Application Status of Co-Processing Municipal Sewage Sludge in Cement Kilns in China

Municipal sewage sludge (MSS) disposal is an urgent issue in China with the continuous growth of sewage treatment capacity. Among various disposal methods, co-processing of MSS in cement kilns has been one of the most promising disposal methods in recent years. The present situation of sewage treatment and sludge disposal, the development of co-processing MSS in a cement kiln, and main disposal routes in China were discussed in this study. The results indicated that China had paid considerable attention to the technology and released correlative policies in the past few years. There were about 35 co-processing projects built in China, all of which were limited by construction scale and pollutant emissions. Due to differences in construction methods and economic conditions, China's co-processing projects mainly employed three routes-direct addition to a transition chamber, addition to a precalciner after direct thermal drying, and addition to a precalciner after indirect drying. Summarizing and analyzing the characteristics of MSS co-processing would facilitate its development in China and similar regions.