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A thermophilic/mesophilic dual digestion system for treating waste activated sludge
Author(s) -
Roberts R,
Le Son,
Forster C F
Publication year - 1999
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(199905)74:5<445::aid-jctb65>3.0.co;2-0
Subject(s) - mesophile , hydraulic retention time , continuous stirred tank reactor , anaerobic digestion , activated sludge , thermophile , pulp and paper industry , waste management , chemistry , methane , retention time , digestion (alchemy) , environmental science , wastewater , chromatography , engineering , biology , biochemistry , bacteria , genetics , organic chemistry , enzyme
Five configurations for a dual digestion were examined. The units were based on three 5 dm 3 completely stirred tank reactors (CSTR). A first‐stage thermophilic digester was used to provided the feed to each of the two second‐stage mesophilic (35 °C) digesters. The thermophilic digester was operated initially at 55 °C with a hydraulic retention time of 4 h and then, later, at 60 °C with a hydraulic retention time of 3 h. The mesophilic digesters were operated at hydraulic retention times of 9, 12 and 15 days. In terms of volatile solids’ (VS) reduction, the systems with a first stage at 60 °C gave the better performance. However, based on the specific methane yield (m 3 CH 4 per kg VS removed), the configuration with a first stage operating at 55 °C and a secondary digester with a hydraulic retention time of 12 days was the most effective. © 1999 Society of Chemical Industry