Water Resources Research Act Program

Details for Project ID 2013PA208B

Developing A Treatment Option for Marcellus Shale Wastewater Through Cultivation of the Algae Dunaliella salina

Institute: Pennsylvania
Year Established: 2013 Start Date: 2013-03-01 End Date: 2015-02-28
Total Federal Funds: $24,027 Total Non-Federal Funds: $52,620

Principal Investigators: Kyle Bibby

Abstract: In Pennsylvania, production of natural gas by hydraulic fracturing of the Marcellus Shale has increased dramatically over the past decade and continued growth is expected. While hydraulic fracturing brings many positive economic benefits, it also results in the production of a large amount of wastewater, termed flowback water. In addition to other constituents, flowback water contains levels of dissolved metals and salts, termed total dissolved solids (TDS), several times higher than those found in the ocean. Disposal options for this waste stream are increasingly limited and expensive. As the use of hydraulic fracturing in Pennsylvania expands, and disposal options decrease, the chance that flowback water is improperly disposed of, either intentionally or unintentionally, increases. Due to high TDS levels and other hazardous constituents, improper disposal of flowback water would potentially have deleterious impacts on surface and groundwater quality. Hydraulic fracturing of the Marcellus Shale is expected to continue for several decades; development of alternative treatment for flowback water is essential to the protection of Pennsylvania’s water resources. This project seeks to develop an onsite treatment option for Marcellus Shale flowback water through cultivation of the algae Dunaliella salina. D. salina is known to thrive in high salinity (high TDS) and remove TDS from solution through electrostatic interaction with its extracellular polymeric substances (EPS). In this approach, algae would be grown on-site in flowback water and TDS would be removed from solution by D. salina EPS, facilitating the removal of TDS through filtration or settling. Additionally, D. salina biomass could be used to produce biological products such as -carotene and lipids for biodiesel, potentially improving the economics of this treatment mechanism. Technical challenges for this project include determining the tolerance of D. salina to the high TDS levels present in flowback water and determining the level of removal of TDS possible by D. salina cultures. To determine the tolerance of D. salina to flowback water, multiple dilutions of flowback water will be amended with necessary nutrients and seeded with D. salina grown up in typical media. Following successful culturing of D. salina in flowback water, continuous culturing, simulating periodic algal harvesting, will be done to demonstrate the uninterrupted productivity of this system. D. salina samples from multiple time points will be analyzed for the concentration of cells in the reactor and cellular characteristics. Nutrient and TDS levels in the water will also be analyzed continually through each experiment to determine nutrient use in the system and TDS removal through adsorption to EPS. While it is certain that further technical developments will be necessary to make this vision a reality, this project will serve to demonstrate the feasibility of this approach and justify future investigation. This project directly addresses three of the four high priority areas in this project RFP. Developing a treatment option for the high TDS in Marcellus Shale flowback water addresses a water resource issue of major importance to Pennsylvania, specifically by investigating impacts of the Marcellus Shale on water resources, remediation of pollutants, and enhancement of water resources. This project assists younger engineers in developing a water research program by facilitating the PI, a new faculty member, begin a Marcellus Shale water treatment research program and by supporting a graduate student and involvement for a postdoctoral scholar and undergraduate student. Finally, this project is expected to result in the production of peer-reviewed literature and outreach activities through the University of Pittsburgh’s Mascaro Center EXCEL program.