Sludge treatment process

Abstract

The invention provides a sludge treatment process. The sludge treatment process comprises the following steps of: pumping sludge in a sludge concentration tank into a sludge conditioning tank for stirring and conditioning to obtain pretreated sludge; pumping the pretreated sludge into a membrane filter press, and extruding and dehydrating the sludge to obtain a sludge cake; conveying the mud caketo low-temperature drying equipment for drying treatment; enabling the filter cake to enter a gasification melting furnace to be gasified and molten to obtain molten slag and first pretreated flue gas, discharging the molten slag after water quenching, and purifying the first pretreated flue gas through a cyclone dust collector and then cooling the first pretreated flue gas through an air preheater and a waste heat boiler; enabling the cooled first pretreated flue gas to enter a gas mixer, and adding ozone into the gas mixer for a mixed oxidation reaction to obtain second pretreated flue gas;feeding the second pretreated flue gas into a spray absorption tower, and absorbing nitrogen and sulfur oxides in the second pretreated flue gas through alkali liquor so as to realize desulfurizationand denitrification; and purifying the second pretreated flue gas discharged from the spray absorption tower through a bag type dust collector, and then discharging the purified flue gas.

Description

technical field [0001] The invention belongs to the technical field of sludge treatment, and in particular relates to a sludge treatment process. Background technique [0002] Sludge is the final product of sewage treatment. It contains a large number of toxic and harmful substances such as pathogenic microorganisms, parasites, and heavy metals. In order to avoid serious secondary pollution to the environment, sludge treatment is very important. At present, the problem of sludge treatment has become a bottleneck restricting the sewage treatment industry, and it is also a problem faced by local governments. Therefore, the harmless disposal of sludge has become an environmental problem that needs to be solved urgently in our country. [0003] The existing foreign sludge treatment methods usually go through the process of landfill, composting, drying, and incineration. However, the more common sludge treatment method in my country is to dehydrate the sludge until the water con...

AI Technical Summary

Problems solved by technology

However, the more common sludge treatment method in my country is to dehydrate the sludge until the water content reaches below 60% and then landfill it. This method not only takes up a lot of land, but also has the risk of pollution leakage

Composting can also cause soil or water pollution

At present, the commonly used sludge treatment method is the method of drying combined with incineration. However, due to the low incineration temperature of the existing sludge incineration, it is easy to produce the "poison of the century", that is, "dioxin". Conventional flue gas treatment facilities Cannot effectively remove "dioxin"

In addition, the fly ash produced by sludge incineration is hazardous waste, and there is a risk of heavy metal precipitation in the waste residue

[0004] The existing sludge treatment processes are complex and diverse, but there is no whole-process process that can completely solve sludge pollution, and there are some problems

For example, the deep dehydration of sludge needs to be dried by heat source or adding reinforcing agents such as lime, which leads to high sludge treatment cost and difficulty in wastewater and waste gas treatment. Adding reinforcing agents such as lime increases the sludge production in a disguised form, and at the same time Increase the difficulty and load of subsequent processes

For tail gas treatment, the reduction method (SNCR) commonly used in the prior art is suitable for the denitrification method at a specific temperature (850°C-1050°C) and in the workplace. Components are corroded and there is a risk of secondary pollution due to ammonia escape

In addition, the existing sludge incineration treatment methods cannot treat sludge with a water content of 96-99wt%, and have high requirements on the calorific value of raw materials, high energy consumption, high cost, complex process, and difficult control

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