Homes in Ivins use culinary water indoors as well as outdoors for irrigation. Years ago, Ivins started requiring new subdivision to equip homes for both culinary and secondary water. The culinary water would be used indoors and the secondary outdoors. Ivins didn’t have the ability to deliver secondary water to those homes at the time, but it was the start of a long-term plan to reduce our use of culinary water. Check your front yard at the street to see if you have both culinary and irrigation lines, like in the image below.
In May, the City received the results of a consultant study on the feasibility of building a wastewater treatment plant (download study PDF). The goal would be to treat wastewater so that it can be delivered back to homes to use outdoors. To do that, the City would need a reservoir to hold the secondary water. And the City would have to connect all the homes and subdivisions together to be able to deliver the secondary water to us.
I think that either in that meeting or another meeting, Chuck Gillette, the head of the Public Works Department suggested another option could be to send the secondary water from the treatment plant to the Gunlock Reservoir. There it would mix with freshwater flows from the Santa Clara River, significantly diluting the treated reuse water. I don’t think that’s an “official” plan at this point, just a thinking-outside-the-box idea.
The combined water would be treated to culinary quality more cost effectively than treating secondary only to culinary quality. This way, although Ivins would still need a wastewater treatment plant, the City would avoid the cost of connecting us all up to a secondary system as well as ongoing maintenance costs. Yes, we would still be using culinary water for irrigation, but other actions by the City might result in reducing our outdoor irrigation needs. I didn’t double-check this with Chuck, but I think this is the general idea he was presenting as a possible alternate scenario.
Well, a new report, Local Waters Alternative to the Lake Powell Pipeline 2.0, recommends cities in Washington County do exactly what Chuck was suggesting (download report PDF). The report recommends that, whether the Lake Powell Pipeline is built or not, Washington County should cap secondary water systems at their current size and focus on expanding culinary water supplies by treating secondary water to culinary quality.
The report says, “…Washington County’s culinary supply should be maximized, and outdoor demands reduced. By using secondary water more efficiently, Washington County can effectively stretch its culinary water supply and continue irrigation of lands currently receiving secondary water.”
Here is more information from the report about treating water to culinary quality.
Wastewater Reuse Treatment
Other technologies have been proven to safely treat recycled water to culinary standards with costs significantly lower than reverse osmosis. Additionally, these treatment processes do not generate a constant brine waste stream which is often challenging and costly to dispose of for inland communities such as those in Washington County.
Non-RO treatment processes including ozonation and biologically activated carbon filtration (O3/BAF) can produce highly purified culinary water at significantly lower cost. The Water Research Foundation reported that costs are often less than half for O3/BAF-based treatment compared to processes including reverse osmosis. Interest in non-RO treatment is not only gaining interest around the United States, but also in Utah.
In 2019, South Jordan City’s Pure SoJo Direct Potable Reuse (DPR) Demonstration Project used a non-RO processes to treat wastewater effluent to produce high quality purified drinking water for consideration as a future alternative water supply. As communities around the country, including in Utah, look to optimize their existing water supplies through potable reuse, safe and effective non-RO treatment will help ensure this supply option is cost-competitive compared to other new supply alternatives.
Further reading
Water Research Foundation. 2019. Ozone Biofiltration for DPR: Non-RO-based treatment schemes involving ozone-BAF can produce high-quality potable water at significant cost savings. Advances in Water Research. January-March 2019, 29 (1), 22-23. (Click here to go to article)
Water Research Foundation. 2018. Potable Reuse Using Ozone-Biofiltration. WateReuse, The Water Research Foundation. September 26, 2018. WateReuse Webcast Series. (Click here to go to report)
Steinle-Darling, E. 2018. Pure Water Proof: Non-RO Demonstration for DPR in Altamonte Springs, Florida. Arizona Water Reuse 2018 Symposium. July 23, 2018 presentation. (Click here to go to presentation)
South Jordan City. 2020. Overview of South Jordan Water Conservation Program & DPR Demonstration Project, South Jordan Utah (Click here to view PDF)
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