Potable Reuse Innovation Webinar Recap

Potable Reuse Innovation Webinar Recap
A CDM Smith webinar sharing the latest breakthroughs in potable reuse research and development—transforming treated wastewater effluent into safe, reliable drinking water supply.

Potable Reuse Innovation

    On March 22nd, 2017, water leaders from around the country joined two CDM Smith experts to learn more about the future of water via potable reuse.
    Topics of this discussion included:
    -- What is the current state of potable reuse in the industry and how are researchers zeroing in on its key challenges?
    -- What R&D break­throughs are driving the industry forward?
    -- What is the future of potable reuse?
    Our panelists brought a range of experience working on potable reuse designs and R&D projects around the country...

    Jennifer Hooper is an envi­ron­men­tal engineer based in Bellevue, Washington with a decade of experience in research and development projects, including pilot and bench studies, statistical analysis, design, micro­bi­o­log­i­cal and analytical techniques, and modeling. Jen has broad expertise in multiple sectors including drinking water, potable reuse, and envi­ron­men­tal remediation.

    William Dowbiggin is a discipline leader for water treatment based in Raleigh, North Carolina with over three decades of experience in water and wastewater treatment engineering. Bill has designed more than 60 major treatment plants, and has carried out more than a dozen water treatment bench-scale and pilot plant R&D projects.
    Potable reuse means releasing highly treated wastewater from a water reclamation facility to a drinking water supply source in order to increase the amount of water supply.
    There are two distinct approaches to potable reuse:

    • Indirect potable reuse, or IPR: releasing highly treated reclaimed water into an envi­ron­men­tal buffer such as a surface water reservoir or an aquifer—that is later withdrawn and treated for potable use. This also arguably includes de facto IPR, where source waters are impacted by upstream wastewater discharges from other utilities. Since many cities are downstream of other cities along rivers, de facto IPR is very common.

    • Direct potable reuse, or DPR: drawing highly treated effluent from a water reclamation facility and sending it directly to a drinking water plant for treatment. This differs from IPR by not having the envi­ron­men­tal buffer, like an aquifer or reservoir, between the wastewater discharge and the drinking water intake.
    This map is from the 2016 update to the Potable Reuse Supplement to EPA's Guidelines for Water Reuse and shows facilities that are currently operating and those that are being studied or planned.

    Planned IPR has been used in certain places for decades and includes 7 to 8% of WWTP effluent. California has more IPR facilities than any other state and has developed the most guidelines and regulations; Washington and Texas also have several facilities. Several other states across the southern U.S. have planned reuse facilities including Colorado, New Mexico, Arizona, Georgia, and Virginia.

    It’s not just regions facing drought that are considering PR. For example, Washington state is looking at PR because industrial demands for high quality treated water, including food processing and large data servers, are driving groundwater recharge projects. Nationwide, planned IPR is growing quickly and will continue to gain momentum.

    Direct potable reuse is only installed in 2 Texas locations, and currently, only the Colorado River Municipal Water District's Big Spring facility is still operating as a DPR facility. DPR is less widely considered than IPR, but the technology and research are advancing quickly, and DPR will become more of the norm in the future.
    It's important to recognize that we are not making new water – all the water on the planet today is the same water that's always been here. We're just being smarter about how we manage the water we have.
    Generally, utilities and communities considering potable reuse fall into at least one of three groups.

    1. Communities facing a significant lack of water, drought conditions, or population changes. This is especially prevalent in California, Texas and across the southern U.S.

    2. Communities looking at high water costs: due to water rights issues, or needing supplies to support growth.

    3. Progressive communities and utilities looking forward in terms of where they will be in 20 years and striving to achieve a net-zero operation.
    IPR has been implemented quite a bit in California, and they have specific rules for it. If discharging directly into a drinking water supply aquifer, California has the very conser­v­a­tive standard of requiring facilities to use reverse osmosis and advanced oxidation, achieving 12/10/10 logs of removal plus inac­ti­va­tion of viruses/crypto/giardia respec­tively. Lesser treatment is allowed for surface application, as in other states.

    But reverse osmosis isn’t financially practical if you don’t have a cost-effective way to discharge the brine, so many utilities are turning to ozone/biofil­tra­tion as an alternative technology when total dissolved solids and nitrate are low.

    We are also working with utilities that are injecting potable reuse water into aquifers, as opposed to a surface water body. This requires very specialized expertise in groundwater, permitting and hydro­ge­ol­ogy. State-specific rules on underground injection control (UIC) drive the project details. We are doing this in California, Florida and Texas already.

    At CDM Smith, we consider ourselves potable reuse pioneers in leading the design of four out of the five operational advanced treatment reuse facilities in California that use the full advanced treatment (FAT) model. These include Orange County Water District's Groundwater Recharge System, the Long Beach Water Replen­ish­ment District's Vander Lans Advanced WTP, the Cambria Emergency Water Supply Project and the West Basin Municipal Water District’s Reclaimed Water Membrane Treatment Facility. But this discussion largely focuses on the work we’re doing for alternative treatment trains beyond FAT that are being evaluated and implemented outside of California.

    Challenges in Imple­ment­ing Potable Reuse

    Challenges in Imple­ment­ing Potable Reuse
    Our experts explain 4 major challenges that utilities face when imple­ment­ing potable reuse in the video clip above!
    CDM Smith is proud to be a leader in potable reuse, and our R&D Program is currently funding projects to advance the science and practice of potable reuse nationwide. We believe that potable reuse is the future of water and so these are no-brainer investments for us. We encourage our staff at all levels to get involved in these R&D projects and help lead water supply innovation through out-of-the-box thinking.

    Research and development is a highly collab­o­ra­tive process, and something that only works with the partic­i­pa­tion of the entire water industry, from utilities to engineering firms to univer­si­ties to research orga­ni­za­tions. To the extent we are successful in driving forward, it’s a testament to that partnership.
    Bill and Jen took us into two pilot plants that CDM Smith designed alongside best-in-class utilities. These pilot plants are the front lines of potable reuse R&D, where ground­break­ing findings are being obtained on a steady basis.
    Upper Occoquan Service Authority (UOSA) IPR Pilot Plant
    Gwinnett County IPR/DPR Pilot Plant
    Then, Jen and Bill walked us through four of the most cutting-edge R&D projects that they're involved in, sharing the drivers behind each project, some details on where and how research is being carried out, and the latest data they've obtained.
    UOSA Ozone Biofil­tra­tion with GAC R&D Project
    Techniques for Safety from DPR Facilities: WRF 4508/WRRF 13-14
    Developing Biofil­tra­tion Guidance: WRF 4555 & 4620
    Researching IPR/DPR Blending Ratios: WE&RF 15-11
    If you’d like to be kept in the loop on future devel­op­ments in these and other potable reuse projects, contact us.
    We ended our discussion by asking our experts to share advice they'd have for utilities considering potable reuse, and to gaze into their crystal balls to predict the future of potable reuse.
    Bill’s take: Thorough studies are essential to resolving treatment and quality issues that are site specific. Public relations efforts and working closely with regulators are necessary for project acceptance. Take a step back and look at the big picture, look at how all your water systems can come together more sustainably.

    Jen’s take: Growing stakeholder support is the most challenging part, and much of this is due to the lack of a regulatory framework for imple­men­ta­tion in most states (outside of California and Texas). There’s still a lot of growth ahead of us in terms of how to move forward and effectively manage public perception.
    Jen's take: Especially with changes to resource avail­abil­ity from climate change and demand from population growth, potable reuse is a significant driver for utilities (partic­u­larly in the south and southwest). We will see more utilities imple­ment­ing DPR, especially in water-stressed locations like California. Los Angeles and San Diego are thoroughly evaluating this. As regulations get formalized and standards of practice for monitoring and control get solidified, we will see more small utilities moving in this direction as well.

    Bill's take: As water demands rise, it’s inevitable that potable reuse will increase. As an industry, we need to help communities to understand, regulate, and implement the process. On the east coast, expect to see a steady rise in IPR for smaller utilities in key geographic locations.
    To learn more about potable reuse, check out more of our water reuse experts, projects and insights below!

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