Emerging Paradigms in Biosolids Management. Dr Bill Barber 15 th February 2013

Transcription

1 Emerging Paradigms in Biosolids Management Dr Bill Barber 15 th February 2013

2 TTDSA Biosolids Production Trend in Europe

3 1) Increasingly Strict Environmental Regulation Traditional wastewater treatment Primary Sludge

4 Stricter wastewater standards Secondary Treatment Primary Sludge Secondary Sludge

5 Nutrient removal Chemical Dosing Ferric alum Ferric alum Chemical Sludge Chemical Sludge

6 Wastewater treatment fundamentally influences the quantity and type of sludge produced and consequently biosolids treatment potential

7 Tightening standards also have other impacts

8 Tightening standards also have other impacts Fat Carbohydrate Protein Fibre

9 Tightening standards also have other impacts Batstone et al., (2011) water Lower biogas Stricter regulation

10 Overall Energy Balance between biogas and aeration requirements Biogas energy generated Aeration energy consumed

11 Overall Energy Balance between biogas and aeration requirements

12 2) Increasing and migrating populations

13 World-wide Biosolids Production

14 Sludge Processing Wastewater treatment Sludge Type Thickening Pre-treatment Mechanical ATAD Series Biological Acid Chemical TAD Thermal Liquid Thermal Other Digestion Pasteurisation Hydrolysis Anaerobic Digestion MAD Composting Liming Dewatering Drying Gasification Lime + Supp Heat Oil from Sludge Transport (Super Critical) Wet Air Oxidation with digestion without digestion Outlets

15 What else can you do with it?

16 Biosolids Outlets Environmental Drivers Wastewater Treatment Biosolids Production Removal of pathogens, organics, metals etc Biosolids Treatment Other Wastes Land Application Combustion Other Landfill Land Reclamation (Mine) Wet Stockpiling Forestry SC(WAO) Building aggregates Recycling Food crops Dry Monoincineration Resource recovery Protein extraction Non-food crops Co-firing Energy crops Power stations Factories

17 European Biosolids Outlets 50% 40% 30% % 10% 0% Land recycled Landfill Compost Incineration Hamburgers

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19 Land availability for biosolids use ESA SSSI National Parks Organically Managed Land Topography Water Courses NVZ PVZ Competition Supermarket pressures

20 Land availability for biosolids use

21 Biosolids in Europe in 2000 Poor knowledge of agricultural market E. Coli scare stories Contamination (heavy metal) Foot & mouth disease Recent closure in sea disposal External pressures Cheap energy

22 Biosolids in Europe in 2000 Solutions with LOW reliance on land application Thermal Drying Incineration Liming (intermediate measure) Landfill

23 Since 2001 A Biosolids Odyssey Avoid Minimise (Re)use Recycle Energy Recovery Landfill disposal

24 Dec - 81 Jun - 83 Dec - 84 Jun - 86 Dec - 87 Jun - 89 Dec - 90 Jun - 92 Dec - 93 Jun - 95 Dec - 96 Jun - 98 Dec - 99 Jun - 01 Dec - 02 Jun - 04 Dec - 05 Jun - 07 Dec - 08 Jun - 10 Dec - 11 Oil Price [$ US/barrel] Energy Price

25 Energy Security

26 Water Industry Advanced Anaerobic Digestion Ultrasonics High Pressure Shear Electric Pulse Chemical Lysis Medium Pressure Maceration Rapid Decompression Thermal Hydrolysis Acid Phase Biological Hydrolysis

27 Benefits of Advanced Digestion Higher biogas production Smaller Digestion Plants Greater Stability Better dewatering Reduced secondary emissions Advanced treated

28 Choice of pre-treatment technology is complex Type of Sludge and wastewater Foaming Pathogen Control Energy generation New Plant Retrofit Spare capacity Biogas Upgrading Dewatering Downstream Processing Liquor treatment Calorific value Costs Capital and operating Odours Carbon source Different sites will require different solutions...

29 Alternative uses for Biogas

30 Biogas yield of wastes relative to sewage sludge FOG, Brewery, Energy Crops Maize, cheese, glycerol, high energy food Molasses, sugar beet, low energy food, grasses, silage Animal mucks and manures, wheat straw

31 Calorific Value (GJ/kg) Calorific Value of Substances

32 Heilbronn Power Station

33 Holistic Energy Recovery from Biosolids Raw (no digestion) Energy recovered 1458 By Water Company 0%

34 Holistic Energy Recovery from Biosolids With anaerobic digestion Energy recovered 1566 By Water Company 48%

35 Holistic Energy Recovery from Biosolids With advanced digestion Energy recovered 1605 By Water Company 64%

36 Cost [$ US/t] Fertiliser Costs Phosphorus Super-phosphate 20% phosphate Super-phosphate 44-46% phosphate Diammonium phosphate ( ) Potassium chloride 60% potassium

37 Cost [$ US/t] Fertiliser Costs Nitrogen Anhydrous ammonia Nitrogen solutions (30%) Urea 44-46% nitrogen Ammonium nitrate

38 Supply Demand Phosphorous - World population increasing Becoming urbanized Changing food habits Global demand increased 4.7 million tones in 3 years (equivalent to USA consumption) kg P/person.year - Peak P predicted at 2035? years of easily mined P remain >70% of all reserves in Morocco China imposed P export tax (+110%)

39 Phosphorus Recovery Struvite Influenced by: Physical parameters WWTP configuration Digestion performance Reactive phosphorous NH 4 Mg PO 4 6H 2 O Aeration Savings

40 Nutrients Cost Effective Recovery? P recovery 1 P recovery 2 P recovery 3 N recovery 1 N recovery 2 Nutrient sales price Market place Chemical costs Site impacts Power costs Makes money $0 Costs money Nutrient recovery consumes large quantities of chemicals and energy..will this be sustainable in the future especially when compared to direct application of nutrients within biosolids?

41 Carbon footprint associated with biosolids/ww treatment CH 4 loss from digesters N 2 O generated from wastewater treatment Electricity for processing Gas for drying Polymer for dewatering Lime for processing Scope 1 Scope 2 Scope 3 Direct emissions Power consumption Other, supply chain Direct Cost Indirect Cost Indirect Cost

42 Influence of Biosolids on Carbon Footprint Carbon Impacts in Biosolids Scope 1 Scope 2 Scope 3 CO 2 e CO 2 e CO 2 e -CO 2 e N 2 O, CH 4 Emissions Power Chemicals Biogas WwTW

43 Influence of Biosolids on Carbon Footprint Carbon Impacts in Biosolids Scope 2 CO 2 e Power WwTW Transport (biosolids, compost) Outlet

44 Influence of Biosolids on Carbon Footprint Carbon Impacts in Biosolids Land Application Power Use - CO 2 e - CO 2 e Fertilizer Displacement Carbon sequestration Fossil Fuel Offset Transport Outlet

45 What is counted under current methodology Carbon Impacts in Biosolids Scope 1 Scope 2 Scope 3 Benefits Scope 2 Benefits CO 2 e CO 2 e CO 2 e CO 2 e CO 2 e CO 2 e Power Power Power WwTW Transport Outlet

46 Opportunities - Which could currently be recognized Energy from biogas produced by anaerobic digestion Low carbon fuel for burning - Potential (but not covered under regulation) Low carbon fertilizer - Other Carbon sequestration

47 Opportunities Biogas - Based on NGER methodology Every kwhr that biogas replaces natural gas reduces carbon footprint by kg CO 2 -e

48 Opportunities Biosolids Burning - Based on NGER methodology Every kwhr that biosolids replaces coal reduces carbon footprint by kg CO 2 -e

49 Opportunities Biosolids Burning 100 MW 280,000 t CO 2 e $6.41M

50 Opportunities Biosolids Burning 95 MW 265,000 t CO 2 e $6.09M Biosolids are worth $315k to the power station in reduced carbon taxes 5 MW You need <13,000 tdsa biosolids to generate 5 MW The biosolids are worth approx $25/tDS to the power station in carbon tax reductions

51 Opportunities Low Carbon Fertilizer - Fertilizers are large consumers of fossil fuels 1 kg N consumes 10 kwhr energy 1 kg P consumes 10 kwhr energy % VS 620 7% N 43.4 kg digested dry solids kg Volatile Solids Nitrogen is worth approx $50.00 kg Nitrogen 10 kwhr/kg N $12.00 $23.00/t CO 2 e kg CO 2 e/kwhr 434 Carbon tax savings t CO 2 e kwhr

52 Opportunities Low Carbon Fertilizer - Fertilizers are large consumers of fossil fuels 1 kg N consumes 10 kwhr energy 1 kg P consumes 10 kwhr energy % VS % P 9.3 kg digested dry solids kg Volatile Solids Phosphorous is worth approx $13.70 kg Phosphorous 10 kwhr/kg P $2.60 $23.00/t CO 2 e kg CO 2 e/kwhr 93 Carbon tax savings t CO 2 e kwhr

53 Carbon benefits of biosolids use Digestion of 1 tonne WAS Digestion of 1 tonne PS Direct fuel replacement (Raw dried) Direct fuel replacement (Dig dried) Carbon Sequestration Fertilizer Displacement (Limed) Fertilizer Displacement (Digested) Carbon benefit (t CO 2 -e/t biosolids used)

54 Biosolids in Europe in 2010 and beyond Improved management of contaminants Increase in energy price Renewable Energy Incentives Increase in fertilizer prices Codes of practice (SSM in UK) Increased awareness of sustainability Nutrient recovery

55 Biosolids in Europe in 2010 Solutions with LOW : energy requirements carbon footprints Solutions with HIGH: energy and nutrient recovery Advanced anaerobic digestion with land recycling Closure of dryers/incinerators Closure of liming systems Co-digestion Biogas upgrading Nutrient recovery

56 Conclusions

57 Thank you