Feasibility analysis on drying and incineration of sewage sludge from a wastewater treatment plant
污水处理厂污泥干化焚烧处理可行性分析

Experiments were carried out in a paddle sludge drying machine and a fluidized bed incinerator to analyze the feasibility of drying and incineration treatment of sewage sludge from Shaoxing Wastewater Treatment Plant (WTP).The sludge natures,as well as the contaminants emission during the treatment process were detected.Results show that,the sludge from Shaoxing WTP has similar characteristics with other sewage sludge,as the ash content is relativily high and the heating value is relativily low.The drying rate can reach up to 0.6 kg/(m2·min) in the small paddle drying machine and a drop of drying rate also appear during the process.The concentration of ammonia,which is the main pollution gas during the sludge drying process,can reach up to 170 mg/Nm3.The condensate from sludge drying process should be treated before discharge,as its COD can reach up to 820 mg/L.Sewage sludge from Shaoxing WTP would combust without any auxiliary fuel when its water content is lower than 30% after drying.The noxious gases and heavy metals in the flue gas should be taken seriously.The leaching toxicity of sludge incineration ash is below the national standard limits.