Sludge Recycling in Europe

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Lewis Sydney Higgins
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1 Sludge Recycling in Europe Professor Stephen R Smith Head of Environmental and Water Resource Engineering Department of Civil and Environmental Engineering Tel +44 (0) ; s.r.smith@imperial.ac.uk

2 Sludge Production in the EU Page 2 Imperial College London

Principal Management Routes for Sludge http://ec.europa.eu/eurostat/statisticsexplained/index.

3 Principal Management Routes for Sludge n_wastewater_treatment,_by_type_of_treatment,_2013_(%c2 %B9)_(%25_of_total_mass)_YB16.png#file

4 Overall Sludge Management Routes in Europe, % 25.2% 49.2% Agriculture Composting Incineration Landfill 14.2% Total sludge production = M t Total sludge managed = Mt (Source: Eurostat)

5 Main Management Outlets and Trends for Sludge UK Europe UK Europe UK & Europe UK & Europe X Page 5 Imperial College London

6 Agricultural Recycling is Usually the BPEO End of Waste could also offer new potential markets and opportunities for recycling sludge products to land Page 6 Imperial College London

7 Potentially Toxic Elements and Pathogens Imperial Page 7 College London

8 DEHP PFCs 17 α-ethinyloestradiol 3 2 PBDE 2' 3' 4 O 4' Br x PCNs 5 6 6' 5' Br y Synthetic Musks (Tonalide) Page 8 Imperial College London

9 Sludge Quality - Dioxin Total TEQ (ng kg -1 DS) USEPA proposed Archived sludge samples - Mogden STWs EU proposed UK Poultry Litter Ash Page 9 Year Imperial College London

10 Emerging Contaminants SMITH, S.R. (2009) Organic contaminants in sewage sludge (biosolids) and their significance for agricultural recycling. Philosophical Transactions of the Royal Society A 367, CLARKE, B.O. AND SMITH, S.R. (2011) Review of emerging organic contaminants in biosolids and assessment of international research priorities for the agricultural use of biosolids. Environment International 37, Long-term vigilance Assessment, monitoring and research Empirical measurements Concentrations, fate and impacts Emerging POPs: Polychlorinated alkanes (PCAs) Perfluorinated compounds (PFCs) Base limits on evidence and risk assessment Page 10 Imperial College London

11 Organic Contaminants Transfer to the Food Chain

The potential transfer of organic contaminants to food arising from the use of biosolids and other recycled wastes as nutrient sources in agriculture H. Rigby, S. Acker, A.

12 The potential transfer of organic contaminants to food arising from the use of biosolids and other recycled wastes as nutrient sources in agriculture H. Rigby, S. Acker, A. Dowding, A. Fernandes, D. Humphries, S. Petch, R. Rautiu, C.K. Reynolds, M. Rose, S.R. Smith ESPP workshop on organic contaminants in sewage biosolids, Malmo, Thursday 27 th October 2016

13 Experimental Design Dairy ingestion trials under controlled conditions wastes spread to land Crop trials controlled growth chamber studies with barley and carrots; field investigation with winter wheat 13

14 Polychlorinated dibenzo-p-dioxins/dibenzonfurans (PCDD/Fs) and polybrominated dibenzo-p-dioxins/dibenzofurans (PBDDs) EC: European Commission (2003) Proposal for a Directive of the European Parliament and of the Council on spreading of sludge on land. 30 April Brussels, Belgium: European Commission. 14

15 Preliminary Results Dairy Cattle Trials Organic contaminant in milk according to waste types - PCDD/Fs as an example Average PCDD/Fs congener concentrations in milk of week 3 in Study II (fat weight basis, significance is determined by Kruskal-Wallis) congeners and TEQ showed significant differences (P < 0.05) between the control and biosolids group, while there were no significant differences between control and the other two treatment groups.

16 Biosolids Management in the UK, Total sludge production = M t Page 16 Imperial College London

17 Biosolids Nitrogen Fertiliser Value Page 17 Imperial College London Mineral N response: y = 0.56x r 2 = 0.54

18 Nitrogen Mass Balance of Conventional WWT and Sludge Anaerobic Digestion 180,000 t/y N to UK WWTP equivalent to 1,440 GWh (1.4 TWh)

fertiliser = 1,400/t of P 180,000 t N/y ~ 18% of N fertiliser 60,000 t P/y ~ 70% of

19 UK N and P Fertiliser Use and Mass Flow through WW 1.0 million t N/y N fertiliser 82,000 t P/y P fertiliser N fertiliser = 800/t of N P fertiliser = 1,400/t of P 180,000 t N/y ~ 18% of N fertiliser 60,000 t P/y ~ 70% of P fertiliser Dependency on P fertiliser imports could be significantly reduced to sustain food production in the UK

20 Rethinking the Process to Maximise N recovery

21 Biopolymers Polyhydroxyalkanoates (PHAs) Polyhydroxybutyrate PHB

Recovery of Industrial Enzymes Global market of 2.

sludge Extracted by a combination of non-ionic detergent

Proteases constitute more than 65% of the global industrial

range of bioconversion reactions Dairy, oleochemical (eg

22 Recovery of Industrial Enzymes Global market of 2.6 billion Protease and lipase are major enzymes in activated sludge Extracted by a combination of non-ionic detergent and/or cation exchange resin treatments and agitation Proteases constitute more than 65% of the global industrial enzyme market Lipases are versatile enzymes applied in a range of bioconversion reactions Dairy, oleochemical (eg biodiesel), detergent, pulp, pharmaceutical, cosmetic, leather, textile, detergent industries

23 Conclusions The available outlets for sludge are limited to land application, incineration with landfill disposal of residual ash and direct landfill disposal There is wide variation in these sludge management practices between European countries On average, about 65% of sludge in Europe is recycled to land The environmental controls on and benefits of agricultural use are well established and it is usually the BPEO for sludge management **HOWEVER** The limited range of outlets for sludge suggests a lack of resilience in sludge management systems Increasing resource recovery in wastewater and sludge treatment: Reduces dependency on current sludge management routes Increases resilience, revenues, and overall resource, economic and environmental sustainability It can also reduce wastewater treatment process energy consumption Many opportunities exist for resource recovery and value addition including: nutrients, bioenzymes, biopolymers, biopesticides, alginates, adsorbents, VFAs

Flame retardants in wastes recycled in agriculture and the potential for transfer to the food chain

Flame retardants in wastes recycled in agriculture and the potential for transfer to the food chain Hannah Rigby 1*, Sophia Acker 1, Alan Dowding 2, Alwyn Fernandes 3, David Humphries 4, Rupert G. Petch