High Dry Solids Dewatering of THP Digested Sludge Thames Water s Plans and Opportunities

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1 High Dry Solids Dewatering of THP Digested Sludge Thames Water s Plans and Opportunities Authors: Paul Fountain, Thames Water Aurelian Perrault, Thames Water Nick Mills, Thames Water Garry Strange, Thames Water 18 th BioSolids Conference 18 th to 20 th November 2013

2 High Dry Solids Dewatering

3 Dry Solids (%) Performances with THP Sludge Chertsey Sludge 25 th July 13 th August Details Final cake DS: 43 to 45% Amount of: 1,200m 3 of Sludge Throughput: 0.5tDS/h Poly consumption: 10 to 12 kg/tds 0 0:00 0:30 1:00 1:30 2:00 Run Time (minutes)

4 Chertsey THP Digested

5 Chertsey THP Digested

6 Dewatering % Dry Solids Bucher Press Dewatering Performance 50% 18 Sludges tested by Thames Water across the range of sludges Bucher Dewatering 45% 40% 35% 30% 25% 20% Probably sample w as not representative 30% more water released 15% 10% 5% 0% High SAS Poor Conv Digest Good Conv Digest Advanced Digestion Undigested TW Conventional Dewatering TW Bucher Testing Chertsey Test THP Chertsey Test Oxford Bucher European Results Series6

7 So how does it stack up financially? Belt Press 250k per press 15k maintenance per year 5 ton weight Painted mild steel Bucher Press 750k per press 25k maintenance per year 25 ton weight per press All parts in contract with sludge are stainless steel Doesn t look good for High Dry Solids Dewatering

8 The Business Case Thames Water - Bucher Press vs Belt Press 20 Year Whole Life Cost 40,000,000 35,000,000 30,000,000 25,000,000 20,000,000 Capex Dewatering 15,000,000 10,000,000 5,000, Belts Bucher Long Reach

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10 The Business Case Thames Water - Bucher Press vs Belt Press 20 Year Whole Life Cost 40,000,000 35,000,000 30,000,000 25,000,000 Capex Storage 20,000,000 15,000,000 Capex Dewatering 10,000,000 5,000, Belts Bucher Long Reach

11 The Business Case Thames Water - Bucher Press vs Belt Press 20 Year Whole Life Cost 6.07 million NPV Savings 40,000,000 35,000,000 30,000,000 25,000,000 20,000,000 15,000,000 10,000,000 Opex Transport Opex Polymer Opex Maintenance Capex Storage Capex Dewatering 5,000, Belts Bucher Long Reach 11

12 Whole Life Cost (20 years) The Business Case Sensitivity Analysis Beckton - Crossness - Belts vs Bucher 120,000, ,000,000 80,000,000 60,000,000 40,000,000 20,000, % 28% 32% 36% 38.5% 40.0% 41.5% 44% Belts Bucher Bucher Bucher Bucher Bucher Bucher Bucher

13 The Business Case Thames Water - Bucher Press vs Belt Press 20 Year Whole Life Cost Expected Position Combined NPV Savings 41.7 million 100,000,000 90,000, million NPV Savings 6.07 million NPV Savings 1.13 million NPV Savings 80,000,000 70,000,000 60,000,000 50,000,000 40,000,000 30,000,000 Opex Transport Opex Polymer Opex Maintenance Capex Rye Meads Capex Storage Capex Dewatering 20,000,000 10,000,000 0 Belts 1 Bucher 2 Belts 3 Bucher 4 Belts 5 Bucher 6 Beckton / Crossness Long Reach Oxford 13

14 Thames Water Investment within Amp5 Site Number Contractor Sludge Status Oxford 4 machines Kier THP Veolia Biothelys Crossness 5 machines Tamesis (Imtech) THP Cambi 1 installed + 3 being installed being installed Beckton 5 machines Tamesis (Imtech) THP Cambi being installed Long Reach 5 machines AECom THP SAS Only Compact Cambi Year 5 of Amp5

15 Thames Water Investment within Amp5 Bucher presses currently going into Crossness

16 Dewatering % Dry Solids Bucher Press Dewatering Performance 50% 18 Sludges tested by Thames Water across the range of sludges Bucher Dewatering 45% 40% 35% 30% 25% 20% Probably sample w as not representative 30% more water released 15% 10% 5% 0% High SAS Poor Conv Digest Good Conv Digest Advanced Digestion Undigested TW Conventional Dewatering TW Bucher Testing Chertsey Test THP Chertsey Test Oxford Bucher European Results Series6

17 Thames Water Sludge Strategy Thames Water is finding it appears always better to digester using the most advanced and cost effective technology possible, and then look at what can be done with the biosolids remaining.

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20 Thames Water Sludge Powered Generators

21 Thames Water Sludge Powered Generators per wet ton feed Current Fuel Raw Cake THP Digested Cake (Equiv) THP Digested Expected Calorific Value of cake 20 MJ/kg 14 MJ/kg 14 MJ/kg Gross heat input to SPG 1,667 kw 1,611 kw 1,865 kw Dry solids of cake 30% 38% 45% Moisture per wet ton feed 700 kg 620 kg 620 kg Heat required to evaporate water 534 kw 478 kw 478 kw Net energy input to SPG 1,132 kw 1,132 kw 1,425 kw 25% increase

22 Thames Water Sludge Powered Generators per wet ton feed Current Fuel Raw Cake THP Digested Cake (Equiv) THP Digested Expected Calorific Value of cake 20 MJ/kg 14 MJ/kg 14 MJ/kg Gross heat input to SPG 1,667 kw 1,611 kw 1,865 kw Dry solids of cake 30% 38% 45% Moisture per wet ton feed 700 kg 620 kg 620 kg Heat required to evaporate water 534 kw 478 kw 478 kw Net energy input to SPG 1,132 kw 1,132 kw 1,425 kw 25% increase

23 Thames Water Sludge Powered Generators per wet ton feed Current Fuel Raw Cake THP Digested Cake (Equiv) THP Digested Expected Calorific Value of cake 20 MJ/kg 14 MJ/kg 14 MJ/kg Gross heat input to SPG 1,667 kw 1,611 kw 1,865 kw Dry solids of cake 30% 38% 45% Moisture per wet ton feed 700 kg 620 kg 620 kg Heat required to evaporate water 534 kw 478 kw 478 kw Net energy input to SPG 1,132 kw 1,132 kw 1,425 kw 25% increase

24 Thames Water Sludge Powered Generators per wet ton feed Current Fuel Raw Cake THP Digested Cake (Equiv) THP Digested Expected Calorific Value of cake 20 MJ/kg 14 MJ/kg 14 MJ/kg Gross heat input to SPG 1,667 kw 1,611 kw 1,865 kw Dry solids of cake 30% 38% 45% Moisture per wet ton feed 700 kg 620 kg 620 kg Heat required to evaporate water 534 kw 478 kw 478 kw Net energy input to SPG 1,132 kw 1,132 kw 1,425 kw 25% increase

25 Future opportunities Advanced Energy Recovery 30%DS 45%DS water content halved (per TDS) Sustainable Thermal Drying Low grade waste heat Belt dryers

26 Future opportunities Advanced Energy Recovery Pyrolysis or Gasification High DS feed (95%DS) from dryer Syngas to CHP 2 x Electrical energy output