Method for treating coal tar sewage

Abstract

The invention discloses a method for treating coal tar sewage. The method comprises the following steps that: (1) the pretreated coal tar sewage is introduced into a catalytic wet oxidation unit to be treated, wherein the reaction pressure of the catalytic wet oxidation unit is 3 to 9MPa, reaction temperature is between 200 and 290 DEG C, a catalyst can be a noble metal catalyst, a metal oxide catalyst or a composite metal catalyst, retention time is 45 to 75 minutes, and chemical oxygen demand (COD), ammonia nitrogen, volatile phenols, CN<-> and sulfides in the sewage are removed; and (2) water is discharged by the catalytic wet oxidation unit and enters an electrolytic advanced oxidation unit, wherein solid diamond alloys are used as an anode and a cathode of the electrolytic advanced oxidation unit, the voltage of the anode and the cathode is 220V, current is 20 to 80A, water in the sewage is electrolyzed to form hydroxyl with high oxidability by electrifying the anode and the cathode, and the rest pollutants such as the COD, the ammonia nitrogen, the volatile phenols and the like in the sewage are further subjected to oxidative decomposition by the hydroxyl. By the method, the effluent index of a sewage treatment system reaches the primary standard in the 'comprehensive sewage discharge standard'.

Description

technical field [0001] The invention relates to a treatment method for sewage, more precisely, relates to a treatment method for coal tar sewage, and belongs to the technical field of environmental protection. Background technique [0002] Medium-temperature coal tar is mainly the product of dry distillation of lignite and other weakly caking coals in vertical carbonization furnaces. Due to the trend of large-scale and centralized tar processing, the processing of medium-temperature coal tar and its environmental problems have attracted more and more attention. Wastewater problem is one of the main problems affecting the environment, especially with the large-scale medium-temperature coal tar processing industry, the problem of difficult wastewater treatment has emerged. Coal tar wastewater contains high concentrations of COD, phenols and other substances, with poor biochemical properties and extremely difficult to treat. Due to the lack of effective coal tar treatment met...

AI Technical Summary

Problems solved by technology

Coal tar wastewater contains high concentrations of COD, phenols and other substances, with poor biochemical properties and extremely difficult to treat

Due to the lack of effective coal tar treatment methods, the industry generally adopts a combination of physical and chemical methods and biochemical methods for treatment, and it is difficult to discharge the effluent after treatment.

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