Grantee Research Project Results
Final Report: Electrochemical Nitrate Remediation of Rural Water
EPA Grant Number: SU836764Title: Electrochemical Nitrate Remediation of Rural Water
Investigators: Gadgil, Ashok
Institution: University of California - Berkeley
EPA Project Officer: Page, Angela
Phase: I
Project Period: November 1, 2016 through October 31, 2017
Project Amount: $15,000
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2016) RFA Text | Recipients Lists
Research Category: Sustainable and Healthy Communities , P3 Awards , P3 Challenge Area - Safe and Sustainable Water Resources
Objective:
Nitrate (NO3-) contamination of groundwater due to agricultural influxes puts many small, rural, and economically disadvantaged communities at risk of devastating health problems. Currently, small-scale treatment options appropriate and affordable for these communities do not exist. We are, therefore, developing a promising new option called electrically regenerated ion-exchange (ERI) technology. Nitrate-specific ion exchange resins (IERs) are inexpensive and effective, however, traditionally, their regeneration requires concentrated acids or bases. Handling and disposal of these corrosive regeneration chemicals adds significant safety issues, cost, and operational complications. Instead, our innovative technology, while using IER, deploys electrical regeneration. This is accomplished by applying an external voltage to locally produce acid and base by an in-situ electrochemical process for IER regeneration. The specific electrochemical processes involved in acid/base generation and IER regeneration currently are under investigation. For the purpose of this grant, we broadly refer to the mechanism as electrolysis of water. One of the main challenges in this approach arises from the IER being made of dielectric (electrically insulating) polymers, which does not allow for electrical regeneration. Therefore, development of methods to make sufficient electrical contact to the IER, enabling efficient electrical regeneration, is fundamental to success of this approach. Specifically, the objectives of Phase I included: 1) Investigate and develop affordable and scalable method(s) of making electrical contact to the IER, and 2) Design, build, and test an ERI prototype. The long-term goal of this research is to develop a low-cost and robust nitrate removal technology suitable for rural, agricultural communities.
Summary/Accomplishments (Outputs/Outcomes):
We are very pleased to report that we have made considerable progress during Phase I. The objectives for Phase I have been substantially met and we are continually planning experimental work for the remainder of the Phase I duration to advance the research further. The results obtained so far under Phase I inform our future efforts and approaches, and are reflected in the goals of Phase II. Our accomplishments are listed as follows:
- We have made electrical contact to the resins sufficient to demonstrate electrical regeneration in composite electrodes.
- We have developed methods and techniques for creating functional electrodes.
- We have designed and built an ERI prototype unit to test electrode performance.
- We have obtained proof of concept results confirming feasibility of ERI technology for nitrate remediation.
Conclusions:
Electrically regenerated ion exchange (ERI) technology is a promising nitrate removal option. We have developed methods and techniques to prepare functional electrodes, and evaluated their nitrate removal performance in a custom ERI prototype. We have demonstrated that ERI can successfully remove nitrate and performs reliably over consecutive cycles. Unique to this technology is the regeneration of ion-exchange resins using an applied voltage instead of conventional methods that use corrosive chemicals. While ERI technology appears highly promising as an option for nitrate remediation, much more work is needed for optimization and long-term durability studies. Further research will allow us to assess the viability of ERI technology as a nitrate treatment option for communities in need.
Supplemental Keywords:
drinking water, water treatment, water purification technologies, drinking water treatment technologies, groundwater remediation, nitrate contaminationThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.