Sequence flow return type sewage treatment method and treatment device

Abstract

The invention discloses a sequence flow return type sewage treatment method which comprises the following steps: conveying sewage to an anoxic / anaerobic tank; conveying the sewage into a contact oxidation tank and performing aeration oxygenation on the sewage in the contact oxidation tank; conveying the supernatant obtained by precipitating in the contact oxidation tank into an electric flocculation and sedimentation tank; returning and mixing the sewage part subjected to electric flocculation, conveying the other part of sewage subjected to electric flocculation into a membrane tank for performing mud-water separation, and discharging the treated water. According to the treatment device disclosed by the invention, an anoxic / anaerobic tank, a contact oxidation tank, an electric flocculation and sedimentation tank and a membrane tank are separated on a treatment unit tank, wherein the contact oxidation tank is communicated with the electric flocculation and sedimentation tank by virtue of a supernatant conveying pipe; a flocculation solution return pipe is arranged on the electric flocculation and sedimentation tank; and the electric flocculation and sedimentation tank is communicated with the membrane tank. The mutual interference and restriction between electric flocculation and biological treatment can be avoided, and the efficiency can be maximized. The method and device disclosed by the invention are widely applied to treatment of domestic sewage on ships and lands and industrial wastewater.

Description

technical field [0001] The invention relates to the technical field of sewage treatment, in particular to a treatment method of domestic sewage from water and land point sources such as rivers and marine vessels, marine equipment, cities and towns. The present invention also relates to a sewage treatment device applying the treatment method. Background technique [0002] Domestic sewage is the sewage produced in the process of human production, and it is the main source of water pollution. It mainly includes feces and washing sewage. With the rapid development of society and economy and the increase of population, the discharge of domestic sewage has become larger and larger, which has become a serious obstacle to economic development and the improvement of people's quality of life. The discharge of domestic sewage from cities, villages and towns and other land residents directly affects people's living environment and the degree of water pollution; the discharge of domesti...

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Problems solved by technology

Because this kind of processing technology and its actual products are limited to the superimposed application of multiple processing technologies, it is impossible to analyze and study the mutual influence between each processing technology and the dependence and flow sequence of each processing technology and their mutual influence, so there is Some inherent shortcomings: First, in the reaction system where electrocoagulation and biological treatment coexist, the external electric field of electrocoagulation will inhibit or weaken the growth and proliferation of microorganisms, affect the metabolic intensity of microorganisms, and cause microorganisms to appear "poisoning" phenomenon; The accumulation of inhibition also weakens the sludge activity and is prone to aging, making it difficult to maintain the operating conditions for a long time

Second, the enhancement of current density can improve the flocculation and precipitation of pollutants in sewage, but the enhancement of current density will also enhance the flocculation and precipitation of microorganisms in sewage, which will reduce the number of microorganisms in sewage, weaken the degradation effect, and sludge run It shows deterioration symptoms, and the sludge transitions from good to worse; when the growth rate of microorganisms is lower than the speed of flocculation and sedimentation, the biological treatment efficiency will be lost, and it will become a pure electro-flocculation system.

Therefore, it is difficult to control the electric field in the electrocoagulation superimposed biological treatment system, and it is difficult to maintain high sludge concentration, which leads to poor stability of the treatment system and hinders the practical application of the electrocoagulation biological reaction system.

Third, in electrocoagulation, metal anodes generate electrons to form metal nitrogen oxides of "micro flocculants". State impurities and suspended impurities are coagulated and precipitated to realize the purification and removal of pollutants in the water body. However, the excessive "flocculant" produced by electrocoagulation not only enhances the coagulation and precipitation of pollutants, but also coagulates and precipitates a large number of microorganisms, making the number of microorganisms and The population decreases, and the reduction in the number and population of microorganisms weakens the microbial degradation function

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