Chromium-containing wastewater treatment and upgrading process

Abstract

The invention relates to a chromium-containing wastewater treatment and upgrading process which is characterized by comprising the following steps: (1) physicochemical pretreatment of chromium-containing wastewater is carried out, namely, the chromium-containing wastewater sequentially passes through a reduction tank, a complex breaking tank, a first pH regulating tank, a first coagulation reaction tank, a first sedimentation tank, a second pH regulating tank, a second coagulation reaction tank, a second sedimentation tank, a third pH regulating tank and a sand filter; (2) the wastewater whichis pretreated in the step (1) and has pollutants reaching the standard is divided into high-salt water and low-salt water according to the salt concentration in the wastewater, wherein after the low-salt water is subjected to biochemical treatment, sand filtration, ultrafiltration and reverse osmosis, the produced water is recycled as reuse water, and the concentrated water and the high-salt water are mixed and enter a high-salt wastewater regulating tank; and (3) electrolytic oxidation, primary precipitation, secondary precipitation and sand filtration are sequentially carried out on the wastewater in the high-salinity wastewater regulating tank, and the wastewater is discharged into a quasi-discharge tank after reaching the standard. The treatment system designed by the invention can adapt to changes of water quality and water quantity of wastewater, and is simple in treatment process, reasonable in investment and small in occupied area.

Description

technical field [0001] The invention relates to a process for treating chromium-containing wastewater, in particular to a process for improving the standard of chromium-containing wastewater, and belongs to the technical field of environmental protection. Background technique [0002] At present, the pollutants in chromium-plating wastewater are mainly chromium pollution, of which chromium pollution will cause damage to water bodies, soils, and ecology. Currently, the commonly used chromium-containing wastewater treatment methods mainly include the following: [0003] (1) Chemical precipitation method: The principle is to add a chemical precipitation agent to produce a chemical reaction to generate insoluble chemical substances, so that the pollutants are precipitated. The advantages are: simple, effective, and low cost. As long as the choice of chemical reaction agent is correct, the dosage can be accurately calculated according to the chemical reaction equation. The disad...

AI Technical Summary

Problems solved by technology

The disadvantages are: poor solid-liquid separation will often affect the effect of chemical precipitation. Generally, various polymer flocculants must be used together, but it will lead to the introduction of impurities, and the amount of sediment is large, which is easy to cause secondary pollution and other problems.

The disadvantages are: it is easy to be saturated with certain mixed flow water, frequent regeneration, and difficult to operate

The disadvantage is that the application of evaporation and concentration consumes a lot of energy and is not economically cost-effective

Disadvantages are: the specifications of the membrane are generally nanoscale, and its pore size is small, so a series of pretreatments are required before entering the membrane treatment

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