Nitrogen fixation of municipal sewage sludge by co-pyrolysis with biomass and KH2PO4-modified biochar addition

In order to reduce nitrogen emissions during municipal sewage sludge (MSS) pyrolysis, the effects of co-pyrolysis of MSS with biomass and the second adsorption of KH 2 PO 4 -modified biochar were investigated. It was found that co-pyrolysis with cellulose inhibited the conversion of nitrogen into pyrolytic gas, and increased the N content in pyrolytic biochar. And the nitrogen fixation rate increased with cellulose addition increasing. Besides, compared with different biomass, MSS co-pyrolysis with 30% sugarcane bagasse had the optimal effect on nitrogen fixation (39%). Moreover, KH 2 PO 4 -modified biochar addition increased the second adsorption of nitrogenous volatiles and fixed nitrogen into oxides-N. The total nitrogen fixation rate reached maximum (47.65%) at 5% KH 2 PO 4 impregnation. Thus, it is an effective nitrogen fixation method that MSS co-pyrolysis of 30% sugarcane bagasse with the second absorption of 5% KH 2 PO 4 -modified biochar. This study provided an effective solution to improve the treatment of municipal sewage sludge by pyrolysis technology.