含压裂返排液洗井废水混凝沉降实验研究

Experimental Study on Coagulation Sedimentation of Well Flushing Wastewater Con⁃taining Fracturing Flowback Fluid

通过室内配制含不同浓度压裂返排液的洗井废水,研究了不同返排液含量的洗井废水的絮凝剂加量和沉降时间。实验结果表明,水样单独加CPAM时,含10%、20%、30%(体积分数)返排液的洗井废水的CPAM最优加入浓度分别为5、6、8 mg/L;含10%返排液的洗井废水在CPAM加入浓度为5 mg/L、PAC加入浓度为250 mg/L、沉降4 h的条件下,含油浓度和悬浮固体浓度可分别降至7.5和16.5 mg/L;含20%返排液的洗井废水在CPAM加入浓度为6 mg/L、PAC加入浓度为300 mg/L、沉降4 h的条件下,含油浓度和悬浮固体浓度可分别降至6.9和18.9 mg/L;含30%返排液的洗井废水在CPAM加入浓度为8 mg/L、PAC加入浓度为350 mg/L、沉降4 h的条件下,含油浓度和悬浮固体浓度可分别降至7.1和16 mg/L,满足现场处理指标。

The addition of flocculant and settling time of well flushing wastewater with different concentration of backflow fluid are studied by laboratory preparation.The experimental results show that when the water sample is added with CPAM alone,the optimal CPAM addition concentration of the flushing wastewater with 10%,20%and 30%(volume fraction)is 5,6 and 8 mg/L,respectively.Under the conditions of CPAM addition concentration of 5 mg/L,PAC addition concentration of 250 mg/L and sedimentation concentration of 4 h,the concentration of oil and suspended solids can be reduced to 7.5 and 16.5 mg/L,respectively.Under the conditions of CPAM addition concentration of 6 mg/L,PAC addition concentration of 300 mg/L and sedimentation for 4 h,the concentration of oil and suspended solids can be reduced to 6.9 and 18.9 mg/L,respectively.Under the conditions of CPAM addition concentration of 8 mg/L,PAC addition concentration of 350 mg/L and sedimentation for 4 h,the concentration of oil and suspended solids can be reduced to 7.1 and 16mg/L,respectively,meeting the on-site treatment targets.