Bio-electrochemical systems [BES] From power to value added chemicals production from wastewater

Transcription

1 Bio-electrochemical systems [BES] From power to value added chemicals production from wastewater Jurg Keller, Korneel Rabaey, Shelley Brown, Zhiguo Yuan Willy Verstraete, Ilse Forrez, Nico Boon Neptune workshop: Technical Solutions for Nutrient and Micropollutants Removal in WWTPs Université Laval, Québec, March 25-26, 2010

2 Outline MFC general Bio-Electrochemical Systmes The MFC component of the Neptune project Neptune workshop: Technical Solutions for Nutrient and Micropollutants Removal in WWTPs Université Laval, Québec, March 25-26, 2010

3 Anode Cathode How does an MFC work? Anode Membrane Cathode Organic Material CO 2 CO 2 Spent air Wastewater Effluent = Electrode (e.g., graphite) = Electrochemically active microorganisms = Cation exchange membrane = Electron = Proton = Air bubble Air (oxygen) 3

4 Anode Cathode Organic Material CO 2 CO 2 Spent air Wastewater Effluent H + e H - 2 OH + = Electrode (e.g., graphite) = Electrochemically active microorganisms = Cation exchange membrane = Electron = Proton = Air bubble O 2 Air (oxygen) 4

5 MFC/BES Novel? Proc. R. Soc. London Ser. B 1911, 84, Neptune workshop: Technical Solutions for Nutrient and Micropollutants Removal in WWTPs Université Laval, Québec, March 25-26, 2010

6 Yatala Pilot Plant World s first MFC pilot plant (a collaboration between the (AWMC) our Neptune partner LabMet, Ghent University (Belgium)). 1m 3 plant, which was started up in Sept Results thus far: * Cell current of 2A (400mV set point voltage) * COD removal of 0.2 kgcodm 3 d -1 as current * Power densities of 0.5 Wm -2 (membrane area) and 8.5 Wm -3 (reactor volume). Neptune workshop: Technical Solutions for Nutrient and Micropollutants Removal in WWTPs Université Laval, Québec, March 25-26, 2010

7 Product value per m 3 (@ 1000 A/m 3 ) - Electricity: ~$1/day - Methane: ~$1/day

8 Bio-Electrochemical Systems Sustainable value from wastewater Wastewater

9 Product value per m 3 (@ 1000 A/m 3 ) - Electricity: ~$1/day - Methane: ~$1/day - Hydrogen: ~$5/day - Hydrogen peroxide: ~$20/day - Sodium hydroxide: ~$30/day - Mix NaOH/H 2 O 2 ~$50/day - 1,3 Propanediol ~$40/day Excluding electricity costs ($1-3/day)!

10 Economic Implications Standard Module Size ~ 1 m 3 Module price $25,000 Wastewater 1-100m 3 /day Wastewater (with reduced organic content) $1/day Electricity Input Caustic soda / Hydrogen peroxide Korneel Rabaey, René Rozendal $ ,000/year

11 Microbial electrolysis cell Anode Cathode Organic Material Power Supply CO 2 CO 2 Spent air Wastewater = Electrode (e.g., graphite) = Electrochemically active microorganisms = Cation exchange membrane = Electron Effluent = Proton = Air bubble René Rozendal Air (oxygen) 12

12 Microbial electrolysis cell Anode Cathode Organic Material Power Supply CO 2 CO 2 H 2 Wastewater Effluent H + H 2 = Electrode (e.g., graphite) = Electrochemically active microorganisms = Cation exchange membrane = Electron = Proton = H 2 bubble René Rozendal 13 1

13 Sulfide Removal in Electrochemical Cell e- C + Treated water S 0 C + H 2 O C + C + Wastewater H - 2 S/HS - O 2 C + ANODE CATHODE, Na + Paritam Dutta

14 % Sulfide-S Removal Concentration of Sulfide-S ( mg L -1 ) Continuous sulfide removal from paper mill wastewater 100 Side 1 Side 2 Influent Effluent No of Days 0 Paritam Dutta

15 Sulfide Removal in Electrochemical Cell e- C + Treated water S 0 C + H 2 O C + C + Wastewater H - 2 S/HS - O 2 C + ANODE CATHODE, Na + Paritam Dutta

16 % Sulfide-S Removal Concentration of Sulfide-S ( mg L -1 ) Continuous sulfide removal from paper mill wastewater 100 Side 1 Side 2 Influent Effluent No of Days 0 Paritam Dutta

17 Before deposition of sulfur after deposition of sulfur after regeneration Sulfide / Polysulfide Paritam Dutta

18 kwh/kg O 2 /H 2 Nitrate Reduction in Bioelectrochemical System COD/H 2 COD/NO Ω NO O 2 N 2 H 2 O CO 2 H 2 N 2 NO 3 - Anode Cathode COD NO 3 - Bernardino Virdis

19 Loop MFC system with external nitrification mg COD L mg NH 4 -N L -1 0 mg NO 3 -N L -1 ph 7 0 COD L mg NH 4 -N L mg NO 3 -N L -1 ph 7 NH mg COD L mg NH 4 -N L -1 0 mg NO 3 -N L -1 ph COD L mg NH 4 -N L mg NO 3 -N L -1 ph 6.5 Power output W m -3 C removal % N removal % COD/N g g Virdis et al. (2008) Water Research

20 Loop MFC system with in-situ nitrification mg COD L mg NH 4 -N L -1 0 mg NO 3 -N L -1 ph COD L mg NH 4 -N L mg NO 3 -N L -1 ph mg COD L mg NH 4 -N L -1 0 mg NO 3 -N L -1 ph 6.6 Power output C removal % N removal % COD/N g g -1 W m ± Virdis et al. in preparation

21 Project Neptune Focus is on the opportunity to use biosolids as an energy source so capture electrons that result from the oxidisation of sludge-cod at the anode of a BES Neptune workshop: Technical Solutions for Nutrient and Micropollutants Removal in WWTPs Université Laval, Québec, March 25-26, 2010

22 Biosolids: solid byproducts produced by sewage treatment processes. A burden for WWTPs: handling and disposing of biosolids is a cost and causes long term GHG emissions if disposed of in landfills. We see biosolids as a high volume, renewable carbon and energy source. Objectives: 1: Quantify energy (electricity) generation when running an MFC on hydrolysed biosolids. 2: Identify factors limiting efficiencies. Neptune workshop: Technical Solutions for Nutrient and Micropollutants Removal in WWTPs Université Laval, Québec, March 25-26, 2010

23 Fermenter effluent 0.2% 9.6% 9.1% 25.4% 9.7% acetic acid propionic acid iso-butyric acid butyric acid iso-valeric acid 10.4% 35.6% valeric acid hexanoic acid VFA [mg/l] ph Κ [ms] Infl Effl Optimal: one day HRT and control ph [solids contribution minimal] Neptune workshop: Technical Solutions for Nutrient and Micropollutants Removal in WWTPs Université Laval, Québec, March 25-26, 2010

24 ph Operating a MFC with real fermented hydrolysed biosolids FINDINGS Load ~ 350mg VFA/L = 2.6gCOD-VFA/L.d -300mV vs Ag/AgCl NOT GREAT PERFORMANCE COMPARED TO OPERATION WITH SYNTHETIC SUBSTRATE! Am WHY? load 2.6gCOD/L load 4.2 gcod/l load 5.2 gcod/l load 8.5 gcod/l load 8.5 gcod/l extra buffer fermenter effluent volume added in ml Neptune workshop: Technical Solutions for Nutrient and Micropollutants Removal in WWTPs Université Laval, Québec, March 25-26, 2010

25 Operating a MFC with real fermented hydrolysed biosolids FINDINGS Load ~ 350mg VFA/L = 2.6gCOD-VFA/L.d -300mV vs Ag/AgCl Am -3 run 1 = 1/3 ferm.eff + 2/3 MQ run 2 = 1/3 ferm.eff + 2/3 MQ + phosphate buffer run 3 = 1/3 ferm.eff + 2/3 MQ + NaCl/KCl mix Neptune workshop: Technical Solutions for Nutrient and Micropollutants Removal in WWTPs Université Laval, Québec, March 25-26, 2010

26 Operating a MFC with real fermented hydrolysed biosolids FINDINGS Run Set-point potential of -300mV vs Ag/AgCl VFA [mg/l] MFC effluent ph Current density [Am -3 ] Coulombic Efficiency {COD-VFA} [%] Syn Synthetic sample /3 ferm.eff + 2/3 syn buffer /3 ferm.eff + 2/3 AD effluent /2 ferm.eff + 1/2 AD effluent /4 ferm.eff + 1/4 AD effluent Neptune workshop: Technical Solutions for Nutrient and Micropollutants Removal in WWTPs Université Laval, Québec, March 25-26, 2010

27 Integrating concept into WWTP Next step is to figure out what to do at the cathode energy or value-added products?

28 Australian project work was funded through International Science Linkages scheme of DIISR This study was part of the EU Neptune project (Contract No , SUSTDEV II.3.2), which was financially supported by grants obtained from the EU Commission within the Energy, Global Change and Ecosystems Program of the Sixth Framework (FP Global-4) Project teams at AWMC, UQ and LabMet, UGent Neptune workshop: Technical Solutions for Nutrient and Micropollutants Removal in WWTPs Université Laval, Québec, March 25-26, 2010

29 6th International Conference on Sewer Processes and Networks 7-10 November 2010 Surfers Paradise, Gold Coast, Australia FULL PAPER OR EXTENDED ABSTRACTS DUE 3 MAY 2010