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In order to improve oil/gas production,fracturing is widely adopted in every oil fields.Waste fluid generated in the process of fracturing which mainly includes fracturing outlet liquid and residual fracturing fluid. The residual fracturing fluid has become one of the current oil/gas field water polluntion sources. Researehing the treatment method of residual fracturing fluid has the important meaning to control oil/gas field waste.This paper made a systematic exposition of souree,constitute,pollutant characteristic and present conditions of residual fracturing waste fluid,and through the analysis on many pollutants in the residual fracturing fluid, it is determined COD,oil,SS and chroma are the main pollutants.According to the degradation of COD, this paper proposes the treatment method with the combination of primary and advanced treatment,and mainly studies the best experimental conditions in each processing.The primary treatment stage includes three parts: NaClO oxidation,bleaching powder oxidation and chemical coagulation,extremely decreases COD so as to make the processing results meet the requirements of advanced treatment.The advanced treatment stage also includes three parts: Fenton oxidation, activated carbon adsorption and TiO2 photocatalysis oxidation,ensuring processing results meet wastewater discharge standard.After primary treatment,the effluent water is clean and transparent, the COD of residual fracturing fluid decreased to 1499.53mg/L from 5409.92mg/L, the removal rate reaches 72.28%. After advanced treatment, the COD of residual fracturing fluid decreased to 149.05mg/L from 1499.53mg/L, the removal rate reaches 90%.Through the treatments,the removal rate of COD reaches 90%,which met theⅡgrade of“Integrated wastewater discharge Standard”, and other pollutants also came up to the standard.
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