Method for processing sewage treatment plant sludge into agricultural fertilizer

Abstract

The invention provides a method for processing sewage treatment plant sludge into an agricultural fertilizer, and relates to a method for producing an agricultural fertilizer from sewage plant sludge. According to the method, sewage treatment plant sludge being subjected to concentration pre-treatment is added with iron sulfide with a mass ratio of 0.3%, and the obtained mixed material enters an aeration digestion device and aeration digestion is performed, wherein the dissolved oxygen during the digestion process is 2.0-1.5 mg / l, and the digestion time is 6 d; the digested sludge enters a horizontal screw material unloading centrifuge and dehydration is performed, and separation is performed to obtain a dehydration liquid and a dehydrated mud cake after the dehydration, wherein the centrifugal separation factor is 1800-2200; the dehydration liquid is filtered and neutralized with a filtration neutralizer comprising fly ash and a gravel mixed filtration material, and the discharged liquid refluxes to the anaerobic denitrification section of the sewage plant, wherein the dissolved organic matter can be used as the carbon source of the denitrification denitrification and be removed; and the mud cake and the fly ash are mixed to achieve the water content of 55-58%, and then a conventional composting treatment is performed so as to obtain the agricultural fertilizer with the N-P-K content of 8-10%. According to the present invention, with the method, it is ensured that heavy metals do not enter the environment, the treatment cost is further reduced by using the waste to treat the waste, and the valuable economic and environmental benefits are provided.

Description

technical field [0001] The invention discloses a method for processing sludge from a sewage treatment plant into agricultural fertilizer, relating to a process for producing agricultural fertilizer from the sludge from a sewage treatment plant. The invention belongs to the technical field of sludge treatment and resource utilization of urban sewage treatment plants. Background technique [0002] Sludge is an inevitable secondary product when urban sewage treatment adopts the mainstream process——biological method. The yield of sludge, calculated as dry solids, was 1.2×10 -4 -2.6×10 -4 t / m 3 ; The annual domestic sewage production per capita of urban residents in my country is 60-100m 3 Therefore, based on the current urban population in my country, if the treatment rate of urban domestic sewage reaches 100%, the corresponding sludge dry solid production rate is 4.5-8.4 million tons / year, and the sludge dewatered cake with a moisture content of 80% Calculated, it can reach...

AI Technical Summary

Problems solved by technology

Since most urban sewage plants in my country treat domestic sewage plants and industrial sewage tail water at the same time, the actual sludge output of urban sewage treatment plants is far greater than this value