The Use of Indigenous Microbial Populations for Biological Treatment of Iranian Oilfield Produced Water

In the present study, possibility of the enrichment of indigenous halophilic and halotolerant prokaryotic consortia from samples obtained from various locations of several Iranian oilfield produced water (PW) desalination units and ability of the individual consortia for COD removal from the PW were investigated. Enrichment was carried out via four subcultures of the various microbial sources using different media. PW of three different desalination units were selected and different source of microorganisms from PW and soil contaminated with PW were applied for enrichment. The enrichment media included PW, PW amended with yeast extract (YE) (0.1% m/v), PW amended with YE and multivitamin solution (0.02% v/v) and MH medium containing autoclaved crude oil (0.05% v/v). The extent of microbial growth in enriched samples was determined using OD and/or protein content measurements. OD and protein data showed that microbial sources cultured in MH medium had higher growth than those cultured in PW. However, reasonable growth was obtained when the enrichment was carried out in PW amended with YE/multivitamin solution. Soil based microbial sources enriched in PW media amended with both YE and multivitamin solution resulted in meaningfully higher extent of growth compared to the corresponding enrichment carried out in PW media amended with YE. However, there was no meaningful difference between the extent of growth observed in the enriched media using the different microbial sources. The extent of the biodegradation of the organic content of the PW media during the enrichment procedure was assessed using COD measurements and reasonable COD removal efficiency was observed. However, linear correlation analysis revealed no statistically significant correlation between the OD and COD removal effieiceny of the enriched samples. The findings of the present study showed the potential of the development of halophilic prokaryotic cosortium for biological treatment of Iranian oilfield PW through suitable enrichment of the indigenuous microbial populations present in PW or PW contaminated soil.

Keywords:

Produced water , Halophilic prokaryotic consortium , Biological treatment , COD removal