Method for processing heavy metal chromium in polluted water of leather production

Abstract

The invention relates to the technical field of polluted water processing methods, in particular to the method for processing heavy metal chromium in polluted water of leather production during the leather producing process. According to the method, the heavy metal chromium in the polluted water is removed by selecting coagulation reagents to perform a reaction of the coagulation reagents and the polluted water, wherein the coagulation reagents are the compounding of a coagulation decoloring agent of which the type is WH-4A and aluminium poly chloride; the weight ratio of the coagulation decoloring agent to the aluminium poly chloride is 7:3; the coagulation reagents are poured into the pipeline totally only before the polluted water flows towards a materialization reaction tank; and the weight ratio of the polluted water to the coagulation reagents is 35:1. Due to the adoption of the method for processing the heavy metal chromium in the polluted water of the leather production, suspended matters, impurities, heavy metal chromium ions and the like in water can be effectively removed, so the discharged water meets the standard; and simultaneously, the produced sludge is pumped out by a filter press to form dry sludge and the processing is convenient.

Description

technical field [0001] The invention relates to the technical field of sewage treatment methods, in particular to a treatment method for heavy metal chromium in leather production sewage in the leather manufacturing process. Background technique [0002] During the leather manufacturing process, many chemicals are used, including chemical agents containing heavy metal chromium, and finally there will be chromium-containing substances remaining in the discharged sewage. At present, the sewage treatment method is to put "coagulant agent" in the physical and chemical reaction tank. Since the "coagulant agent" can only remove the chroma and suspended solids in the sewage, it cannot effectively remove chromium substances, and because of the "coagulant agent" Coagulant "in the physical and chemical reaction tank, the physical and chemical reaction is slow and insufficient when the water flow is small, and the chroma and suspended solids in the sewage cannot be effectively controll...

AI Technical Summary

Problems solved by technology

[0005] (1) The amount of sludge produced by iron salt coagulants is very large;

[0006] (2) The pH value required by the reaction conditions is not suitable for the pH value of sewage;

[0007] (3) The remaining salts are unfavorable to aerobic biochemical treatment and have a great impact;

[0008] (4) After treatment, the water quality is unclear and the chroma is high

[0010] However, the disadvantages of ferrous sulfate as a coagulant are: (1), Fe 2+ There will be a large amount of residual in the sewage, so that in the subsequent biochemical aeration process of the treated effluent, Fe 2+ Oxidized to Fe 3+

Fe 3+ Under neutral conditions, flocs will be produced and accumulated in the biochemical sludge, which will make the biochemical sludge mineralized, the activity is not high, and the filler is not easy to form a film, so the removal rate of COD is reduced.

In this way, the removal target of biochemical treatment cannot be guaranteed or cannot be achieved at all.

[0011] (2), due to the presence of Fe in water 3+ , so that the appearance of the effluent is yellow and turbid, it is not easy to settle down in a short time, the appearance of the effluent is not good, and the suspended matter may exceed the standard