Growing Algae in Produced Water Generated During Oil and Gas Production Using Hydraulic Fracturing Technique

Abstract

Hydraulic fracturing technology is widely used for recovering natural gas and oil from tight oil and gas reserves. Large volumes of wastewater are generated during this process. Produced water is considered wastewater by the regulators, hence, need to be treated or disposed accordingly. This study examines algal treatment of produced water. Eleven microalgae strains were examined. Wastewater quality before and after algae treatment was evaluated. Algal biomass grown in produced water was characterized for its volatile matter, fixed carbon and ash contents. The experimental results indicate that microalgae can grow in produced water. The chemical composition of the algal biomass obtained in produced water was strain specific. Cyanobacteria SP47 exhibited the highest high heating value and fixed carbon among the strains examined in this study. About 60 % total dissolved solids, 100 % nitrate and phosphate, over 65 % boron reduction in produced water could be achieved. This study has demonstrated that algal treatment of produced water can significantly reduce the costs and the adverse environmental impact of hydraulic fracturing technology.