Study of the application and methods for the comprehensive treatment of municipal solid waste in northeastern China

Comprehensive treatment of municipal solid waste (MSW) is an important issue facing current research. On the basis of MSW composition analysis, this paper investigates the sorting methods of MSW and the utilization of waste in northeastern China by combining theory, experimentation and practice. According to the physical and chemical properties of waste, manual sorting must first be completed followed by magnetic separation, pneumatic separation and water concentration. A green brick can later be made by mixing the crushed construction waste, which is selected manually, with other waste that is selected by machine. Select organic compounds can also be used to make methane by fermentation at temperatures of 35±3°C at a inoculation rate about 25% and a PH value of near 7.0; the resulting solid rate would need to be controlled within 9–21%. The methane could be used to generate electricity after removing sulfur and CO2 and drying. An organic–inorganic fertilizer could be made by adding 20–30% of crushed plant stalks into the biogas fermenter and mixing it evenly with added N, P and K after dehydration, secondary fermentation and granulation drying. Both the electricity and exhaust heat could be utilized to improve the utilization of energy. When applied to a model city, the comprehensive treatment system proposed is shown to improve resource utilization by approximately about 40% compared with conventional methods; thus, the goals of waste reduction and recycling have been achieved.