Fertilizer production from municipal sludge and its application prospect
Municipal sludge is a kind of solid waste produced in the treatment of municipal domestic sewage and industrial sewage. According to statistics, urban sewage treatment plant discharges dry sludge about 200,000 every year with an annual increase of 20% in our country . A large number of untreated sludge piled up in the open air causes serious urban environmental pollution, so the sludge in urgent need to be a proper disposal. The properties of sludge 1. The composition of sludge Sludge is mainly an organic residue. It is composed of bacterial cells, inorganic particles, colloides and other components, high moisture content, perishable, odor. Municipal sludge contains higher organic matter, nitrogen and phosphorus. The easily degradable components in sludge organic matter accounting for up to 60% of the total amount of organic matter, and the fertilizer supply capacity is relatively strong, so it is a good organic fertilizer source. 2. The importance of sludge treatment The sludge without harmless treatment will produce many hazards. It mainly includes land occupation, soil pollution, water pollution, air pollution, sludge which contains a large number of pathogenic bacteria threatening human health. In addition, the moisture content of sludge is very high and the volume is...