Enhanced biomethane production from waste activated sludge anaerobic digestion by ceramsite and amended Fe 2 O 3 ceramsite

Wastes recycling and reutilization technique could simultaneously fulfill waste control and energy recovery sustainably, which has attracted increasing attention. This work proposed a novel waste reuse technology utilizing ceramsite and amended Fe O -ceramsite made from waste activated sludge (WAS) as additives to promote the yield of methane from WAS anaerobic digestion (AD). Experimental results demonstrated that compared to the control (85.05 ± 0.2 mL CH /g-VS), the cumulative methane yield was effectively enhanced by 14% and 40% when ceramsite and Fe O -ceramsite were added. Further investigation revealed that ceramsite, especially the Fe O -ceramsite, enriched the populations of key anaerobes involved in hydrolysis, acidification, and methanogenesis. Meanwhile, potential syntrophic metabolisms between syntrophic bacteria and methanogens were confirmed in the Fe O -ceramsite AD system. Mechanisms studies exhibited that ceramsite and Fe O -ceramsite reinforced intermediate processes for methane production. The favorable pore structure, enhanced Fe (III) reduction capacity and conductivity also contributed a lot to the AD process.