Method for treating sludge with heavy metals exceeding standard

Abstract

The invention discloses a method for treating sludge with heavy metals exceeding the standard. The method comprises the following steps: mixing 2300 parts by weight of the sludge with water content of 80% (weight percentage) or below and heavy metal content exceeding the standard, 4.6-6.9 parts by weight of aerobic microbial agent, 690-805 parts by weight of auxiliary material and 184-276 parts by weight of heavy metal passivating agent and carrying out fermentation for 15-20 days for obtaining the sludge after the treatment; the aerobic microbial agent comprises the active ingredients of Bacillus subtilis, Bacillus stearothermophilus, Aspergillus niger, thermophilic sporotrichum and Saccharomyces cerevisiae; and the auxiliary material is one or any combination of shale, peat, sawdust, coco peat or cassava residue. The purpose of adding the aerobic microbial agent is to kill harmful microbes, pathogen and helminth eggs in the materials, decompose toxic and harmful organic matters and realize reduction, stabilization and harmless treatment of the materials; and the addition of the heavy metal passivating agent can transform the heavy metal form without causing the direct damage to organisms. The sludge after the treatment can be used for safe landfill, soil can be covered on a landfill field, and plants can be grown in the soil, thereby beautifying the environment and improving the ecology.

Description

technical field [0001] The invention relates to a method for treating heavy metal excess sludge. Background technique [0002] The world's first sewage treatment plant was built in London in 1895, and municipal sludge has been produced since then. In the process of activated sludge treatment of sewage, heavy metals in sewage are absorbed by bacteria, adsorbed on the surface of bacteria and mineral particles, and co-precipitated with some inorganic salts (such as phosphate, sulfate, etc.), so that 50% of the sewage - More than 80% of heavy metals are concentrated in the output sludge. Due to the secondary pollution caused by sludge to the environment, people have been looking for suitable sludge treatment and disposal methods. There are many kinds of heavy metals in municipal sludge, mainly including Cu, Zn, Pb, Ni, Cr, Hg, Cd, etc., which is one of the most important obstacles to the utilization of sludge resources. The types of heavy metals contained in urban sludge in v...

AI Technical Summary

Problems solved by technology

However, its disadvantage is that it needs to occupy land, pollute the groundwater body, and cause a large amount of seepage liquid. Improper disposal will cause environmental pollution on the surface, and it has not reached the national reduction, stabilization and harmlessness of sludge treatment and disposal. requirements

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