长庆高矿化度含油污水生化处理新技术研究及应用

Research and Application on High Salinity Oily Sewage Treatment by Biochemical Technology

针对长庆油田低渗透、非均质性强、地层水矿化度高等特点,以试验区活性污泥和油污土壤为菌源,应用物理诱变选育技术,研发出可在矿化度10～100 g/L范围存活的本源高效菌种体系Ca-Vi。室内开展了该菌种除油效果评价及对原油的降解作用、污水腐蚀性等试验研究。结果表明,该菌种除油效果明显,除油率可达91%以上,生化处理后含油量均低于10.0 mg/L;微生物对ZJ站、YY1站大分子原油降解效果较好;污水经生化处理后腐蚀性降低,XW5和YY1站现场挂片试验,腐蚀速率由0.228 mm/a和0.4231mm/a分别降至0.066 mm/a和0.0213 mm/a。污水生化处理工艺适用于处理pH 6～8、温度20～35℃、CODcr≤2000 mg/L、含油量≤250 mg/L的污水;处理初期投加的微生物菌种活性大于1014个/mL,曝气池中溶解氧≥2 mg/L。处理后水中含油≤10 mg/L,有机杂质≤15 mg/L,达到油田污水回注水质标准,且运行稳定。现场试验效果证明,长庆高矿化度采出水生化处理新技术有进一步扩大规模、推广应用的良好前景。

Considering the characteristics of low permeability,strong heterogeneity and high salinity of Changqing oilfield,the high efficient indigenous microbial strains Ca-Vi,which can live with the salinity of 10～100 g/L,had been developed by the physical mutagenesis breeding techniques using the activated sludge and oil polluted soil of pilot area as the bacteria source.The strain deoiling effect evaluation,oil degradation test and produced water corrosive test were conducted.The results showed that the Ca-Vi microbial strains had significant deoiling effect,as a result,the oil removal rate was over 91% and oil content was lower than 10.0 mg/L after biological treatment.The Ca-Vi microbial strains had good oil degradation effect on the macromolecule crude oil of ZJ station and YY1 station.The corrosion rate of the produced water of XW5 station and YY1 station decreased from 0.228 mm/a to 0.066 mm/a and from 0.4231 mm/a to 0.0213 mm/a,respectively,after biological treatment.The biological treatment technology could be applied to treat the produced water with pH 6～8,20～35℃,CODcr≤2000 mg/L,oil content≤250 mg/L,in the initial treatment stage the number of vial bacteria should be above 1014 per mL,and the content of the dissolved oxygen in aeration tank should be over 2 mg/L.The oil content of the purified water was≤10 mg/L,and the mechanical impurity was≤15 mg/L,reaching to the reinjection standard of the produced water.Field test results demonstrated that the new high salinity oily sewage treatment technology of Changing oil filed had the good prospect of further expansion and application.