SIDESTREAM TREATMENT STUDY FOR SAN FRANCISCO BAY DISCHARGERS: A COORDINATED REGIONAL APPROACH TO MANAGING NUTRIENTS

New sustainable cost-effective nitrogen removal technologies were evaluated for treating conventional and non-conventional wastewater sidestreams. Pilot testing of nonproprietary anammox and two embryonic technologies were conducted at multiple wastewater treatment plants around the San Francisco Bay (Bay). Results show the anammox-type processes can treat sidestreams containing ~500 to 1,940 mg NH4+-N/L, with a start-up time of 3 to 12 months depending on the initial seed. The anammox processes handled average ammonia loading rates of 0.36 to 1.11 kg-N/m3-reactor/d and achieved 84–97% ammonia and 60–95% inorganic nitrogen removals. However, catastrophic process upsets were experienced when treating non-conventional sidestreams at two test sites resulting in little to no anammox activity. Future work is necessary to ensure the resiliency and reliability of anammox processes under various feed and operating conditions especially for non-conventional sidestreams at relatively high loading rates.Potential nutrient load reductions and costs are being quantified for the region to understand the role of sidestream treatment in reducing overall wastewater nutrient discharges to the Bay. Total nitrogen (TN) load reduction if all candidate plants implemented sidestream treatment is estimated to be 15–22% across the Bay (18,410–24,550 lbs TN/day). Depending on ammonia mass loading, the order-of-magnitude cost for sidestream treatment using anammox technology ranges from <$1/lb to ~$15/lb N removed, about half of traditional nitrification treatment costs.