setting criteria for eow for bioresources applied to land: the … · 2019-03-22 · setting...

Setting Criteria for EoW for

Bioresources Applied to Land:

The Technical Case,

the Technical Limits

Professor Stephen R Smith

Department of Civil and Environmental Engineering

Tel +44 (0)207 5946051 Email [email protected]

Data Availability and Techniques to

Formulate EoW Criteria

The extensive scientific understanding available on land application of

bioresources can be used to establish EoW criteria to maximise recycling

of these materials as fully recovered fertilisers and soil conditioning

products and by-products

Key factors to be considered in EoW criteria include treatment, pathogens,

potentially toxic elements and organic contaminants

Risk assessment techniques can bring together the technical data into a

comprehensive framework for evaluating EoW criteria and limits, but

depend heavily on the type of research data and the assumptions used.

Global Phosphorus Production

© Imperial College London

Energy Consumed by Wheat Production


Institution of Mechanical Engineers (2013) Global food - waste not, want not.

Global Food Prices on the Rise


Raw Material

Process

Primary Product

Use

End of Life Disposal

Production Residues

Waste

By-product

Waste

Waste Framework Directive

6

Recovery Operation

WFD – Article 5

WFD - Article 6

End of Waste Status – WFD Article 6

According to Article 6 (1) and (2) of the WFD 2008:

“....certain specified waste shall cease to be waste.... when it has undergone a recovery, including recycling, operation and complies with specific criteria to be developed.....” in line with certain legal conditions, in particular:

WFD - Article 6

The substance or object is commonly used for specific purposes;

A market or demand exists for such a substance or object;

The substance or object fulfils the technical requirements for the specific purposes and meets the existing legislation and standards applicable to products; and

The use of the substance or object will not lead to overall adverse environmental or human health impacts

QPs and standards only focus on

source separated materials:

Why discriminate against mixed

input materials if they can attain

rationally based standards?

Is it to do with pathogens?

Time-temperature Conditions to Eliminate Pathogens

(Strauch, 1991) and Microbiological Criteria

Treatment E. coli Salmonella

Conventional 2 log reduction <10

5 g

-1DS

Enhanced 6 log reduction <1000 g

-1 DS

Absent in 2 g DS

Compost & Digestate

1 <1000 g

-1 FW Absent in

25 g FW

1PAS100, PAS110, IPTS (2013)


Microbiological Risk Assessment (Gale, 2005)

MRA confirms anecdotal evidence of no disease outbreaks in human population with controlled use of sewage sludge

MRA indicates the minimal risk to health from sludge pathogens

Although pathogens would be the

immediate concern for public health,

technological processes mitigate

the risks

Is it to do with PTEs?

PTEs in Biosolids Have Fallen


0

200

400

600

800

1000

1200

1400

1983 1990 1996 1998 1999 2000 2001 2002 2003 2004 2005 2006

To

tal c

on

ce

ntr

ati

on

(m

g k

g-1

DS

)

Year

Zn

Cu

Pb

Cr

Ni

PTEs in UK Biosolids

Metals in Livestock Waste Compared to Sludge (mg kg-1 DS)


Zn Cu

Poultry 475 75

Pig 650 470

Sludge 612 309

Heavy Metal Concentrations (mg kg-1 DS) in Composts or

Biosolids NOT Associated with Negative Ecological Impacts

Zn Cu

Perucci et al., (1992) 647 240

Smith (1992) 1100 1120

Giusquiani et al. (1994) 647 240

Pascual et al. (1999) 650 237

García-Gil et al., (2000) 1325 548

Wong et al. (2001) 3052 492

Crecchia et al. (2001, 2004) 382 158

Speir et al. (2004) 476 275

Bhattacharyya et al. (2005) 691 149

De Brouwere & Smolders (2006) 949 211

Mean

(Wong et al removed from Zn value)

1000 (760) 370

We need to rethink the basis for metal limits for low

metal materials……..

Sludge properties control

availability as metal content

declines

Sludge A is high metal and

requires soil limits

Sludge B is low metal and can

be applied indefinitely without

soil limits (a product limit would

apply)

Ma is the metal availability

threshold to protect sensitive

ecological processes

Tc is the total soil limit value to

protect sensitive ecological

processes for high metal sludge


Bio

availa

ble

meta

l conte

nt

in s

oil

Total soil concentration

Ma

Sludge A

Sludge B

Tc

PTE EoW Limits (mg kg-1 DS)


PTE PAS100/110 IPTS 2013

Zn 400 600

Cu 200 200

Ni 50 50

Cd 1.5 1.5

Pb 200 120

Cr 100 100

There is no rational basis to exclude

mixed input materials from EoW

criteria based on PTEs, but a more

rational basis is required for some

elements – Cu in particular

Is it to do with organic

contaminants?

This is probably the main source of

the uncertainty

What’s the problem?

• Over 50 million unique chemicals in CAS (Chemical Abstracts Service)

database

• 143,000 registered in industrial use in Europe

• Represent potential biosolids/OFMSW contaminants derived from

industrial, urban and domestic sources

• Environmental and health concerns:

• Toxicity, mutagenicity, carcinogenicity, endocrine disruption, developmental

toxins, ecotoxicity, antibiotic resistance

Types and Range of Potential OCs is Very Diverse

DEHP

B rx B ry

23

4

5 6 6' 5'

4'

3'2'

O

PBDE

PCNs

PFCs

17 -ethinyloestradiol

Synthetic Musks (Tonalide)

The Consensus View – Organic Contaminants

Lester, 1983

Overcash, 1983

Davis et al., 1984

Dean and Suess, 1985

Jacobs et al., 1987

Rogers 1987

O'Connor et al., 1991

Sweetman, 1991

Wild and Jones, 1991

USEPA, 1992

Chang et al., 1995

UKWIR, 1995

Smith, 1996

Carrington et al., 1998

Smith, 1999

ArthurAndersen, 2001

Erhardt and Prüeß, 2001

Water Env Assoc of Ontario, 2001

Smith and Riddel-Black, 2006

EC Joint Research Centre

•‘organic contaminants in

sludge are not expected to

pose major health problems to

the human population when

sludge is re-used for

agricultural purposes’

•‘it does not make much sense

to include PCDD/F, PCBs and

PAHs in routine monitoring

programmes’

Maximum OC Concentrations in Sewage Sludge for

Agriculture (mg kg-1 DS except PCDD/F: ng TEQ kg-1 DS)

AOX

DEHP LAS NP/NPE PAH PCB PCDD/F

EC (2000)a 500 100 2600 50 6b 0.8c 100

EC

(2003b)a

5000 450 6b 0.8c 100

Denmark 50 1300 10 3b

Sweden 50 3d 0.4c

Lower

Austria

500 0.2e 100

Germany 500 0.2e 100

France 9.5f 0.8cg

USA 300h Notes: a proposed but withdrawn and basis subject to review b sum of 9 congeners: acenapthene, fluorene, phenanthrene, fluoranthene, pyrene, benzo(b+j+k)fluoranthene, benzo(a)pyrene, benzo(ghi)perylene, indeno(1,2,3-c,d)pyrene. c sum of 7 congeners: PCB 28, 52, 101, 118, 138, 153, 180 d sum of 6 congeners e each of the 6 congeners: PCB 28, 52, 101, 138, 153, 180 f sum of 3 congeners: fluoranthene, benzofluoranthen(b), benzo(a)pyrene g for pasture the limit is 0.5 mg kg-1 DS h following detailed risk assessment US EPA final decision was not to regulate PCDD/Fs (US EPA, 2003)

IPTS proposed limit for ΣPAH16 in EoW

criteria for separated materials:

6 mg kg-1 DS

1 sample yr -1 up to 50000t then per 50000 t

(WHO limit in soil: 16 mg kg-1 as benzo-a-pyrene)

Rationale for Limit Values for PAHs in Sludge (and also

Compost/Digestate)

• The introduction of PAH (and other OC) limits is precautionary and not

technically based

• ‘Achievable’ values

• No European consensus

• Danish standards include a limit of 6mg/kg dm (based on the Σ9 congeners)

• France has limits for fluoranthene (4 mg/kg dm), benzo(b)fluoranthene (2.5

mg/kg dm) and benzo(a)pyrene (1.5 mg/kg dm)

• Germany in 2007 set a limit for benzo(a)pyrene of 1 mg/kg dm

• Outside of Europe there is general consensus that PAHs in sludge do

not pose a public health risk

• US EPA considered benzo(a)pyrene (amongst other organics) but concluded

that limit values were unnecessary

• The WHO concluded that ‘the total human intake of identified organic

pollutants from sludge application to land is minor and is unlikely to cause

adverse health effects’

• Australia and New Zealand have organic limits but do not regulate PAHs

Many countries have sewage sludge that would exceed

the European proposed limit

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000

ΣP

AH

μg

kg

-1 D

S

ΣPAHs in Source-separated Compost

n=26

n=2

n=6

n=7

n=29

n=15

n=30

n=3

n=1 n=6 n=60

n=4 n=14

n=78

n=3

0

2

4

6

8

10

12

mg

k

g-1

DS

Filled bars = median; open bars = mean

ΣPAHs in Greenwaste Compost

n=4 n=1 n=3

n=1

n=13

n=5 n=30 n=1

n=3 n=12

n=2 n=4

n=12

0

2

4

6

8

10

12

mg

k

g-1

DS


ΣPAHs in Mechanically Sorted MSW Compost

n=11

n=5

n=5

n=4

0

4

8

12

16

20

24

Luxembourg Guide Value

Germany 1992 (Kumer et al., 1992)

Germany 1993 (Fricke & Vogtmann et al., 1993)

Brazil 1998 (Grossi et al.,

1998)

USA 2001 (McGowin et

al., 2001)

France 2002 (Houot et al.,

2002)

Denmark 2003 (Moeller et al., 2003)

Poland 2007 (Oleszczuk et

al., 2007)

Australia 2008 (Hyder LTD, 2008)

mg

k

g-1

DS


Sewage Sludge Risk Assessment Framework

PAH Public Health Risk Assessment

• Exposure Pathways used ‘reasonable’ worst case scenarios

• Exposure assessments applied to adults and children separately

• Four Pathways examined:

Pathway 1 – Direct human consumption

Pathway 2 – Plant accumulation

Pathway 3 – Grazing animal accumulation

Pathway 4 – Drinking water contamination

• The ‘Pica’ condition was excluded

• 7 PAH congeners examined on the basis of available toxicological

information: naphthalene, acenaphthene, anthracene, fluorene,

fluoranthene, pyrene and benzo(a)pyrene

• For each exposure Pathway the key output was a safety derived

soil/sludge limit value for each congener

• Risk assessment undertaken using accepted international guidelines

Compounds

Pathway 1 – Direct human exposure

Child Adult

Naphthalene 3000 28000

Acenap h thene 9000 84000

Anthracene 45000 420000

Fluorene 6000 56000

Fluoranthene 6000 56000

Pyrene 4500 42000

Benzo(a) pyrene * *

PAH Risk Assessment

Pathway 1 – Direct human exposure (oral ingestion)

Safety derived soil/sludge limit values (mg kg-1 DS):

Key points:

• Mass of soil or sludge

amended soil needed to be ingested to reach Tolerable Daily Intake (TDI) is >1kg

• *benzo(a)pyrene [B(a)P]

cannot be derived as background soil levels exceed the safe limit value

PAH Risk Assessment

Pathway 2 – Plant accumulation

Safety derived soil/sludge limit values (mg kg-1 DS)

Compounds

Pathway 2 – Plant

accumulation

Child Adult

Naphthalene 4.4 17.8

Acenap h thene 19.9 79.7

Anthracene 145.0 5 80.2

Fluorene 15.0 60.1

Fluoranthene 25.5 102.3

Pyrene 17.0 68.2

Benzo(a) pyrene * *

Key points:

• Primary bio-transfer

mechanism via root vegetables

• Assessment assumed all intake from carrots grown on sludge amended soil

• *benzo(a)pyrene [B(a)P]

cannot be derived as background soil levels exceed the safe limit value

PAH Risk Assessment

Pathway 3 – Grazing animal accumulation

Safety derived soil/sludge limit values (mg kg-1 DS)

Compounds

Pathway 3 –

Animal accumulation

Grazing Dairy

Child Adult Child Adult

Naphthalene 176 147 157 131

Acenap h thene 466 388 396 330

Anthracene 2440 2034 1940 1617

Fluorene 309 257 257 214

Fluoranthene 385 321 287 240

Pyrene 265 22 1 203 170

Benzo(a) pyrene *

* * *

Key points:

• Primary bio-transfer

mechanism via pasture

• *benzo(a)pyrene [B(a)P] cannot be derived as background soil levels exceed the safe limit value

• *benzo(a)pyrene [B(a)P] cannot be derived as background soil levels exceed the safe limit value

PAH Risk Assessment Conclusions

• PAHs are typically strongly bound to the sludge-soil matrix resulting

in minimal plant uptake

• Therefore, transfer through the food chain from sludge-amended soil

is negligible

• Based on an understanding of the transfer mechanisms, the

uncertainties in the derivation of safety limits, and the strict controls

that already exist in the UK to restrict return periods, harvest and

grazing intervals, PAHs in sludge recycled to land do not pose an

unreasonable risk to public health and that any restrictions on the

basis of public health cannot be justified.

• There is no technical justification for PAHs

in EoW criteria!!!

IPTS argue that a PAH limit is justified

in EoW criteria for biodegradable

waste because ‘it is in line with

existing national legislation’

Page 135 IPTS (2013)

Limits on OCs in Compost in Different European Countries

Austria c

Denmark d Austrian

Fertiliser e

Luxembourg f

Switzerland Baden-

Württemberg g

AOX 500

DEHP 50

LAS 1300 h

NP/NPE 30

PAH a 6 3 3 10 4 6

PCB 1 0.2 0.1 0.2

PCDD/F b 50 20-50 20 20 17-22

OCPs 1

Remarks Limit values Guide values

a. Σ 16 PAHs defined by US EPA;

b. Σ 17 (2,3,7,8-chlorosubstituted PCDD/Fs);

c. Limit values for mixed MSW compost only;

d. Limit values for biowaste compost, 1 analysis per year;

e. Austrian Fertilizer Ordinance (1994);

f. Guide values for fresh and matured compost;

g. Composting Decree Baden-Württemberg (1994);

h. Danish Ministry of Environment and Energy (2000). This is mainly justified for sludge, in particular when stabilized

anaerobically;

i. The unit is mg kg-1 DS for all organic pollutants except PCDD/F: ng TEQ kg-1 DS.

• Anaerobic Digestion

• Composting

• MBT

• Pyrolysis

• Combustion

• Mineralisation

• Solubility

• Sorption

• Ecotoxicity

• Commercial

• Industrial

• Municipal

• Sludges and Biosolids

• Ecological Benefit

• Ecosystem Services

• Agronomic Benefit

Nutrients Fertiliser value

P resources N, S, trace elements

Climate Change Optimisation and

Sustainability

Wastes Variability Properties

Contaminants Nutrients Resources

Treatments

Nutrient/contaminant mass

balance

Pre/post treatment

Improved nutrient value

Soil

Mass balances

Microbiological

Ecological

Biochemical

Soil health

NERC RRfW Programme Recycling Nutrient Resources in Waste for Food Security and

Environmental Sustainability

Food Standards Agency Investigation of the Potential Transfer and Uptake of Contaminants into

Food Arising From The Use of Recycled Waste in Agriculture

setting criteria for eow for bioresources applied to land: the … · 2019-03-22 · setting...

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