SEALING SYSTEM FOR LAFAYETTE
Lafayette Utilities System (LUS) serves the people of Lafayette, Louisiana and aims to provide them with quality electric power, water and wastewater services at reasonable rates. It is a customer owned and operated utility established in 1896. LUC employs 400 staff and is a Department of Lafayette Consolidated Government. Lafayette Wastewater Treatment Division has 33000 customers and runs four sewerage treatment plants handling 18,5 million gallons per day, its Collection Division maintains 650miles of pipe and 9900 manholes. The Collection Division has had problems throughout its sewer network with severe infiltration during periods of rainfall and has made strenuous efforts to seal the system, using most no dig methods replacing some pipe with new PVC and employing local and partial repair methods with limited success. Early in April 2003 the LUS Wastewater Collection Division Superintendent Stephen Rainey took a major step forward to meet his cost saving objectives by undertaking successfully a full scale trial of the Sanipor Sealing System in the Robert Lee Circle, Ophelia Drive and Beverley locations of the City
The demonstration project, budget $50,000 involved five sections running manhole to manhole of clay and PVC pipe. The total length of 8" main was 1496 feet and included 24 laterals of 4" and 6"diameter ranging in length from 30 to 120 feet, totalling some1800 feet. There were 7 brick manholes 36" and 48"in diameter approximately seven feet deep. A major benefit of the Sanipor system is that the treatment tests and seals the entire system and a water drop test can be used to provide a simple visual demonstration of the efficacy of the process. In this test a section of the network, the main complete with its laterals and manholes is isolated and flooded with water up to ground level or above using a special hydrostatic head tube if required. The extent of water exfiltration into the ground will indicate the presence of leaks and voids in the pipe bedding. As treatment proceeds the rate of addition of the chemical reactant will slow and cease as the combination seals the source of leakage and demonstrates the water tightness of the section. The water drop test can be used periodically at intervals to demonstrate the continuing efficacy of the process over time.
The LUS Wastewater Collection Division decided to test the Sanipor system throughout the entirety of the trial sections, they installed cleanouts at the upstream ends of the laterals close to properties and sealed the entire network including manholes from the cleanouts to the main. The trials were scheduled at a rate of one section per day but in the event the whole exercise took seven days as the local crew familiarised themselves with the equipment and the process. City officials, the crew and researchers from TTC Louisiana Technical University were fascinated by the dramatic change in rate of exfiltration between the initial pre treatment water test and the final dosage of sealant.
