Cheese whey (CW), a by-product of cheese manufacturing mainly containing lactose, proteins, lipids, mineral salts and exerting high biochemical and chemical oxygen demand, is considered a suitable candidate for both bio-H2 and bio-CH4 production via a double stage anaerobic digestion process. In the present study, an experimental campaign was performed on two CW samples of different origin, namely CW1 and CW2, with or without an external inoculum, at various operating pHs. With no inoculum addition, the highest final cumulative production of 81.6 Nl H2/kg TOCCW at pH = 7.5 and 166.4 Nl H2/kg TOCCW at pH = 6.5 was observed for CW1 and CW2, respectively. Bio-H2 production was significantly increased as a result of inoculum addition, with a yield of 233.4 Nl H2/kg TOCCW at pH = 6.0 when thermally pretreated activated sludge was mixed to CW2 at a CW2/AS ratio of 45/55 w/w. In the case of the double stage batch process for H2 and CH4 production, CW2 showed a final yield of ~155 NlH2/TOCCW and ~ 1170 Nl CH4/kg TOCCW, the latter being ~50% higher than the yield of conventional process. Under semi-continuous conditions, the double-stage digestion of CW1 led to a stable production of ~ 70 Nl H2/kg TOCCW and ~ 640 Nl CH4/kg TOCCW.
Combined H2 and CH4 production from cheese whey
DE GIOANNIS, GIORGIA;FRIARGIU, MARCO;MUNTONI, ALDO;SPIGA, DANIELA
2013-01-01
Abstract
Cheese whey (CW), a by-product of cheese manufacturing mainly containing lactose, proteins, lipids, mineral salts and exerting high biochemical and chemical oxygen demand, is considered a suitable candidate for both bio-H2 and bio-CH4 production via a double stage anaerobic digestion process. In the present study, an experimental campaign was performed on two CW samples of different origin, namely CW1 and CW2, with or without an external inoculum, at various operating pHs. With no inoculum addition, the highest final cumulative production of 81.6 Nl H2/kg TOCCW at pH = 7.5 and 166.4 Nl H2/kg TOCCW at pH = 6.5 was observed for CW1 and CW2, respectively. Bio-H2 production was significantly increased as a result of inoculum addition, with a yield of 233.4 Nl H2/kg TOCCW at pH = 6.0 when thermally pretreated activated sludge was mixed to CW2 at a CW2/AS ratio of 45/55 w/w. In the case of the double stage batch process for H2 and CH4 production, CW2 showed a final yield of ~155 NlH2/TOCCW and ~ 1170 Nl CH4/kg TOCCW, the latter being ~50% higher than the yield of conventional process. Under semi-continuous conditions, the double-stage digestion of CW1 led to a stable production of ~ 70 Nl H2/kg TOCCW and ~ 640 Nl CH4/kg TOCCW.
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
