Studying The Safety Of Alternative Water Sources
It’s no secret that utilities are becoming hard-pressed to supply water. Drought and population growth are undeniably straining the availability of drinking water and they are only going to continue to do so in the near future. While it’s undoubtedly time to tap alternative water sources to reinforce supplies, these alternatives must be properly vetted to ensure they meet the standards that keep consumers healthy.
The Water Research Foundation (WRF), which sponsors studies to advance the drinking water industry, has announced its latest project, “Conventional Drinking Water Treatment of Alternative Water Sources: Source Water Requirements,” with the goal of determining quality parameters for integrating stormwater, graywater, and treated wastewater into municipal water supplies and providing a new source for safe drinking water.
“Many regions are looking to diversify supplies for reasons including but not limited to water scarcity, climate change, and population growth,” said Alison Witheridge, a WRF research manager focused on stormwater. “In these regions, necessity is driving innovation and there has been a great deal of research, pilot and demonstration projects, and encouragement of graywater, stormwater, and reclaimed water for non-potable use as an offset for total water demand."
The study is one of many focused on how the world will deal with dwindling water supplies, but WRF believes its findings could go beyond what has been done for non-potable supplies. Witheridge points out that while research — like the National Academy of Sciences report on “Using Graywater and Stormwater to Enhance Local Water Supplies” — has been conducted on reuse of stormwater and graywater, little is known about the safety of consuming the final product.
“This project is intended to take this assessment of alternative supplies a step further for consideration for potable use,” she said. “The focus of the project is to determine water quality parameter ranges that are protective of public health and would enable utilities to expand their water supply portfolio by utilizing conventional treatment of stormwater, graywater, and, to a lesser extent, treated wastewater.”
According to Witheridge, the project will:
- Quantify parameters, including observed concentration ranges, in the alternative supplies and establish quality objectives with respect to those parameters as they are necessary to protect public health.
- Characterize conventional treatment effectiveness for those parameters, identifying when it would not be enough and additional treatment is necessary.
- Identify the minimum design, operational, and monitoring requirements to achieve and verify conventional treatment performance.
- Identify knowledge gaps and research needs.
To achieve these objects, researchers will undertake a combination of literature review focusing on the characteristics of alternative supplies; data collection and review through a workshop with utility, university, and government partners; and an additional workshop to develop source water quality requirements.
“Following this workshop, a synthesis document will be developed to document the results and recommendations from the literature review, data collection and review, workshops, final recommendations, case studies, and future research needs and data gaps,” said Witheridge.
Researchers have been pulled from a variety of institutions. The principal investigator, Chris Hill, is Arcadis’ national practice leader for water supply and treatment. Co-principal Doug Owen has more than 30 years of experience in water quality, treatment, and supply planning as the president of Owen Water Consulting. Co-principal Dr. Shane Trussell, of Trussell Technologies, is a civil engineer who has authored more than 57 publications and presentations.
“We are anticipating literature review and data collection draft results by summer 2017,” Witheridge said. “The complete synthesis document is scheduled to be published in March of 2018. Preliminary results will be presented at conferences and through WRF updates as they are available.”
When the team does reach its conclusions, it’s likely that drinking water utilities will be all the more eager to hear about ways they can safely expand supplies.
“Water providers that are or may in the future need to identify new water sources will be interested in the results of this project,” said Witheridge. “Whether they are facing drought, population growth, or decreased source water quality in existing supplies, stormwater, graywater, and treated wastewater may be viable options as part of a diversified water portfolio.”