Anaerobic digestion and energy recovery of high salt solid wastes using marine methanogens

点击翻译按钮获取中文摘要

When marine sediment collected from Hiroshima Bay was cultured in artificial seawater containing 3% NaCl at 37 C, active methane production was observed. The well-acclimated methanogens could grow at even 9% NaCl. Novel halo-tolerant acetoclastic methanogen was estimated to belong to Methanosaeta sp. based on rDNA sequence analysis since the homology of 16S rDNA between isolated methanogen and Methanosaeta concilii was 90% but it might be new genera. The acclimated acetoclastic methanogens was applied to continuous methane fermentation of acetate with an UASB reactor, acetate (77 mM from 200g wet mud) which was released from organic matters in sea sediment mud by anaerobic treatment was successfully converted to CH_4 giving 90 mM/d at 3.0 d^<-1> of dilution rate. Furthermore, using marine sediments as culture seed, soybean solid waste (25g wet/l) was converted to CH_4 at 25 mmol/m^3/d of maximum CH_4 production rate giving 15% solid reduction after 30 d, indicating that for the treatment of soybean solid waste, two step methane fermentation process consisting of hydrolytic and acid formation reactor, and methane formation reactor in which halo-tolerant methanogen can be used would be feasible for more efficient solid reduction.