Method for processing chrome wastewater

Abstract

The invention improves the reduction-precipitation process of traditional hexavalent chrome wastewater, changes the pH value of the trivalent chromium ion precipitation in the original process, and avoids the problem that the treated yielding water does not reach the mark caused by that the trivalent chromium precipitation is oxidized newly to generate the hexavalent chrome when performing the settlement and the filtering under the alkalescence condition. When avoiding the trivalent chromium is easily oxidized under the alkalescence condition, the adding quantity of reducing agent can be effectively reduced when reducing the hexavalent chrome. During the settlement procedure of the trivalent chromium ion in the process, the originally required precipitation pH value range 8.5-9.5 is changed, and the pH value range is adjusted to 6.0-6.3. After the settlement and the filtering, an adsorption unit is added. Treated earthnut shells are adopted to be used as a sorbent, so the trivalent chromium ion left in the solution after the adsorption and the filtering can be effectively adsorbed to lead the discharging of the yielding water to reach the mark. The sorbent containing the adsorption adopts acid solution with the pH value being 2-3 for the elution, and eluant can enter into a reduction reactor for adjusting the pH value of raw water.

Description

Technical field: [0001] The invention belongs to the technical field of environmental engineering, and in particular relates to the treatment of chromium-containing wastewater by adopting a method combining chemical precipitation and biological adsorption. Background technique: [0002] As we all know, almost all electroplating factories have chromium plating production lines, and chromium salts are also required for pre-plating and post-plating treatments of other plating types, so the amount of chromium-containing wastewater is predictable. my country's treatment of chromium-containing wastewater has a long history, which can be divided into chemical adsorption method, ion exchange method, electrolysis method, membrane separation method and so on. my country's treatment of chromium-containing wastewater has also gone through several stages of development. [0003] In the 1960s, a small number of domestic electroplating factories used ferrous sulfate-lime method to treat c...

AI Technical Summary

Problems solved by technology

[0003] In the 1960s, a small number of domestic electroplating plants used ferrous sulfate-lime method to treat chromium plating wastewater. Although this method can eliminate Cr 6+ pollution, but there is a large amount of sludge and there is no way out, so it has to be discarded

The above reasons will cause the treatment of chromium-containing wastewater to fail to meet the standard

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