Methane production from screened dairy manure using a fixed-film reactor

• Published in: Agricultural wastes Vol. 9; no. 3; pp. 175 - 188
• Main Authors: Lo, K.V., Whitehead, A.J., Liao, P.H., Bulley, N.R.
• Format: Journal Article
• Language: English
• Published: London Elsevier B.V 1984; Applied Science Publishers
• Subjects: Applied sciences; Biological and medical sciences; Biotechnology; Energy; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Methods. Procedures. Technologies; Microbial engineering. Fermentation and microbial culture technology; Miscellaneous; Natural energy; Manure; Natural energy; Bovine; Sewage digester; Laboratory scale; Biomass; Anaerobic digestion; Canada; Bioreactor; Agricultural waste; Performance; Animal waste; Comparative study
• ISSN: 0141-4607; 1878-3171
• DOI: 10.1016/0141-4607(84)90078-7

A laboratory scale comparison of two anaerobic digester designs-conventional and fixed film—was performed. Screened, 1:1 manure/water slurry was fermented in 4 litre reactors at 30°C, with intermittent mixing. Feed material (4·0% Total Solids, 2·8% Volatile Solids) was added once per day at loading rates representing hydraulic retention times (HRT) of 16 to 1 days. For HRTs less than 1 day (i.e. 1h), all of the waste was drained (once each hour) and the digester refilled with fresh feed. Maximum methane productivity (litre gas litre −1 digester day −1) of 6·33 litre CH 4 litre −1 day −1 was obtained from the fixed-film reactor at a loading rate of 672 g VS litre −1 day −1 (1 h HRT). Anaerobic digestion efficiency (litre gas g −1 Volatile Solids added) was highest in the fixed-film reactor operated at a 3·6 day HRT, when COD and VS reductions reached 38·4% and 27·6%, respectively. At HRT of less than 6 days, the conventional digester would not sustain a high gas-production rate because of bacterial biomass washout. Data indicate that the increased gas production capability of the fixed film becomes evident only at HRT of less than 6 days. The maximum film loading rate (gVS m −2 day −1) and methane productivity (litre CH 4 m −2 day −1) were not attained within the HRT range studied. Average biogas methane content from the fixed-film reactor (68·6%) was slightly higher than from the conventional digester (63·5%). Results indicate that a high potential reduction of required digester volume is possible through application of the fixed-film concept.