RTW >Engineering Services > Pueblo West Metro District
Pueblo West Metro District Wastewater Treatment Plant Expansion
The District's existing 0.6-mgd plant required upgrade and expansion in both hydraulic and nitrification capacity as determined by the Colorado Department of Public Health & Environment. Tetra Tech RTW conducted an engineering study based on a design flow of 1.75 mgd. The study considered four treatment alternatives: SBR, RBC, oxidation ditch, and single-basin biological nitrogen removal (SBBNR). The SBBNR process was chosen because it was the lowest-cost alternative, it had been demonstrated as a reliable process for BOD and TSS removal as well as nitrification, and it optimized use of much of the existing lagoon system.
The process included two aerated earthen basins, two secondary clarifiers, and three WAS and three RAS pumps. Nutrient removal, including ammonia and nitrate, was accomplished by providing aerobic and anoxic zones within the aeration basins. Other plant modifications included increasing the capacity of the two existing lift stations, adding an enclosed headworks facility that included screening and grit removal, adding an administrative/operations building, replacing the chlorine disinfection facilities with UV disinfection, and using two existing lagoons for biosolids treatment and storage.