A zero-discharge treatment method and system for electroplating wastewater

Abstract

The invention belongs to the field of heavy metal wastewater treatment, and particularly relates to an electroplating wastewater zero-discharge treatment method and system. The electroplating wastewater zero-discharge treatment method comprises the following steps: a. sending collected electroplating pretreatment wastewater into an organic wastewater collecting well, and pumping the organic wastewater in the collecting well into a regulating tank; b. respectively pumping cleaning water into a chemical reaction tank by a lifting pump, and pumping supernates in all precipitation tanks into the regulating tank; c. sending the wastewater in the regulating tank into an external membrane bioreactor and a tubular microfiltration membrane system to carry out solid-liquid separation, and sending the product water into a clear water tank; d. absorbing water from the clear water tank by using a high-pressure pump of a reverse osmosis membrane separation system, sending the produced water into a reuse water tank, sending concentrated water of the reverse osmosis membrane separation system into a reverse osmosis circulating concentration system; and e. evaporating to purify heavy metals, recovering the heavy metal salts, and enabling the distilled water to flow back into the regulating tank. The method effectively integrates the chemical precipitation technique, external membrane bioreactor technique, reverse osmosis membrane separation and concentration technique, low-temperature evaporation separation technique and the like; and in the electroplating cleaning wastewater treatment and recovery process, the water recovery rate is up to 95% above, and all the solid metal salts are recovered.

Description

technical field [0001] The invention relates to the field of heavy metal wastewater treatment, in particular to a zero-discharge treatment method and system for electroplating wastewater. Background technique [0002] At present, the mainstream process for treating electroplating wastewater at home and abroad is still the chemical precipitation method, that is, by adding agents such as sodium hydroxide (NaOH) or sodium sulfide (NaS), the heavy metal ions in the wastewater form the hydroxide or sulfide of the metal. substances, precipitated under optimal pH conditions. The sludge is press-filtered into a mud cake, which is transported to a qualified hazardous waste disposal unit for disposal. [0003] In recent years, on the basis of the chemical precipitation method, biological treatment or submerged membrane bioreactor treatment facilities have been added in China, and the water reuse rate has reached 60%. However, the existing electroplating wastewater treatment process ...

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Problems solved by technology

[0004] The invention provides a zero-discharge treatment method and system for electroplating wastewater, aiming to solve the problem that the existing reverse osmosis influent pretreatment process has a low degree of automation, high labor intensity, and unstable effluent quality, making it difficult to ensure subsequent reverse osmosis Technical problems of long-term stable operation of desalination equipment

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