Technical Advances in Water Reuse: Meeting Water Quality Objectives without Membranes

Authors:

  • Ben Stanford, PhD, Tricia Drummey, PE - Hazen and Sawyer

As continued population growth and climate extremes place heavy burdens on our nation’s water supplies, water agencies and policy makers are examining innovative ways to stretch water supplies, to manage these pressures, and to provide reliability and redundancy in their supply portfolio. As such, many water agencies are considering the implementation of planned potable reuse of municipal wastewater, either directly or indirectly, to help achieve these objectives.

For the vast majority of existing potable reuse projects, a combination of microfiltration membranes followed by reverse osmosis and ultraviolet light with advanced oxidation processes (MF-RO-UV/AOP) has been used in the water recycling plant. Such treatment systems are referred to as “full advanced treatment” (FAT) and offer many advantages in terms of removing salinity, hardness, chemical contaminants, and microbes. However, FAT systems are expensive, require management of the RO concentrate (brine), have many operational complexities that require specialized staff, and may not be required for all potable water reuse applications.

Several recent projects completed by Hazen and Sawyer have evaluated combinations of non-membrane based technologies (e.g., ozone, biofiltration, ion exchange, UV/AOP) to meet water quality objectives while providing a cost-effective solution for water reuse. Both FAT and non-membrane based treatment systems have advantages and disadvantages, and the knowledge base around such systems is evolving at a rapid pace. This presentation will use data from our existing research studies to demonstrate how non-membrane based water reuse processes can be used to reach water quality goals, will present information on relative costs of comparable systems, and will provide a discussion on advantages and challenges associated with selecting water reuse technologies.

For more information, please contact the author at bstanford@hazenandsawyer.com.

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Horizons Fall 2017 (pdf)

Horizons showcases significant water, wastewater, reuse, and stormwater projects and innovations that help our clients to achieve their goals, and can help you achieve yours. Articles are written by top engineers and process group leaders, demonstrating and explaining the beneficial application of a variety of technologies and tools.

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