HERAKLION 2019 International Conference on Sustainable Solid Waste - PowerPoint PPT Presentation

HERAKLION 2019 International Conference on Sustainable Solid Waste Management 26 – 29 June 2019 Performance comparison between mesophilic and thermophilic anaerobic digestion processes carried out on waste activated sludge A. Cerutti 1 , G. Campo 1 , M.C. Zanetti 1 , G. Scibilia 2 , E. Lorenzi 2 , B. Ruffjno 1 1 Department Environment, Land and Infrastructure Engineering, Politecnico di T orino, T orino, I-10129, Italy 2 Research Center, Società Metropolitana Acque T orino S.p.A., Viale Maestri del Lavoro, 4 – 10127 T orino, Italy

http://www.cambi.com 2 STRATEGIES Waste Activated Pre / intermediate Sludge MESOPHILIC tretments AD Extracellular Polymeric Bacteri Substance a (EPS) Dark- Glowing color brown color from Shana et al., 2015 Low degradability ▼ Low effjciency of the AD process • Low dewaterability

http://www.cambi.com 2 STRATEGIES Waste Activated Pre / intermediate Sludge MESOPHILIC tretments AD Extracellular Polymeric Bacteri Substance a (EPS) Dark- Glowing color brown color from Shana et al., 2015 ? Low degradability ▼ THERMOPHILIC Low effjciency of the AD process • Low dewaterability AD

In this presentation: MODELING PHASE EXPERIMENTAL PHASE Simplifjed Anaerobic Digestion Model 1 (ADM1) Calibratio Mesophilic AD of WAS in a 300L CSTR n Validatio n Calibratio Thermophilic AD of WAS in a 44L CSTR n Thermophilic AD of WAS in a 300L Validatio CSTR n

In this presentation: MODELING PHASE EXPERIMENTAL PHASE Simplifjed Anaerobic Digestion Model 1 (ADM1) Calibratio Mesophilic AD of WAS in a 300L CSTR n Validatio n Calibratio Thermophilic AD of WAS in a 44L CSTR n Thermophilic AD of WAS in a 300L Validatio CSTR n k: fjrst order kinetics Mesophilic cond. costant [ 1/d ] WA B 0 : biomethane S Thermophilic cond. potential [ Nm 3 /kgVS ]

Experimental MESOPHILIC THERMOPHILIC phase CONDITION 38°C, CONDITION 55°C, HRT HRT 20 d 20 d Pre-thickened WAS (TS, VS, pH, FOS / TAC) 5 days / week Biogas 300 L (CH 4 , CO 2 , O 2 , C.S.T.R. Bal.) 5 days / week Digestate (TS, VS, pH, FOS / TAC) 5 days / week

Experimental MESOPHILIC THERMOPHILIC phase CONDITION 38°C, CONDITION 55°C, HRT HRT 20 d 20 d Pre-thickened WAS (TS, VS, pH, FOS / TAC) 5 days / week 44 L C.S.T.R. Biogas 300 L (CH 4 , CO 2 , O 2 , C.S.T.R. Bal.) 5 days / week Digestate (TS, VS, pH, FOS / TAC) 5 days / week

Experimental MESOPHILIC THERMOPHILIC phase CONDITION 38°C, CONDITION 55°C, HRT HRT 20 d 20 d Pre-thickened WAS (TS, VS, pH, FOS / TAC) 5 days / week 44 L C.S.T.R. Biogas 300 L (CH 4 , CO 2 , O 2 , C.S.T.R. Bal.) 5 days / week 300 L C.S.T.R. Digestate (TS, VS, pH, FOS / TAC) 5 days / week

Castiglione T orinese SMAT WWTP 2,300,000 e.p. Thermophilic digesters Sludge line: from pre- thickeners to digesters Static pre-thickener Thermophilic inoculum WAS sample Thickened from 2,5 to 3% TS Mesophilic inoculum

Industrial design Experiment (optimal HRT) al phase B exp , VS exp removal Modeling phase k, B 0 naerobic Digestion Model 1 (ADM1) (Batstone DJ. et al., 2002) ying hypothesis: olysis is assumed to be the limiting step of AD  methane production can be modelled through a fjrst order k

CSTR Digester Biogas VS b VS TOT VS b VS nb VS nb NVS NVS

CSTR Digester Biogas VS b VS TOT VS b Y VS nb VS nb NVS NVS

CALIBRATION Daily VS concentration 14 kg VS / m3 13 12 11 THERMOPHILIC WAS AD 10 44 L CSTReactor 9 57 days AD 8 29 alimentations 7 6 0 5 10 15 20 25 30 35 40 45 50 55 60 Days

CALIBRATION Daily VS concentration Model Experimental 14 kg VS / m3 13 THERMOPHILIC WAS AD 12 11 K = 0,380 1/d 10 9 Y = 42 % 8 B O = 0,218 7 Nm 3 /kg VS 6 0 5 10 15 20 25 30 35 40 45 50 55 60 Days

VALIDATION THERMOPHILIC WAS Cumulative methane production Model WAS AD 12,00 K = 0,380 1/d 10,00 Y = 42 % B O = 0,218 8,00 Nm 3 /kg VS Nm3 6,00 THERMOPHILIC 4,00 WAS AD 300 L CSTReactor 2,00 58 days AD 35 alimentations 0,00 0 12 24 36 48 60 Days

VALIDATION THERMOPHILIC WAS Cumulative methane production Model Experimental WAS AD 1,40 K = 0,380 1/d 1,20 Y = 42 % B O = 0,218 1,00 Nm 3 /kg VS Nm3 0,80 0,60 THERMOPHILIC WAS AD 0,40 300 L CSTReactor Error < 1% 0,20 58 days AD 35 alimentations 0,00 0 12 24 36 48 60 Days

CST Reactor Steady state condition B 20d = 0,193 Nm 3 /kg VS 1 stage HRT =20 A.D. d B 10+10d = 0,209 Nm 3 /kg VS 2 stage HRT =10 HRT =10 A.D. d d

WAS A.D. in WWTP Castiglione Torinese Present conditions WAS Mesophilic AD 38 °C K = 0,085 1/d B O = 0,147 Nm 3 /kg VS B 20d = 0,090 Nm 3 /kg VS

WAS A.D. in WWTP Castiglione Torinese Present conditions Scenario 1 WAS WAS Thermophilic AD 55 °C Mesophilic AD 38 °C K = 0,380 1/d + 347 K = 0,085 1/d % B O = 0,147 Nm 3 /kg B O = 0,218 Nm 3 /kg VS VS B 20d = 0,193 B 20d = 0,090 Nm 3 /kg VS Nm 3 /kg VS + 108 %

WAS A.D. in WWTP Castiglione Torinese Present conditions Scenario 1 Scenario 2 WAS WAS WAS O Thermophilic AD 55 °C Pretreatment + AD 38°C Mesophilic AD 38 °C R K = 0,380 1/d R NaOH 4g/100g TS + 347 K = 0,085 1/d O + % B O = 0,147 Nm 3 /kg 90 °C, 1,5h M W B O = 0,218 Nm 3 /kg VS O VS T B 20d = 0,193 B 20d = 0,226 B 20d = 0,090 Nm 3 /kg VS Nm 3 /kg VS Nm 3 /kg VS + 108 + 144 % %

Conclusio ns • The WAS AD in thermophilic condition improved the biochemical methane potential by 50 % related to the mesophilic condition; • The raw WAS was only slowly biodegradable (k =0.085 d -1 ) but the thermophilic condition increased the hydrolysis constant by 347 %; • Due to the thermophilic condition; the WAS biodegradability rose from 28 to 42 %, with an increase of 50 %; • In steady state condition with HRT equal to 20 days, the specifjc methane production increase in the order of 108 % related to the mesophilic condition.

HERAKLION 2019 International Conference on Sustainable Solid Waste Management 26 – 29 June 2019 Performance comparison between mesophilic and thermophilic anaerobic digestion processes carried out on waste activated sludge Thank you for your attention! A. Cerutti 1 , G. Campo 1 , M.C. Zanetti 1 , G. Scibilia 2 , E. Lorenzi 2 , B. Ruffjno 1 alberto.cerutti@polito.it http://www.wearwe.polito.it 1 Department Environment, Land and Infrastructure Engineering, Politecnico di T orino, T orino, I-10129, Italy 2 Research Center, Società Metropolitana Acque T orino S.p.A., Viale Maestri del Lavoro, 4 – 10127 T orino, Italy