Steel composite wastewater recycle-water double-membrane demineralization system and technique

Abstract

The invention provides a system and a process for desalting recycle-water of iron and steel combined sewage by a bi-membrane method, which belong to the technical field of treatment and recycling of sewage. The system comprises a cooling tower, a raw water tank, a micro-flocculation filter device, a flow by-pass activated carbon filter kettle, a laminated filter, an ultrafiltration system, an ultrafilter, a reverse osmosis system, and a reverse osmosis desalination water tank. The system and the process are used for solving the problem of desalination of the recycle-water of sewage by the bi-membrane method for steel enterprises. In the system and the process, the pretreated water is treated through the ultrafiltration device by bi-membrane desalination to meet the requirement that SDI is less than or equal to 3, and the water is subjected to desalinating treatment through the reverse osmosis device. The system and the process treat the recycle-water of the iron and steel combined sewage by a mode combining preoxidation, micro-flocculation filtration, flow by-pass activated carbon filtration and self-cleaning filtration, thereby greatly improving the operating stability and the service life of the bi-membrane desalination system, effectively realizing sewage reclamation and 'zero drainage' of the sewage, and having important practical value on the desalination of the recycle-water of the iron and steel combined sewage.

Description

technical field [0001] The invention belongs to the technical field of iron and steel sewage treatment and reuse, and in particular relates to a system and process for desalination of iron and steel comprehensive sewage reused by a double-membrane method, which is suitable for advanced treatment and desalination and reuse of iron and steel comprehensive sewage. Background technique [0002] Sewage reuse is an important way for iron and steel enterprises to achieve "water saving and emission reduction". In order to save water and increase the reuse rate of water resources in the entire iron and steel plant, iron and steel companies, which are large water users, have successively invested in sewage treatment plants to reuse the treated water in order to save the replenishment of water sources; at the same time, Due to factors such as concentration and evaporation of the entire steel plant water system, the sewage water entering the sewage treatment plant has complex water qual...

AI Technical Summary

Problems solved by technology

Obviously, these measures can only improve the water quality entering the double-membrane desalination system from some aspects; although some measures can solve some problems, they have created new problems. For example, the method of injecting powdered activated carbon can be more economical. Reduce the content of dissolved organic matter, but it is easy to block the subsequent laminated filter and UF

[0004] The above situation leads to the following main problems in the existing double-membrane desalination system for comprehensive sewage reuse water: ① The ultrafiltration system is susceptible to colloidal fouling, resulting in an increase in transmembrane pressure difference, a decrease in membrane flux, and a significant increase in cleaning frequency; ② The reverse osmosis system is easily polluted by heavy metal ions such as iron and manganese in the sewage, or microorganisms can grow due to the presence of organic matter in some dead ends

③ All kinds of fouling will increase the operating pressure, chemical consumption and power consumption of the double membrane desalination system

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