Calcium Peroxide Promoted Anaerobic Co-digestion of Plant Waste and Excess Sludge to Produce Methane

Abstract

Plant waste (PW) and excess sludge (ES) are two main organic matters of municipal solid waste. However, there are few reports on their anaerobic co-digestion. In this work, the mixed proportion of PW and ES anaerobic co digestion was first optimized at mesophilic temperature, and then the anaerobic co-digestion of PW and ES was enhanced with strong oxidant calcium peroxide (CP). The results showed that the optimal mixing ratio of PW and ES was 1/1 (in terms of volatile solids), and the C/N of mixed digestion substrate was 23.5/1, the maximum methane production was 172.6 mL/g (in terms of volatile solids). CP could enhance methane production from anaerobic co-digestion of PW and ES. When the content of CP was 0.2 g/g (in terms of total suspended solids), the maximum methane production was 234.8 mL/g, about 1.4 times of the blank. The mechanism investigation showed that CP promoted the release of organic matter during the co-digestion, and the higher the content of CP, the greater the release of soluble chemical oxygen demand. The presence of appropriate amount of CP promoted the activities of key enzymes in anaerobic fermentation process, and then increased the efficiency of methane production. The results of this work provide an alternative strategy for the resource utilization of PW and ES.

Study on the Effect of Two-Phase Anaerobic Co-Digestion of Rice Straw and Rural Sludge on Hydrogen and Methane Production

“…Qiuying Huang [19] studied a co-fermentation method to improve the gas production performance of rice straw and obtained the same results. In order to construct an efficient and stable rice straw sludge with a combined anaerobic digestion system, Yiran Wang [20] conducted a batch experiment of combined anaerobic digestion using different types of rice straw and excess sludge. The research results showed that the addition of rice straw significantly increased the methane content compared to the single anaerobic digestion of sludge.…”