A deep treatment process for electroplating sewage

Abstract

The invention discloses an advanced treatment process for electroplating sewage. The process is characterized by comprising the following steps: A, preparing a wax-containing sewage treatment agent; B, preparing an advanced treatment agent; C, preparing a coagulation accelerant; D, splitting sewage; E, treating wax-containing sewage; F, treating cyanogen-containing sewage; G, treating chromium-containing sewage; H, treating comprehensive sewage; and I, carrying out coagulating sedimentation. Compared with the prior art, the process disclosed by the invention has the advantages that 1, almost COD (Chemical Oxygen Demand) in electroplating sewage is originated from wax-containing sewage, the electroplating sewage is independently treated, and the wax-containing sewage treatment agent is specialized to remove phosphate radicals, silicates, surfactants, COD and some heavy metals together in coprecipitation, and meanwhile, components which can complex with heavy metals are removed; 2, for sewage without cyanogen and chromium by conventional processes, the advanced treatment agent is further added under an acidic condition, wherein Fe<3+> and Fe<2+> have a synergistic effect to make up the damage caused by insufficiency or over-dosage of medication in cyanogen- and chromium-containing pretreatment.

Description

technical field [0001] The invention relates to a sewage treatment process, in particular to an electroplating sewage advanced treatment process. Background technique [0002] Traditionally, each electroplating plant only pre-treats the cyanide-containing sewage separately, basically mixing the wax-removing water with the sewage containing copper, chromium, nickel, and zinc for pretreatment, and then mixing it with the pretreated cyanide-containing sewage Finally, add alkali or lime to adjust the pH to about 8, add a small amount of PVA (some factories do not add it) and a small amount of PAM, and coagulate and precipitate. There are following deficiencies in this treatment method: 1. Although the ORP potentiometer is used to control the dosage of cyanide-containing sewage at present, the potentiometer is all installed on the continuous sewage treatment system, but sometimes the sewage is less and cannot be treated with the continuous system , it is necessary to use artific...

AI Technical Summary

Problems solved by technology

There are following deficiencies in this treatment method: 1. Although the ORP potentiometer is used to control the dosage of cyanide-containing sewage at present, the potentiometer is all installed on the continuous sewage treatment system, but sometimes the sewage is less and cannot be treated with the continuous system , it is necessary to use artificial dosing treatment, it is difficult to achieve proper medication; 2, the chromium-containing sewage is adjusted to about PH=3 with sulfuric acid, and then sodium metabisulfite is added. 6+ ) to blue (Cr 3+ ), the dosage is also difficult to be accurately put in place; 3, then the sewage in the aforementioned 1st and 2nd steps is mixed, adjust about PH=8 with lime or caustic soda, then add a small amount of PVA (the factory that has even does not add) and a small amount PAM, let it settle and separate before discharge

If the NaCl0 in the cyanide-containing sewage is excessive, the Cr 3+ Oxidized to Cr 6+ , if the dosage of cyanide-containing sewage is insufficient, CN - The treatment is not clean, not only the cyanide exceeds the standard, but also heavy metals such as copper, nickel, zinc and CN - Both complexes exceed the standard. At the same time, the COD of the wax removal water is very high, and there are substances complexed with heavy metals, so it is difficult to meet the standard.