MODULE 2 – ALTERNATIVE WASTE TREATMENT TECHNOLOGIES (AWT)

DR DARREN PERRIN

The aim / learning outcome of this module is to provide an overview on the range of technologies that are available for the treatment of mixed waste streams and a brief understanding of the factors which influence the deliverability and operation of different alternative waste treatment technologies (AWTs).

• What are AWT’s and their role in a strategic framework• The impact of collection strategies on AWT feedstock• Factors influencing the deliverability of AWT• Clear strategy in procuring an AWT

MODULE OUTLINE

MODULE 2 – AWT – THE TECHNOLOGIES

DR DARREN PERRIN

• What does the definition include?

• Track record

• Europe, America and Japan - Successful operational experience and knowledge principally within Europe, America and Japan, but examples across the globe.

• Australia / New Zealand - Mixed performance, recent focus primarily on organics

• What do they do ?

• Mechanical Sorting / Separation / Pre-treatment• Biological Processes• Physiochemical Processes• Thermal Processes

• No ‘one stop’ solution suitable for all

• Lack of information makes it difficult to compare fairly

WHAT IS AWT?

• 100% kerbside recycling? - At what cost?

• We will always have residual (general mixed) waste

• We will always have a need for landfill

• Challenge is to:• Understand how much residual waste• Understand what the residual waste consists of• Design and implement appropriate technology to manage the waste in a

manner which meets the local and regional strategic objectives in accordance with the waste hierarchy

• Have a common understanding on what the process will and won’t do and manage expectations accordingly.

THE ROLE OF THE AWT TO MANAGE WASTE

• Biological Technologies:

• Composting (in-vessel)• Anaerobic digestion)

• Mechanical and Biological treatment (MBT)

• Sort first / bio-treat second• Bio-treat first / sort second (bio drying)

• Mechanical Heat Treatment (MHT) / Autoclaving

• Advanced Thermal Treatment (ATT)

• Gasification • Pyrolysis • Plasma gasification

• Mass burn incineration (energy from waste)

• Grate combustion• Fluidized bed combustion

THE TECHNOLOGIES

AWT WITHIN THE WASTE HIERARCHY

AWT

AWT

AWT

AWT

AWT - Not the answer, but part of an integrated solution.......

AWT

Avoid

Minimise Recycle

EXAMPLES OF THE TECHNOLOGIES

THE WASTE MANAGEMENT SYSTEM

• Aerobic Digestion - in the presence of “air”

• Anaerobic Digestion- in the absence of “air”

BIOLOGICAL TECHNOLOGIES

Windrow In Vessel Composting Biodrying

• Composting is the microbial decomposition of organic material in the presence of oxygen to produce compost. There are two main types of composting:• Open windrow is most commonly used in Australia for green garden waste• In-vessel composting is common in Europe and increasingly being taken up in

Australia for green garden and food waste

COMPOSTING

• Anaerobic digestion is the microbial decomposition of organic matter into biogas (approximately 60% methane and 40% carbon dioxide) and digestate (solid or liquid) in an oxygen depleted environment.• Two main types: Wet (>80% moisture) and Dry (50 to 80% moisture)• Typical waste feedstock include source segregated organics from household

and commercial premises, biosolids, manure and farm slurries and purpose grown crops.

ANAEROBIC DIGESTION

• Mechanical Biological Treatment is a generic term for an integration of several processes and technologies commonly found in different waste management facilities such as MRFs and biological treatment facilities.

• Using mechanical and biological processes to separate / prepare mixed waste into usable fractions and / or render it more ‘stable’ for deposit into landfill.

• They commonly use composting or anaerobic digestion for treatment of mixed general waste to separate / prepare this into usable fractions and / or render it more ‘stable’ for deposit into landfill.

MECHANICAL BIOLOGICAL TREATMENT

MECHANICAL AND BIOLOGICAL TREATMENT Inputs

• Mixed Waste

Issues• Not an end process in its own right • Outputs need a market• Bio-drying process does not necessarily

stabilise material

Benefits• Can maximise recycling • Relatively proven European track record• Treatment of waste with “no stack”

Outputs • Recyclables • CLO• RDF

• Mechanical Heat Treatment is use of steam based thermal treatment, with or without pressure, in conjunction with mechanical processing for clinical and mixed general waste.

• There are two main types of facility that use mechanical heat treatment:• Autoclaving – a batch steam processing in a metal vessel under the action of

pressure• Rotary kiln - continuous heat treatment in a rotating vessel, not under

pressure

MECHANICAL HEAT TREATMENT

MECHANICAL HEAT TREATMENTInputs • Mixed Waste Input

Issues• Energy intensive • Need output for biodegradable

fraction.Benefits• Relatively lower capital cost• Simple technology • Cleans metals and glass inputs• Sanitises waste (pressure cooking)• Separation of waste easier after

processing

Outputs • Clean Dry Recyclables • Fibre Flock

• Advanced Thermal Treatment (ATT) is an umbrella term that is used to categorise waste treatment technologies that utilise thermal processes to treat mixed general waste that are different to incineration.

• Primarily those that employ pyrolysis and/or gasification to process mixed general waste and also exclude full combustion thermal processes (i.e. incineration).

ADVANCED THERMAL TREATMENT (ATT)

• Gasification • Thermal and chemical conversion of carbon based material within mixed

general waste into mainly gaseous outputs. Temperatures are in the range of 800-1100°C with air as the gasification agent and up to about 1500°C with oxygen. Overall gasification processes are exothermal, i.e. producing heat

• Pyrolysis • The thermal degradation of organic materials within mixed general waste

MSW in absence of oxygen. Temperatures are typically around 300-800°C. Overall the process is endothermic, i.e., energy is required for the pyrolysis process to proceed.

ADVANCED THERMAL TREATMENT (ATT)

ATT – HOW IT WORKS

ADVANCED THERMAL TREATMENTInputs • Prefers single / pre-

treated waste streams

Issues• A variety of operational risks due to history• Differentiation from incineration• “true” gasification and “staged” gasification • Not all systems have energy efficiency benefits over

incineration• High capital cost

Benefits• Produces renewable energy in the form of syngas• Reduces waste volume, destroys BMW• Potential benefits of small scale or integrated facilities• Smaller scale than mass burn (niche applications)• Potential for smaller Air Pollution Control equipment

Outputs • Gas (Syngas)• Oil and tar • Ash and Metals

• Incineration involves combustion of mixed general, clinical and hazardous waste with sufficient quantities of air in temperatures often in excess of 850°C. The main types are:• Fixed grate• Moving grate• Fluidised bed• Rotary kiln

INCINERATION

INCINERATIONInputs • Mixed or Single Waste Input

Issues• Poor public perception • Potentially large land take

Capital intensive • Commercially viable approx. 100k tpa

+ Benefits• Proven technology with long track record • Reduces waste volumes• Established markets for outputs

Outputs • Heat used to produce electricity (and/or

a local user)• Bottom ash can be recycled (20 – 30%)• Metals for recycling (3 -5 %)• Air pollution control residues (4 - 7%)

LEVELS OF AIR IN COMBUSTION PROCESSES

MODULE 2 – AWT – THE CHALLENGES

DR DARREN PERRIN

CHALLENGES

• Perceptions

• Meeting expectations and risk transfer

• Assessing commercial deliverability

• Affordability

What goes in .... must come out! – poor quality input leads to poor quality output

MEETING EXPECTATIONS AND RISK TRANSFER

EXERCISE – AWT ISSUES

Strengths• X• X• X

Opportunities • X• X• X

Weakness • X• X• X

Threats• X• X• X

• Different composition

• Different materials which can be recycled / composted

• Materials which can’t be recycled or composted

• Energy Value • Gross Calorific Value (GCV)• Moisture Content

• Net Calorific Value (NCV)

• Ash generation potential

• Proportion of Biomass

WHAT IS MIXED RESIDUAL (GENERAL) WASTE ?

THE CONUNDRUM – COMPETITION FOR MATERIAL

?

Waste Collection Schemes

Alternative Waste Treatment Technology

Waste Material

EXERCISE

• Naughts and Crosses

THE CONUNDRUM – DIFFERENT AUTHORITIES

Waste Collection Schemes

Alternative Waste Treatment Technology

Waste Collection Schemes

Waste Collection Schemes

Waste Collection Schemes

THE CONUNDRUM – DIFFERENT SCHEMES

Waste Collection Schemes

Scheme Design

Materials Targeted Presentation Separation EfficiencyContamination

Waste Generated Demographics Composition Area

Characteristics

THE CHALLENGE.......

Alternative Waste Treatment Technology

?

?

? ?

? ?

?

?

WASTE COMPOSITION

WASTE COMPOSITION CAN VARY

MATERIAL FLOWS AVAILABLE

Refuse Organic

Self Haul

Recycling

SYSTEM INTERACTION

Biological Treatment

IVCAD Windrow

AWT

Landfill

ATT MHT MBT

EFW

Power

Product

RecyclingGeneral Waste

Organic

MRF Bulking

Sort and Transfer

Refuse Recycling

Bring Sites

8.1% Newspapers

7.9% Glass bottles and Jars

3.4% Drink and Food Cans

Organic

COLLECTION SYSTEMS CHANGES

• Change number of households offered a service

• Change number of households who use the service

• Change how often they use the service

• Change what materials are targeted

• Change how effectively the material is captured i.e. placed in the correct container

= 3 / 5 = 60% Set Out Rate

Wk 3

Refuse

= 4 / 5 = 80% Participation Rate

= 2 / 5 = 40% Set Out Rate

Wk 1

= 2 / 5 = 40% Set Out Rate

Wk 2

Recycling

RECOGNITION, CAPTURE AND DIVERSION RATE

20

15 5

25% Capture Rate

= Total10

10

10

5 5

50% Recognition Rate 0% Recognition Rate

10

10

10

5 5

50% Recognition Rate 0% Recognition Rate

10

30

15 5

17% Diversion Rate

= Total10

There is material remaining in the General Waste container

• Assumption: No kerbside recyclables collection system in place, 200,000 tpa of household general waste generated;

• Question: If ‘you’ introduced a kerbside recycling scheme in your council area, approximately how many tonnes of residual waste would you have left to treat in an mixed waste AWT facility?

WASTE FEEDSTOCK EXERCISE (IN GROUPS)

NOT ALL MATERIALS ARE TARGETED

Primary Material Category

Primary Composition

Secondary Material Category

Secondary Composition

Paper 14.4%

Newspaper and Magazines 6.7%Other Recyclable Paper 4.8%Non-Recyclable Paper 2.9%

Plastic 5.9%Plastic Bottles 2.6%Plastic Packaging 2.6%Other Plastic 0.7%

Glass 10.2% Glass Packaging 9.6%Other Glass 0.6%

SENSITIVITY OF TARGETED MATERIALS

Coverage (90%)

Participation (70%)

Recognition (60%)

X

X

Material Available (Composition 5%)

Waste Generation 100,000 tonnes

5,000 tonnes

4,500 tonnes

3,150 tonnes

1,890 tonnes

• Assumption: No kerbside recyclables collection system in place, 200,000 tpa of household general waste generated;

• Question: - If ‘you’ introduced a kerbside recycling scheme in your council area, approximately how many tonnes of residual waste would you have left to treat in an mixed waste AWT facility?

• Now • Assume

• 50,000 available in composition • Coverage of 90%• Participation 70%• Recognition 60%

WASTE FEEDSTOCK EXERCISE (IN GROUPS)

– Change recognition ?– Change participation ?

MODULE 2 – AWT – THE PURCHASE

DR DARREN PERRIN

PROCESS IN OBTAINING AN AWT

Define What Your Strategic Priorities Are

Develop Evaluation Criteria

Develop Procurement Strategy

Develop Weightings Validate Weighting and Evaluation Criteria

Commence Procurement Process

Obtain Pre-Procurement Information

• Reduce the mass and volume of waste?

• Produce an end product:

• Quality Compost ? • Recyclables ?• High end value recyclables ?

• Pre-treat the waste to produce a feedstock for another process?

• RDF ?• SRF ?

• Generate and export power or heat?

• Electricity?• Heat / Steam ?• Biogas ?• Synagas ?

• Stabilise the waste prior to disposal to landfill?

• Maximise the life of landfill assets?

DEFINING STRATEGIC PURPOSE OF AWT

• Understand data available (waste flows, composition, performance, population / household growth

• Political landscape and sensitivities

• Understand / Map out stakeholders

• Determine Contract Specification• Input (sets service requirements)• Output (sets performance standards)

• Understand and plan programme

• Procurement Plan

PRE-PROCUREMENT ACTIVITY

• Scope and duration

• Contract type (O,DBO, DBFO, DBFOM)

• Funding

• Provision of Facilities / staffing

• Partnering

• Market appetite

• Planning, sites and approvals

PROCUREMENT PLAN

• In most cases, a car will get you from A to B

• Lots of different cars out there

• If entering a car yard, what do you tell the salesman are the key things you want…..

• Key Questions?• What is important to you? e.g. Speed, colour, number of seats, fuel efficiency,

age, reliability, appearance, reputation of manufacturer, cost• Are any of these more important?• If so, which are more important and by how much?• Are any of these show stoppers? i.e. you have 3 kids therefore a 2 seater car

is not possible• Can you group some of these together?

EVALUATION CRITERIA IS LIKE BUYING A CAR

• Tier 1 is the main grouping

• Tier 2 is the categories within the grouping

• Performance• Fuel efficiency • Speed • Emissions

• Cost • Deprecation• Cost to buy • Cost to maintain

TIER 1 AND TIER 2 CRITERIA

TIER 1 AND TIER 2 WEIGHTING

– Performance 20%– Fuel efficiency 30%– Speed 50%– Emissions 20%

100%– Cost 50%

– Deprecation 20%– Cost to buy 60%– Cost to maintain 20%

100%– Track record 30%

– Reliability 50%– Reputation of manufacturer 50%

100%

• Sales man will be unhappy if he has invested ½ day showing you

• 2 seater cars if you have 3 kids• Cars which are not within your budget • Providing a test drive for cars you “know you don’t want” that don’t meet

your criteria. • A salesman will be more attracted to a customer who has a clear

idea of what the car needs to do than a customer who is asking the salesman to pick a car for them

• You may be having the car serviced at the garage; therefore you want to start on a “good relationship”.

• You are unlikely to take the car with you i.e. needs financing, engine checks, certificates etc.

REMEMBER ……

• Important to have a clear, robust evaluation criteria to communicate to the market “what you want”

• Changing criteria through the process “could” result in a challenge i.e. people invested a lot of time and money

• A well thought through criteria allows you to “direct” solutions you want and filter out those you don’t want

• Need to be VERY aware of incorrect criteria weightings which can result in the wrong solution being selected

REMEMBER……………..