Design, Start–up and Permitting of a Demonstration–scale Decentralized Water Recycling Facility to Promote Water Recycling and Sustainability

Abstract

With increasing population and an uncertainty in the long-term sustainability of reliable potable water sources, many cities have decided to investigate water reuse as a means to compliment water supply demand. The City of Anaheim (California) recently completed construction of a 100,000 gpd decentralized water recycling facility that produces Title 22 disinfected tertiary effluent. The process equipment including fine screen, MBR, ozone, UV, carbon adsorbers for odor control and recycled water pumps along with associated appurtenances were all housed in a small footprint (1800 ft 2 ) next to the City Hall. The facility was designed to blend in with existing surrounding structures and architectural styles, and look aesthetically appealing. The project team faced significant challenges during the design and startup, which included 1) accommodating equipment in a small footprint 2) obtaining permits from regulatory agencies for these relatively newer treatment processes, and 3) optimizing plant operation to meet end user demand. Despite these challenges, the startup was completed successfully. During the performance testing, the effluent produced from the facility had average BOD, COD and TOC concentrations of 5, 22 and 6 mg/L, respectively. The WRF achieved complete nitrification and partial denitrification with average ammonia and nitrate concentrations of 0.3 and 8.0 mg/L-N, respectively. The bioassay validation and 14-day coliform testing performed on the ozone system demonstrated that the ozone system achieved greater than 5-log removal of seeded MS-2 bacteriophage and total coliform bacterial concentration of less than 1 CFU/100 mL.