Assessment of AWT systems in Tampa Bay area

A study was conducted to evaluate the performance of eight full-scale advanced wastewater treatment (AWT) facilities using biological nutrient removal (BNR) processes as the primary mechanism for removing carbon, nitrogen, and phosphorus from domestic wastewater. One year of operating data from each facility was obtained from monthly operating reports (MORs) provided by plant operators. BNR processes evaluated were: 5-Stage Bardenpho, A(2)/O, and Carrousel systems and/or oxidation ditches preceded by anaerobic/anoxic selectors. Plant inspections and interviews with chief operators were undertaken to understand how each facility was operated, and the type and quantity of chemicals used. Influent and effluent five-day carbonaceous biochemical oxygen demand (CBOD5), total suspended solids (TSS), and total phosphorus (TP) were evaluated in addition to influent total Kjeldahl nitrogen (TKN) and effluent total nitrogen (TN). In all cases, annual average effluent requirements of 5 mg/L, 5 mg/L, and 3 mg/L for CBOD5, TSS, and TN were achieved. Facilities with a 1 mg/L annual average effluent TP limit met permit requirements. Percent removals, monthly average effluent concentrations, detention times, secondary clarifier design information, and chemical dosages are presented.