Biological power generation and earthworm assisted sludge treatment wetland to remove organic matter in sludge and synchronous power generation

摘要

In order to eliminate the weak degradation ability of organic matter in sludge treatment wetland (STW). In current work, a combined biological power generation and earthworm assisted sludge treatment wetland (BE-STW) system is proposed for the first time to accelerate degradation and dehydration process of organics in STW, thusly, recovering biomass energy in sludge. Experimental results show that S_4 system (earthworm and bioelec-tricity combined) yields a voltage of 0.832 V and maximum power density of 94.98 W/m~2 in the 5th day. The combination of earthworm, microorganism and plants in STW system can reduce the ratio of volatile solids to total solids (VS/TS) to 15% while the removal rate of total chemical oxygen demand (TCOD) reaches 92.1%. The BE-STW system increases sludge particle size while reduces absolute value of Zeta and extracellular polymeric substances (EPS) content, so that the moisture content of effluent sludge retains to 66.8%. Meanwhile, the richness of bacterial communities in S4 proves that bioelectrochemistry and earthworm can effectively improve the sludge treatment effect.