Treatment system and treatment method for reducing amount of volatile heavy metal sludge in desulfurization wastewater

Abstract

The invention relates to a treatment system and a treatment method for reducing the amount of volatile heavy metal sludge in desulfurization wastewater. A two-stage chemical precipitation technique is adopted to treat desulfurization wastewater, hydrochloric acid is added to regulate the wastewater in the first stage of chemical precipitation, so that the wastewater becomes acidic, polyaluminium chloride as polycoagulant and polyacrylamide as coagulant aid are added for flocculation reaction, consequently, the content of the volatile heavy metal in the sludge in the first stage of chemical precipitation is greatly reduced, while the amount of the sludge is increased, and thereby the sludge can be added into a boiler and burnt; calcium hydroxide is added to regulate the wastewater in the second stage of chemical precipitation, so that the wastewater becomes alkaline, heavy metal precipitator-organic sulfur (TMT15) is added to combined with the heavy metal in the wastewater to form highly stable chelate, molysite as polycoagulant and polyacrylamide as coagulant aid are added, so that the sludge in the second stage of precipitation is rich in the heavy metal, while the amount of the sludge is little, and thereby the sludge can be buried alone. Hydrochloric acid and sodium hypochlorite are added into clean water, so that the treated discharged water can meet the requirements of GB8978-1996 and DL / T 997-2006 standards.

Description

technical field [0001] The invention belongs to the field of cleaning and environmental protection, and in particular relates to a desulfurization wastewater volatile heavy metal sludge reduction treatment system and treatment method. After treatment by this method, the heavy metals in the desulfurization wastewater are concentrated in a small amount of sludge, which can be buried separately, and most of the remaining sludge containing less volatile heavy metals can be mixed with coal and sent to the boiler for incineration. Background technique [0002] At present, the conventional wet desulfurization wastewater treatment of power plants adopts a single-stage chemical precipitation method. After adding slaked lime, coagulant, coagulant, organic sulfur and other chemicals to the wastewater, the solid-liquid separation is carried out in the clarifier, and the clean water is added After adjusting the pH value with hydrochloric acid to meet the requirements of GB8978-1996 "Comp...

AI Technical Summary

Problems solved by technology

In order to reduce the disposal cost of desulfurization waste cement slag, it can be considered to mix it with coal and send it to the coal-fired boiler of the power plant for incineration, but because the slag contains volatile heavy metals (mainly mercury), it will return to the flue gas after direct incineration , resulting in an increase in the concentration of volatile heavy metals in the final exhaust flue gas, which is not conducive to the protection of the atmospheric environment

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