Biological Treatment of Synthetic and Real Oilfield Produced Water of Varying Salinity Using an Isolated Halophilic Bacterial Consortium

Produced water or oilfield wastewater is the largest volume of a waste stream associated with oil and gas production and is a mixture of different organic and inorganic compounds including a high concentration of salt. The aim of this study was to investigate the treatment of synthetic and real produced water using a consortium of isolated halophilic bacteria from oil-contaminated salinesoil. Also the influence of different NaClconcentrations in the range 10-200 g L-1 on the performance of this consortia of halophilic microorganisms for biodegradation of syntheticproduced water has been investigated. The performance and efficiency of these isolated bacteria has been studied by obtaining the COD and OD (in 254 nm) and total protein concentration data. The results of runs with synthetic produced water with NaCl concetration of 50 g L-1 showed protein concentration of around 127.4 mg L-1 after 5 days of incubation, COD removal of 75% after 15 days of incubation and hydrocarbon removal of 94.5% after 7 days of incubation. The results of runs at different salt concentrations showed that the highest COD removal efficiency (75.2%) and concentration of total protein (122.01 mg L-1) was achieved at a NaCl concentration of 50 g L-1. Experiments with real produced water obtained from Cheshme khosh oilfield showed that despite the high concentration of salt (190 g L-1) in this wastewater, relatively high CODremoval efficiencies (around 87.2%) were obtained after 40 days.extracellular polymeric substances (EPS) and soluble microbial products (SMP) were also measured and a preliminary run was also carried out in a membrane bioreactor (MBR) which indicated that membrane can have a minor role in the removal of pollutants from produced water and also membrane fouling might not be very serious. The findings of the present work indicate that the use the isolated halophilicbacterial consortium in a membrane bioreactor can potentially be a suitable strategy treatment of Iranian oilfield produced waters. for the

کلیدواژه ها:

produced water ، halophilic bateria ، biological treatment ، salinity