稠化酸返排液深度处理试验研究

Experimental Study on Depth Treatment of Thickened Acid Flowback Liquid

针对陕北某气井稠化酸返排液pH值低、SS高、COD高、矿化度高和透光率低的特点,提出采用微电解-Fenton联合工艺处理稠化酸返排液,以期达到降低返排液COD,为后续混凝和活性炭吸附处理提供有利条件。试验结果表明:在铁屑20g、活性炭15g、H_2O_2 900mg/L,微电解-Fenton联合处理2h;调节pH值至7.5左右,PAC 700mg/L、PAM 50mg/L,混凝处理30min;活性炭40g/L,活性炭吸附处理40min的条件下,处理后的稠化酸返排液pH值为7.50、SS降至15mg/L、COD降至109.3mg/L、透光率提高至99.5%,水质达到GB 8978—1996《污水综合排放标准》二级标准。

Aiming at the characteristics of low pH,high SS content,high COD,high salinity and low light transmittance of the thickened acid flowback liquid from a gas well in North Shaanxi,this paper proposes a technology combined with microelectrolysis and Fenton to decrease the COD of the flowback liquid and to provide advantage for further coagulation and activated carbon adsorption treatments.The treatment conditions were as follows:20g of iron scrap,15 g of activated carbon,900mg/L of H_2O_2,with 2hours'reaction,30 min coagulation treatment by adding 700 mg/L of PAC and 50 mg/L of PAM,and 40 min of activated carbon adsorption.The SS and COD of the treated liquid decreased to 15mg/L and 109.3mg/L and the light transmittance increase to 99.5%,which met the requirements in'Integrated Wastewater Discharge Standard'(GB 8978—1996).