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Co‐digestion of Municipal Sewage Sludges and Pre‐hydrolysed Woody Agricultural Wastes
Author(s) -
Converti Attilio,
Drago Fabio,
Ghiazza Giovanni,
Borghi Marco Del,
Macchiavello Amedeo
Publication year - 1997
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/(sici)1097-4660(199706)69:2<231::aid-jctb690>3.0.co;2-7
Subject(s) - anaerobic digestion , biogas , hydrolysis , pulp and paper industry , chemistry , sewage sludge , methane , bioenergy , straw , lignin , waste management , sewage , environmental science , biofuel , environmental engineering , organic chemistry , inorganic chemistry , engineering
Material balance has been used to evaluate the COD behaviour and the time required for fed‐batch digestion of mixtures of domestic sludges and pre‐hydrolysed agricultural wastes. Pre‐hydrolysis of the feed materials has been used to penetrate the strong lignocellulosic structure of these wastes as well as to increase the fraction of soluble organic substances in the mixture. The influence of the organic loading rate on the main process parameters (methane, carbon dioxide, total biogas productions and their respective conversion yields) has also been investigated. The organic load has been varied from 0·8 up to 6·1 g COD dm −3 day −1 , corresponding to a range of volatile solids load of 0·6–4·5 g VS dm −3 day −1 for the material under consideration. These values are slightly higher than those usually employed in conventional digester for domestic sewage sludges. However, methane production reached a maximum rate of only 5·6 mmol dm −3 day −1 at an organic loading rate of 4·6 g COD dm −3 day −1 , while both CH 4 content and production of biogas rapidly fell over 2·2 g COD dm −3 day −1 . On the whole, these results suggest that removal of lignin is necessary in order to carry out the continuous anaerobic digestion of pre‐hydrolysed agricultural wastes rich in woody materials. © 1997 SCI.