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Impact of salinity on the population dynamics of microorganisms in a membrane bioreactor treating produced water

Kose Mutlu, Borte, Ozgun, Hale, Ersahin, Mustafa Evren, Kaya, Recep, Eliduzgun, Selvihan, Altinbas, Mahmut, Kinaci, Cumali, Koyuncu, Ismail
The Science of the total environment 2019 v.646 pp. 1080-1089
biomass, effluents, fouling, membrane bioreactors, microbial communities, microorganisms, nanofiltration, oils, population dynamics, reverse osmosis, salinity, wastewater, wells
Biomass characteristics may change subject to a salinity increase when treating high strength wastewater. In this study, the impact of salinity in a membrane bioreactor (MBR) was investigated for the treatment of produced water (PW). MBR was operated as a pre-treatment prior to nanofiltration (NF) and reverse osmosis (RO). Mixed PW, that was originated from different oil, gas, and oil-gas wells, were subjected to pre-treatment for 146 days including three different operational phases: Low-salinity (~10 mS/cm), gradual increased salinity (10–40 mS/cm) and high salinity (~40 mS/cm). The results of this study showed that microorganisms could adapt using real wastewater and treat PW up to a certain level of the salinity. At high salinity levels of PW, the floc structure started to be disrupted and membrane fouling was accelerated. PCR-DGGE analysis confirmed the changes in microbial communities' composition in relation with high salinity. The results of the final treatment experiments presented that NF and RO treatment produced high-quality effluents that could be suitable for reuse.