City of Ennis: Wastewater Treatment Plant 48″ Sewer Line

SPI completed an initial planning assessment on the City’s existing deteriorated 24” main gravity feed to the WWTP. The existing sewer line was located in a cross-country drainage that was very difficult to access and maintain. This sewer line was identified as a critical source of infiltration and inflow (I&I), and loading on the sewer line had exceeded functional capacity. A significant collapse and breach in the line resulted in a sanitary sewer overflow (SSO) that was reported to the TCEQ. The City installed a temporary repair to the sewer line, but was under a strict TCEQ deadline to complete a final repair. A fast-track design and construction schedule was developed that allowed the City to maintain compliance with this TCEQ requirement. Design for a new multi-phase 48” sewer main was completed ahead of schedule. Using a multi-phase approach and alternate bid considerations for pipe materials, the project’s qualified low bidder was under budget for Phase 1 which consisted of 4,175 LF of 48” gravity sewer PVC, 160 LF of 24” gravity sewer PVC, over 20 manholes, misc. pavement repair, and ROW clearing. The project was completed under budget, and ahead of schedule in September 2020.
The City incorporated Phase 2 and Phase 3 construction within their Capital Improvements Plan.
SPI conducted a preliminary planning assessment on the City’s existing 24-inch main gravity feed to the WWTP, which had deteriorated significantly. The sewer line was situated in a cross-country drainage area, presenting challenges for access and maintenance. Additionally, it was identified as a major source of infiltration and inflow (I&I), with loading exceeding its functional capacity. A significant collapse and breach in the line resulted in a sanitary sewer overflow (SSO), which was reported to the TCEQ.

The City implemented a temporary repair to address the SSO, but faced a strict deadline from the TCEQ to complete a permanent solution. To meet this requirement, a fast-track design and construction schedule was developed. The design for a new multi-phase 48-inch sewer main was completed ahead of schedule.

The project adopted a multi-phase approach and considered alternative bid options for pipe materials. This strategy resulted in the selection of a qualified low bidder who was under budget for Phase 1. This phase encompassed 4,175 LF of 48-inch gravity sewer PVC, 160 LF of 24-inch gravity sewer PVC, over 20 manholes, miscellaneous pavement repair, and ROW clearing.

The project was successfully completed ahead of schedule and under budget in September 2020. The City subsequently incorporated Phase 2 and Phase 3 construction into their Capital Improvements Plan.