The integration of a methane-producing microbial electrolysis cell (MEC) into two-phase anaerobic digestion (TP-AD) was investigated, by using effluents from a pilot-scale TP-AD treating the organic fraction of municipal solid waste. The MEC was aimed at exploiting residual COD of TP-AD effluents at the MEC anode in order to support CO2 removal and methane generation at the MEC cathode (fed by a CO2-rich gas phase, simulating a biogas). Feeding by 2nd phase digestate caused a loss of MEC performance, due to poor biodegradability of digestate COD under chosen anodic operating conditions (+0.2 V vs SHE, HRT 13 h, organic load 2.3 g COD/L d). On the other hand, by using the 1st phase fermentate (rich in volatile fatty acids, VFA), good MEC performance was recovered with a current of 60 +/- 4 mA and a methane production rate of 33 +/- 3 meq/L d. However, periodic baskwashing was also necessary to recover fouling effects. Moreover, partial nitrogen removal (228 mg N/L d) from the fermentate was obtained because ammonium was transported across the separation membrane and then recovered through the cathodic concentrated spill (at 3177 +/- 97 mg N/L). Cation transport also generated net alkalinity which strongly contributed to CO2 removal (besides methane generation). (C) 2017 Elsevier B.V. All rights reserved.

Using effluents from two-phase anaerobic digestion to feed a methane-producing microbial electrolysis

M. Gottardo;F. Micolucci;M. Villano;M. Majone
2017-01-01

Abstract

The integration of a methane-producing microbial electrolysis cell (MEC) into two-phase anaerobic digestion (TP-AD) was investigated, by using effluents from a pilot-scale TP-AD treating the organic fraction of municipal solid waste. The MEC was aimed at exploiting residual COD of TP-AD effluents at the MEC anode in order to support CO2 removal and methane generation at the MEC cathode (fed by a CO2-rich gas phase, simulating a biogas). Feeding by 2nd phase digestate caused a loss of MEC performance, due to poor biodegradability of digestate COD under chosen anodic operating conditions (+0.2 V vs SHE, HRT 13 h, organic load 2.3 g COD/L d). On the other hand, by using the 1st phase fermentate (rich in volatile fatty acids, VFA), good MEC performance was recovered with a current of 60 +/- 4 mA and a methane production rate of 33 +/- 3 meq/L d. However, periodic baskwashing was also necessary to recover fouling effects. Moreover, partial nitrogen removal (228 mg N/L d) from the fermentate was obtained because ammonium was transported across the separation membrane and then recovered through the cathodic concentrated spill (at 3177 +/- 97 mg N/L). Cation transport also generated net alkalinity which strongly contributed to CO2 removal (besides methane generation). (C) 2017 Elsevier B.V. All rights reserved.
File in questo prodotto:
File Dimensione Formato  
2017b.pdf

Open Access dal 13/07/2019

Tipologia: Versione dell'editore
Licenza: Accesso libero (no vincoli)
Dimensione 861.18 kB
Formato Adobe PDF
861.18 kB Adobe PDF Visualizza/Apri

I documenti in ARCA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10278/5022960
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 23
  • ???jsp.display-item.citation.isi??? 20
social impact