AbstractsBiology & Animal Science

Supplemental aeration may be a viable treatment strategy for ammonia removal in the treatment wetlands at the Arcata Wastewater Treatment Facility (AWTF). Aeration may ameliorate adverse effects of seasonal low temperatures and high loading rates on ammonia removal by facilitating nitrification. This work compares ammonia removal for three pilot-scale treatment wetland porosity configurations to determine if submerged surface area limits nitrification during aeration treatment and cold climate conditions. A 144 cubic foot hydraulic flume with an aspect ratio of 14:1 (length:width), and planted with mature emergent macrophytes was used for study. The pilot-scale treatment wetland was fed secondary treated wastewater from the Arcata Wastewater Treatment Facility. The lowest porosity configuration (porosity: 0.60) demonstrated the highest ammonia removal performance. Higher porosity configurations (porosity: 0.75 and 0.86) demonstrated lower ammonia removal and nitrite production, suggesting aeration assisted nitrification may be limited by submerged surface area. Baseline (pre-aeration) ammonia removal for the pilot and full-scale treatment wetlands was compared to evaluate scale-up potential of the pilot-scale aeration system. A lack of similitude between pilot and fullscale baseline treatment performance suggests that differences in internal carbon and nitrogen loading may constrain direct use of pilot-scale system results for full-scale aeration system design.