By Haley Morton
As much of the Western U.S. navigates a historic drought, community leaders and water utilities are exploring innovative options to expand their water resource portfolios. One approach that is gaining traction is potable water reuse, a treatment process for returning wastewater to high-quality drinking water.
Potable water reuse offers a new opportunity to boost the sustainability of water supply for residents. While it has been long considered as an option in the U.S., it has not been as widely adopted — although this is changing as more communities face severe drought conditions. These conditions, coupled with growing populations, have compounded water resource management challenges. Potable water reuse can play a critical role in helping states, tribes, cities and other communities meet their future drinking water needs with a diversified portfolio of water sources.
This process often involves two types of reuse: indirect and direct potable reuse. Indirect potable reuse uses an environmental buffer, such as a lake or river, before the water is treated at a drinking water treatment plant. Direct potable reuse involves the treatment and distribution of water without an environmental buffer. Before implementing potable water reuse processes, it’s important to consider several factors to achieve successful rollout.
- Raw water blending and buffer time: Water treatment plants can consider adding a tank up front — used as a test zone — that checks the water quality before it enters the treatment process. The buffer, or response time, can identify issues with the reuse water source, and allow time to develop a response or divert water, which is critical.
- Technologies and identifying multiple barriers: These barriers can help reduce the risk of contaminants. Physical and chemical barriers to pathogens and other contaminants of concern in reuse water can include traditional treatment processes such as coagulation, media filtration, membrane filtration and chlorine disinfection. Advanced treatment processes such as UV or ozone oxidation, adsorption or ion exchange provide protection against reuse contaminants.
- Monitoring plan with indicator compounds: This plan is essential in informing the effectiveness of existing treatment systems.
- Early communication with state permitting agencies: There are regulations in place that require certain permits from the state before beginning the design and construction project for potable reuse treatment systems. Early communication with these agencies helps streamline the permitting process and allows teams to avoid project delays.
- Early communication with the public: New or changing water projects affect other utilities interested in implementing potable water reuse. Early communication and public engagement is essential to help explain the technical aspects of potable reuse to avoid any negative perceptions about the process.
As the necessity for and increased awareness around potable water reuse continues, technologies supporting this process will allow agencies to capture wastewater and return high-quality potable water, ultimately reducing the impacts of drought and population growth on the nation’s water supply.
Haley Morton is an environmental engineer at Burns & McDonnell. She leads and assists in the design of water treatment systems for municipal and industrial applications, primarily potable water treatment and distribution.