The primary goal of this project was to demonstrate the performance of a biological oxidation filtration treatment process for oxidation of ammonia present in groundwater. This pilot-scale investigation helped develop design and operational conditions for implementing biological oxidation filtration at full-scale. Design parameters tested included filter media type, filter loading rate, backwash frequency, microbial acclimatization period, intermittent use, etc. In addition to oxidation of ammonia, the proposed treatment process was anticipated to lower disinfection by-product (DBP) formation potential and hydrogen sulfide odor in the treated water, reduce chemical doses and operational costs, and result in biologically stable water. Tailored collaboration partner: Golden State Water Company. Published in 2016.