Integrated Desalination and Wastewater Treatment Systems for Enhanced Water and Energy RecoveryEPA Grant Number: SU835721
Title: Integrated Desalination and Wastewater Treatment Systems for Enhanced Water and Energy Recovery
Investigators: Gude, Veera Gnaneswar
Institution: Mississippi State University
EPA Project Officer: Hahn, Intaek
Project Period: August 15, 2014 through August 14, 2015
Project Amount: $15,000
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2014) RFA Text | Recipients Lists
Research Category: Pollution Prevention/Sustainable Development , P3 Challenge Area - Water , P3 Awards , Sustainability
The objective of this project is to design and develop an integrated microbial desalination system to treat wastewater with nitrogen removal for electricity generation and to produce desalinated water simultaneously. The anode chamber with wastewater (substrate, electron donor) and cathode chamber with anammox process (nitrite/nitrate as electron acceptor) separated by a desalination chamber, will accommodate for simultaneous wastewater and saline water treatment due to ion migration between the anode and cathode chambers along with electricity generation and nitrogen removal.
Microbial desalination cells (MDCs) provide efficient wastewater treatment combined with electricity generation and desalination of saline water. The premise for MDC performance is based on the principles that bio-electrochemical (BES) systems convert wastewaters into treated effluents with electricity production; and ionic species migration within the system facilitates desalination. A microbial desalination cell (MDC) can be constructed by including an additional saline water chamber in a microbial fuel cell using anion and cation exchange membranes. Municipal wastewater can be used to serve as substrate provider (electron donor) in the microbial desalination cells. A novel concept to provide advanced wastewater treatment (nitrogen removal) in the cathode section by anammox process to increase electron mobility (i.e. electric current) in microbial desalination cells is proposed in this research. Treated effluent from the anode chamber will be allowed to pass through an aeration chamber (stoichiometric-limited oxygen supply) prior to the cathode chamber to remove nitrogen and to utilize nitrate/nitrite as electron acceptor for electricity production.
This process provides advanced wastewater treatment with nitrogen removal and eliminates current issues encountered in microbial desalination cells such as salt accumulation in treated wastewater, pH drop/rise in anode and cathode chambers and provision of strong, environmental friendly electron acceptor, nitrite/nitrite with power generation. Key findings in this research will improve current understanding of the microbial desalination systems performance for their potential large-scale application in the water and environmental industry. The proposed process both in the anode and cathode chambers reduces low sludge volumes compared to traditional activated sludge and nitrification/ denitrification processes and eliminates the need for addition of external carbon source. Thus the proposed design eliminates the need for energy supply and reduces the costs associated with chemicals. The proposed process has the potential produce net positive energy contrary to the conventional activated sludge and nitrification/denitrification processes.