Zone 7 Utilizes Ozonation Water Treatment Process by Zone 7 Water Agency Sep 1, 2020 Zone 7 Water Agency’s Ozonation Project at the Del Valle Water Treatment Plant is now online. This is the latest investment by Zone 7 to make the treatment process more efficient and improve water quality to better serve the community. “By investing in best-in-class technology, Zone 7 demonstrates our commitment to high-quality water,” said Board President Olivia Sanwong. “Ozonation is a proven, successful treatment method that will improve our water, making it cleaner, safer and better tasting – straight from the tap.” The Del Valle Water Treatment Plant, which has been serving Zone 7 well since it was built in the 1970s, has been upgraded to utilize a powerful disinfectant called ozone. The Ozonation Project, which is part of Zone 7’s Capital Improvement Plan, represents a capital investment of $49 million, funded by bonds. The new treatment system will improve overall water quality for an estimated 40 million gallons per day (mgd) production capacity. Algal blooms are among the challenges in treating Zone 7’s raw water supply. The blooms are normal, but they are becoming more frequent. The algae can cause taste and odor problems, and it makes the water more difficult to treat. After reviewing various treatment technologies, Zone 7 selected ozone to replace chlorine as the main disinfectant, resulting in higher quality finished water provided to customers. Studies have shown that ozone makes the treatment process more efficient and improves water quality. This investment improves Zone 7 water by treating taste and odor impacts from algae growth, reducing chlorine-related byproducts, and killing even more pathogens than chlorine. Another benefit of ozone is that it is the technology of choice for treating other contaminants of emerging concern, such as cyanotoxins produced by blue-green algae, endocrine disruptors and pharmaceuticals that can make their way into raw water supplies. Zone 7 is also investing in ozonation at the Patterson Pass Water Treatment Plant; that system is scheduled to go online in 2022. Watch the Del Valle Treatment Plant Ozonation Project video recapping the project and how ozone treatment works. More information about ozone treatment is also available on Zone 7’s website.