Process for treating and recovering dye industrial wastewater

Abstract

The invention discloses a process for treating and recovering dye industrial wastewater. The process comprises the following steps of: collecting cyclizing wastewater, adding a calcium hydroxide solution, reacting until the pH value is 5 to 7, and recovering a precipitate to obtain calcium hydrophosphate; adding the calcium hydroxide solution continuously, reacting until the pH value is 10 to 12,and recovering a precipitate to obtain calcium phosphate; adding an acidulant for neutralizing; collecting pigment wastewater, rectifying at the temperature of between 75 and 85 DEG C, and recoveringfractions to obtain ethanol; collecting soda boiling wastewater, mixing the soda boiling wastewater and the treated cyclizing wastewater and pigment wastewater to obtain mixed wastewater, adding the acidulant into the mixed wastewater, regulating the pH value to be 2 to 4, separating a precipitate out, and performing suction filtration and distillation on the precipitate to obtain benzoic acid; and performing primary materialization treatment, biochemical treatment and advanced treatment on the treated mixed wastewater sequentially, and discharging. According to the process, useful substancesin the dye wastewater are recovered, so that the production cost is saved, the load of the subsequent wastewater treatment process is reduced, the discharge of the wastewater can reach the standard, and the economic benefit is improved effectively.

Description

technical field [0001] The invention relates to the field of comprehensive utilization and treatment of waste water, in particular to a dye production waste water treatment and recovery process. Background technique [0002] The textile printing and dyeing industry is one of the traditional pillar industries in China, but it is also a major pollutant discharger in the industry. The dye wastewater generated is large in volume and difficult to treat. It is the focus of research on wastewater treatment technology. The production process of traditional pigment red mainly includes cyclization, alkali boiling and pigmentation stages. Among them, cyclization wastewater is produced in the cyclization stage, including wastewater containing phosphoric acid and benzoic acid and washing wastewater; alkali boiling wastewater is produced in the alkali boiling stage, mainly alkaline wastewater; and pigmentation wastewater is produced in the pigmentation stage, mainly containing ethanol and...

AI Technical Summary

Problems solved by technology

Although these three methods have achieved the treatment of dye wastewater, the useful components in the dye wastewater have not been recovered, and the wastewater treatment process is cumbersome, with high energy consumption and high treatment costs.

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