Overview and details of the sessions of this conference. Please select a date or location to show only sessions at that day or location. Please select a single session for detailed view (with abstracts and downloads if available).
Session Chair: Dick Talley, Stantec Consulting Services, Inc;
3:00pm - 3:45pm
Commissioning a Treatment Plant for a Future Owner: The Story of Tehaleh
Christopher Stoll1, Sue Lawrence2
1Kennedy/Jenks Consultants; 2SL Environmental; ,
The Tehaleh Development is an employment based planned community that sits on 5,000 acres just South of Bonney Lake, WA. Full build out of the development is upwards of 10,000 homes which equates to nearly 25,000 people. After attempting multiple options to develop sewer capacity, the developer, Newland Communities, decided to build their own wastewater treatment plant to ensure capacity for the longevity of the community. Before embarking on the journey to plan, design and construct the Cascadia WWTP, Newland entered into a developer agreement with Pierce County Planning and Public Works (Sewer Department) to detail the steps of the process including testing, commissioning and ownership/operations transition of the WWTP to Pierce County. The WWTP was commissioned in October of 2018 with significant coordination between Newland, Pierce County, the engineer, Kennedy/Jenks and the contractor, McClure and Sons. Commissioning was a four-month process in which Pierce County was operating the WWTP prior to accepting ownership which started with a two-week process of demonstrating permit compliance for total nitrogen removal (which the WWTP did by the second day of full operations). Some challenges encountered included seeding the biological process, programming of the MBR system with the final effluent pumps and maintaining utility water pressure and availability for screening operation. This presentation will discuss and highlight the challenges, successes and lessons learned from this unique process of commissioning a developer lead WWTP with the future owner.
3:45pm - 4:30pm
36-inch UV-CIPP: How a Newer Technology Can Reduce Downtown Impacts
Mike Linn1, Kyler King1, Rob Lee2
1City of Salem, Oregon; 2Murraysmith; ,
The City of Salem (City) identified the Liberty Street Trunk Sewer as deteriorating due to hydrogen sulfide degradation and in need of rehabilitation. The trunk is approximately 3,200 linear feet of 24-inch to 36-inch diameter sewer, is 20+ feet deep, and generally runs south to north within an Oregon Department of Transportation (ODOT) controlled right of way (State Highway 99E). The roadway is one of the main thoroughfares that provides access in and out of downtown Salem. Many access manholes for the sewer are in the center of the busy two-lane roadway, with residential properties on either side.
The City evaluated the feasible technologies that not only would provide the extension of asset life, but minimize impacts in this heavily-traveled traffic corridor. Based on work hour restrictions, ODOT requirements for maintaining traffic, impact to residences, present and future sewer capacity needs, and bypass pumping costs and complexities, the City selected ultraviolet-light cured-in-place-pipe (UV-CIPP) as the rehabilitation technology.
This presentation will focus on the project constraints that led to the selection of UV-CIPP, the differences between UV and thermal curing processes and construction laydown area, and lessons learned during construction.
4:30pm - 5:15pm
Elevating the Profile of the Tualatin Interceptor through Trenchless Construction
Rob Peacock1, Wade Denny2
1Kennedy Jenks Consultants, United States of America; 2Clean Water Services; ,
The Tualatin Interceptor conveys wastewater from suburban Washington County to Clean Water Services’ Durham Advanced Wastewater Treatment Facility (AWWTF). As part of the West Durham Basin Improvements Program, the interceptor from King City to the Durham AWWTF is being replaced with a new interceptor that provides capacity to buildout of the service area. The existing interceptor was constructed in 1974 and includes two inverted siphon crossings of the Tualatin River. As the service area is projected to grow, new larger inverted siphons will be required if the system will continue to operate exclusively by gravity.
Clean Water Services’ project success criteria required the new crossings maintain gravity conveyance across the river, have a low maintenance costs, could be constructed within the required timeframe, and maintain their commitment to the protection of the Tualatin River watershed. These criteria limited the number of viable solutions. The original siphons where constructed using open-cut methods, however, open cut construction would not likely be permitted in 2018; therefore, the project team began focusing on trenchless technology.
The project team evaluated alternatives for the King City Siphon and the Cook Park Siphon to meet the project success criteria. However, given the developed nature of the crossings in 2018 and the topographical constraints of the existing gravity system, design and construction using traditional means and trenchless technologies were challenged. Trenchless alternatives were considered for both crossings, and a different construction method was selected for each siphon based on feasibility of meeting Clean Water Services’ success criteria.
This presentation will walk through the development of alternatives, the construction methods evaluated, and how the District’s criteria were met for the Tualatin River Crossing.
The project was completed as a Progressive Design-Build project and included a North American record for tightest vertical curve Microtunnel.