A sludge treatment method based on wet oxidation

Abstract

The invention relates to a sludge treatment method based on wet oxidation. The sludge treatment method comprises the following steps: fully mixing a sludge material and hot liquid in a physical-chemical pre-treater during a pretreatment process; after the preparation of the sludge material is completed, conveying the sludge material into an oxidation reaction process; during the oxidation reaction process, carrying out wet oxidation reaction between the sludge material and oxygen of which the temperature is 60 DEG C-80 DEG C in an oxidation reactor, wherein gas and high-temperature material are generated after the wet oxidation reaction is completed, and the gas mainly contains carbon dioxide and water vapor and is directly discharged into the air; enabling the high-temperature material to enter into a flash dehydration process, wherein the high-temperature material firstly enters a flash tank for flashing to produce gas and material, the produced gas is purified and then discharged into the air; enabling the generated material to pass through a heat exchanger, then carrying out solid-liquid separation to obtain separated solids and liquid which can be used for the second time. By the sludge treatment method, the sludge can be efficiently and reasonably treated so that the treated sludge can be recycled. The sludge treatment method can be widely applied to sludge treatment.

Description

technical field [0001] The invention relates to a sludge treatment method, in particular to a sludge treatment method based on wet oxidation. Background technique [0002] Urban sewage treatment plants produce a large amount of sludge in the process of sewage treatment. The sludge has a high moisture content, is perishable, has a strong odor, and contains a large number of pathogenic bacteria, parasite eggs, cadmium, chromium, lead, mercury, arsenic, etc. Heavy metals and toxic, harmful and carcinogenic substances that are difficult to degrade will cause direct or potential pollution to the environment if they are not properly disposed of. According to the "Twelfth Five-Year Plan for Energy Conservation and Emission Reduction" issued by the State Council, by 2015, the urban sewage treatment rate and sludge harmless disposal rate will reach 85% and 70% respectively, and the county sewage treatment rate will reach 70%. The annual output of sludge reaches 35 million tons. If sl...

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Problems solved by technology

[0003] At present, the common treatment methods for sludge in my country include landfill, fertilizer utilization, drying and incineration, etc. Among them, the operation of landfill is simple and the cost is low. Large size, difficult site selection, difficult treatment of leachate and may affect groundwater quality and other safety hazards. Later, with people's requirements for green food and vigilance against soil pollution, the standards for agricultural use of sludge fertilizers have become increasingly stringent, and due to reasons such as inconvenient use and poor fertilizer efficiency, they cannot compete with chemical fertilizers. It is difficult for sludge to be used as agricultural fertilizers. Continue; sludge drying technology refers to the use of heat to destroy the gel structure of sludge, and to disinfect and sterilize the sludge. However, the drying process consumes high energy, complex equipment, high investment and operating costs, and reduces The advantages of sludge incineration are small footprint, fast processing, large processing capacity, and obvious reduction, but it will produce environmental pollutants such as acid flue gas, ash and fly ash, and subsequent treatment is required

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