Pretreatment method of nonionic surfactant wastewater

Abstract

The invention relates to a pretreatment method of nonionic surfactant wastewater. The invention aims to provide a method which has the characteristics of high treatment efficiency, capability of full automation operation of the treatment system and lower operating cost. The technical scheme is as follows: the method sequentially comprises the following steps: a. regulating the pH value of wastewater in a wastewater regulating tank to 2.0-4.0 with sulfuric acid, and meanwhile, adding a catalyst FeSO4; b. sending the wastewater treated by the step a into an electrolytic reaction tank filled with an oxidizer to perform electrolytic treatment, sending into a catalytic oxidation reaction tank to perform sufficient oxidation reaction, and meanwhile, enabling the wastewater output after the reaction of the catalytic oxidation reaction tank to flow to the electrolytic reaction tank according to a certain internal circulation proportion; and c. sending the wastewater output by the catalytic oxidation reaction tank in the step b into a flocculating settling unit to perform settling treatment, sending the supernate into a subsequent treatment technique, and treating the waste residues according to the specifications.

Description

technical field [0001] The invention belongs to the technical field of environmental protection wastewater treatment, and in particular relates to a pretreatment method for nonionic surfactant wastewater. Background technique [0002] Due to its high surface activity, non-ionic surfactant (NIS) has a lower surface tension in aqueous solution, and the critical micelle concentration of non-ionic surfactant is generally lower than that of anionic surfactant, so it has more Good emulsification and cleaning ability make it the most used surfactant after anionic surfactants. In recent years, the production capacity of nonionic surfactants in my country is also growing rapidly. At present, polyoxyethylene type and polyol nonionic surfactants account for a relatively high proportion in the market, and these substances are all refractory to biodegradable organic substances. The large-scale production and use of nonionic surfactants increase the risk of the environment. [0003] Surfa...

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Problems solved by technology

[0003] Surfactants mainly enter the environment through wastewater discharge. Surfactants in wastewater will cause water foaming and toxicity. Surfactants foaming in water will reduce the reoxygenation rate and degree of oxygenation in water, deteriorating water quality and affecting The survival of aquatic organisms hinders the self-purification of water bodies

At the same time, surfactants can also emulsify other pollutants in the water body, increase the concentration of pollutants, and cause indirect pollution

In addition, a large amount of foam will also affect the settling performance of sludge in wastewater, thereby affecting the treatment efficiency of wastewater treatment facilities

[0004] Of course, there are currently no environmental quality standards and emission standards for nonionic surfactants, but considering their adverse effects on the environment, it is still necessary to develop targeted removal technologies and treatment facilities

In view of the special physical and chemical properties of nonionic surfactants, which are different from anionic surfactant wastewater, the treatment effect of conventional coagulation sedimentation + biochemical treatment processes is not ideal; although physical removal methods such as foam separation can achieve separation from water The purpose of expelling non-ionic surfactants, but fundamentally did not destroy the structure of non-ionic surfactants, the removal is not complete

Advanced oxidation technologies such as traditional wet oxidation can destroy the structure of nonionic surfactants and eliminate the toxicity of nonionic surfactants, but the cost is relatively high, and it faces the problem of foam control under severe reaction conditions

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