ETV analysis of earthworm composting technology in municipal sludge

Earthworm composting technology can reduce the excess sludge of sewage treatment plant and treat it with resources. According to the procedure of environmental technology verification, this paper tests and analyzes the environmental protection effect and environmental impact of earthworm composting technology scientifically, objectively and fairly. The results showed that the concentration of heavy metals and the number of fecal coliforms in earthworm dung met the limit requirements of the "Organic Fertilizer"(NY 525-2012), and the moisture content, organic matter concentration and total nutrients in earthworm dung did not meet the limit requirements of the "Organic Fertilizer"(NY 525-2012), so it was not suitable to be used directly. It is used as an organic fertilizer, and the mass reduction rate of the mixture after earthworm composting is more than 45%; the sludge treatment capacity (dry weight meter) of the process is 0.24 kgm−2d−1, the yield of earthworm dung (dry weight meter) is 0.06 kgm−2d−1, and the yield of earthworm (dry weight meter) is 0.02 kgm−2d−1. The reduction effect of earthworm composting process on organic waste (sludge and straw), the concentration of heavy metals and the number of Fecal coliform, all the indicators can meet the verification statement of the enterprise.