Method for modifying and dewatering sludge

Abstract

The invention belongs to the technical field of environmental protection, and particularly relates to a method for modifying and dewatering sludge. The method provided by the invention comprises the following steps: adding water to sludge which is subjected to primary dewatering by a sewage treatment plant, thereby enhancing the flowability of the sludge; adding fine particles with high water permeability into the sludge, and evenly stirring; adding a polymeric flocculant into the mixture, so that the fine particles are coated by the sludge to form a complicated structure; and finally, pumping the mixture into a plate-and-frame filter press to carry out pressure filtration, thereby obtaining a secondary dewatered filter cake of which the water content is lower than 60%. The invention has the advantages of stable technique, simple process, low price of additive materials, low operating cost, and short pressure filtration time; heavy metals in the sludge precipitate in the sludge due to the coprecipitation action; and the effluent water of pressure filtration is clear.

Description

technical field [0001] The invention belongs to the technical field of environmental protection, and in particular relates to a method for dewatering sludge, in particular to a method for conditioning and dehydrating sludge by using medicaments. Background technique [0002] With the popularization of sewage treatment facilities, the improvement of treatment rate and the deepening of treatment degree, the amount of sludge produced by sewage plants has increased significantly. The capacity reaches 122 million cubic meters, which will generate a large amount of activated sludge, and the secondary pollution caused by it can no longer be ignored. Sludge is a solid sediment produced in the process of water and sewage treatment, and generally comes from water treatment pretreatment, primary sedimentation tanks, secondary sedimentation tanks, etc. In the past, the construction of sewage treatment plants often only paid attention to the sewage treatment to meet the discharge standa...

AI Technical Summary

Problems solved by technology

The domestic patent application number is 200810048825.5 and the patent application number is 200710150706.6. The patents use inorganic composite conditioners to treat sludge, and the treatment effect is better, but there is a problem that the calorific value of the treated sludge decreases more due to the high addition amount.

The patent application number is 200810198539.7, which adopts a compound sludge conditioning method, and adds surfactant 1227, flocculant and auxiliary agent (the medium after picking edible mushrooms) to the sludge to achieve the effect of deep dehydration of the sludge. However, there is still the problem of high processing costs

[0006] To sum up, the currently published articles and patents mainly use flocculants and some surfactants to condition the sludge and then dehydrate it. The basic process is to make the sludge bacteria The micelles aggregate, and the gradually increasing aggregate structure finally precipitates in water. By further adding polymer flocculants and concentrating by physical methods, most or part of the so-called free water can be removed. Using this conditioning treatment method, Generally, the moisture content of sludge can be as low as 60%, but it needs to consume a lot of chemicals, and the operating cost is high.