Insight into the potentiality of big biochar particle as an amendment in aerobic composting of sewage sludge

Abstract To assess the potential of big biochar as composting amendment, the study was performed on aerobic composting of sewage sludge amended with litchi wood biochar (10% of fresh mixture weight, 20–40 mm) in a 400 L bioreactor system. Physicochemical properties and microbial activities were monitored during the first fermentation process of aerobic compost. Application of big biochar reduced peak temperature and shortened thermophilic phase, but increased the activities of aryl-sulfatase, β-glucosidase, and dehydrogenase, which led to higher removal efficiency of total carbon, nitrogen, and sulphur. Big biochar inhibited degradation of organic matters in composting. Therefore, a comprehensive assessment including physicochemical and microbial properties can help to better understand the effect of big biochar on sewage sludge composting.