CWEA Wastewater Professional :: April 2014 March 2014 Volume 2 | Page 35

Technical Article | City of Anaheim’s Water Sustainability Campus (MBR), ozone and UV system. Disinfection of membrane filtrate (MBR effluent) is achieved entirely by the ozone system and the UV system is provided for educational purpose only. Chlorine is added before water enters the distribution system to prevent biological growth in the distribution system. Designing a robust odor control system Since the WRF is a wastewater treatment facility in an enclosed building, it is subjected to the National Fire Protection Association (NFPA) regulations.Additionally, the WRF has to meet the permit requirements for the Air Quality Management District (AQMD).Without an innovative design, these regulatory requirements would result in a large odor control facility for the WRF, which would not be feasible considering the footprint limitations. Therefore, the odor control system was designed such that the fine screen and the biological tanks were isolated and ventilated at a higher air flow rate (12 air changes per hour) than the remaining area of the WRF (six (6) air changes per hour). Access hatches for the biological tanks and the roll-up door for the building were equipped with limit switches to allow automation/control of the air supply to, and exhaust from, different parts of the building under different conditions. Use of such automation allowed minimizing the volume of air to be treated and footprint of the odor control system while meeting the regulatory requirements. Obtaining the permits The WRF is the first facility in California to utilize external MBR Figure 3 – Process flow schematic of the City of Anaheim’s Water Recycling Facility. system followed by an ozone disinfection process for water recycling and hence, the permitting process included validation testing of the ozone system.The bioassay testing of the ozone system demonstrated that the ozone system achieved greater than 5-log removal of seeded MS-2 virus as required by CDPH. Additionally, the ozone system achieved total coliform bacterial concentration of less than 1 CFU/100 mL over the 14-day test period.With influent BOD concentration varying from 147 to 347 mg/L, the effluent BOD concentration was consistently less than 10 mg/L.The WRF achieved complete nitrification with effluent ammonia concentration consistently below 1.0 mg/L-N.The effluent nitrate concentrations were below 10 mg/L-N for most of the performance testing period.The air quality testing showed H2S concentration of less than 0.25 ppm in the treated air discharged from the facility. The WRF has now received the necessary permits and by the time this article is published, the City plans to start utilizing the recycled water for toilet flushing and landscape irrigation. The exemplary design of the WRF and its success in promoting water conservation and recycling has inspired nearby cities and even colleges to build a water recycling facility on their campuses. Zakir Hirani*, John Ciccotelli, and Michael Moore: MWH, 618 Michillinda Ave. Suite 200, Arcadia, CA 91007 William Moorhead, David Shen: City of Anaheim, 201 S. Anaheim Blvd., CA 92805 *Corresponding author - email: zakir. [email protected] Wastewater Professional April 2014 33