Leather wastewater treating method

Abstract

The invention discloses a leather wastewater treating method, comprising the following steps: (1) allowing chromium-containing wastewater to enter into a reaction tank for a reaction, subjecting settled sludge to press filtration with a filter press, separating chromium mud for separate treatment and allowing an obtained filtrate to enter into a regulating tank; (2) filtering rest wastewater (raw hide and skin washing water containing high-concentration Cl, alkaline depilation liming wastewater containing calcium and sulfur and degreasing wastewater containing grease and other saponified matters) with gratings and then allowing the rest wastewater to enter into the regulating tank; (3) adjusting the wastewater in the regulating tank (to a pH value of 7 to 8) and delivering the wastewater to an air floatation tank; (4) removing grease in the air floatation tank through air floatation, delivering obtained sludge to a sludge tank and allowing obtained liquid to enter into an anoxic tank for treatment; (5) allowing wastewater treated in the anoxic tank to enter into an aerobic tank; and (6) allowing wastewater treated in the aerobic tank to enter into a secondary sedimentation tank for treatment so as to obtain wastewater according with emission standards. With the method, the wastewater reaches national emission standards.

Description

technical field [0001] The invention relates to the field of wastewater treatment, in particular to a leather wastewater treatment method. Background technique [0002] Leather production can be divided into two parts, wet operation and dry operation. The wet operation is mainly the preparation section and the tanning section, and the dry operation is mainly the finishing section. The production links and their main pollutants are shown in the table below. [0003] [0004] Source of wastewater: Production wastewater is mainly composed of the following parts: raw hide washing water containing high concentration of Cl, alkaline depilation and liming wastewater containing calcium and sulfur, degreasing wastewater containing oil and other saponified substances, chromium containing trivalent chromium Tanning wastewater and fatliquoring dyeing wastewater, among which degreasing wastewater, dehairing and liming wastewater and chrome tanning wastewater are the most polluted. ...

AI Technical Summary

Problems solved by technology

[0005] The main characteristics and treatment difficulties of wastewater: due to the use of a large amount of organic raw materials in the production process, the content of organic matter in the wastewater is high; due to the use of dyes, tanning agents and other auxiliary agents in the production, the chroma of the wastewater is relatively high; The sulfide and protein in the water are decomposed, and the wastewater has a strong odor; because the water contains sulfide and chromium salts, the wastewater has strong toxicity; because of the raw materials, the wastewater has a high oil content

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