Municipal sludge reduction method

Abstract

The invention discloses a municipal sludge reduction method. The method includes the steps of: 1) introducing municipal sludge into a sludge concentration tank for concentration, and letting the supernatant flow back to the front end of a sewage treatment plant; 2) introducing the concentrated municipal sludge into a biological conditioning tank I, adding ferrous salt and sulfur powder, conductingstirring and aeration, and performing first-stage conditioning; 3) introducing the municipal sludge subjected to the first-stage conditioning into a biological conditioning tank II, replenishing ferrous salt and sulfur powder, and conducting stirring and second-stage conditioning; 4) introducing the municipal sludge subjected to the second-stage conditioning into a modification tank, adding acid,and performing modification treatment; and 5) introducing the modified municipal sludge into a diaphragm filter, adding an external magnetic field, and performing filter pressing to obtain a filter cake and filtrate, subjecting the filter cake to concentrated treatment, and returning the filtrate to the sludge concentration tank. The municipal sludge reduction method provided by the invention hasthe advantages of small reagent dosage, low energy consumption, simple treatment process, good sludge reduction effect and the like, and can reduce the water content of sludge to 50% or below.

Description

technical field [0001] The invention relates to a municipal sludge reduction method. Background technique [0002] With the continuous improvement of the level of urbanization in our country, the urban area is getting larger and larger, the construction of municipal sewage treatment facilities has been developed at a high speed, and the discharge volume and treatment rate of sewage are constantly increasing. However, a large amount of municipal sludge will be produced in the process of sewage treatment. Calculated with a moisture content of 80%, the annual output of sludge in my country has already exceeded 30 million tons, and it is increasing year by year. It is estimated that by 2020, it will exceed 60 million tons. Municipal sludge The problem of how to deal with it has become increasingly prominent, and the situation is very serious. [0003] Municipal sludge contains a large amount of organic pollutants, inorganic pollutants, pathogens, heavy metal elements, etc. It ha...

AI Technical Summary

Problems solved by technology

At present, the commonly used process is to mechanically dehydrate the municipal sludge first, reduce the water content of the municipal sludge, and then dry it through drying equipment. This process can greatly reduce the energy consumption in the drying process, but there are the following problems: 1) In the mechanical dehydration stage, lime + ferric chloride or polyacrylamide is generally used to condition the sludge. The dosage of the agent is large (accounting for about 30% of the weight of the dry sludge), and the impurities introduced into the sludge are more , the resource utilization rate of the dried sludge is low, and the sludge conditioned by polyacrylamide is difficult to dewater, and its own air permeability is poor, which is not conducive to later drying, and the cost of polyacrylamide is relatively high; 2) Conventional drying Drying equipment generally uses direct heating or fermentation for drying. The energy consumption of direct heating and drying is high, and the gaseous water vapor needs to be discharged in time. A large amount of heat energy is wasted as vaporization heat. At the same time, dust and odor will be lost during the drying process. It has a great impact on the environment, and additional dust removal and deodorization facilities need to be added, while fermentation and drying take a long time, occupy a large area, and cause a large loss of organic matter during the fermentation process

Images