Pima County and its contractor, B&F Contracting Inc., are scheduled to begin work in your area on the North Rillito Interceptor (NRI) Rehabilitation Project. The NRI is a major sewer line that runs along the north side of the Rillito River from an area near Woodland and Bear Canyon Roads, west to the Tres Rios Water Reclamation Facility.
Following is a brief description of work that will be performed:
- Manhole adjustments – The contractor will replace the steel manhole frames and covers, and pour new concrete collars around the manhole covers.
- Set-up of the Flow Management System (bypass) – The contractor will install temporary, above ground, pumps and piping that will transport the sewer flows while the sewer rehabilitation work is underway. Most of the system will be located along the dirt walking-path portion of the Loop, however, there may be smaller pipes and pumps located within some of the complexes (common areas and/or roadways) that front along the Loop path.
- Once the Flow Management System is in operation, it will run 24-hours a day, 7-days a week until all rehabilitation work along this portion of the sewer line has been completed. 24-hour operations should be expected during the month of May.
- Cured In Place Pipe (CIPP) lining operation – a resin saturated lining will be inserted into the existing sewer line at certain manholes. The lining is then cured with hot water, which causes the lining to harden and adhere to the existing pipe, creating a new “pipe within a pipe.” During this phase of the operation, residents may notice a styrene smell (think of a new shower curtain), which is a normal part of the CIPP process. The best way to prevent smelling this in your home is to make sure all your drain traps have water in them, especially on plumbing fixtures that are not used very often.
- Once the curing process (hot water pumped through the sewer pipes) begins, it will run 24-hours a day until the lining material hardens. This may take up to three days per lining segment. Some communities could see up to six days of CIPP activities.
- Excess CIPP lining material will be removed at each manhole along the rehabilitated sewer line.
- Manhole rehabilitation – crews will prep and coat the existing manholes along the mainline sewer
- Flow Management System (bypass) shutdown – the system will be turned off and the temporary pumps and piping will be removed.
Most work will take place during the day, however, during the lining and curing operation, there will be 24-hour activities, especially near manholes where the lining and cure water is being inserted.
Residents should also expect some parking and lane restrictions in areas where the manholes are located.
The above outlined work is expected to be completed by the end of June 2016.