Improving methane production from wheat straw by digestate liquor recirculation in continuous stirred tank processes

摘要: Wheat straw is an abundant, cheap substrate that can be used for methane production. However, the nutrient content in inadequate fermentation. In this study, recycling digestate liquor was implemented single-stage continuous stirred tank processes enrichment of with aim improving The VS-based organic loading rate set at 2 g/(L d) and solid retention time 40 days. When wheat alone as substrate, yields achieved on average 240 ml CH4/g VS giving a 21% improvement over without recycling. time, suffered from declining poor stability evidenced by low pH. To maintain process stability, co-digested sewage sludge or supplemented macronutrients (nitrogen phosphorous). As result, could operated stably, achieving ranging 288 to 296 VS. Besides, not sturdily supplementation highest yield (296 16 VS) co-digestion plus after filtration (retention nutrients microorganisms). This comparable maximum expected 293 13 batch test. present study therefore demonstrated lead decreased dilution vital reactors thereby rendering high performance stability. (C) 2015 Elsevier Ltd. All rights reserved.