OCWD Receives Grant to Study Advanced Water Treatment
OCWD’s research and development department was awarded a research grant from the Water Environment & Reuse Foundation (WE&RF) for a successful proposal entitled “Evaluating Post Treatment Challenges for Potable Reuse Applications.” The project team will include Trussell Technologies, Stanford University, and a number of water agencies who will serve as participating utilities. The total grant funding from WE&RF with significant contributions from the participating utilities is $230,000.
The objective of the research study will be to evaluate and make recommendations for improving post treatment water stabilization for potable reuse, which refers to the last step of the advanced water treatment train in which the water pH is adjusted and chemicals such as lime are added to stabilize the water. At the GWRS, this is the decarbonation and lime addition step that follows the microfiltration-reverse osmosis-ultraviolet / advanced oxidation process train. This last treatment step is critical for agencies like OCWD that employ advanced water treatment to reclaim what was once municipal wastewater for groundwater recharge and injection (potable reuse).
Three key challenges will be evaluated in this project: minimizing corrosion of pipelines and facilities, potential mobilization (release) of native metals into the groundwater during recharge, and formation of disinfection byproducts during advanced treatment like N-nitrosodimethylamine (NDMA). In their successful proposal, the project team highlighted the fact that these three, seemingly separate topics are interrelated in the form of trade-offs that must be managed during post treatment; for example, raising pH is good for minimizing corrosion but can increase the formation of NDMA.
The project team has strengths in each of these focus areas, and through literature review, laboratory experimentation, pilot testing, and equipment evaluation. This two-year project will provide a multi-faceted assessment of post treatment specifically for the potable reuse industry.
OCWD is a leader in potable reuse and will continue to collaborate on studies and programs that further the advancement of water reuse—a solution to long-term water reliability.