采油污水生物降解性实验研究

Research of Determination Methods for Biodegradability of Oilfield Produced Waters

测定了胜利油田3类4种采出污水原样及气浮预处理水样的BOD5和CODcr,通过测定值的分析处理,对采油污水的可生化性(生化降解性)进行了考察和表征。孤五联聚驱污水BOD5/CODcr值低,为0.1101,可生化性差,大北联、渤三联水驱污水及陈庄联热采稠油污水的该比值高,分别为0.7998、0.5512、0.6237,可生化性好;气浮使各污水的该比值升高,升高率分别为63.61%和9.78%、30.04%、16.32%,使CODcr值降低,降低率分别为52.99%和19.02%、35.55%、25.68%。气浮水样生化培养前后CODcr变化值与BOD5的比值、BOD5随生化培养时间增大的趋势大小、BOD5日增大量与生化培养时间关系反映了同一结果。考察了气浮时间对孤三联聚驱污水与大北联水驱污水CODcr及其去除率、BOD5及其去除率、BOD5/CODcr值的影响,所有曲线均分为变化缓慢、急剧、缓慢三段,最佳气浮时间分别为12和10小时。

The biodegradability of 4 produced waters in 3 classes,original and air floated,was investigated through determining BOD5 and CODcr and analyzing and treating the experimental data.Produced water from a polymer flooded reservoir and taken at oil gathering/water treating plant（OG/WTP） Gu-5,had a low BOD5/CODcr value of 0.1101 and was more difficult to be biodegraded while produced waters from water flooded low permeability reservoirs and taken at OG/WTP Dabei and Bo-3 and from a thermally recovered heavy crude oil reservoir and taken at OG/WTP Chenzhuang,having high BOD5/CODcr values of 0.7988,0.5512,and 0.6237,were easily biodegradable.Air floatation raised these values of the 4 produced waters by 63.61%,9.78%,30.04%,and 16.32% and reduced their CODcr values by 52.99%,19.02%,35.55%,and 25.68%,respectively.Similar phenomena were observed and shown by changes in CODcr caused by biocultivation reduced to BOD5 for air floated produced waters,tendencies of BOD5 raise and daily increase in BOD5 in the course of air floatation.The changes of CODcr,BOD5,their removing rate and BOD5/CODcr in the course of air floatation were investigated and all these curves could be divided into slowly,dramatically and slowly changeing stages,giving an optimal floatation time of 12 and 10 hrs for produced waters from OG/WTP Gu-5 and Dabei,respectively.