Treatment method of heavy metal wastewater

Abstract

The invention provides a treatment method of heavy metal wastewater, and particularly relates to a method for treating heavy metal wastewater by virtue of a precipitation method. The method comprises the following steps: adding sodium sulfide in a heavy metal wastewater treatment process, reacting sulfur ions with heavy metal ions in the wastewater to generate particulate matters, further adding sulfide precipitates of heavy metal, stirring, standing, and accelerating the sedimentation of micro particulate matters and other substances by using generated particulate matter precipitates; further preferably adding quartz sand, and accelerating the rapid sedimentation of the particulate matters and other substances under the wrapping action of quartz sand; further performing subsequent process treatment including sand filtration and ion exchange on a supernatant liquor obtained after sedimentation to reach the emission standard; and periodically discharging and collecting part of the precipitates, and recycling heavy metals in the precipitates. Because the method provided by the invention is simple in working procedure, low in cost and high in efficiency, the method can be widely applied to the treatment of industrial wastewater particularly the heavy metal wastewater.

Description

technical field [0001] The invention belongs to an industrial sewage treatment method, in particular to a method for treating heavy metal wastewater discharged from the chemical plating industry and realizing resource recycling. Background technique [0002] Electroplating is a process that uses chemical methods to decorate, protect and obtain some new properties on metal and non-metal surfaces. In order to ensure the quality of electroplating products, so that the metal coating has a smooth and good appearance and is firmly combined with the substrate, the dirt (oil, rust, scale, etc.) on the surface of the plating (substrate) must be thoroughly cleaned before electroplating. And after electroplating, clean the adhesion solution on the surface of the plated parts. Therefore, a large amount of wastewater must be discharged during the electroplating production process. The composition of electroplating wastewater is complex. The pollution caused by it is roughly: the pollu...

AI Technical Summary

Problems solved by technology

However, at present, there are still some problems in the biological treatment of electroplating wastewater: the reaction efficiency of functional bacteria needs to be improved; the reproduction speed of functional bacteria is slow; the treated water is difficult to reuse

The electroplating wastewater treated by electrodialysis requires a high concentration of metal ions, and there is a problem of concentration polarization, which causes membrane scaling and affects the life of the membrane.

[0011] Although the prior art CN101239761A discloses a method for reclaiming nickel sulfate precipitates from waste water by using sodium sulfide and nickel hydrochloride precipitation, it is difficult to rapidly settle other particles in the waste water, and it is difficult to achieve the purpose of rapid treatment of heavy metal waste water

[0012] Among the various existing methods for treating electroplating wastewater, the most widely used is the precipitation method, which has the advantages of simple operation, easy access to raw materials, low treatment cost, convenient management, and comprehensive removal of harmful components of electroless nickel plating waste liquid; but It also has its disadvantages, the sedimentation speed is slow, and additional coagulants and flocculants are required

This has caused the disadvantages of increased mud production and heavy metals are not easy to recover

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