System and method for treating water recycled from straw pulp papermaking wastewater

Abstract

The invention discloses a system and a method for treating water recycled from straw pulp papermaking wastewater. The system is formed by sequentially or respectively connecting a regulating tank, a primary efficient coagulative precipitation tank, a secondary efficient coagulative precipitation tank, a middle water tank, an ultrafiltration membrane treatment device, a reverse osmosis membrane treatment device, an ozone contact oxidation tower, an active carbon adsorption tower, an acid regulating tank, a higher oxidization reaction tank, a neutralizing precipitation tank and a water-producing tank. The system organically combines the coagulative precipitation treatment, the higher oxidization treatment, the ozone catalysis oxidation treatment and the treatment of an ultrafiltration membrane and a nanofiltration membrane, treats the water recycled from the straw pulp papermaking wastewater by using a physical and chemical treatment technology and a shunting treatment and combined effluent treatment process and mode, can ensure that the large scale recycled water of the straw pulp papermaking industry reaches the requirement of reuse water after treated and does not affect a papermaking process and a paper product on the premise of ensuring the low operating cost, and the treated reverse osmosis concentrated water reaches the emission standard of the industry.

Description

technical field [0001] The invention relates to the field of wastewater treatment, in particular to a reclaimed water treatment system and treatment method for advanced treatment of straw pulp papermaking wastewater. Background technique [0002] At present, there are many methods for the reuse of water in straw pulp and papermaking wastewater, which are mainly divided into physical methods and chemical methods. [0003] Through treatment measures such as coagulation and sedimentation, adsorption, and chemical oxidation, it is still difficult to completely eliminate water quality indicators such as dissolved solids, chromaticity, chemical oxygen demand, and electrical conductivity in reclaimed water, and incompletely purified reclaimed water is still in production due to poor water quality. It cannot be reused on the surface, and it often causes pollution and harm to the surrounding ecological environment when it is discharged externally. Some more advanced treatment proces...

AI Technical Summary

Problems solved by technology

However, this technology that only uses coagulation and filtration can no longer meet the strict treatment requirements of water quality indicators.

Due to the huge amount of water consumed by the paper industry, if the adsorption method is used to treat reclaimed water, a large amount of adsorbents are required. After the adsorption of these adsorbents is saturated, there will be a complex regeneration process, which is difficult to operate and difficult to realize.

However, the chemical oxidation method, such as advanced oxidation technology, has a good removal effect on organic matter and chroma, but the operating cost is also high, and it does not remove dissolved solids and conductivity, and cannot meet the water quality requirements of industrial reuse water.

[0004] Membrane technology is a relatively mature wastewater advanced treatment process. After membrane filtration, the quality of effluent water can fully meet the requirements for reuse, but there are still 10% to 25% of concentrated water that cannot be solved. The biodegradability of this part of water is even worse. And the concentration of pollutants in it is relatively high, which still needs to be treated, which makes the membrane treatment process unable to complete the advanced treatment requirements alone. If other treatment facilities are added, the already high treatment costs will continue to increase

Moreover, for the water in papermaking, there will be many fine fibers and silicate dissolved solids in the wastewater. These fibers and silicate scaling can easily block the membrane pores. They are different from ordinary calcium and magnesium scaling. Cleaning It is very difficult, so that the life of the membrane module is shortened sharply, the depreciation cost is increased, and even the normal operation cannot be achieved.

[0005] Due to the large water volume and complex water quality of papermaking wastewater, the existing single treatment process cannot meet the treatment requirements for reclaimed water reuse, but how to realize the application of membrane treatment technology in the reclaimed water of straw pulp and papermaking wastewater as much as possible to reduce the operating cost Cost, concentrated water volume and treatment costs are the problems that need to be solved at present

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