To meet the requirements of a consent decree that the City of Chattanooga is managing, the city's Waste Resources Division hired Burns & McDonnell to evaluate and rehabilitate several sections of existing interceptor sewers. Initially, the project scope was to line the sewers to meet the requirements. As we evaluated the conditions of the sewer system, our team provided design-bid-build execution services to help the city garner the greatest value for the project. In addition to lining the sewers, we designed the system to make the sewers as water-tight as possible. The new design will enable the system to withstand 10 feet of head/internal pressure, reducing sanitary sewer overflows (SSOs). To complete the project within the city’s budget, our team also provided value-engineering — working closely with the contractor to reduce construction costs.
Our evaluation of the trunk sewer conditions involved closed-circuit television (CCTV), sonar, manhole and field investigations to determine the needed repairs. The project analyzed multiple alternatives to rehabilitate the trunk sewers to prevent SSOs and inflow and infiltration (I/I). The team also dealt with the complexity of the sewer system’s location in a sensitive area with wetlands and endangered species.
Before design completion, we contacted permitting authorities, contractors and material vendors to determine the project feasibility and estimate construction costs. Our team produced a technical memorandum, preliminary drawings and a cost estimate for the city’s consideration and review. The city approved the design and construction began in July 2015. Our team will conduct construction inspections by a resident project representative.
Field, CCTV and manhole investigations
Environmental and cultural resources surveys and mitigation