A novel sewage sludge biochar and ferrate synergetic conditioning for enhancing sludge dewaterability

Abstract

A great prospect of sewage sludge self-recycling as a conditioner supports the research. A synergetic conditioning effect and mechanism were reflected after the synergistic conditioning experiment, and the corresponding separated experiment of biochar, K2FeO4 or acid treatment on WAS. All of the biochar, K2FeO4 and acid treatment could reduce the water content of sludge cake. Biochar had good effect on WAS settleability, although the influence of the biochar dosage was weak. Similar to K2FeO4, acid treatment also could reinforce the disintegration degree effectively, but it deteriorated the filter property of WAS. In the situation of synergistic condition, owing to the strong oxidation of K2FeO4, most of the sludge flocs was disintegrated, thus the settleability and filter property of WAS were still bad, even the biochar worked as a skeleton builder. It is encouraging to find that, even without acid treatment, there is a great decline of water content of sludge cake in the situation of synergistic condition.