Batch and semi-continuous anaerobic digestion of cheese whey for combined H2 and CH4 production

DE GIOANNIS, GIORGIA;FRIARGIU, MARCO;Massi E;MUNTONI, ALDO;Polettini A;Pomi R;Spiga D.

2014-01-01

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Abstract

An experimental campaign was performed on cheese whey (CW), a by-product of cheese manufacturing, in order to biologically treat the residual fraction of CW that cannot be used for other applications. In the present paper, the results of batch and semi-continuous anaerobic digestion tests, aimed at assessing the combined biological production of H2 and CH4 using a two-stage process, are discussed. The best performance under batch conditions corresponded to a yield of 179.7 Nl H2/kg TOCwhey for the hydrogenogenic stage and 1156 Nl CH4/kg TOCwhey,i. Compared to the conventional single-stage process (which displayed a methane yield of 962 Nl CH4/kg TOCwhey,i), a 20% gain in methane production was observed as best performance of the two-stage process. Semi-continuous two-stage conditions led to a maximum stable production of roughly 80.8 Nl H2/kg TOCwhey,i and 660.7 Nl CH4/kg TOCwhey,i.