Agenda Date: 07/16/2024
Subject:
Title
Resolution 81-2024: Approving a construction contract between the City of Littleton and Inliner Solutions LLC for the 2024 Sanitary Sewer Interceptor Rehabilitation Project
Body
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From: |
James L. Becklenberg, City Manager |
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Prepared by: |
Carolyn Roan, Project Manager, Public Works |
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Presentations: |
Brent Soderlin, Interim Public Works Director |
PURPOSE:
Does council support a construction contract with Inliner Solutions LLC for $2.9 million in order to rehabilitate the remaining segments of the city’s sewer interceptor pipe?
LONG-TERM OUTCOME(S) SERVED:
Sustainable Community with Natural Beauty; High-Quality Governance
DISCUSSION:
Much of the sewer interceptor pipe is constructed of concrete, which deteriorates over time in the corrosive environment of wastewater and associated gases. This is typical of sewers worldwide. Without rehabilitation, the sewer would develop holes, break and/or collapse, leading to health risk associated with sewer wastewater in the subsurface soil and groundwater of the South Platte River (which is an environmental violation), and possible sinkholes at the ground surface (often in roadways), both of which are very impactful and expensive to remedy. The industry standard practice is to proactively rehabilitate such pipes with a liner that can be inserted into the existing pipe, as opposed to digging and replacing the pipe, which is both more expensive and more impactful.
BACKGROUND:
The original sewer interceptor pipe in the city was constructed in 1959 within Santa Fe Drive, from the Lee Gulch trunkline extending north to the former wastewater treatment plant located near Santa Fe Dr and Belleview Avenue. In 1976, the interceptor was extended with a larger pipe (diameter range from 54” to 66”) to accommodate additional flows from surrounding sanitation districts, and this pipe led to a new wastewater plant (now called South Platte Renew), and the old wastewater plant was dismantled. Some segments of the interceptor have since been reconstructed for various reasons, but most have been rehabilitated in place with a liner to extend its service life.
In 2008, the city began to rehabilitate the interceptor starting at the north end near the South Platte Renew wastewater treatment plant. Due to the cost, the rehabilitation has occurred in phases, with approximately 1-2 million dollars spent each year. After a closed-circuit television (CCTV) inspection of all the city sewer pipes in 2018, the city has spent approximately $2 million per year on the most critical segments of sewer (some of which were identified as collapsing or with severe corrosion degradation). The project proposed for 2024 includes rehabilitating the last remaining segments of the interceptor pipe from Lee Gulch to the wastewater plant that have yet to be rehabilitated.
In regard to the bidding process, a request for bids (RFB) was posted on the Rocky Mountain E-Purchasing System. Two valid bids were received on July 28th, 2024. Inliner Solutions, LLC was the low bid.
Prior Actions or Discussions
The need for sewer system maintenance and master planning has been brought to Council in various actions in the past, as well as the annual sewer maintenance budget.
FISCAL IMPACTS:
The cost to the city for this contract is $2,920,026, based upon the lowest bid received from Inliner Solutions LLC. The project is fully funded from the sewer enterprise fund’s line items for sewer interceptor and other sewer maintenance and is budgeted and included in the 2024 Budget.
STAFF RECOMMENDATION:
Staff recommends approval of Resolution 81-2024.
ALTERNATIVES:
Denying approval of the project will leave segments of the sewer interceptor susceptible to additional corrosion and potential collapse. The alternative to rehabilitation in place is to excavate and replace pipe, however this is longer in duration and more expensive, with impacts to travel and noise. Traffic lanes would be closed for extended periods of time, including segments within Santa Fe Drive. Because sanitary sewer pipe is typically deep, the resulting excavation of such pipe and the surface area disturbance is large. Denying approval of this project, in part or wholly, delays overdue maintenance on these segments of the interceptor increasing changes of collapse.
PROPOSED MOTION:
Proposed Motion
I move to approve Resolution 81-2024 approving a construction contract between the city of Littleton and Inliner Solutions LLC for the 2024 Sanitary Sewer Interceptor Rehabilitation Project.