Treatment process and device for wastewater containing benzene

Abstract

The invention relates to a treatment process and device for wastewater containing benzene. The device comprises a pretreatment unit, an ozone oxidation unit, a biochemical treatment unit and a double-membrane advanced treatment unit which are sequentially connected. The treatment process comprises the steps of: firstly adding lime to the wastewater for softening the wastewater, then adding a coagulant for polyferric sulfate coagulation, adding a flocculating agent for flocculation, precipitating and clarifying, and then sending clear liquid into a sand filtering layer, wherein yielding water enters an ozone contact tank for ozone aeration and oxidation, carrying out biochemical treatment on the wastewater subjected to ozone oxidation by adopting a biological aerated filter treatment process and a moving bed biomembrane reactor so as to further degrade COD (Chemical Oxidant Demand), and carrying out ultra-filtration and reverse osmosis double-membrane treatment on the wastewater for desalination. According to the invention, through combination of the treatment units, the removal rate of CODcr with benzene rings in the fed water can be up to above 80%, and the removal rate of SS (Suspended Solids) is about 90%, and the removal rate of ammonia nitrogen is above 85% before fed water enters a RO (Reverse Osmosis) membrane. For a double-membrane system, the cleaning period is increased by 3-4 times, and the service life of the membrane is prolonged by 1-2 years.

Description

Technical field [0001] The invention relates to a wastewater treatment process and device. Background technique [0002] As our country's awareness of environmental protection increases and water resources become increasingly scarce due to industrialization, urban water reuse is increasingly being used in actual production. In general urban sewage treatment projects, the treated sewage is directly discharged after reaching the national discharge standards. For cities with serious water shortages, in order to meet the needs of industrial water, the wastewater that meets the standards is recycled and utilized to achieve reclaimed water recovery. use. There are many ways and methods to realize reclaimed water reuse. In recent years, the process of using UF+RO (ultrafiltration + reverse osmosis) as the core treatment unit has gradually become mainstream and is increasingly used in actual projects. During some practices, it was found that for some treated sewage, there are some...

AI Technical Summary

Problems solved by technology

In some practice, it is found that for some treated sewage, there are some problems when using the double-membrane method for recycling treatment, mainly in the following aspects: biochemical treatment is generally selected in the sewage treatment process, and the sewage CODcr after biochemical treatment It can meet the specified value of the national discharge standard (less than 60mg / L), but for the reuse water system, this index is much higher than the water inlet requirement of the RO membrane system, resulting in rapid membrane system pollution, serious decline in production capacity, and greatly shortened membrane service life. Thereby increasing the operating cost of the system and restricting the promotion and utilization of reclaimed water reuse technology

Therefore, it is necessary to re-biochemically treat the sewage entering the double-membrane system. However, since the biochemical treatment has already been carried out in the previous sewage treatment process, the reproducibility of the biochemically treated wastewater, especially the wastewater containing benzene rings, is very poor.

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