The wastewater collection system experiences infiltration of groundwater and stormwater through wastewater pipes that have become cracked or damaged over time. Infiltration increases treatment costs for the city at the wastewater treatment plant. This project aims to reduce infiltration in a selection of pipes needing rehabilitation throughout the city using a pipe lining system that is injected into the pipe and then cured with heat or ultraviolet light.
- Alternatives Considered:
(a) Leaving existing sewer collection pipe in place with no mitigation. While this incurs no construction costs, it does not address the infiltration of water into the sewer collection system which is increasing the city’s treatment costs for wastewater.
(b) UV Curing Pipelining: This alternative is comparable to thermal curing, however for the pipe diameters considered for the project it is more expensive. As with the thermal curing there is minimal construction impact to customers and the infiltration is corrected.
(c) Full Replacement: This alternative is the complete replacement of the sewer collection pipe, rather than rehabbing it with a lining. This is an expensive construction project that will result in a significant impact on the streets of our customers.
- Preferred Alternative: The preferred alternative is a Thermal Cured Pipelining. This alternative corrects the infiltration issue of aged wastewater collection pipes and minimizes the impact construction has on our customers.
- Any projected rate increases: Each year the department models the future 10 years of capital and operating expenses and plans out the necessary rate and other revenue needed to meet the costs. This project is included in that model and so the effect of the project on customer rates is minimal and has already been taken into account. Receiving funding through the SRF loan will reduce the cost of the capital funding for this project and ease the demand on revenue arising from it.
- Construction will be occurring in the central area of the city in already disturbed soil, mostly in the street. Environmental impacts will be minimal.
Cured in Place Pipelining Project