The Navajo Tribal Utility Authority has agreed to bring six wastewater treatment facilities into compliance with the federal and Navajo laws in...
California tourist town embarks on recycled water project
Known as the gateway to Big Sur, San Simeon, Calif., is home to approximately 460 full-time residents as well as a constant stream of tourists. The city is located on the southern end of a 90-mile stretch of U.S. Highway 1 between Hearst Castle and Monterey, making it one of the last stops for tourists looking to embark on a scenic coastal drive.
The San Simeon Community Service District’s (SSCSD) wastewater treatment plant is designed to handle the flows that result from population fluctuations. Flows average 80,000 gal per day (gpd) in the winter and 100,000 gpd in the summer. The plant has a total capacity of 200,000 gpd.
Built in 1961, the secondary treatment plant originally consisted of a single aeration basin and clarifier. Twelve years later, two additional aeration basins and clarifiers were added. In 1986, a fourth aeration basin and clarifier were added, along with a chlorine contact chamber and an equalization basin. The plant’s outfall is the Pacific Ocean.
Responding to Violations
In 2005, the SSCSD was cited and fined by the State Water Resources Control Board (SWRCB) for effluent violations concerning coliform and chlorine residual.
“The issue was mainly caused by deferred maintenance in the overall treatment process and a chlorine contact chamber that was undersized and short-circuiting,” said Charles Grace, general manager for the SSCSD.
Upon receiving the violations, the district got to work repairing broken clarifiers and blowers, adding baffling to the chlorine contact chamber and improving the chamber’s sodium hypochlorite and chlorine injection points.
From there, the district worked with the SWRCB to identify a supplemental environmental project toward which the SSCSD could place a portion of its fine to correct the violations. What resulted were plans to install a small-scale recycled water system at the treatment plant. After obtaining approval for the project, the district began its search for equipment in 2009.
“Our first approach was to look for something that would treat 100% of the plant flow,” Grace said. “When we determined that to be cost-prohibitive, we [had to look] for devices that would meet or treat a portion of the plant’s flow.” The equipment also needed to be modular, with a small footprint, and have the ability to be expanded with ease. It also needed to produce California Title 22-approved recycled drinking water.
The SSCSD eventually settled on an Amiad filtration system with HiPOx disinfection technology. The system is able to handle 43,200 gpd—approximately half of the plant’s average daily effluent flow.
Integrating the two technologies created some challenges, but the project’s engineers were able to design solutions to overcome some of the equipment’s limitations. For example, the disinfection system is designed to run continuously, but in order for the filtration system to backwash, the filtration system occasionally needs to stop running.
“Using an existing control panel, the Amiad engineers and HiPOx engineers were able to integrate a recirculation feature into the HiPOx to allow it to go into a recirc while the Amiad backwashes,” Grace said. “This was the first time Amiad and HiPOx teamed up on a system such as this and we’re pleased with the water it does produce.”
Construction of the system was completed in July 2013; the SSCSD has since applied for a permit to distribute the recycled water. Approval was expected in December 2013, but at press time had not yet been obtained.
Sharing the Wealth
When the SSCSD receives permission to distribute the recycled water, it will help alleviate some of the irrigation issues caused by drought conditions in the area.
“We’re praying for rain. That’s why the small-scale water recycling facility is such a good thing for us,” said Jerry Copeland, chief plant operator and superintendent of the SSCSD. “Right now we’re in water conservation mode and you aren’t allowed to water your plants. People are going to be able to use the recycled water for landscape irrigation.”
The district also hopes to expand the system and supply the area’s eight hotels with recycled water for their laundry. The end goal is for the expansion to allow the system to process a total of 50 gal per minute, allowing the community to recycle all of its effluent.