Acrylonitrile wastewater treatment method

Abstract

The invention discloses an acrylonitrile wastewater treatment method, and belongs to the technical field of wastewater treatment. The method comprises the following steps of: wastewater in a water collecting tank enters a quick mixing area under the action of a lift pump; a first dosing tank is used for adding a flocculating agent into the quick mixing area; the flocculating agent and the wastewater are quickly mixed in a short time and then enter a slow mixing area through water holes; a coagulant aid is added into the slow mixing area by the second dosing tank; the coagulant aid and sewage in the slow mixing area are subjected to a sufficient flocculation reaction and then flow into a settling area to be subjected to settling separation; a separated supernatant enters a membrane pool; microorganisms in the membrane pool are used for biodegrading organic pollutants in the wastewater; under the pumping action of a water outlet pump, the wastewater in the membrane pool is filtered by each filtering membrane assembly, a clear liquid generated by filtering is converged into a water collecting plate from the inner cavity of the membrane frame and then flows out through the water outletpipe, an aeration device continuously blows air bubbles into the membrane pool, and a suspended filler in the membrane pool is fluidized and dispersed in the membrane pool. According to the invention, the effluent quality of acrylonitrile wastewater can be improved, and membrane pollution can be alleviated.

Description

technical field [0001] The invention relates to a method for treating acrylonitrile wastewater, which belongs to the technical field of wastewater treatment. Background technique [0002] As one of the important chemical raw materials, acrylonitrile has broad application prospects in the fields of acrylic fiber, nitrile rubber, adiponitrile, acrylamide, ABS resin, synthetic fiber, synthetic rubber, and synthetic plastic production. There are 10 sets of acrylonitrile plants in my country, with an annual output of more than 1 million tons of acrylonitrile. Affected by rising demand for acrylonitrile and low inventory, the world's acrylonitrile production capacity, including China, has increased significantly in recent years. In the production process of acrylonitrile, every 1 ton of acrylonitrile produced is accompanied by about 1 ton of waste water, and the quenching, absorption, and recovery systems need a large amount of water as quenching water, absorption water and solve...

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Problems solved by technology

[0003] At present, the main methods of treating acrylonitrile wastewater in my country are: (1) incineration method, which has the advantage of thorough treatment, but the energy consumption of wastewater treatment is high, and the energy consumption cost of burning a ton of wastewater is about 230 to 250 yuan, and the actual operation process In the process, harmful gases are produced due to combustion, causing secondary pollution and air pollution. In addition, its own equipment is also prone to fouling

(2) The evaporative distillation method has the disadvantages of high energy consumption, incomplete treatment and high treatment cost

(3) Fenton (Fenton) reagent method, hydrogen peroxide and catalyst Fe 2+ The oxidation system constituted is called Fenton's reagent, in Fe 2+ Under the action of catalysis, hydrogen peroxide can generate active hydroxyl radicals, thereby triggering free radical chain reactions, accelerating the oxidation of organic matter and reducing substances, thereby effectively reducing COD in acrylonitrile wastewater. This method is a pretreatment method for acrylonitrile wastewater. It is a relatively effective method, but the hydrogen peroxide is easy to decompose ineffectively in the operation process, resulting in a decrease in treatment efficiency and an increase in treatment cost, and it is difficult to realize the high-efficiency and low-cost treatment of acrylonitrile wastewater by Fenton reagent

However, when the existing membrane separation technology is used to treat acrylonitrile wastewater, there is a serious problem of membrane fouling. In addition, the removal rate of acrylonitrile in wastewater still needs to be improved.

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