The City of Hayti retained the service of Horner & Shifrin for a City-wide wastewater I&I reduction and wastewater treatment facility rehabilitation project. Hayti’s existing system is primarily composed of over 130,000 linear feet of vitrified clay pipe and brick manholes. The I&I is so severe that the town’s lift stations can run for weeks during the wet season resulting in the necessity to overhaul 15 of the 17 City’s lift stations. The City’s aerated lagoon equipment has largely failed and must be replaced to meet the increasingly stringent WWTF effluent limits set by Missouri’s Department of Natural Resources.
The $6.62 Million Dollar project was funded through USDA-Rural Development and CDBG includes the inspection, design, and construction management to reduce the collection system I&I, rehabilitate the City’s lift stations, and replace the City’s existing aerated lagoon for ammonia reduction. The resulting solution is expected to substantially reduce the amount of I&I entering the system through a series of gravity main In-Situ liners, cementitious manhole lining, sewer wye grouting, and lift station rehabilitation. The WWTF technology evaluation is currently underway.
To facilitate the project, H&S developed a secure web-based ESRI GIS application and database of system attributes and performed data migration of existing sewer system drawing files into the GIS system. Inspection crews conducted survey-grade GPS survey of structures detailed manhole inspections utilizing NASSCO standards to collect physical dimensions, structural conditions, sources of possible I/I, etc., and smoke testing to identify public and private defects. Mobile devices linked to the web-based GIS are used to collect all data, inspection notes, and photographs in real-time providing up to the minute data and status of field operations.
Sub-consultant CCTV crews will provide additional detail data gathered from visual pipe inspections. CCTV inspection video and PDF reports will be added to the web-based GIS to provide direct access for City staff to the data. The project will culminate in a bid letting that is anticipated in late 2020, which will include two contracts. The first will be for gravity main In-Situ lining, manhole grouting, and lateral wye testing/repairs. The second will include WWTF upgrades, lift station retrofits, and collection system point repairs. The design goal is to reduce system I&I by approximately 65-75%.