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A novel free ammonia based pretreatment technology to enhance anaerobic methane production from primary sludge
Author(s) -
Wei Wei,
Zhou Xu,
Xie GuoJun,
Duan Haoran,
Wang Qilin
Publication year - 2017
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.26348
Subject(s) - chemistry , anaerobic digestion , methane , ammonia , anaerobic exercise , chemical oxygen demand , hydrolysis , microbial consortium , food science , nuclear chemistry , biochemistry , waste management , sewage treatment , organic chemistry , microorganism , bacteria , biology , physiology , engineering , genetics
ABSTRACT This study proposed a novel free ammonia (FA, i.e., NH 3 ) pretreatment technology to enhance anaerobic methane production from primary sludge for the first time. The solubilization of primary sludge was substantially enhanced following 24 h FA pretreatment (250–680 mg NH 3 ‐N/L), by which the release of soluble chemical oxygen demand (SCOD) (i.e., 0.4 mg SCOD/mg VS added; VS: volatile solids) was approximately 10 times as much as that without pretreatment (i.e., 0.03 mg SCOD/mg VS added). Then, biochemical methane potential (BMP) tests demonstrated that FA pretreatment of 250–680 mg NH 3 ‐N/L was capable of enhancing anaerobic methane production while the digestion time was more than 7 days. Model based analysis indicated that the improved anaerobic methane production was due to an increased biochemical methane potential (B 0 ) of 8–17% (i.e., from 331 to 357–387 L CH 4 /kg VS added), with the highest B 0 achieved at 420 mg NH 3 ‐N/L pretreatment. However, FA pretreatment of 250–680 mg NH 3 ‐N/L decreased hydrolysis rate (k) by 24–38% compared with control (i.e., from 0.29 d −1 to 0.18–0.22 d −1 ), which explained the lower methane production over the first 7 days’ digestion period. Economic analysis and environmental evaluation demonstrated that FA pretreatment technology was environmentally friendly and economically favorable. Biotechnol. Bioeng. 2017;114: 2245–2252. © 2017 Wiley Periodicals, Inc.