- Wastewater Utility Master Plan
In 1990, the Knoxville Utilities Board (KUB) acquired the wastewater collection and treatment utility from the City of Knoxville, Tennessee. Several suburban areas outside Knoxville were also acquired. The acquisition of the wastewater utility and aging facilities prompted the board to undertake a detailed master plan of the collection system and treatment facilities through the year 2010.
Our team performed evaluation and master planning for five major watersheds encompassing nearly 100 square miles. Approximately 450,000 linear feet of sanitary sewers, ranging in size from 12 to 84 inches, were evaluated. In addition, the study included evaluation of six treatment plants and 33 pumping stations.
Population and census data, along with land use and zoning data, was used to develop population and wastewater flow projections for 5-, 10-, 15- and 20-year periods for each watershed and each of the wastewater treatment plants. Our personnel monitored collection system flows at 18 locations. Flows were continuously recorded through several cycles of wet and dry weather at sites strategically placed to subdivide each major watershed into subbasins that represented commercial, residential and industrial areas. A physical inventory of the collection system was performed.Using the flow monitoring data and flow projections, a PC-based model was constructed to identify base flow rates, diurnal flow patterns, infiltration and inflow, and responses to storm events. The model was then used to identify problem areas for both existing and projected future conditions. Once problem areas were identified and physically inspected, the model was used to predict the systemwide impact of various alternatives for correcting deficiencies. Alternatives evaluated included installing parallel relief sewers, increasing pump station capacity and removal of excessive I/I.
The pump stations and wastewater treatment plant’s existing conditions and capabilities were evaluated both for present and future requirements. Facility deficiencies were identified and recommended improvements were presented, along with their estimated costs. Improvements recommendations were given for both the physical facilities and for operational parameters.
Additional items that were covered in the master plan included sludge management, industrial pretreatment program and SCADA system evaluation. The sludge management evaluation addressed KUB’s current sludge practices and future regulations to see what improvements or operational changes were necessary to meet the ongoing sludge regulations. The SCADA system evaluation reviewed the existing system and its deficiencies, the effects of the sparsely populated areas, provided several alternative evaluations, and provided conclusions and recommendations with cost estimates.
Nearly $45 million in facility and operational improvements were recommended for implementation over the planning period. We conducted master planning with close involvement of client management, engineering and operations staff. The study was completed on time and under its $440,000 budget over an 18-month period.
- Master planning
- Hydraulic modeling and analysis
- Five inverted siphons
- SCADA evaluation