High-salt complex wastewater reuse and zero discharge integrated equipment and technology

Abstract

The invention relates to high-salt complex wastewater reuse and zero discharge integrated equipment and a technology. The equipment provided by the invention comprises a pretreatment system, a reuse and reduction system and a zero discharge system. The technology comprises the following steps: carrying out homogenization and averaged quantity on high-salt complex wastewater, successively adding sodium hydroxide, sodium carbonate, PAC and PAM to carry out coagulation treatment, letting a mixed liquor which has undergone coagulation treatment enter a filter tank for sedimentation and filtration by the use of an immersed microfiltration membrane, letting a supernatant enter a reverse osmosis treatment process, letting pure water obtained by reverse osmosis treatment enter a reuse water tank for utilization, further condensing condensed brine, and crystallizing the condensed brine or putting the condensed brine into an evaporation pond for atomization and evaporation processing, wherein the reverse osmosis treatment adopts three-level RO: a medium-pressure membrane element is firstly used for desalination and condensation; a high-pressure membrane element is then used for further desalination and condensation; and a ultrahigh-pressure membrane element is finally used for further desalination and condensation. According to the invention, 95% of reverse osmosis concentrated water or analogous high-salt complex wastewater can be recovered for reutilization, only 5% of high strong brine is left to undergo evaporative crystallization or enter the natural evaporation pond. Water resources are fully recycled, and reuse and zero discharge costs of high-salt complex wastewater are reduced.

Description

technical field [0001] The invention relates to a comprehensive treatment equipment and process for high-salt complex wastewater, which is a multi-equipment integrated system aimed at the reuse and zero discharge of industrial reverse osmosis concentrated water and complex wastewater with high salt content and high organic content. Background technique [0002] In recent years, more and more attention has been paid to the waste water and circulating cooling sewage generated in industrial production processes such as electric power, metallurgy, oil refining, and coal chemical industry. With the continuous increase of the cost of water resources and the strengthening of the state's control over corporate sewage discharge, sewage reuse technology has been widely popularized. During this process, reverse osmosis membrane technology (RO) has gradually become an important means in the fields of industrial circulating water treatment, wastewater reuse and seawater desalination. ...

AI Technical Summary

Problems solved by technology

[0003] However, there are still two problems in the use of reverse osmosis technology: one is the high desalination rate of reverse osmosis technology. Generally, the stable desalination rate of reverse osmosis equipment is above 98%, that is, more than 98% of the salt enters the reverse osmosis concentrated water; Second, the water recycling rate is low, which generally can only reach 70%-80%, and about 20%-30% of concentrated water is still discharged. The large discharge volume has caused a huge waste of water resources.

[0005] Comprehensive analysis of the above three schemes, the first scheme is only for the treatment of organic matter in wastewater, however, general sewage treatment is through a long process of biochemical treatment, the remaining part of the organic matter is extremely poor in biodegradability, or even non-biochemical, Therefore, the removal effect of this part by chemical catalytic oxidation alone is very limited. The most important thing is that it has no removal effect on the high-salt components of wastewater, and high-concentration salt will reduce the biochemical operation effect; the second option Despite its rationality in theory, reverse osmosis concentrated water is high-salt wastewater that has been concentrated at least 4 times from raw water, and all scaling ions such as calcium and magnesium, heavy metal ions, silicon ions, etc. The concentration of pollutants such as biochemical organic matter is already very high. Therefore, the recovery rate of the wastewater by ordinary reverse osmosis membranes is extremely low, and even seawater desalination membranes can only achieve 40-55%, and the remaining concentrated water is still relatively large. The third option is the most thorough treatment of high-salt wastewater, and the relative technology is also the most mature. The disadvantage is that the treatment cost is too high, and a large amount of steam is required in the process. High salt water is used for treatment, and the evaporation and crystallization reaction equipment has high requirements on materials, resulting in too much one-time investment

Images