the risks to the greatest extent possible prior to commencing on with treatment of hazardous

wastes in cement kilns on a routine basis:


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1. An approved environmental impact assessment EIA and all necessary

national/local licences;

2. Compliance with all relevant national and local regulations;

3. Compliance with the Basel and the Stockholm Convention;

4. Approved location, technical infrastructure and processing equipment;

5. Reliable and adequate power and water supply;

6. Adequate air pollution control devices and continuous emission monitoring

ensuring compliance with regulation and permits; needs to be verified through

regular baseline monitoring;

7. Exit gas conditioning/cooling and low temperatures (<2000C) in the air

pollution control device to prevent dioxin formation;

8. Clear management and organisational structure with unambiguous

responsibilities, reporting lines and feedback mechanism;

9. An error reporting system for employees;

10. Qualified and skilled employees to manage hazardous wastes and health, safety

and environmental issues;

11. Adequate emergency and safety equipment and procedures, and regular

training;

12. Authorised and licensed collection, transport and handling of hazardous

wastes;


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13. Safe and sound receiving, storage, preparation and feeding of hazardous

wastes;

14. Adequate laboratory facilities and equipment for hazardous waste acceptance

and feeding control;

15. Demonstration of hazardous waste destruction performance through test burns;

16. Adequate record keeping of hazardous wastes and emissions;

17. Adequate product quality control routines;

18. An environmental management and continuous improvement system certified

according to ISO 14001, EMAS or similar;

19. Regular independent audits, emission monitoring and reporting;

20. Regular stakeholder dialogues with local community and authorities, and for

responding to comments and complaints;

21. Open disclosure of performance reports on a regular basis.


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2. General considerations

This chapter summarise general measures and considerations, which needs to be in

place when starting with pre-processing and co-processing in cement plants.

2.1 Compliance with regulations

Relevant and appropriate legislative and regulatory framework has to be in place and

enforced to guarantee a high level of environmental protection. The pre-processing facility

and cement plant operator must:

a) Identify all relevant laws, regulations, permits, standards, and company policies

relating to safety, health, environment, and quality control, and its compliance must be

continually reviewed;

b) Share this information with the employees and make sure that they are aware of their

responsibilities under them.

2.2 Location, health and safety aspects

Consider site location of the pre-processing and the co-processing plant and its

suitability carefully as this may avoid risks associated with proximity to populations of

concerns, impact of releases, logistics, transport, infrastructure, as well as having in place

technical solutions for vapours, odours, infiltration into environmental media, etc. The pre-

processing facility and cement plant operator must:

a) Develop robust emergency procedures as well as procedures for operation and

maintenance that cover safety of neighbours, workers and installations;


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b) Systematically review operation and maintenance procedures.

2.3 Training

The pre-processing facility and cement plant operator must develop and implement

appropriate and documented training programs for employees on operation, safety, health, and

environment and quality issues relevant to their jobs. Train new employees during an

induction process and personnel reporting to work on a site for the first time should be trained

through a site induction program. Keep training records on file. The training program should

include the following:

a) General and job specific safety rules;

b) Safe operation of all equipment;

c) Compliance with existing permits for working with hazardous waste;

d) Details of the site emergency plan and procedures;

e) Procedures for handling hazardous wastes and alternative fuels and raw materials as

well as detection of warning indicators such as barrel expansion, smoke from

stockpiles, spillages or leaks;

f) Use and maintenance of personal protective equipment (PPE);

g) Waste labelling (composition, storage requirements and risks) and requirements for

segregation of incompatible wastes (such as minimum distances, firewalls and

containment cells).


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Such training programs should also be given to contractors and, in some instances,

suppliers.

2.4 Involvement and communication

Adequate documentation and information are mandatory, providing an informed basis

for openness and transparency about health and safety measures and standards, and ensuring

that employees and authorities have such information well before starting any use of

hazardous waste. All relevant authorities have to be involved during the permitting process,

and the pre-processing facility and cement plant operator must:

a) Establish credibility through open, consistent, and continuous communication with the

authorities and other involved stakeholders. All necessary information must be

provided to allow stakeholders to understand the purpose of co-processing AFRs in a

cement kiln, the context, the function of the parties involved and decision-making

procedures;

b) Provide necessary information to ensure that authorities are able to evaluate and

understand the entire process;

c) Establish a stakeholder engagement plan for working with the local community and

authorities, including procedures for responding to community interests, comments, or

complaints; give prompt feedback.

2.5 Reporting performance

Building trust with stakeholders requires both transparency and accountability in the

cement plant operator and its site operations. The production of regular reports on

performance in all areas of interest helps to provide key stakeholders with the information


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they need to make a fair and balanced judgment of the company’s or site’s activities and

performance.

2.6 Environmentally sound management

Environmentally sound management (ESM) is a policy concept that more broadly

applies to hazardous wastes within the Basel and Stockholm Convention. In its article 2,

paragraph 8, the Basel Convention (1989; 2006) defines ESM of hazardous wastes or other

wastes as “taking all practicable steps to ensure that hazardous wastes or other wastes are

managed in a manner which will protect human health and the environment against adverse

effects which may result from such wastes.”

To comply with the ESM criteria, a number of legal, institutional and technical

conditions must be met, in particular that:

a) A regulatory and enforcement infrastructure ensures compliance with applicable

regulations;

b) The facility should be authorized and have an adequate standard of technology and

pollution control to deal with hazardous wastes;

c) The facility should have an applicable environmental management system (EMS) in

place;

d) The facility should take sufficient measures to safeguard occupational and

environmental health and safety;

e) The facility should have an adequate monitoring, recording and reporting programme;

f) People involved in the management of hazardous wastes are capable and adequately

trained in their capacity.


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g) That the facility should have an adequate emergency plan; and

h) The effects of the activities needs to be monitored and appropriate action should be

taken in cases where monitoring gives indications that the management of hazardous

wastes has resulted in unacceptable releases.

2.7 Environmental management system

The pre-processing facility and cement plant operator should have an environmental

management system (EMS) in place, ensuring continuous improvement of its performance.

The two most frequently used guidelines for EMS design are the international standard, ISO

14001, and the European standard, EMAS.

ISO 14001 provides guidelines that can be implemented by almost any type of

organization in any country and was designed primarily to improve management. EMAS, on

the other hand, is designed to bring about changes in environmental performance. Preparing

for and complying with ISO 14001 involves several steps:

a) Conducting an initial environmental review;

b) Identifying environmental aspects and impacts;

c) Setting an environmental policy;

d) Understanding and complying with local environmental legislation and regulations

and other standards to which the organization subscribes;

e) Setting environmental objectives and targets;

f) Setting and implementing an environmental management program;

g) Setting and implementing environmental procedures;


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h) Establishing environmental training and awareness;

i) Establishing an environmental communication system;

j) Establishing a system for document and operational control;

k) Installing an emergency preparedness and response plan;

l) Monitoring and measuring;

m) Understanding non-conformance and implementing correction and prevention;

n) Having an audit, and

o) Management review and control.


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3. Initial waste and impact evaluation by the cement plant

The aim of the initial acceptance procedures is to set the outer boundaries and limits

for wastes, which can be accepted by a particular kiln, and the conditions and requirements

for their preparation and delivery specification. Any waste fed to a cement kiln should:

a) Be homogenous;

b) Have stable heat and moisture content;

c) Have stable chemical and physical composition;

d) Have a pre-specified size distribution.

In real-life, a cement plant operator usually receives wastes from various producers

with various waste characteristics and to fulfil the requirements mentioned above wastes must

be pre-processed prior to delivering to the cement plant. The cement plant operator must

however specify their requirements for waste acceptance with the waste owner and the pre-

processing facility prior to any deliverables.

3.1 Waste evaluation

Accept only wastes from trustworthy parties throughout the supply chain, with

traceability ensured prior to reception by the facility and with unsuitable wastes refused. The

pre-processing facility and cement plant operator must develop an evaluation and acceptance

procedure that includes the following features:

a) To evaluate possible impacts before delivering it to the cement plant or pre-processing

facility, each waste supplier must prepare a representative sample. This must include

a datasheet detailing the chemical and physical properties, information on relevant


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health, safety, and environmental considerations during transport, handling, and use of

the material. It must also specify the source of the particular shipments being made;

b) Test and check the sample’s physical and chemical characteristics against

specifications.

Figure 4. Types of wastes used by the European cement industry (Ökopol GmbH,

2007).

3.2 Assessment of possible impacts

When the cement plant operator and the pre-processing facility have received

information about the waste, he must:

a) Assess the potential impact of transporting, unloading, storing, and using the material

on the health and safety of employees, contractors, and the community. Ensure that

equipment or management practices required to address these impacts are in place;


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Figure 5. Assessment of possible impacts (Neosys Ag & Ecoscan SA, 2004)


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b) Assess what personal protective equipment will be required for employees to safely

handle the waste on site;

c) Assess the compatibility of wastes; reactive or non-compatible wastes must not be

mixed;

d) Assess the effect the waste may have on the process operation. Chlorine, fluorine,

sulphur, and alkali content in wastes may build up in the kiln system, leading to

accumulation, clogging, and unstable operation; excess in chlorine or alkali may

produce cement kiln dust or bypass dust (and may require installation of a bypass)

which must be removed, recycled or disposed of responsibly. The heat value is the

key parameter for the energy provided to the process. Wastes with high water content

may reduce the productivity and efficiency of the kiln system and the ash content

affects the chemical composition of the cement and may require an adjustment of the

composition of the raw materials mix;

Raw meal

Raw gas

Cyclonepreheater

Rotary kilnCooling air

Evaporation cooler

Mill dryer

Dust recycling

Electrostatic precipitator

Clean gas

Clean gas

Dust collection

ClinkerGrate cooler

Burner

Figure 6. Rotary kiln with cyclone preheater and gas dust collection


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e) Assess the potential impact on process stability and quality of the final product;

f) Assess the effect the waste may have on plant emissions and whether new equipment

or procedures are needed to ensure that there is no negative impact on the

environment;

g) Determine what materials analysis data the waste supplier will be required to provide

with each delivery, and whether each load needs to be tested prior to off-loading at the

site.

3.3 Commonly restricted wastes

Develop a uniform list of restricted wastes valid for the plant based on the previous

impact assessment and the plants raw material and fuel composition. Certain cement

companies choose not to treat the following wastes and materials:

a) Electronic waste;

b) Entire Batteries;

c) Infectious and biological active medical waste;

d) Mineral acids and corrosives;

e) Explosives;

f) Asbestos;

g) Radioactive waste;

h) Unsorted municipal waste;

i) Unknown/unidentified wastes.


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Individual companies may exclude additional materials depending on local

circumstances and company policy.

Shipments crossing international boundaries and classified as hazardous waste under

the Basel Convention must meet with the requirements of the Convention.

3.3.1 Risky wastes

When the waste composition cannot be described in detail (e.g. small amounts of

pesticides or laboratory chemicals), the cement plant operator and the pre-processing facility

may agree with the waste producer on specific packaging requirements, making sure that the

waste will not react during transport, or within containers. For example, risks may arise from:

a) Wastes with phosphides;

b) Wastes with isocyanates;

c) Waste with peroxides;

d) Wastes with alkaline metals (e.g., or other reactive metals);

e) Cyanide with acids;

f) Wastes forming acid gases during combustion;

g) Wastes with mercury and thallium.

3.4 Check list for acceptance control

Delivered wastes must generally undergo specific admission controls, whereby the

previously received declaration by the waste producer provides the starting point. After


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comparison by visual and analytical investigations with the data contained in the declaration,

the waste is either accepted and allocated to the appropriate pre-processing and/or storage

area, or rejected in the case of significant deviations.

Prior to signing any commercial contract, the cement plant operator must make sure

that:

a) The waste generator, collector, pre-processing facility provides adequate information

on composition and risks of the material;

b) They do not accept any substances, compounds or preparations which are not allowed

or on the “negative list”;

Figure 7. Example of decision tree used for guidance of the acceptance or refusal of

AFRs (GTZ-Holcim, 2006).


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c) They prohibit blending of incompatible materials and perform compatibility tests if

needed;

d) They perform sampling on the site of the generator, collector or the pre-processing

facility and analysis before acceptance of commercial contracts. Sampling and

analysis can be done by own or external, certified laboratories;

e) They do not start transportation to plant site before completion of the acceptance

process. This acceptance process does not replace sampling and analysis of waste

deliveries at the plant sites;

f) They communicate the inherent safety and health risks indicated by the waste

generator, collector, pre-processor or identified by the sample analysis to the

downstream operations (transport, pre- and co-processing) to ensure that PPE and

installations are adapted accordingly;

g) They provide simple, clear and practical handling procedures, based on the material

properties, to each person who will work with the waste;

h) They provide the commercial employees with adequate training in chemistry to allow

them to enforce the waste acceptance criteria.


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4. Waste collection and transport

Waste collection, handling and transport to the cement plant operator or the pre-

processing facility must be effectively monitored, and be in full compliance with existing

regulatory requirements; only qualified, authorised and licensed transport companies shall be

used.

4.1 Waste collection and handling

The main concerns when handling wastes are human exposure, accidental release to

the environment and contamination of other waste streams. Train staff in the correct methods

of collecting and handling wastes. Handle hazardous wastes separately from other waste

types in order to prevent contamination and recommended practices for this purpose include:

a) Inspect drums and containers for leaks, holes, rust, and high temperature (handle

hazardous wastes at temperatures below 25 oC, if possible, due to the increased

volatility at higher temperatures);

b) Ensure that spill containment measures is adequate and would contain liquid wastes if

spilled;

c) Place plastic sheeting or absorbent mats under containers before opening containers if

the surface of the containment area is not coated with a smooth surface material (paint,

urethane, epoxy);

d) Remove liquid hazardous wastes either by removing the drain plug or by pumping

with a peristaltic pump and Teflon or silicon tubing;

e) Use dedicated pumps, tubing and drums, not used for any other purpose, to transfer

liquid wastes;


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f) Clean up any spills with cloths, paper towels or absorbent;

g) Triple rinse contaminated surfaces with a solvent such as kerosene to remove all of the

residual hazardous wastes;

h) Treat all absorbents and solvent from triple rinsing, disposable protective clothing and

plastic sheeting as hazardous wastes.

4.2 Waste transport

Wastes consisting of, containing or contaminated with hazardous materials must be

packaged prior to transport. Liquid hazardous wastes should be placed inter alia in double-

bung steel drums (e.g. 16-gauge steel coated inside with epoxy). Containers used for storage

should meet transport requirements in anticipation that they may be transported in the future.

Figure 8. Drums with hydrocarbon sludge arrives at the pre-processing plant


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Drums may be placed on pallets for movement by forklift truck and for storage, but

must be strapped to the pallets prior to movement. All drums and containers must be clearly

labelled with both a hazard-warning label and a label that gives the details of the drum, with

its content, type of waste, and name and telephone number of the responsible person.

The pre-processing facility and cement plant operator must ensure that:

a) Vehicles are fit for operation according to local regulations and waste specifications;

b) Vehicles are clean (no spillage or residues);

c) Drivers have received appropriate training in the transport of waste, including

emergency response, based on local regulations (at a minimum).

d) Drivers refuse to load and transport barrels, big bags or other waste packages, which

are damaged, leaking or showing other conspicuous warning signs (e.g. barrel

expansion from pressure build-up, elevated temperature etc.).


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5. Waste reception and handling

Wastes received in drums at the pre-processing facility and cement plant must be

packed, labelled and loaded properly to ensure that waste material reaches the plant in good

condition. The transport of packed waste, typically waste in drums should present detailed

instructions on the types of material. All wastes received at the plant should initially be

treated as being unknown and hazardous until compliance with specifications has been

positively verified.

Vehicles carrying wastes must stop upon arrival and make the necessary

identifications. Such vehicles should be:

a) Weighed in and out of the site and deliveries must be recorded;

b) Documents relating to vehicles carrying hazardous waste must be checked and the

compliance with site acceptance specifications and regulations determined;

c) Document checks should cover waste certificates, transport certificates, etc.;

d) Instructions for unloading, including safety and emergency instructions, should be

provided in due time to vehicle drivers.

e) A vehicle found not to comply should not be allowed to enter the site.

5.1.1 Management for non-compliant deliveries

Written instructions must describe what to do in case of non-compliance with

specifications and the waste producer must be informed about non-compliant deliveries. If

non-compliance cannot be cleared with producer, the shipment must be rejected and if

required in the permit, authorities must be notified.


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Deliveries should be evaluated for each waste producer on a statistical basis in order to

assess the performance and reliability of the producers; periodically review contracts

accordingly.

5.2 Checking, sampling and testing incoming wastes – general considerations

Delivered wastes must undergo specific admission controls, whereby the previously

received declaration by the waste producer provides the starting point. Sample and analyze

vehicle loads once on site according to the frequency and protocol defined in the site control

plan; check agreement with site specifications according to the plan of control. Accept wastes

once their properties are confirmed to agree with specifications.

Figure 9. Inspection of drums with hydrocarbon sludge before pre-processing


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5.2.1 Assess incoming wastes

Apply a suitable regime for the assessment of incoming waste. Such assessment must

reveal:

a) That the wastes received are within the range suitable for the installation;

b) Whether the wastes need special handling/storage/treatment/removal for off-site

transfer;

c) Whether the wastes are as described by the supplier (for contractual, operational or

legal reasons).

5.2.2 Techniques for checking

Techniques for checking vary from simple visual assessment to full chemical analysis.

The extent of the procedures adopted will depend upon:

a) Nature and composition of waste;

b) Heterogeneity of the waste;

c) Known difficulties with wastes (of a certain type or from a certain source);

d) Specific sensitivities of the installation concerned (e.g. certain substances known to

cause operational difficulties);

e) Whether the waste is of a known or unknown origin (should be avoided);

f) Existence or absence of a quality controlled specification for the waste;

g) Whether the wastes have been dealt with before and the plants experiences with it.


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5.2.3 Inspection

Apply the following inspection scheme:

a) Control and comparison of data in the declaration list in comparison with delivered

waste;

b) Sampling and analysis of all bulk tankers;

c) Random checking of drummed loads;

d) Unpacking and checking of packaged loads;

e) Assessment of combustion parameters;

f) Blending tests on liquid wastes prior to storage;

g) Control of flashpoint for wastes in the bunker;

h) Screening of waste input for elemental composition e.g. by XRF and/or other

appropriate techniques.

5.2.4 Detectors for radioactive materials

The inclusion of radioactive sources or substances in waste, can lead to operational

and safety problems. Very low “background” levels of radioactivity are present throughout

the natural environment and will be found in wastes – such levels do not require specific

measures for their detection and control. However, some wastes are at risk of containing

higher levels.


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Radioactive materials can often be detected using specific detectors situated at, for

example, the entrance to the plant. Tests of waste loads that may have a higher risk of

contamination can be carried out. Plastic scintillation detectors are one type of detector used;

these measure photons from gamma emitting radionuclides and to a lesser extent from beta

emitters.

5.3 Reception and handling

There should be written procedures and instructions in place for the unloading,

handling, and storage of the solid and liquid wastes used on site, i.e.:

a) Designated routes for vehicles carrying specified hazardous wastes should be clearly

identified within the site;

b) Relevant employees should be trained in the company’s operating procedures, and

compliance with such procedures should be audited regularly;

c) Appropriate signs indicating the nature of hazardous wastes should be in place at

storage, stockpiling, and tank locations;

d) Storage facilities should be operated in such a way as to control emissions to air,

water, and soil.

5.3.1 Labelling

In general, waste delivery is accompanied by a suitable description of the waste; an

appropriate assessment of this description and the waste itself forms a basic part of waste

quality control. An indicative list of the most important parameters for labelling includes:

a) Name and address of the deliverer;


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b) Origin of the waste;

c) Volume;

d) Water and ash content;

e) Calorific value;

f) Concentration of chlorides, fluorides, sulphur and heavy metals.

Figure 10. UN Dangerous Goods Transport Labelling


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6. Waste pre-processing

The use of wastes must not detract from smooth and continuous cement kiln operation,

product quality, or the site’s normal environmental performance implying that wastes used in

cement kilns must be homogenous and have a stable chemical composition and heat content,

and a pre-specified size distribution. Pre-processing and preparation with the objective of

providing a more homogeneous feed and more stable combustion conditions may therefore be

necessary.

Such pre-processing can include drying, shredding, grinding or mixing depending on

the type of waste. Pre-processing is usually done in a purpose made facility, which may be

located outside or inside the cement plant. If the alternative fuel is prepared outside the

cement plant, the fuels only need to be stored at the cement plant and then proportioned for

feeding them to the cement kiln.

6.1 Alternative fuels

Alternative fuels can be subdivided into five classes:

1. Gaseous alternative fuels, for example coke oven gases, refinery waste gas, pyrolysis

gas, landfill gas, etc.

2. Liquid alternative fuels, for example low chlorine spent solvents, lubricating as well as

vegetable oils and fats, distillation residues, hydraulic oils, insulating oils, etc. Some

equipment can be sealed under a nitrogen blanket to reduce fire and explosion risks

when handling liquids.

3. Pulverized, granulated or fine crushed solid alternative fuels, for example ground

waste wood, sawdust, planer shavings, dried sewage sludge, granulated plastic, animal

flours, agricultural residues, residues from food production, fine crushed tyres, etc.


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4. Coarse crushed solid alternative fuels, for example crushed tyres, rubber/plastic waste,

waste wood, re-agglomerated organic matter, etc.

5. Lump alternative fuels, for example whole tyres, plastic bales, material in bags and

drums, etc.

Mixing and homogenisation of wastes will generally improve feeding and combustion

behaviour. Mixing of wastes can involve risks and should be carried out according to a

prescribed recipe.

6.2 Pre-processing and mixing of alternative fuels

Techniques used for waste pre-processing and mixing are wide ranging, and may

include:

a) Mixing and homogenising of liquid wastes to meet input requirements, e.g. viscosity,

composition and/or heat content;

b) Shredding, crushing, and shearing of packaged wastes and bulky combustible wastes,

e.g. tyres;

c) Mixing of wastes in a bunker using a grab or other machine (e.g. sprelling machines

for sewage sludge);

d) Production of refuse derived fuel (RDF), usually produced from source separated

waste and/or other non hazardous waste.


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Figure 11. Multi purpose plant for lump AF

Figure 12. Tyre handling concept


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Solid heterogeneous wastes can be mixed in a bunker or a pit prior to loading into

transport or feed systems. In bunkers, the mixing involves blending of wastes using cranes

and the crane operators can identify potentially problematic loads (e.g. baled wastes, discrete

items that cannot be mixed or will cause loading/feeding problems) and ensure that these are

removed, shredded or directly blended (as appropriate) with other wastes. Crane capacity

must be sufficient to allow mixing and loading at a suitable rate.

Figure 13. Emptying of drums with hydrocarbon sludge in a mixing pit.

6.3 Segregation of waste types for safe processing

Waste acceptance procedures and storage depend on the chemical and physical

characteristics of the waste. Appropriate waste assessment is an essential element in the


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selection of storage and input operations and is strongly related to the checking, sampling and

assessment of incoming wastes.

The segregation techniques applied vary according to the type of wastes received at

the plant. Segregation relates to maintaining separation of materials to avoid hazardous

mixtures. Extensive procedures are required to separate chemically incompatible materials.

Table 1. Compatibility and reactions

Proper labelling of the wastes (e.g. in accordance with the European Waste Catalogue)

that are delivered in containers, assists their identification and traceability, and ensures:

a) Knowledge of waste content, which is required for choice of handling/processing

operations;

b) The operators ability to trace sources of problems and then to take steps to eliminate or

control them;


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c) The ability to demonstrate conformance with restrictions on waste types and quantities

received/processed.

Bar code systems and scan readers can be used for packaged and liquid wastes. The

costs of such systems are low in relation to the benefits.

Figure 14. Shredded tyres and rubber waste

6.4 General design considerations

Carefully consider the cement plant and the pre-processing facility layout to ensure

access for day-to-day operations, emergency escape routes, and maintainability of the plant

and equipment.

Apply recognized standards to the design of installations and equipment. Any

modification to installations and equipment should meet requirements set in the standards.


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Thoroughly evaluate existing equipment refitted for a different service from a safety and

performance standpoint before resuming commercial production. Document any

modifications to installations and equipment.

Assess operations for health and safety risks or concerns to ensure that equipment is

safe and to minimize risks of endangering people or installations, or damaging the

environment. Use appropriate procedures to assess risks or hazards for each stage of the

design process. Only competent and qualified personnel should undertake or oversee such

hazard and operability studies.

6.4.1 Design for reception and storage of hazardous wastes

Establish suitable and safe transfer systems from transportation to the storage area to

avoid risks from spillage, fugitive emissions or vapour. Suitable vapour filtration and capture

equipment should be in place to minimize impact to the reception point and surrounding areas

from unloading activities.

Transfer and storage areas must be designed to manage and contain accidental spills

into rainwater or firewater, which may be contaminated by the materials. This requires

appropriate design for isolation, containment, and treatment as follows:

a) All ground area within diced, storage areas must be sealed so that spills will not

penetrate the ground;

b) Sealed concrete surfaces with well controlled drainage are recommended;

c) All leaks, spills, rainwater etc. should be easily collected and saved for destruction;

d) No runoff water from the waste chemical storage area should be discharged to sewers.

Any such runoff should be redirected into storage tank for subsequent high

temperature destruction in the kiln;


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e) Leak free design should be specified whenever possible;

f) Methods to contain and recover piping leaks without environmental contamination

should be provided;

g) Adequate alarms for abnormal conditions should be provided.

Monitoring systems capable of detecting volatile organic vapours should be placed at

key process locations to signal accidental waste fuel leaks. Periodic monitoring for volatile

organic compound emissions should be provided.

All volatile organic emissions from waste storage and pre-processing facilities could

be exhausted to the cement kiln for complete destruction. Alternatively, a closed vapour line

between the storage tank vents and the tank trucks should be provided to return the displaced

volatile organic vapours from the storage tanks to the tank truck, when loading the tanks.

A back up carbon adsorption vapour control system could be provided to control

volatile organic compound storage tank breathing emissions. Explosion proof safety valves

should be used.

6.4.2 Housekeeping

General tidiness and cleanliness contribute to an enhanced working environment and

can allow potential operational problems to be identified in advance. The main elements of

good housekeeping are:

a) The use of systems to identify and locate/store wastes received according to their

risks;

b) The prevention of dust emissions from operating equipment;


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c) Effective waste water management;

d) Effective preventive maintenance.


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7. Waste storage

Limit waste volumes in storage and waste storage time to a minimum, i.e. maximum

allowed waste storage should be determined on the installed fire protection systems, which

should include early warning sensors like temperature and smoke detectors.

Define limits for waste and processed wastes storage times per type of material in the

permit, taking into consideration the corresponding health and safety risks (toxicity,

reactivity, flammability/explosion potential, and storage conditions) and local regulations.

Assure that storage facilities fit their purpose. In general, the storage of wastes needs,

additionally, to take into account the unknown nature and composition of wastes, as this gives

rise to additional risks and uncertainties. In many cases, this uncertainty means that higher

specification storage systems are applied for wastes than for well-characterised raw materials.

A common practice is to ensure, as far as possible, that hazardous wastes are stored in

the same containers (drums) that are used for transport; thus avoiding the need for additional

handling and transfer.

Good communication between the waste producer and the waste manager help to

ensure wastes are stored and transferred, etc., such that risks all along the chain are well

managed. It is also important that only well characterised and compatible wastes are stored in

tanks or bunkers.

7.1 Liquid and solid wastes

Appropriate waste assessment is an essential element in the selection of storage and

loading options. Some issues to note are:


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a) For the storage of solid hazardous waste, many plants are equipped with a bunker from

where the waste is fed into the installation by cranes or feed hoppers;

b) Liquid hazardous waste and sludge’s, these are usually stored in a tank farm. Some

tanks have storage under an inert (e.g. N2) atmosphere. Liquid waste may be pumped

via pipelines to the kiln. Sludge’s can be fed by using special “viscous-matter” pumps.

Appropriate storage for liquids should meet relevant safety and design codes for

storage pressures and temperatures and should have adequate secondary containment;

c) Some kilns are able to feed certain substances, such as toxic, odorous liquids, by

means of a direct injection device, directly from the transport container into the kiln.

Hazardous wastes should be stored in an isolated area, preferable well fenced and

locked, to provide good security from intruders and vandals. Incompatible wastes must be

kept separate. The waste liquid storage sump area should be enclosed and all went gases from

such area and storage tank should be vented to an emission control system. Solid materials

handling systems should have adequate dust control systems.

Figure 15. Storage of drummed waste at a pre-processing facility


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7.2 Storage time

Storage design should be appropriate to maintain the quality and storage time of the

materials. The design should prevent build-up of old materials for solids and apply mixing or

agitation to prevent settlements in liquids.

Storage of hazardous waste should be for as brief a period as possible and in accordance

with the permit and regulation. Recommended maximum storage times are:

a) 10 days for waste mixtures, and hazardous wastes;

b) 21 days for hazardous waste impregnated substrates;

c) For non-hazardous AFR, storage time is limited by the designed storage capacity and

installed fire suppression systems.

7.3 Storage of solid waste

Solid and un-pumpable pasty waste that has been degassed and does not smell can be

stored temporarily in bunkers. Storage and mixing areas can be separated in the bunker. This

can be achieved through several design segments. The bunker must be designed in such a

way that ground emissions can be prevented.

The bunker and container storage must be enclosed unless health and safety reasons

(danger of explosion and fire) exist. The air in the bunker may be removed and ducted to the

kiln. In anticipating fires, monitors such as heat-detecting cameras are used, in addition to

constant monitoring by personnel (control room, operator).


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Figure 16. Multi purpose plant for granulated AFRs

7.3.1 Storage of pumpable waste

Larger amounts of fluid and pumpable pasty wastes are temporarily stored in tanks

that must be available in sufficient numbers and sizes to accommodate reacting liquids

separately (danger of explosion, polymerisation).

Tanks, pipelines, valves, and seals must be adapted to the waste characteristics in

terms of construction, material selection, and design. They must be sufficiently corrosion-

proof, and offer the option of cleaning and sampling. Flat bed tanks are generally only

deployed for large loads.

It may be necessary to homogenise the tank contents with mechanical or hydraulic

agitators. Depending on the waste characteristics, some tanks must be heated indirectly and

insulated. Tanks are set in catch basins that must be designed for the stored material, with

bund volumes chosen so that they can hold the liquid waste in the event of leakage.


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Figure 17. Multi purpose plant for liquid AFRs

Figure 18. Tanks for liquid hazardous wastes. Pipes are connected directly to the

main burner.


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7.4 Storage for containers and tank containers

For safety reasons, hazardous waste is often accumulated in special containers, which

can be delivered directly to the plant. Delivery is also taken of bulk liquids.

The delivered containers may be stored or the contents transferred. In some cases,

according to a risk assessment, the waste may be directly injected via a separate pipeline into

the kiln. Heated transfer lines may be used for wastes that are only liquid at higher

temperatures.

Storage areas for containers and tank containers are usually located outside, with or

without roofs. Drainage from these areas is generally controlled, as contamination may arise.

7.5 Safety aspects of storage

The following measures will strengthen safety:

a) Storage areas should be kept clear of uncontrolled combustible materials;

b) Clear safety warnings, no smoking, fire, evacuation route, and any procedures signs

should be clearly posted;

c) An emergency shower and eye washing station should be clearly marked and located

near the storage of liquid alternative fuels;

d) A fire protection system must be available at all times and should meet all standards

and specifications from local authorities (e.g. local fire department);

e) Adequate alarms should be provided to alert all personnel about emergency situations;


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f) Communications equipment should be maintained at the site so that the control room

and the local fire department can be contacted immediately in case of a fire;

g) Equipment should be grounded and appropriate anti-static devices and adequate

electrical devices selected (e.g. motors, instruments, etc.).

7.5.1 The use of fire detection and control systems

Automatic fire detection systems should be used in waste storage areas as well as for

fabric and static filters, electrical and control rooms, and other identified risk areas.

Automatic fire control systems should be applied in some cases, most commonly when

storing flammable liquid waste although also in other risk areas.

Foam and carbon dioxide control systems provide advantages in some circumstances

e.g. for the storage of flammable liquids. Foam nozzles are commonly used in MSW

incineration plants in the waste storage bunker. Water systems with monitors, water cannons

with the option to use water or foam, and dry powder systems are also used.

Nitrogen blanketing may be used in fixed coke filters, fabric filters, tank farms, or for

the pre-treatment and kiln loading facilities for hazardous wastes.

Continuous automatic measurement of temperature can be carried out on the surface of

wastes stored in the bunkers. Temperature variations can be used to trigger an acoustic alarm.

There are also other safety devices, such as:

a) Nozzles above the waste feed hoppers;

b) Fire resistant walls to separate transformers and retention devices under transformers;

c) Gas detection above gas distribution module.


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When ammonia is used, its storage requires specific safety measures, i.e. NH3

detection and water spray devices to absorb releases.


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8. Best available techniques and best environmental practise

(BAT/BEP)

Technological advancement of the cement industry will concentrate on the further

development of new technology, on the utilization of secondary materials and other

supplementary cementitious materials. In recent years, improvement of cement production

lines with precalcining systems includes the new homogenization technology, new preheating

and precalcining systems with the capacity of up to ten thousand tons of cement per day,

various new types of crushing and grinding systems, new operation and management systems,

new environmental protection measures such as the use of new bag dust collector and low

NOx burner. The utilization of secondary materials and supplementary cementitious materials

may save huge amounts of natural resources.

8.1 BAT/BEP for cement production

Dry preheater/precalciner kilns are regarded to be the best available techniques (BAT)

and to constitute the Best Environmental Practise (BEP). These technologies are also the

most economically feasible option, which constitutes a competitive advantage and thereby

contributes to gradually phase out older, polluting and less competitive technologies.

For new plants and major upgrades the best available techniques for the production of

cement clinker is a dry process kiln with multi-stage preheating and precalcination. A smooth

and stable kiln process, operating close to the process parameter set points, is beneficial for all

kiln emissions as well as the energy use. This can be obtained by applying:

• Process control optimisation, including computer-based automatic control systems;

• The use of modern fuel feed systems;


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• Minimising fuel energy use by means of preheating and precalcination to the extent

possible, considering the existing kiln system configuration.

Careful selection and control of substances entering the kiln can reduce emissions and

when practicable, homogenous raw materials and fuels with low contents of sulfur, nitrogen,

chlorine, metals and volatile organic compounds should be selected.

8.2 BAT/BEP for controlling emissions of PCDD/PCDFs

A smooth and stable kiln process, operating close to the process parameter set points is

beneficial for all kiln emissions as well as the energy use (UNEP, 2007). PCDD/PCDF control

in cement production becomes a simultaneous effort to reduce the precursor and/or organic

concentrations, preferably by finding a combination of optimum production rate and optimum

gas temperatures and oxygen level at the raw material feed end of the kiln, and reducing the

APCD temperature.

Feeding of alternative raw materials as part of raw material mix should be avoided if it

includes elevated concentrations of organics and no alternative fuels should be fed during

start-up and shut down. The most important measure to avoid PCDD/PCDF formation in wet

kilns seems to be quick cooling of the kiln exhaust gases to lower than 200 0C. Modern

preheater and precalciner kilns have this feature already inherent in the process design and

have APCD temperatures less than 150 0C. Operating practices such as minimising the build-

up particulate matter on surfaces can assist in maintaining low PCDD/PCDF emissions.

8.3 Conventional fuels

Three different types of conventional or fossil fuels are used in cement kiln firing in

decreasing order of importance:


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• Pulverized coal and petcoke;

• Fuel oil (heavy);

• Natural gas.

In order to keep heat losses at minimum, cement kilns are operated at lowest

reasonable excess oxygen factors. This requires highly uniform and reliable fuel metering as

well as the fuel being present in a form which allows for easy and complete combustion (fuel

preparation process and fuel storage). These conditions are fulfilled by all pulverized, liquid

and gaseous fuels, be it conventional or alternative fuels. The main fuel input (65 – 85%) has

therefore to be of this type whereas the remaining 15 – 35% may be fed in coarse crushed or

lumpy form.

Fuel feed points to the cement kiln system are via the:

• Main burner at the rotary kiln outlet end;

• Feed chute at the transition chamber at the rotary kiln inlet end (for lump fuel);

• Fuel burners to the riser duct;

• Precalciner burners to the precalciner;

• Feed chute to the precalciner (for lump fuel);

• Mid-kiln valve to long wet and dry kilns (for lump fuel).

The fuel introduced via the main burner to the hot zone of the rotary kiln therein

produces the main flame with flame temperatures around 2000° C. For process optimisation

reasons the flame has to be adjustable within limits. The flame is shaped and adjusted by the


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so-called primary air (10 – 15% of total combustion air) through interaction of the outer axial

air ring channel as well as of the conical inner air ring channel of the (main) burner.

Figure 19. Feed points for solid waste fuel


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9. Co-processing of alternative fuels

Conventional fuels are today increasingly substituted by non-conventional, non- fossil

(gaseous, liquid, pulverized, coarse crushed) alternative (or secondary) fuels for resource

efficiency and economical reasons.

Many regulations do not restrict the use of AFRs / hazardous wastes to certain

categories or concentration limits; some focus on emissions limits only. Other regulations

specify an explicit list of acceptable AFRs with maximum and/or minimum values for various

parameters, e.g. heavy metals, chlorine, calorific value etc. called the “positive” list and some

regulations specify a negative list with waste categories not allowed. Independent of concept

chosen, it will be the local raw material and fuel chemistry, the infrastructure and the cement

production process, the availability of equipment for controlling, handling and feeding the

waste materials, and finally site specific health, safety and environmental issues which

determines the waste categories to be accepted at the specific plant.

9.1 Input control – general rules

Use wastes only after the supplier, the chemical and physical properties and

specifications of the materials have been clearly identified.

Consistent long-term supply of appropriate hazardous waste is required to maintain

stable conditions during operation. Content of sulphur, nitrogen, chlorine, fluorine, metals

and volatile organic compounds needs to be specified and carefully controlled. Limitations

with respect to the product and/or the process should be established.

Feeding of waste to the kiln must ensure exposure to:

a) Sufficient temperature;


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b) Sufficient retention time;

c) Sufficient mixing conditions;

d) Sufficient oxygen.

The waste type and composition will determine the adequate feeding point; i.e. the

main burner or the secondary burner in precalciner/preheater will ensure temperature > 900 oC. No waste should be fed as part of raw mix feed if it contains organics, and no waste feed

during start-up and shutdown.

Handling and feed systems should be appropriate to the waste used and must ensure

stable and controlled input to the kiln. The operator should assess risks from fugitive

emissions; equipment failure modes and appropriate safeguards should be incorporated into

the design to prevent environmental pollution, health, and safety problems.

Automated monitors should be employed to alert operators in the event of a waste

handling problem. A pressure transducer located in the waste piping at the entrance of the

kiln should be provided to turn off the waste fuel pump automatically in the event of a sudden

pressure drop due to pipe rupture or pump failure.

Interlocks should be provided to stop the flow of waste automatically if either normal

fuel or feed supply or combustion airflow is interrupted (fans stopped or reduced), or if

carbon monoxide levels indicate problems with combustion efficiency.

9.2 Selection of feed point

The use of AFRs should not detract from smooth and continuous kiln operation,

product quality, or the site’s normal environmental performance. Therefore, a constant

quality and feed rate of the waste materials must be ensured.


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The feed point for wastes into the kiln should be selected according to the nature (and,

if relevant, hazardous characteristics) of the wastes used. Gaseous, liquid, and finely

pulverized alternative fuels can be fed to the kiln system via any of the feed points mentioned

in the previous chapter. Coarse crushed and lump fuels can be fed to the transition chamber

or to the mid-kiln valve only (with some exceptions). Hazardous wastes should be introduced

in the high-temperature combustion zone of the kiln system, i.e. the main burner, the

precalciner burner, the secondary firing at the preheater, or the mid-kiln (for long dry and wet

kilns).

The following is valid:

a) Persistent organic pollutants and highly chlorinated organic compounds should be

introduced at the main burner to ensure complete combustion due to the high

combustion temperature and long retention time. Other feed points are appropriate

only where test have shown high destruction and removal efficiency rates;

Figure 20. Feeding of liquid hazardous waste through the main burner


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b) Alternative raw materials with volatile organic components should not be introduced

with other raw materials in the process, unless tests have shown that undesired

emissions at the stack do not occur; such raw materials can be fed through a double or

triple flap arrangement into the kiln inlet;

Figure 21. Feeding of solid waste to the kiln inlet

c) Mineral inorganic wastes free of organic compounds can be added to the raw meal or

raw slurry preparation system. Mineral wastes containing significantly quantities of

organic components are introduced via the solid fuels handling system, i.e. directly to

the main burner, to the secondary firing or, rarely, to the calcining zone of long wet or

dry kilns;


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d) Mineral additions such as granulated blast furnace slag, fly ash from thermal power

plants or industrial gypsum can be fed to the cement mill.

Figure 22. Feeding of alternative raw materials to the raw mill


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9.3 Operations and process control

Operating requirements should be developed to specify the acceptable composition of

the waste feed, including acceptable variations in the physical and/or chemical properties of

the waste. For each waste, the operating requirements should specify acceptable operating

limits for feed rates, temperatures, retention time, oxygen etc.

Figure 23. Feeding of mineral additions to the cement mill

For start-up, shutdown, or upset conditions of the kiln, written instructions should be

issued, describing conditions of use of wastes. Kiln operators should know and understand

these instructions.


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The general principle of good operational control of the kiln system using

conventional fuels and raw materials should be applied. In particular, all relevant process

parameters should be measured, recorded and evaluated continuously and may cover:

a) Free lime;

b) Oxygen concentration;

c) Carbon monoxide concentration.

Figure 24. Feeding of whole and shredded tyres to a triple flap sluice in the kiln inlet


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9.3.1 Kiln operation and feeding of wastes

The plant should characterize a good operation and use this as a basis to improve other

operational performance.

Having characterized a good and stable kiln, establish reference data by adding

controlled doses of waste, and look at changes and required controls and practice to control

emissions. The impact of wastes on the total input of circulating volatile elements such as

chlorine, sulphur, or alkalis must be assessed carefully prior to acceptance as they may cause

operational troubles in the kiln system.

The kiln process must be operated to achieve stable conditions, which may be

achieved by applying process control optimization (including computer-based automatic

control systems) and use of modern, gravimetric solid fuel feed systems.

Input limits and operational set points for these components should be set individually

by the site based on the process type and on the specific site conditions.

Procedures for stopping waste feed in the event of an equipment malfunction or other

emergency must be implemented and the set points for each operating parameter that would

activate feed cut-off must be specified. The waste feed must also be cut off when operating

conditions deviate from limits established in the permit.

No hazardous waste burning should take place unless the cement kiln is operating at

normal temperatures in the range of 1100 oC to 1600 oC and instrumentation must be provided

to record continuously the rate of flow of these wastes.

Feeding of hazardous wastes should not be permitted during periods of kiln start-up,

shutdown, major upset or conventional (coal) fuel interruption.

Kiln coating temperature should be measured by a recording optical pyrometer and

conventional (coal) fuel flow should be continuously measured and recorded.


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Examples of system controls and set points, which could provide for automatic

shutdown of introduction of hazardous wastes in the event any of the following conditions

occur:

a) Cement kiln temperatures fall below 1100 oC;

b) Conventional raw meal and fuel flow interruption;

c) Kiln speed decrease to below 60 RPH;

d) Loss of draft in the firing hood and main fan stoppage;

e) The kiln should be operated at all times in an oxidizing atmosphere. Oxygen in the

kiln exhaust gases must be maintained at a level of not less than 1.5% and be

continuously recorded;

f) If the outside skin temperature of the kiln exceeds 500 oC, the feed of hazardous

wastes should be stopped and shutdown should be initiated for repair of the refractory.

Reintroduction of hazardous wastes should not take place until such lining repairs are

completed;

g) Waste introduction into the kiln should cease in the event of kiln ring formation;

h) Hazardous wastes must not be used during failure of the air pollution control devices.

The kiln exhaust gases must be quickly conditioned and cooled the lower than 200 °C

to avoid formation and release of dioxins and other POPs;

i) Fugitive emissions must be prevented and controlled and the off-gas dust from the

filters should be fed back into the kiln to the maximum extent practicable, in order to

reduce issues related to treatment and emissions. Dust that cannot be recycled should

be managed in a manner demonstrated to be safe.


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9.4 Laboratory and quality control

The plant needs an adequate laboratory, with sufficient infrastructure, sampling

equipment, instrumentation and test equipment. Inter-laboratory tests should be carried out

periodically in order to check and improve the performances and maintenance of the

laboratory. Personnel must be competent and should be trained according to their specific

needs and to the nature of the AFR or hazardous wastes used.

Figure 25. Sampling and analysis of AFRs at the pre-processing facility

Fuels, raw materials, and any AFRs or wastes entering, being processed or produced at

the site, should be controlled regularly. A plan should provide detailed instructions for:

a) Personnel assignment;


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b) Sampling;

c) Frequency of sampling and analysis;

d) Laboratory protocols and standards;

e) Calibration procedures and maintenance;

f) Recording and reporting protocol.


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10. Cement quality

The cement plant must carry out chemical and physical analysis for all relevant

parameters concerning cement quality and potential clinker contamination on a routine basis

and all data must be kept recorded.

Co-processing of AFRs shall not affect the cement quality and this must be

documented. The operator must be aware that fluorine, phosphate and zinc influences setting

time and strength development of the cement, that chlorine, sulphur and alkalis affect overall

product quality and that chromium may cause allergic reactions in sensitive users.

The classification of cements in terms of their strength-giving properties has been

practised for many years. It is impractical for cement producers to test the cements they make

with all the many different sands and aggregates and in the wide range of mix proportions

they are likely to meet in practice. Standard test procedures have therefore been developed to

enable manufacturers to control their production. The strength-giving characteristics of

cements can take the form of assessments at early (2- 3 days) or late (28 days) ages or both.

The European ENV 197-1 places primary emphasis upon the 28-day strength and for this

purpose introduces three classes, 32.5, 42.5 and 52.5 representing the minimum characteristic

strength, in N/mm2, which the cement is required to achieve at 28 days from tests made in

accordance with the test method described in European Standard EN 196-1.


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11. Emission monitoring

Emission monitoring is obligatory in order to demonstrate compliance with existing

laws, regulations, and agreements. Emission monitoring is also needed for controlling the

input of conventional materials and their potential impacts. Sulphides in raw materials may

result in the release of SO2 and organic carbon in raw materials will result in CO, CO2 and

volatile organic compound (VOC) emissions. Heavy metals in fuel and raw material,

especially volatile heavy metals, which are not completely captured in the clinker, must be

assessed, monitored and controlled.

11.1 Emission limit values for cement kilns in Europe

For emissions to air, cement kilns co-processing AFR and treating hazardous wastes in

the EU must comply with the Directive 2000/76/EC and must meet the emissions limits in

flue gases given in table 2 below, corrected to 273 K, 101.3 kPa, 10% O2 and dry gas.

Table 2 Daily average values for cement plants co-incineration of hazardous waste

(less than 40% of the resulting heat release must come from waste), at 10%

O2, dry gas; all values in mg/m3; dioxins and furans in ng/m3.

Pollutant C

Total dust 30 HCl 10 HF 1 NOx 5001)/8002) Cd + Tl 0.05 Hg 0.05 Sb, As, Pb, Cr, Co, Cu, Mn, Ni, V 0.5 Dioxins and furans 0.1 SO2 503) TOC 103)

1) new plants 2) existing plants 3) exceptions may be authorized by the

component authority in cases where SO2 and TOC do not result from the waste.


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11.2 Continuous emission measurements

To monitor the process and accurately quantify the emissions, continuous emission

measurements are recommended for the following parameters:

a) Exhaust volume;

b) Humidity;

c) Temperatures;

d) Particulate matter;

e) O2;

f) NOx;

g) SO2;

h) CO;

i) Volatile organic compounds (VOC);

j) HCl;

k) Pressure.

11.3 Regular monitoring

Periodical monitoring should be conducted for the following substances on a regular

basis:

a) Metals and their compounds;

b) Total organic carbon;

c) HF;


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d) NH3;

e) PCDD/PCDF;

f) Chlorobenzenes, HCB and PCBs including coplanar congeners and

chloronaphthalenes.

Figure 26. Sampling of stack gas for dioxins

11.4 Occasional monitoring

Measurements of the following substances may be required occasionally under special

operating conditions:

a) Demonstration of the destruction and removal efficiency (DRE) and the destruction

efficiency (DE);

b) Benzene, toluene and xylene;


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c) Polycyclic aromatic hydrocarbons;

d) Other organic pollutants.

It is especially important to measure metals when wastes with higher metal content are

used as raw materials or fuels.

11.5 Additional measures for exit gas cleaning

Activated carbon filter has high removal efficiency for trace pollutants (> 90%).

Pollutants such as sulphur dioxide (SO2), organic compounds, metals, ammonia (NH3),

ammonium (NH4+) compounds, hydrogen chloride (HCl), hydrogen fluoride (HF) and

residual dust may also be removed from the exhaust gases by adsorption on activated carbon.

Selective catalytic reduction can be applied for NOx control. The process reduces NO

and NO2 to N2 with the help of NH3 and a catalyst at a temperature range of about 300 °- 400

°C, which imply heating of the exhaust gases.


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12. Test burn and performance verification

Test burns are recommended for the demonstration of the destruction and removal

efficiency (DRE) and the destruction efficiency (DE) of certain principal organic hazardous

compounds (POHC) in a cement kiln (see Annex 2). The DRE is calculated on the basis of

mass of the POHC content fed to the kiln, minus the mass of the remaining POHC content in

the stack emissions, divided by the mass of the POHC content within the feed.

The DRE considers emissions to air only. The DE considers all out-streams (liquid

and solids) in addition to the air emissions and is the most comprehensive way of verifying

the performance. Test burns with hazardous compounds require professional supervision and

independent verification.

The following conditions should be fulfilled in a test burn:

a) The destruction and removal efficiency for hazardous compound should be at least

99.99%. Chlorinated aromatic compounds should be chosen as a test compound if

available because they are generally difficult to destroy. For POPs, a DRE/DE of

≥99.9999% should be achieved.

b) The cement kiln should meet an emissions limit for PCDDs/PCDFs of 0.1 ng

TEQ/Nm3 both under baseline and test burn conditions.

c) The cement kiln should comply with existing emission limit values.

Test burns with non-hazardous hazardous waste are usually not a regulatory

requirement but are sometimes done to evaluate the behaviour of the process and the

influence on main gaseous emissions and the cement clinker quality when feeding waste to

the kiln. Such simplified tests are usually conducted by process engineers at the cement plant

using already installed on-line monitoring equipment and process operational data.


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13. On-site security and safety

Adequate systems and procedures should be in place to minimize the risk of

unauthorized access to AFRs and hazardous wastes used on-site. An emergency response

plan should be in place, which:

a) Identifies potential spill or contamination areas;

b) Defines clean-up procedures;

c) Identifies areas of high risk on site or in the local community;

d) Provides written instructions in the event of an emergency;

e) Documents equipment required in the event of an emergency;

f) Assigns responsibilities to employees and local officials;

g) Details emergency response training requirements;

h) Describes reporting and communication requirements both within the company and

with interested external stakeholders.

The emergency response plan may be reviewed with relevant external emergency

services and emergency drills should be arranged with the local community emergency

response services to ensure a coordinated response under emergency conditions.

Safety and emergency instructions, such as Material Safety Data Sheets, must be

provided to employees and contractors in due time, and should be easily understandable.

Hazards relating to new materials should be reviewed with operating staff prior to using such


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materials in the facility. Conducting a job safety analysis is one approach to identifying

hazards and potential exposures, along with appropriate control practices and techniques.

Automated handling equipment should be used wherever possible.

13.1 Personal protective and emergency equipment

Adequate personal protective equipment should be made available to employees and

contractors, and to individuals visiting the installation. Its use should be required. This

includes but is not limited to:

a) Helmet;

b) Glasses;

c) Gloves;

d) Hearing protection;

e) Safety shoes;

f) Respiratory protection;

g) Other protective equipment specified in the Material Safety Data Sheets.

Emergency equipment, such as fire extinguishers, self contained breathing masks,

sorbent materials and shower stations should be sited in the immediate vicinity of the waste

chemical storage area. Employees should be trained in their proper use.

The plant needs to have specially trained and authorized personnel at the storage and

pumping site for unloading and storage of hazardous wastes. When authorized operating


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personnel are not on site, the storage and pumping area should be made sufficiently secure to

prevent site access and operation of the storage and unloading system.

Figure 27. Personal protective equipment when handling POPs contaminated soil

Wherever a contact risk such as infection or skin irritation exists, the company should

provide appropriate facilities for operators to take required hygiene precautions.


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Maintenance work should be authorized by plant management, and carried out once a

supervisor has checked the area and necessary precautions have been taken.

Special procedures, instructions, and training should be in place for such routine

operations as:

h) Working at height, including proper tie-off practices and use of safety harnesses;

i) Confined space entry where air quality, explosive mixtures, dust, or other hazards may

be present;

j) Electrical lock-out, to prevent accidental reactivation of electrical equipment

undergoing maintenance;

k) “Hot works” (i.e. welding, cutting, etc.) in areas that may contain flammable

materials.


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14. Content of a co-processing permit/licence

Any pre-processing facility or cement plant co-processing of AFRs or treating organic

hazardous wastes must have a permit or licence issued by the national competent authority.

Such a permit must describe requirements and restrictions of operation and should be

developed in close cooperation with local competent authorities, with the pre-processing

facility and the cement plant.

The permit should allow certain flexibility to allow for future development and

adjustments, but needs to reflect the technical feasibility, infrastructure and its equipment,

location, types of AFRs, as well as health, safety and environmental issues.

The pre-processing facility and the cement plant should have separate permits. The

following chapters suggest and list crucial elements of a possible permit for a cement plant.

14.1 Plant organisation and components

A permit document should provide a short description of the plant, its history,

ownership, its location and its background and intentions for co-processing of AFRs and/or

treatment of hazardous wastes, as well as more detailed information of:

a) Organisational structure (also for AFR), management, employees, training;

b) Environmental management system, audits, emission monitoring and reporting;

c) Environmental impact assessment, current and previous permits and its compliance;

d) Laboratory facilities and product quality control routines;


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e) Clinker process technology, i.e. rotary kiln(s), pre-heaters, pre-calciner, burners,

stacks and process control system;

f) Raw material quarrying (expected lifetime), transport, preparation, storage and

feeding;

g) Fuel sources, preparation, storage and feeding;

h) Conveying facilities, crushers, mills, coolers;

i) Baseline emissions, continuous emission monitoring equipment, exit gas conditioning

and cooling, air pollution control devices;

j) Modes of operation, e.g. drying of raw material in the raw mill with the exit gas etc.

k) AFR equipment, receiving, storage and pre-processing, feeding and control;

l) Health, environment, emergency and safety issues;

m) Cement production and dispatch;

n) Water and power sources and reliability;

o) Noise and sewage water treatment;

p) On-site control, security and safety.

14.2 Application documents

The information above should be documented properly, e.g. by:

a) Plant pictures, topographical and geographical maps also indicating nearby resources;


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b) Description of the operation of the plant with name and make of equipments;

c) Constructions documents for AFR and hazardous waste activities;

d) Description of the intended AFRs, as sources, generation, processing, installation,

supply, quality control and assurance system;

e) Available alternative treatment options for hazardous waste, and pro-et-cons for

selecting this plant;

f) An EIA and an evaluation of general environmental issues, the performance of the

APCD and the emission situation;

g) An impacts evaluation of the use of AFRs/hazardous wastes on the surroundings, on

the process stability, product quality, air pollution emission prognosis (e.g. dust, NOX,

SO2, heavy metals, VOC, HCl, PCDDs/PCDFs etc.), odour and noise;

h) Procedures for the implementation and maintenance of pollution prevention and

occupational health and safety standards;

i) Involvement with stakeholders and public information.

14.3 Plant data

A table describing all necessary information in short on plant fact essentials, as name,

address, phone and fax, web address, names of plant managers, contact details to closest

hospital, fire and police, transport access gates, water and power supply.


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14.4 AFR / hazardous wastes acceptance

Some regulations do not restrict the use of AFRs or organic hazardous wastes to

certain categories or concentration limits; they focus on emissions limits values only, i.e.

implying that the co-processing practise shall not affect or increase the emissions. The

Directive 2000/76/EC on the incineration of waste in the European Union specify that if “in a

co-incineration plant more than 40% of the resulting heat release comes from hazardous waste

(unspecified), the emission limit values for incinerators must apply”.

Some regulations specify an explicit list of acceptable AFRs with maximum and/or

minimum values for various parameters, e.g. heavy metals, chlorine, heat content/calorific

value etc., often called the “positive” list. Annex 1 list some constraints and

recommendations for certain input parameters. Some regulations specify a “negative” list

with waste categories not allowed, e.g. as described in chapter 3.3.

A combination of emissions limit values and a negative waste list may be the easiest to

practice for the cement companies and the controlling authorities. If properly enforced, this

concept has shown to constitute a satisfactory regulatory concept.

Independent of concept chosen, a permit must contain details of the AFRs / hazardous

wastes permitted /not permitted to be used at the particular plant and should provide the

following information:

a) Concept for acceptance of AFRs / hazardous wastes, i.e. negative or positive

list;

For each of the categories of alternative fuel, alternative raw material and hazardous

waste permitted to use at the plant the following information should be described in the

permit:

b) Types, volumes/masses, percentage of input, quality and characteristics (gross

chemical composition, chlorine, heat and water content etc.);


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c) Origin and main suppliers;

d) Special requirements for collection and transport and specification of

documents that must follow deliveries;

e) Requirements and procedures for control, sampling and analysis at the point of

recipient;

f) Procedures to follow when deliverables are in non-compliance;

g) Requirements and procedures for chemical and physical analysis, testing

compatibility or other tests, as well as requirements for keeping and storing

samples of the AFR/hazardous waste;

h) Requirements for pre-processing and preparation;

i) Requirements and conditions for storage;

j) Requirements and conditions for feeding to the process, on start up and shut

down as well as requirements for interlocks and set points for stopping waste

feed;

k) Procedures and requirements for collection and analysis of process and

environmental samples as well as health checks of employees;

l) Procedures, requirements and conditions for carrying out test burns;

m) In case of hazardous waste treatment, procedures and requirements for issuing

a certificate of Destruction;

n) Requirements for record keeping and information dissemination.


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14.5 Monitoring and control of combustion

The cement plant must provide input limits and operational set points for each of the

categories of alternative fuel, alternative raw material and hazardous waste permitted to use.

The permit must describe:

a) Normal good and stable kiln/process operation without feeding of AFRs/hazardous

wastes, i.e. description of the baseline conditions;

b) Normal readings of the continuous emission monitoring equipment (CEM) and CO-

levels without feeding of AFRs/hazardous wastes, i.e. description of the baseline

conditions;

c) Normal values for cement quality without feeding of AFRs/hazardous wastes, i.e.

description of the baseline conditions;

d) Stable smooth kiln/process operation with controlled and separate feeding of

AFRs/hazardous wastes, i.e. description of the normal co-processing conditions;

e) Readings of the CEM and CO-levels with controlled and separate feeding of

AFRs/hazardous wastes, i.e. description of the normal co-processing conditions;

f) Values for cement quality with controlled and separate feeding of AFRs/hazardous

wastes, i.e. description of the normal co-processing conditions;

g) Operational modes, i.e. differences in direct compound mode when it comes to

emissions;

h) Emission limit values/window for the CEMs, O2 and for CO-levels;

i) Conventional raw meal and fuel feed requirements;

j) Kiln production and kiln speed requirements;


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k) Maximum kiln coating temperatures (if relevant);

l) Minimum kiln inlet and outlet temperatures;

m) Minimum retention time at specific temperatures;

n) Minimum kiln inlet and outlet oxygen concentration (CEM);

o) Procedures for operation of the air pollution control devices and its maximum “down-

time”, as well as requirements for exhaust gas conditioning;

p) Operation procedures when loss of draft in the firing hood or fan stoppage;

q) Operation procedures in the event of kiln ring formation or cyclone blockage;

r) Operation procedures in the event of major fugitive emissions;

s) Operation procedures for recycling of dusts.

14.6 Air pollution control

All exit gases must be cleaned and discharged via stacks with sufficient height and

dispersion capability. Requirements of local regulation must be included in the permit.

14.7 Monitoring of emissions

The competent authority must describe requirements for the installation and operation

of continuous emission monitoring equipment, as well as requirements and conditions for

periodical monitoring and test burns.


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Emission measurements must be conducted on a regular basis, be representative and

always converted to standardized conditions (dry gas, pressure, temperature and oxygen

concentration), i.e. be comparable, and possible to evaluate and verify. The regulated air

pollutants and the subsequent emission limit values most be provided by the National

regulation and the competent authority, which also needs to specify the conditions for

compliance.

14.8 Qualified laboratories

To ensure a uniform measurement practice, representative measurement results and

comparable quality procedures, only independent third party qualified laboratories with

satisfactory sampling, analysis and calibration procedures should be used. The location and

configuration of the sampling point(s) must be coordinated with the competent authorities.

14.9 Excerpts of the Directive 2000/76/EC on the incineration of waste in the

European Union - Article 4 - Application and permit

1. Without prejudice to Article 11 of Directive 75/442/EEC or to Article 3 of Directive

91/689/EEC, no incineration or co-incineration plant shall operate without a permit to

carry out these activities.

2. Without prejudice to Directive 96/61/EC, the application for a permit for an

incineration or co-incineration plant to the competent authority shall include a

description of the measures which are envisaged to guarantee that:

(a) the plant is designed, equipped and will be operated in such a manner that the

requirements of this Directive are taking into account the categories of waste to

be incinerated;


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(b) the heat generated during the incineration and co-incineration process is

recovered as far as practicable e.g. through combined heat and power, the

generating of process steam or district heating;

(c) the residues will be minimized in their amount and harmfulness and recycled

where appropriate;

(d) the disposal of the residues which cannot be prevented, reduced or recycled

will be carried out in conformity with national and Community legislation.

3. The permit shall be granted only if the application shows that the proposed

measurement techniques for emissions into the air comply with Annex III and, as

regards water, comply with Annex III paragraphs 1 and 2.

4. The permit granted by the competent authority for an incineration or co-incineration

plant shall, in addition to complying with any applicable requirement laid down in

Directives 91/271/EEC, 96/61/EC, 96/62/EC, 76/464/EEC and 1999/31/EC:

(a) list explicitly the categories of waste which may be treated. The list shall use

at least the categories of waste set up in the European Waste Catalogue (EWC),

if possible, and contain information on the quantity of waste, where

appropriate;

(b) include the total waste incinerating or co-incinerating capacity of the plant;

(c) specify the sampling and measurement procedures used to satisfy the

obligations imposed for periodic measurements of each air and water

pollutants.

5. The permit granted by the competent authority to an incineration or co-incineration

plant using hazardous waste shall in addition to paragraph 4:

(a) list the quantities of the different categories of hazardous waste which may be

treated;


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(b) specify the minimum and maximum mass flows of those hazardous wastes,

their lowest and maximum calorific values and their maximum contents of

pollutants, e.g. PCB, PCP, chlorine, fluorine, sulphur, heavy metals.

6. Without prejudice to the provisions of the Treaty, Member States may list the

categories of waste to be mentioned in the permit which can be co-incinerated in

defined categories of co-incineration plants.

7. Without prejudice to Directive 96/61/EC, the competent authority shall periodically

reconsider and, where necessary, update permit conditions.

8. Where the operator of an incineration or co-incineration plant for non-hazardous waste

is envisaging a change of operation which would involve the incineration or co-

incineration of hazardous waste, this shall be regarded as a substantial change within

the meaning of Article 2(10)(b) of Directive 96/61/EC and Article 12(2) of that

Directive shall apply.

9. If an incineration or co-incineration plant does not comply with the conditions of the

permit, in particular with the emission limit values for air and water, the competent

authority shall take action to enforce compliance.


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15. References and bibliography

Basel Convention, 1989. Basel Convention on the control of transboundary movements

of hazardous wastes and their disposal adopted by the conference of the plenipotentiaries.

Secretariat of the Basel Convention, 13 - 15 Chemin des Anemones, CH - 1219 Chatelaine,

Geneva, Switzerland.

Basel Convention, 2007. General technical guidelines for the environmentally sound

management of wastes consisting of, containing or contaminated with persistent organic

pollutants (POPs). http://www.basel.int/techmatters/techguid/ frsetmain.php?topicId=0

Council Directive, 2000. Council Directive 2000/76/EC on the Incineration of Waste.

Official Journal of the European Communities, Brussels, Official Journal L 332, 28/12/2000.

Federal Register, 1997. Hazardous Waste Combustors; Revised Standards; Proposed

Rule. Federal Register: January 7, 1997 (Volume 62, Number 4, Page 960-962.

http://www.epa.gov/docs/fedrgstr/EPA-WASTE/1997/January/Day-07/pr-809DIR/pr-

809.html

Federal Register, 1998. National Emission Standards for Hazardous Air Pollutants;

Proposed Standards for Hazardous Air Pollutants Emissions for the Portland Cement

Manufacturing Industry; Proposed Rule. Tuesday March 24, 1998. Part II, Environmental

Protection Agency, 40 CFR, Part 63.

Federal Register, 1999. National Emissions Standards for Hazardous Air Pollutants – US

EPA – Final Rule. Part II, 40 CFR, Part 60. September 30, 52827-53077.

Federal Register, 1999a. National emission standards for hazardous air pollutants for

source categories; Portland Cement manufacturing industry. June 14, 64:31897-31962.

Federal Register, 1999b. NESHAPS: Final standards for hazardous air pollutants for

hazardous waste combustors. September 30, 64:52828-53077.

http://www.basel.int/techmatters/techguid/ frsetmain.php?topicId=0

http://www.epa.gov/docs/fedrgstr/EPA-WASTE/1997/January/Day-07/pr-809DIR/pr-809.html

http://www.epa.gov/docs/fedrgstr/EPA-WASTE/1997/January/Day-07/pr-809DIR/pr-809.html


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Federal Register, 1999c. Standards for the Management of Cement Kiln Dust; Proposed

Rule. August 20, 64:161.


EPA – CFR Promulgated Test Methods (TM). Vol. 65, No. 201, October 17.

Federal Register, 2002a. National Emissions Standards for Hazardous Air Pollutants –

US EPA – Interim Standards Rule. Part II, 40 CFR Part 63. February 13, 6792.

Federal Register, 2002b. “National Emissions Standards for Hazardous Air Pollutants –

US EPA – Final Rule”. Part II, 40 CFR Parts 63, 266 and 270. February 14, 6968.

Federal Register, 2002c. NESHAP: Standards for Hazardous Air Pollutants for

Hazardous Waste Combustors (Final Replacement Standards and Phase II)--Notice of Data

Availability Federal Register. July 2, 2002 (Volume 67, Number 127 Page 44371.

http://frwebgate.access.gpo.gov/cgi-bin/getdoc.cgi?dbname=2002_ register& docid=02-

16642-filed.pdf

Federal Register, 2004. National emission standards for hazardous air pollutants:

proposed standards for hazardous air pollutants for Hazardous Waste Combustors (Phase 1

Final replacement standards and Phase II): Proposed rule. April 20, 69:21998-21385.

Federal Register, 2005. NESHAP: Standards for Hazardous Air Pollutants for Hazardous

Waste Combustors (FinalRule). [http://www.epa.gov/EPA-WASTE/2005/October/Day-

12/f18824b.htm]

GTZ-Holcim, 2006. Guidelines on Co-Processing Waste Materials in Cement Production.

http://www.holcim.com

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Techniques for Waste Incineration. European Commison, August 2007.

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Karstensen, K. H., 1994. Burning of hazardous Wastes as Co-Fuel in a Cement Kiln -

Does it Affect the Environmental Quality of Cement? - Leaching from Cement Based

Materials. Studies in Environmental Science 60, "Environmental Aspects of Construction

with Waste Materials", Elsevier, Amsterdam, the Netherlands. ISBN 0-444-81853-7.

Karstensen, K. H., 1998. Benefits of incinerating hazardous wastes in cement kilns. FAO

Pesticide Disposal Series 6, Prevention and disposal of obsolete and unwanted pesticide

stocks in Africa and the Near East, Third consultation meeting. Food and Agriculture

Organization of the United Nations, Rome, 1998.

Karstensen, K. H., 2001a. Incineration of principal organic hazardous compounds and

hazardous wastes in cement kilns – Which requirements should be fulfilled? First Continental

Conference for Africa on the Environmentally Sound Management of Unwanted Stocks of

Hazardous Wastes and their Prevention. Basel Convention, Rabat, 8-12 January.

Karstensen, K. H., 2001b. Disposal of obsolete pesticides in cement kilns in developing

countries – Lessons learned and how to proceed. 6th International HCH and Pesticide Forum,

Poznan, Poland, 20-22 March.

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and Opportunities for Improvement. Report to the United Nations Industrial Development

Organization. 31 January.

Karstensen, K. H., Kinh, N. K., Thang, L. B., Viet, P. H., Tuan, N. D., Toi, D. T., Hung,

N. H., Quan, T. M., Hanh, L. D. and Thang, D.H., 2006. Environmentally Sound Destruction

of Obsolete Pesticides in Developing Countries Using Cement Kilns. Environ. Sci. & Policy,

9, 577-586.

Karstensen, K.H., 2008. Formation, release and control of dioxins in cement kilns – a

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Neosys ag & Ecoscan sa, 2004. AFR criteria guidelines for co-processing in cement kilns.

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Management (ESM) of Waste. www.oecd.org

UNEP, 2001. The Stockholm Convention on Persistent Organic Pollutants. United

Nations Environmental Programme. http://www.chem.unep.ch/sc/default.htm.

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and Furan Releases. UNEP Chemicals, International Environment House, 11-13 chemin des

Anémones, CH-1219 Châtelaine, Geneva, Switzerland.

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Best Environmental Practices. Expert group on BAT/BEP - Cement Kilns firing hazardous

Waste, submitted February 2007. UNEP. http://www.pops.int/documents/guidance/

batbep/batbepguide_en.pdf

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the Selection and Use of Fuels and Raw Materials in the Cement Manufacturing Process.

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community legislation for the control of waste incineration and co-incineration. European

Commission Service Contract, No.070501/2006/446211/MAR/C4.

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Annex 1 AFR criteria guidelines for co-processing in cement kilns.

Excecutive summary of the report “AFR criteria guidelines for co-processing in

cement kilns”, Neosys & Ecoscan, 2004.

Recently the relative advantages of different waste elimination technologies have been studied by use of a

“triple balance” approach (ecological, economical, social). The advantage of a valorization as AFR is

obvious for many classes of waste. This advantage, however, is depending on the waste characteristics as

well as on other (social and economic) circumstances.

Additionally there exist many legal and other constraints to the intake of specific substances into the cement

system.

It seems therefore worthwile to investigate more closely how the waste should be selected to be sure that a

valorization as AFR in a cement plant is a favorable solution to it.

The evaluation of the several parameters characterizing the waste brings a lot of constraints and

recommendations to be included in a selection procedure of AFR processable wastes. The aims are

- to fulfill any legal requirements about pollution, safety and technical standards

- to assure that the waste used as AFR undergo their most favorable treatment compared

to possible other treatments with other technologies with respect to the triple balance approach

known from the study « Comparative Evaluation of three Industrial Waste Treatment Technologies

using a Triple Balance Approach »

- to exclude damaging effects to the product (cement) or the production process.

- to minimize the net cost of the waste process (recommendations for plant management) The

constraints and recommendations depend on the legal regulations applied to the waste characterizing

parameters, but also on their influence on the ecological, economical and social balances applied to

the waste process.

Taking into account these conditions we have found the following constraints and recommendations:


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Parameter Constraint Recommendation Comments Cd intake by AFR < 0.27 kg / ton

of clinker - don’t use waste if Cd could

be valorized (> some 1000 ppm)

- check as well toxicity

derived from impact by air emission

Cr no room for Cr intake by AFR when EU limitations are applied! intake by AFR < 0.009 kg / ton to stay within the natural deviations of intake by raw material no significant constraint of intake by AFR when CrVI is reduced “end of pipe”

- in any case: don’t use waste

if Cr could be valorized (> some 10000 ppm)

because of the concentration limit of 2 mg/l of CrVI in the concrete water (work safety) corresponding to an AFR of about 300 ppm Cr (25 MJ/kg , 20% of energy use by AFR)

Cu no significant constraint - don’t use waste if Cu could be valorized (> some 10000 ppm)

Hg intake by AFR < 0.00012 kg / ton of clinker

derived from impact by air emission

Ni no significant constraint - don’t use waste if Ni could be valorized (> some 10000

ppm)

Zn intake by AFR < 10 kg / ton of clinker

- don’t use waste if Zn could be valorized (> some 10000 ppm)

derived from impact on product quality and by leaching with the same result

Sn no significant constraint - don’t use waste if Sn could be valorized (> some 1000 ppm)

Pb no significant constraint - don’t use waste if Pb could be valorized (> some 10000 ppm)

- check as well toxicity

As intake by AFR < 12 kg / ton of clinker (which is not a very significant constraint for As)

- check as well toxicity derived from the impact by air emission

Sb no significant constraint - check as well toxicity Tl intake by AFR < 0.012 kg / ton

of clinker if the system pre- vents for Tl-accumulation (bypass of CKD) no tolerance for Tl otherwise

- check as well toxicity derived from the impact by air emission

Cl intake by AFR < 0.04 kg / ton of clinker when no Cl-bypass is used. intake by AFR < 1.8 kg / ton of clinker otherwise

- check as well toxicity (especially in case of chlorinated organics)

- check as well corrosivity

derived from the impact on process safety

derived from the impact by leaching

F intake by AFR < 0.2 kg / ton of clinker

- check as well toxicity - check as well corrosivity

derived from the impact on process safety


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Na and K (Alkalis)

intake by AFR < 10 kg / ton of clinker

- check as well corrosivity derived from the impact on product quality and process safety

P intake by AFR < 3.5 kg / ton of clinker

- check as well toxicity derived from the impact on product quality

S intake as sulphate (SO4): unlimited intake as oxidizable S by AF: < 3.0 kg / ton of clinker

intake as oxidizable S by AR: < 0.9 kg / ton of clinker or

even smaller, depending on the chemical characteritics of the S source

derived from the impact on process safety additional restriction from the impact by air emission de- pends on the quality of the raw meal!

VOC no constraint - prohibit escape of VOC’s to the atmosphere!

- check as well explosivity and toxicity

substances containing VOC must enter the system by the kiln

Calorific value

no constraint - the higher the better

Physical state

no constraint - avoid inhomogeneous physical states because of higher cost and hihger risk

Conditioning no constraint - promote the delivery of harmless waste in bulk, and hazardous waste in drain- able drums

Toxicity specific constraints for specific substances might be given by local authorities

- analyse the nature of accepted waste

- use protection equipment for the workers in case of toxic waste

Explosivity specific constraints for specific substances might be given by local authorities

- analyse the nature of accepted waste

- use protection measures for the workers and equipment in case of explosive waste

- perform a risk analysis to decide upon acceptation

Corrosivity no constraints - analyse the nature of accepted waste

- use protection measures for the workers and equipment in case of explosive waste

- perform a risk analysis to decide on acceptation


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Annex 2 Test burn with toxic insecticides in Vietnam


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Introduction

The accumulation and inadequate management of obsolete pesticides and other

hazardous chemicals constitute a threat to health and environment, locally, regionally and

globally. Estimates indicate that more than 500,000 tons of obsolete pesticides are

accumulated globally, especially in developing countries (FAO, 2001a). FAO has been

addressing this issue and disposed of approximately 3000 tons in more than ten countries in

Africa and the Near East since the beginning of the 1990s (FAO, 2001b), less than 1 % of the

existing stocks.

A considerable amount of the accumulated obsolete pesticides are persistent organic

pollutants (POPs) that possess toxic properties, resist degradation, bio-accumulate and are

transported, through air, water and migratory species, across international boundaries and

deposited far from their place of release, where they accumulate in terrestrial and aquatic

ecosystems (Vallack et al., 1998; Jones and de Voogt, 1999). Organochlorine pesticide

residues have been detected in air, water, soil, sediment, fish, and birds globally even more

than one decade after being banned and it's reasonable to believe that contaminated sites and

stockpiled waste still represent locally and regionally important on-going primary source

inputs of hazardous compounds to the global environment (Brevik et al., 2004).

The Arctic, where subsistence living is common, is a sink region for POPs.

Norwegian and Canadian researchers find more POPs in Polar bear on the remote North

Atlantic island Svalbard than on the mainland America and there is currently a great concern

in Norway about a 5-10 times increase in the POPs concentration in fish and other animals in

the Barents Sea the last 10-15 years (Gabrielsen et al., 2004). POPs have shown to interfere

with hormone function and genetic regulation, and myriad dysfunctions can be induced by


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low-dose POPs exposure during development (De Vito and Birnbaum, 1995; McDonal, 2002;

Godduhn and Duffy, 2003; WHO, 2003; Gupta, 2004; Jobling et al., 2004).

Several international conventions aim to protect human health and the environment by

requiring Parties to take measures to reduce or eliminate releases of POPs from intentional

production and use, from stockpiles and wastes and from unintentional release. The Aarhus

Protocol (UNECE, 1998) covers 16 POPs, 11 of which are pesticides, which are aldrin,

dieldrin, endrin, chlordane, DDT, heptachlor, hexachlorobenzene (HCB), mirex, chlordecone,

lindane, and toxaphene. The Stockholm Convention on POPs (UNEP, 2001) covers for the

time being 12 compounds or groups of compounds, which are polychlorinated biphenyls

(PCB), polychlorinated dibenzo-p-dioxins and dibenzo-furans (PCDD/Fs) and 9 of the same

pesticides as the Aarhus Protocol, except chlordecone and lindane.

There is currently no reliable information available of what quantities these POPs

constitute on a global level but these conventions acknowledge that there is an urgent need for

environmentally sound disposal and that developing countries and countries with economies

in transition need to strengthen their national capabilities on sound management of hazardous

chemicals (UNEP, 2001). One of the intentions of the Basel Convention on the Control of

Transboundary Movement of Hazardous Wastes is to stimulate local treatment of hazardous

wastes and to avoid shipment across borders (Basel Convention, 1989).

Pesticide wastes from clean up in Africa have so far been shipped to Europe for high-

temperature combustion in dedicated incinerators at an average cost of US $ 3500 per ton

(FAO, 1999; Science in Africa, 2002). Apart from being costly, this practise also involves

environmental risks due to long transport distances and it doesn’t contribute with needed

capacity building on hazardous waste management in the affected countries. High

temperature incineration is usually absent as a dedicated technology option in developing

countries but high temperature cement kilns are however common in most countries and can


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constitute an affordable, environmentally sound and sustainable treatment alternative to

export (Karstensen, 1998 a and b; Karstensen, 2001 a and b; Karstensen, 2004 b). The only

treatment option for organic hazardous wastes in Norway the last 25 years has been co-

processing in cement kilns (Viken and Waage, 1983; Benestad, 1989; Karstensen, 1998 a).

The Stockholm Convention has mandated the Basel Convention (2006) to develop

technical guidelines for environmentally sound management of wastes consisting of or

contaminated with POPs. An important criterion for environmentally sound destruction and

irreversible transformation is to achieve a sufficient destruction efficiency (DE) or destruction

and removal efficiency (DRE). A DRE value greater than 99.9999 % is required for POPs in

the United States (US) (Federal Register, 1999). The DRE consider emissions to air only

while the more comprehensive DE is also taking into account all other out-streams, i.e.

products and liquid and solid residues.

The Basel Convention technical guidelines consider ten technologies to be suitable for

environmentally sound destruction/disposal of POPs (Basel Convention, 2006). The most

common among these are hazardous waste incineration and cement kilns, which also

constitute the largest disposal capacity. The remaining eight technologies have comparatively

low capacities (some are still at laboratory scale), are technically sophisticated and currently

not affordable by many developing countries (UNEP, 2004). A thorough and objective

comparison between these technologies on aspects like sustainability, suitability, destruction

performance, robustness, cost-efficiency, patent restrictions (availability), competence

requirements and capacities is needed.


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Cement production and co-processing of hazardous wastes

Portland cement is made by heating a mixture of calcareous and argillaceous materials

to a temperature of about 1450 oC. In this process, partial fusion occurs and nodules of so-

called clinker are formed. The cooled clinker is mixed with a few percent of gypsum, and

sometimes other cementitious materials, and ground into a fine meal – cement (Duda, 1985;

IPPC, 2001). In the clinker burning process, which is primarily done in rotary kilns, it is

essential to maintain kiln charge temperatures of approximately 1450 °C and gas temperatures

in the main flame of about 2000 °C. The cement industry is today widely distributed

throughout the world and produced in 2003 approximately 1940 million tons of cement

(Cembureau, 2004). When new plants are built in emerging markets and developing

countries, usually the best available techniques (BAT) applies (IPPC, 2001; Karstensen, 2006

b).

Cement kilns have proven to be effective means of recovering value from waste

materials and co-processing in cement kilns is now an integral component in the spectrum of

viable options for treating hazardous industrial wastes, mainly practised in developed

countries (Balbo et al., 1998). A cement kiln possess many inherent features which makes it

ideal for hazardous waste treatment; high temperatures, long residence time, surplus oxygen

during and after combustion, good turbulence and mixing conditions, thermal inertia, counter

currently dry scrubbing of the exit gas by alkaline raw material (neutralises acid gases like

hydrogen chloride), fixation of the traces of heavy metals in the clinker structure, no

production of by-products such as slag, ashes or liquid residues and complete recovery of

energy and raw material components in the waste (Chadbourne, 1997).

Numerous tests in developed countries have demonstrated that there is essentially no

difference in the emissions or the product quality when waste materials are used to replace the


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fuels and ingredients needed to produce cement clinker (Lauber, 1982; Branscome et al.,

1985; Lauber, 1987; Garg, 1990; Karstensen, 1994; Chadbourne, 1997). Mac Donald et al.

(1977) carried out test burns with hazardous chlorinated hydrocarbons containing up to 46 %

chlorine in a wet cement kiln in Canada and concluded that "all starting materials, including

50 % PCBs, were completely destroyed" and "that all chlorinated hydrocarbon wastes may be

used in cement kilns without adverse effect on air pollution levels". Similar tests with

chlorinated and fluorinated hydrocarbons conducted in a wet kiln in Sweden showed that the

DRE of PCBs were better than 99.99998 % and that there were no change in product quality

or any influence on process conditions with a chlorine input up to 0.7 % of the clinker

production (Ahling, 1979). Viken and Waage (1980) carried out test burns in a wet kiln in

Norway feeding 50 kg PCBs per hour, showing a DRE better than 99.9999 % and no traces of

PCB in clinker or dusts could be detected. Benestad (1989) carried out studies in a dry

cement kiln in Norway in 1983 and 1987 and concluded that "the type of hazardous waste

used as a co-fuel does not influence the emissions" and that the destruction of PCB was better

than 99.9999 %. Suderman and Nisbet (1992) concluded from a study in Canada that there is

"no significant difference in stack emissions when 20-40 % of the conventional fuel is

replaced by liquid wastes".

Disposal of obsolete pesticides and POPs in developing countries using cement kilns - lessons learned

Despite the obvious need, surprisingly few studies have reported results from obsolete

pesticide and POPs destruction using cement kilns in developing countries.


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Malaysia

The German development aid organisation GTZ carried out the first reported disposal

operation with obsolete pesticides using a cement kiln in Malaysia in the middle of the 1980s

(Schimpf, 1990). Solid and concentrated liquid pesticides were dissolved in kerosene and fuel

oil in a 5 m3 storage tank with an agitator and fed through the main burner into the kiln. A

mixture of 2,4-D and 2,4,5-T were destroyed in the main flame of the kiln. Before, during

and after the disposal, dust samples were taken from the electro static precipitator (ESP) and

analysed for PCDD/Fs. No PCDD/Fs where detected, but the report doesn't provide any

information of the quantification limits for PCDD/Fs, nor any information about the amounts

of pesticides destroyed, the concentration of the active ingredients, the feed rate into the kiln

or the DE/DRE.

Pakistan

A total of 17,000 litre of 9 different organophosphates and 3 different organochlorines

pesticides mixtures were destroyed in a cement kiln in Pakistan by the US Aid in 1987

(Huden, 1990). Waste pesticides were pumped from a tank truck and injected at an average

rate of 294 litres per hour for the organophosphates and 46 litres per hour for the

organochlorines. The injector achieved fine atomisation using compressed air and was tested

successfully with diesel fuel. The ”cocktail” of pesticides, however, contained sludge's that

settled to the bottom of the tank truck, causing viscosity to fluctuate depending on

temperature and degree of agitation. These unanticipated conditions caused a variety of

problems. The kiln met the standards for dust emission but not the DRE requirement or the

HCl emissions limit. Products of incomplete combustion (PIC) were examined using gas


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chromatography mass spectrometry (GC-MS) but were not detected. Analyses of solid

process samples, raw meal feed, and clinker and ESP dust showed no detectable pesticides.

Tanzania

Mismanagement of large quantities of 4,6-dinitro-o-cresol (DNOC) during several

years in the 1980s and 1990s caused serious environmental and ecological damages to the

wildlife in Lake Rukwe in west Tanzania. DNOC belongs to the group of nitro-compounds

and is classified to be highly hazardous (group lb) in accordance to the WHO (2002)

classification and is highly toxic to fish and explosive in its dry form. GTZ carried out a test

burn with 1:1 DNOC/diesel-mixture in a cement kiln west of Dar-Es-Salaam in 1996

(Schimpf, 1998). A series of technical problems led to delays, especially during the testing

phase and the composition of the exit gas concentration of CO, CO2, O2, NOx and the

temperature fluctuated during the test burn but no DNOC residues were detected in the clinker

or the filter dust. Approximately 57,500 litres of 20 % DNOC were co-processed in the kiln

within a period of about 7 weeks. The 400 old DNOC drums were melted and recycled as

iron for construction purposes. The cost of the disposal was estimated to be approximately

4300 US$ per ton of DNOC, a cost lying in the “upper range of normal disposal costs”

according to Schimpf (1998). This way of calculating the disposal cost seems however to be

dubious - the total project cost, 245,000 US $ over four years, is divided on the 57 ton of

pesticides disposed.

Poland

In a Polish test burn reported by Stobiecki et al. (2003) different mixes of 12 obsolete

pesticides and POPs were introduced into a cement kiln (no details about the process type or


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operating conditions) over a period of three days. The different pesticide mixtures were

blended into three batches with light heating oil and constituted 11.5 %, 29.4 % and 30.5 % of

pesticides respectively. The mixes were fed through the main flame together with the coal in

an introduction rate of approximately 400 kg/h over three different periods and the results was

compared to baseline conditions, i.e. when coal only was used as a fuel. None of the

pesticides were detected in the exit gas (detection limit between 1 and 0.02 μg/m3) or in the

clinker (detection limit between 0.05 and 0.001 mg/kg). Physical and chemical testing of

clinker gave normal and similar results for all conditions. The PCDD/Fs emissions were

0.009 ng I-TEQ/Nm3 with coal only and 0.015, 0.053 and 0.068 ng I-TEQ/Nm3 when feeding

the three fuel mixes with pesticides respectively.

Lessons learned

None of the described projects were able to demonstrate the destruction efficiency, an

important criterion for the evaluation of environmentally sound destruction/disposal (Basel

Convention, 2006), but also important for achieving acceptance for this treatment option

among various stakeholders.

The absence of PCDD/Fs in the ESP dust in the GTZ project in Malaysia is not

enough to verify the destruction performance, nor did it provide information of the

quantification limits for PCDD/Fs. There is however no reason to believe that 2,4-D and

2,4,5-T were not safely destroyed in the main flame but the DE/DRE should have been

established.

For the purpose of the test burn in Pakistan it might have been wise to insist on using a

uniform, higher grade waste pesticide and restricting the test to one compound in each

pesticide group. Uncertainty of availability of the ideal test candidate, likely long haul


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transport, and need to get on with the job, forced the team into a truly real case waste disposal

situation, the complexity of which did not become apparent until they were well committed

and could not turn back (Huden, 1990). Better early sampling of candidate pesticides could

have told the team more of what was ahead as well as determined a better choice of pesticides

for the test burn. The choice of laboratory is of course also important. The concentration of

pesticides in the feed was too low to measure the DE/DRE, probably due to a combination of

low active ingredient and low feed rate. Further on, in selecting a cement plant for waste co-

processing, the power supply reliability is essential. The actual plant was plagued by many

power interruptions. When designing the waste injection and delivery system, the team

expected to work with free flowing liquids but received sludge which caused numerous

problems. The waste products should have been blended in a dedicated tank, equipped with

an agitator and fed to the fuel line equipped with a cut-off valve. The important public

relations issue was according to Huden (1990) not given enough attention. To assume that a

potentially touchy subject best be kept quiet, is dangerously naive. The press, community

leaders and labour unions can quickly turn into enemies when they are not informed of the

intent of such an undertaking. With proper care, popular acceptance is much more likely than

not, particularly when the benefit of participating in risk reduction can be understood.

The kiln chosen for the disposal operation of DNOC in Tanzania (Schimpf, 1990) was

obviously not the best choice and illustrates clearly the necessity of performing a proper

technical feasibility study prior to the kiln selection. The kiln broke down regularly during

the disposal operation, the refractory of the kiln was damaged, the outer wall of the satellite

cooler burned through, the power fluctuated and the raw meal feed was disrupted. There was

no sampling of DNOC in the exit gas, i.e. no possibility to demonstrate the DE/DRE. To

measure DNOC in ESP dust and clinker, and CO2, O2 and NOx in the exit gas is not


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sufficient. The project experienced resistance from the plant employees and showed clearly

the necessity of transparency, information and good communication with involved parties.

Stobiecki et al. (2003) analysed the stack gas and the clinker for the 12 obsolete

pesticides fed to the kiln but did not, for unknown reasons, report the DE/DRE.

Test burn with obsolete pesticides in a Vietnamese cement kiln

Lessons learned from the described projects established the basis for a joint test burn

project with the Vietnamese authorities and Holcim Cement Company. The objective was to

investigate if their cement kiln in the South of Vietnam was able to co-process and destroy

obsolete pesticides/hazardous wastes in an irreversible and environmental sound manner, i.e.

with no influence on the emissions when fossil fuel was partly replaced by hazardous waste.

Information about the test burn was disseminated well in advance to all relevant stakeholders

and the actual test burn was inspected by scientists from universities and research institutes in

Vietnam. Several conditions had to be fulfilled prior to the test burn:

• Project supervision by third party experts.

• Independent stack gas sampling and analysis by an accredited company.

• An environmental impact assessment (EIA) following the Vietnamese requirements

had been successfully completed (Decision 155, 1999; HCMC, 2002).

• The transport and the handling of the hazardous waste should comply with the

hazardous waste management regulation in Vietnam, Decision 155 (1999).


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• The emission levels should comply with the Vietnamese emission limit values in the

standard TCVN 5939-1995 and TCVN 5940-1995 (Decision 155, 1999; Karstensen et

al., 2003 a).

• The cement kiln process had been evaluated to be technical and chemical feasible for

co-processing of hazardous wastes.

• Power and water supply had been evaluated to be stable and adequate.

• The hazardous waste receiving, handling, storage and introduction process had been

evaluated to be stable, safe and robust.

• All involved staff and subcontractors had received adequate information and training

and the project objective had been communicated transparently to all stakeholders.

• Emergency and safety procedures had been implemented, i.e. personal protective gear

should be used and fire extinguishing and equipment/material for cleaning up spills

should be available.

• Procedures for stopping waste feed in the event of an equipment malfunction or other

emergency had been implemented and the set points for each operating parameter that

would activate feed cut-off had been specified.


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Cement plant description

The cement plant is located about 300 km west of Ho Chi Minh City, in Hon Chong,

Kien Giang Province and produces cement clinker in a new dry suspension preheater rotary

cement kiln equipped with a precalciner, a best available techniques plant (IPPC, 2001). The

kiln rotates with a speed of 3.5 rounds per minute, is 4.6 meter in diameter, 72 meter long

with a 110 meter high double string 5-stage preheater tower and produces approximately 4400

tons of clinker per day.

The gas flows in the system provides combustion air to the main burner and the

precalciner, and is primarily taken from cooling air in the clinker cooler which ensures

maximum heat recovery. Under normal operation, the exit gas from the preheater is directed

through a conditioning tower to the raw material mill and the coal mill for drying purpose. A

small portion of the gas (8 %) can be directed to a by-pass system to reduce build-up of

chlorine and alkalis if needed. After drying, the gas is de-dusted in high efficiency ESP

before entering the main stack.

The production process is monitored and controlled through an advanced control

system with continuous on-line monitoring of the following parameters: the kiln inlet gas is

analysed for temperature, O2, CO and NOx; the preheater outlet gas for temperature, O2, CO

and NOx and the stack outlet gas for temperature, O2, CO, CO2, NO, NO2, SO2, HCl, NH3,

H2O and volatile organic carbon (VOC). The main stack is 122 meter high and approximately

4 meter in diameter.


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Obsolete pesticides used in the test burn

The greatest challenge in the first phase of the project was to identify a local available

obsolete pesticide which could fit the purpose of being a suitable test burn candidate and

avoid the trouble Huden (1990) faced in Pakistan.

A solvent-based insecticide mix with two active ingredients, 18.8 % Fenobucarb and

2.4 % Fipronil, was identified at an international pesticide company in Dong Nai Province.

The insecticide had expired, was deemed unusable and approximately 40,000 litres was stored

in 200 steel drums waiting for a suitable treatment option. The active ingredients of the

insecticide were solved in cyclohexanone and aromatic solvents. The concentration was

regarded to be sufficient to be able to demonstrate the necessary DE/DRE of 99.99 %.

Fenobucarb has a molecular weight of 207.3 with the sum molecular formula C12H17NO2.

OCHCH2CH3

CH3

OC

CH3NH

Fig. 1 Chemical structure of Fenobucarb.

Fipronil has a molecular weight of 437.2 with the sum molecular formula

C12H4Cl2F6N4OS and contain 16.2 % chlorine and 26.06 % fluorine. Fenobucarb and

Fipronil contain 6.7 % and 12.8 % nitrogen respectively.

F3C N

Cl

Cl

N CN

SO

CF3NH2

Fig. 2 Chemical structure of Fipronil.


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Both Fenobucarb and Fipronil are sold as active ingredients in separate insecticide

formulations and they are potent insect killers, with different mechanisms and reaction time.

Both active ingredients are classified by the World Health Organisation to be moderately

hazardous (class II) on their scale from extremely to slightly hazardous (WHO, 2002). The

insecticides were also considered to be representative of other obsolete pesticide and

hazardous waste streams needing a treatment option in Vietnam and would as such constitute

an illustrative example (Quyen et al., 1995; DoSTE, 1998; Hung, D.Q. and Thiemann, W.,

2002; Karstensen et al., 2003 a and b; Minh et al., 2004; World Bank, 2004). The other

requirement, which was based on the lessons learned from the earlier studies, was the need of

having sufficient amounts and concentration of a homogeneous compound.

The insecticide mix was a free flowing liquid with a viscosity similar to water and

easy to pump through a separate channel in the main burner, a three channel burner feeding

anthracite coal only under normal operations. The product had been screened through 0.25

mm sieve and no settlements, particles or polymerization or degradation of the active

ingredient were observed. The Plant Protection Department in Ho Chi Minh City confirmed

that the product was homogenous and contained 18.8 % Fenobucarb and 2.4 % Fipronil.

Quantitative and qualitative analysis is usually done by high pressure liquid chromatography

with ultra violet detection or by gas chromatography with electron capture detection (Kawata

et al., 1995; Vilchez et al., 2001).

A 16 m3 steel tank for receiving, blending and feeding of the insecticide mix was build

and connected to the light fuel oil pumping system with automatic dosage and switch off/on

through the main control system. The tank was equipped with a diaphragm pumping system

and was placed in a bunded concrete construction for spill recovery. The insecticide mix was


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pumped from the tank through stainless steel pipes through a calibrated flow meter and into

the main flame together with coal.

The transport of the 200 steel drums with insecticide was carried out by 10 trucks and

organised by the owner. The emptying of the insecticide drums were done manually with a

steel lance, chemical resistant hose and a diaphragm pump connected directly to the feeding

tank and was carried out by trained personnel. Safety during transportation, handling and

transfer had the highest priority and due care was demonstrated during the course of the test.

Personnel were equipped with personnel protective gear including organic vapour cartridge

face masks. Preventive measures were in place in case of exposure, spillage and fire. All

installations and drums were earthed. Empty drums were taken back to the owner in Dong

Nai by the same trucks.

Outline of the test burn

The entire test was conducted over two days, 16 and 17 October 2003, starting first

day with a baseline study with coal feeding only and then the test burn the second day were

parts of the coal was substituted by the insecticide mix. The plant was run both days in a

normal mode, i.e. whit the kiln gases directed through the raw mill for drying purpose.

The sampling of solid process samples, i.e. raw meal, clinker, fine coal, and dust from

the ESP was carried out by trained plant staff. An Australian independent test company

accredited according to EN ISO/IEC 17025 was hired to carry out the stack gas sampling.

They subcontracted other accredited laboratories in Australia and Europe to do the chemical

analysis.

The insecticide mix was introduced to the kiln starting with 1000 litres per hour (l/h),

increasing to 2000 l/h six hours before the stack sampling started in order to stabilise test


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conditions. During the stack sampling campaign, 2030 litre of insecticide mix was fed to the

kiln per hour and all together 39,500 litres were destroyed in less than 20 hours. After

emptying, tank and pipes were cleaned with light fuel oil and fed to the kiln.

Process and sampling conditions during testing

292 tons/h of raw meal was fed to the preheater and 179 tons/h of clinker was

produced during the test. Feeding of coal to the secondary precalciner burner was stable at 13

tons/h both days; the coal feed to the main primary burner was reduced by 1.5 tons from 7 to

5.5 tons/h when the insecticide mix was introduced to compensate for the heat input of the

solvent.

The coal feed to the main burner was not reduced sufficiently during the test burn due

to an analysis error of the heat content of the insecticide mix. Measurements prior to the test

had shown a calorific value of 22.5 MJ but during the test it was realised that this had to be

wrong because the temperature of the kiln increased. This was confirmed by new analysis

after the test burn when the calorific value of the insecticide mix was measured to be 36.6–

38.1 MJ/kg (due to the aromatic solvents). Fine coal is by comparison 30 MJ/kg, i.e. the coal

feed to the main burner should have been reduced by 2.5 tons to balance the heat requirement

of the kiln.

Emissions results and discussion


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Destruction efficiency of the insecticides

To make sure that Fenobucarb and Fipronil was not a PIC normally found in the stack

emissions, Fenobucarb and Fipronil were also analysed in the samples taken during the

baseline test. Both DE and DRE were measured during the test. The DE is calculated on the

basis of mass of the insecticide fed to the kiln, minus the mass of the remaining insecticide in

the stack emissions, in the clinker and the ESP dust, divided by the mass of the insecticide

within the feed, according to the following equation:

DE = [(Win - Wout) / Win] x 100

were Win is the mass of Fenobucarb and Fipronil entering the kiln and Wout is the mass exiting

the stack gas and through the clinker and ESP dust. The actual cement plant doesn't produce

any liquid effluents. The DRE considers emissions to air only.

The introduction of 2030 l/h insecticide amounts to 362 kg pure Fenobucarb and 46.2

kg pure Fipronil per hour when corrected for the density, 0.95 (kg/l). No Fenobucarb or

Fipronil were detected in the clinker, the ESP dusts (the detection limit was 2 ng/gram) or in

the exit gas (the detection limit was 21 ng/m3 and 14 ng/m3 respectively). The DE/DRE is

calculated on the basis of the material volumes produced and an average stack gas volume of

484,800 normal cubic metre per hour (Nm3/h) corrected to 10 % oxygen.

Table 1 Fenobucarb and Fipronil in the stack (ng/m3). Calculated DE and

DRE.

Baseline Test Burn DRE test burn DE test burn

Fenobucarb <18 <21 >99.999997 % >99.9999969 %

Fipronil <12 <14 >99.999985 % >99.9999832 %


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The US EPA regulation would require a DRE of 99.99 % for these insecticides; no DE

demonstration is however required (Federal Register, 1999). There is no requirement for

demonstrating the DE/DRE in the Vietnamese regulation.

Result of organic compounds

Sampling for PCDD/Fs, PCBs, and polyaromatic hydrocarbons (PAHs), HCB,

Fenobucarb and Fipronil was performed in accordance with US EPA Method 23 (Federal

Register, 2000). This method has been proven to be effective for the sampling of a wide

range of semi-volatile organic compounds from combustion systems, including PCBs, PAHs,

HCB and pesticides. The XAD-2 resin was spiked prior to sampling with isotopically

labelled PCDD/Fs surrogate standards. In the laboratory, PCDD/F, PAH and PCB recovery

standards were added to the sample components. The filter, resin and impinger solutions

were extracted with organic solvents and the extract purified by chemical treatment and solid

phase chromatographic techniques. Analysis of PCDD/Fs was performed using high

resolution gas chromatography with high resolution mass spectrometry in accordance with US

EPA Method 8190 (Federal Register, 2000). The total toxic equivalents (TEQs) for 2,3,7,8-

substituted PCDD/F congeners were calculated using international toxic equivalency factors

(TEFs).

The method of extraction and purification of PAHs and PCBs are based on US EPA

Methods 3540 (Soxhlet extraction of solid phase), 3510 (liquid/liquid extraction of aqueous

phase), 3630 (SiO2 gel column) and 3640 (GPC) (Federal Register, 2000). PAHs were

analysed using high-resolution gas chromatography with low-resolution mass spectrometry.

Analysis of PCBs was performed using high-resolution gas chromatography with high-

resolution mass spectrometry determining “dioxin-like” PCB congeners with the TEF scheme


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provided by WHO 1998 (Federal Register, 2000). HCB and the insecticides were determined

directly from the solid and liquid phase extracts (US EPA Methods 3540 and 3510) using

high-resolution gas chromatography with low-resolution mass spectrometry (Federal Register,

2000). Sampling and analysis of VOC was performed in accordance with the US EPA

Method 18 (Federal Register, 2000).

This was the first time PCDD/Fs were measured in an industrial facility in Vietnam.

There is currently no PCDD/F emission limit value for cement kilns but hospital waste

incinerators have an ELV of 1 ng I-TEQ/Nm3. No 2,3,7,8-substituted PCDD/Fs could be

quantified.

HCB is currently not subject to common regulatory monitoring in cement plants but

may be a requirement under the Stockholm Convention in the future. HCB was below the

detection limit both days. The PAH emission was low and independent of the insecticide

disposal. There is currently no ELV for PAH or HCB in Vietnam.

VOC and benzene were measured in the stack both days and were found in low

concentrations, less than 4 % and 13 % of the current ELV respectively. Emissions of VOC

and benzene are usually due to volatilisation of hydrocarbons in the raw materials when

heated in the preheater and is normal in cement production.

Of the PAHs measured, only fluorene, phenanthrene and fluoranthene were identified

in low concentrations in the baseline test and only phenanthrene was identified in low

concentration during the test burn. Naphthalene couldn't be quantified in any of the samples

as it was found to be a contaminant in the XAD-2 resin.


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Table 2 Concentration of PAH, HCB, benzene and VOC (dry gas at 273 K,

101.3 kPa and 10 % O2)

Unit Baseline Test burn ELV Vietnam

Σ PAH (μg/m3 ) 1.8 0.49 -

HCB (ng/m3) < 31 < 35 -

Benzene (mg/m3) 2.2 3.2 80

VOC (mg/m3) 17 26 200

All the dioxin like PCBs was below the detection limit. There is currently no ELV for

PCBs in Vietnam. PCBs are not commonly monitored on a regular basis in cement plants but

will be a requirement under the Stockholm Convention in the future.

Result of acids and gases

Hydrogen fluoride and ammonia were measured to be below the detection limit both

days and hydrogen chloride was well below the emission limit value. Sampling and analysis

were performed in accordance with US EPA Method 26A (Federal Register, 2000). Even if

the insecticide contained both chlorine and fluorine, the emissions were not affected.

The result for CO was well below the current emission limit value of 225 mg/Nm3 and

independent of the insecticide disposal. Carbon monoxide can arise from any organic content

in the raw materials and, occasionally, due to the incomplete combustion of fuel. The

contribution from the raw materials will be exhausted with the kiln gases. Control of CO is


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critical in cement kilns when ESP is used for particulate abatement. If the level of CO in the

ESP rises, typically to 0.5 % by volume then the ESP electrical system is automatically

switched off to eliminate the risk of explosion. The oxygen content measured during the test

is within the normal range in cement kilns. Oxygen and carbon dioxide concentrations were

monitored in accordance with US EPA Method 3A and carbon monoxide in accordance with

US EPA Method 10 (Federal Register, 2000).

The result of SO2 was less than 1 % of the emission limit value (225 mg/Nm3) and

independent of the insecticide disposal. 99 % of the sulphur oxides emitted from cement kilns

is in the form of SO2 and originates mainly from sulphides and organically bound sulphur in

fuels and raw materials (Oss and Padovi, 2003).

The reason for the high NOx levels during the test burn was due to high heat input

through the main flame due to wrong information about heat content of the insecticide mix

prior to the test. The coal feed was approximately 1 ton higher than required. The easy

burnability of the solvent of the insecticide mix compared to hard coal probably caused a

more intense flame in the main burner as well as added 31 kg of nitrogen per hour. The

consequence of this inadequate compensation was higher temperature in the kiln and higher

NOx levels. The NOx level was however higher than the ELV also under the baseline

measurements (under investigation). The result confirms what most studies have concluded

with earlier, that more than 90 % of the NOx emissions from cement kilns are NO, the rest is

NO2 (Oss and Padovi, 2003).

NO and NO2 concentrations were monitored in accordance with US EPA Method 7E

and sulphur dioxide concentrations in accordance with US EPA Method 6C (Federal Register,

2000).


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Table 3 Gaseous compounds (mg/Nm3)

Baseline Test Burn ELV Vietnam

HCl 2.1 2.4 90

HF <0.21 <0.23 4.5

NH3 <1.0 <0.44 45

CO 99 131 225

O2 (%) 5.24 5.21 -

SO2 1.8 2.0 225

NO2 21 40 -

NO 760 1220 -

NOx expressed as NO2 1180 1910 1000

Results of solid particles and metals

The concentration of dust was 33 and 20 mg/Nm3 for the baseline test and the test burn

respectively, i.e. independent of the insecticide disposal. The ELV in Vietnam is 100

mg/Nm3. Sampling of solid particles was conducted in accordance with US EPA Method 5

(Federal Register, 2000).

The analysis results of arsenic, cadmium, cobalt, chromium, copper, mercury,

manganese, nickel, lead, antimony, tin, thallium, vanadium and zinc are given in table 4.

Vietnamese ELVs are given for arsenic, cadmium, copper, lead, antimony and zinc and all the

results were in compliance. The sources of heavy metals to a cement kiln are raw materials

and fuels and will be site specific. The emission levels uncovered in this test are low and not

influenced by the insecticide disposal. The results of tin are probably due to contamination or


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interferences in the analytical technique used in the laboratory. Sampling and analysis of

metals were performed in accordance with US EPA Method 29 (Federal Register, 2000). Hg

was analysed by cold vapour atomic absorption spectroscopy (CV-AAS), the other metals by

using inductively coupled argon plasma emission spectroscopy - mass spectrometry (ICP-

MS).

Table 4 Metal concentration in µg/Nm3

Baseline Test Burn ELV

As <5.4 <2.7 4500

Cd 0.71 0.74 450

Co <0.54 <0.27

Cr 1.7 4.3

Cu <1.1 0.71 9000

Hg 4.7 0.33

Mn 12 14

Ni 1.6 1.8

Pb <4.3 <2.2 4500

Sb <3.3 <1.6 11,250

Sn 71 38

Tl <2.7 <1.4

V <0.65 0.82

Zn 13 2.7 13,500


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Solid samples and product quality

Raw meal, fine coal, ESP dusts and clinker were sampled every second hour during

the two days and analysed for main and trace inorganic components as well as insecticides.

The results showed no effect of the insecticide disposal. The clinker had an average

concentration of chlorine of 18 and 19 mg/kg under baseline and test burn conditions

respectively; the fluorine was <0.40 mg/kg for all samples. All the dusts produced by the ESP

are recovered and reintroduced back to the process, i.e. no residues or waste is produced.

Ordinary quality testing was performed on clinker, cement and concrete produced the

two days and comprised fineness of the cement, loss of ignition, water demand, initial and

final setting time and the strength of the concrete after 1 day, 3 days, 7 days and 28 days. The

results were within normal ranges and showed that the product quality was unaffected by the

introduction of the insecticide.

Discussion

Already in the 1970s the pesticide industry knew by practise that even persistent

compounds were completely destroy at combustion temperatures around 1000 oC and a few

seconds retention time (Karstensen, 2006 a). Laboratory studies and thermodynamic

calculations confirm this. A cement kiln possess many inherent features which makes it ideal

for hazardous chemicals treatment; high temperatures up to 2000 oC in the main flame,

several seconds residence time, surplus oxygen, good turbulence and mixing conditions.

Some of the early projects carried out by GTZ and US Aid might have assumed that

any cement kiln would qualify to dispose obsolete pesticides. Even though all cement kilns


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needs high temperature to produce clinker, not all are necessarily suited for hazardous waste

destruction without upgrading or modification. The feasibility has to be assessed case by

case, and will depend on technical, chemical and environmental conditions, waste and raw

material composition, location, infrastructure, policy and regulation, permit conditions,

competence, acceptability etc. (Karstensen, 1998 a and b; Karstensen 2001 a and b).

A feasible cement kiln will together with environmentally sound management and

operational procedures, adequate safety arrangements and input control secure the same level

of environmental protection in developing countries as in the EU and the US. As clearly

illustrated in this study - instead of representing a threat to environment and health and

causing problems for the owner, the hazardous insecticide was safely destroyed in a local

cement kiln at same time as non-renewable fossil fuel was saved. The cost savings of using a

local cement kiln will be considerable compared with other treatment options, also export, and

can contribute to make developing countries self reliant with regards to hazardous waste

treatment. Building of hazardous waste incinerators imply large investments and high

running costs and is normally not affordable to developing countries.

The test burn demonstrated the best destruction efficiency ever demonstrated; 10,000

times better than required by the US regulation, the most stringent in the world today. Except

for the NOx emissions, all the test results were in compliance with the Vietnamese regulation.

The results of the PCDD/F measurements are in line with the results of a study on POPs

emission from cement kilns conducted by the World Business Council for Sustainable

Development (Karstensen, 2004 and 2006b) - a study evaluating around 2200 PCDD/F

measurements and concluding that co-processing of hazardous waste does not seem to

influence or change the emissions of POPs from modern BAT cement kilns.


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Conclusion

Continued accumulation and inadequate management of obsolete pesticides and POPs

constitute a threat to health and environment, especially in developing countries. High

temperature combustion has shown to be the best way to destroy most of these chemicals but

only a few projects utilising high temperature cement kilns have been reported and none has

prior to this test been able to verify the destruction efficiency under developing country

conditions.

The test burn conducted with two hazardous insecticides in a cement kiln in Vietnam

demonstrated the best destruction efficiency ever measured. All the test results, except for the

NOx, were in compliance with the most stringent regulations. This was the first time

PCDD/Fs, PCBs and HCB were measured in an industrial facility in Vietnam and all the

results were below the detection limits. This proved that the destruction had been complete

and irreversible, and in full compliance with the requirements of the Stockholm Convention

of being environmentally sound, i.e. not causing any new formation of PCDD/Fs, HCB or

PCBs.

Environmentally sound disposal of hazardous chemicals is costly if export or new

disposal facilities are considered and may not be affordable to many developing countries.

Cement kilns are however commonly available in most countries and modern best available

techniques kilns are nowadays primarily built in emerging markets. A feasible cement kiln

can constitute an affordable, environmentally sound and sustainable treatment option for

many hazardous chemicals if adequate procedures are implemented.


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