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The City of Wood Dale, a suburban community in DuPage County, Illinois, serves approximately 14,000 residents and supports a robust industrial sector due to its proximity to O’Hare International Airport. Key infrastructure investments during the city’s rapid expansion in the 1960s and 1970s included the Klefstad Lift Station, designed to handle wastewater flows from a mix of industrial, commercial, and residential areas. Over decades, the lift station became a vital component of the City’s wastewater management system.
By early 2023, the Klefstad Lift Station faced urgent challenges. A major new industrial user was set to nearly double daily flow rates from 120,000 gallons per day (GPD) to 220,000 GPD, increasing demand on an already strained system. Compounding this issue, the station’s aging infrastructure—particularly a failing cementitious liner in the wet well—caused significant operational inefficiencies, leaving only one pump functional and increasing the risk of system failure during wet weather events.
Recognizing the station’s critical role, the City of Wood Dale developed a comprehensive and expedited rehabilitation plan. Collaborating with RJN Group, the strategy prioritized minimally invasive, innovative solutions to address structural and hydraulic deficiencies while minimizing disruption to the surrounding community. The plan ensured the lift station could meet growing demands, safeguard public health, and continue supporting the city’s economic base.
Klefstad Lift Station Area
The Klefstad Lift Station rehabilitation was meticulously planned to address significant challenges while minimizing costs, risks, and disruptions. A major focus of the design was reducing the substantial cost of bypass operations, which can account for up to 50% of project expenses. The strategy emphasized a comprehensive rehabilitation approach, addressing all critical vulnerabilities in a single effort to enhance long-term system reliability.
Before RJN’s site visits, the City’s data was reviewed to establish a baseline understanding of the Klefstad Lift Station’s operations. While the 2009 rehabilitation plans detailed updates like a cementitious liner in the wet well, pump replacements, and electrical and SCADA system upgrades, no original construction drawings existed. This lack of documentation complicated understanding the infrastructure’s history, particularly for the 2,800 LF ductile iron pipe (DIP) force main, which discharges into a manhole on Wood Dale Road.
The force main, estimated to be 60 years old based on historical aerial imagery, was neither replaced nor rehabilitated in 2009, and no record drawings existed. The City’s knowledge was limited to an approximate GIS path and a few documented break locations, including a significant one 1,700 LF downstream near a utility crossing with a 12-inch water main. Without detailed profiles or condition data, a comprehensive assessment was critical to addressing vulnerabilities and planning rehabilitation.
Additionally, the pumps installed in 2009 struggled with wet weather flows, underscoring the system’s operational challenges—issues needing resolution before accommodating a new industrial user.
During the site visit, significant structural issues were observed at the lift station, primarily due to hydrogen sulfide (H2S) corrosion. The wet well piping showed roughness, blistering, and peeling, while the discharge manhole and wet well walls displayed advanced deterioration from a failing cementitious liner that was clogging Pump 1.
Wet Well Cementitious Liner
Reduced flow could be attributed to a number of different things including friction losses in the force main, impeller damages, etc. Regardless of the cause, the velocity was below 2 feet per second increasing the risk of debris and deposit build up in the force main.
A structural assessment, including a 360° GoPro inspection, identified extensive H2S corrosion and liner deterioration. The wet well access hatch was damaged, with missing handles and bolts and worn safety netting, requiring replacement. Corroded areas included the wet well, valve vault, and discharge manhole, threatening structural integrity and system capacity.
Failing Cementitious Liner
Recommendations included rehabilitating the discharge manhole with a durable lining, restoring the wet well’s structural integrity, removal and replacement of corroded wet well piping, valve vault upgrades, and force main pressure pipelining.
The City expanded the project scope to include the force main, ensuring a comprehensive rehabilitation and minimizing future disruptions. This approach allowed the force main to be addressed during the same construction phase, optimizing the timeline. The final design focused on:
Multiple pipelining and structural lining techniques, such as CIPP and FFRP, were included in the specifications to give contractors flexibility in choosing efficient, cost-effective methods. This fostered competitive bidding and ensured methods aligned with contractor expertise and project constraints.
Following bidding, the awarded contractor proposed utilizing the existing easement for a bypass path, as it was shorter than the original proposed in the design. This path traversed a section of the City’s industrial corridor, an area heavily trafficked by semi-trucks.
Collaborating with 32 businesses, a homeowners’ association, utility providers, and the DuPage County Division of Transportation, the team focused on bypass logistics, traffic control, and minimizing construction disruptions. These discussions shaped a bypass placement plan that balanced road ramps with trenched sections for optimal performance and minimal impact.
The resulting bypass system, spanning 3,100 linear feet, was a testament to meticulous planning and teamwork. It featured five road ramps and buried segments at three critical points to accommodate traffic and utility constraints. Agreement on the final bypass plan, which required two months of negotiation and coordination, underscored the commitment to stakeholder needs and project efficiency.
Once installed, the bypass underwent rigorous water-filling and pressure testing to ensure reliability. With the bypass system approved by the City, the project advanced to construction, achieving a key milestone in the timeline.
The wet well underwent comprehensive refurbishment, including the removal and replacement of deteriorating access hatches and corroded mechanical piping. Access hatches, previously lacking essential safety features, were replaced to meet modern safety standards. Existing pumps were sent to the manufacturer for refurbishment and planned for reinstallation.
To restore the wet well walls, the project utilized SprayWall®, a high-performance polyurethane structural liner, ensuring enhanced durability and protection against future corrosion. Preparation efforts included power washing with hot water to remove grease, sandblasting for surface cleaning, applying cementitious liner coat, and applying chemical grout to seal off groundwater infiltration. These steps ensured a robust bond between the liner and the wet well, critical for the project’s success.
The valve vault was also upgraded, with the replacement of corroded plug valves and quick-connect piping. These enhancements improved flow control, operational reliability, and ease of future maintenance, meeting the lift station’s increased operational demands.
The force main rehabilitation presented unique challenges that demanded innovative solutions. Initially, the Contractor proposed Primus Line® folded flexible reinforced plastic (FFRP), a liner optimized for pressurized pipelines, leveraging its efficiency and minimal access requirements. However, during excavation, it was discovered that the final 100 feet of the force main were non-pressurized, requiring a hybrid approach.
FFRP Lining Installation
Locating the force main proved difficult due to discrepancies in GIS data. Hydro-excavation provided three access pits: one near the lift station, another 1,300 feet downstream, and the third at a high point in the system 100 feet upstream of the discharge manhole. During televising inspections, a 45° bend, caused by a storm sewer crossing, was identified and subsequently replaced with two 22.5° bends to reduce operational pressure impacts.
Force Main Alignment Adjustment
Force main cleaning employed progressive pigging, however, a low point in the force main profile retained water despite dewatering efforts, necessitating an adaptive installation plan.
This approach underscored the project’s focus on innovation and adaptability to ensure success in a challenging industrial environment.
Trenchless rehabilitation methods were used in both the wet well refurbishment and the force main lining to minimize surface disruption, restore operational and hydraulic capacities, extend the life existing equipment, reduce demolition debris, and reduce the overall project costs.
Following thorough sandblasting, the wet well surface was meticulously prepared for the application of a polyurethane structural liner. Pre-heating the material to the optimal temperature ensured proper consistency and adhesion, while drying the wet well surface eliminated bonding issues.
Pump strokes were carefully monitored and thickness checks were conducted periodically to ensure the required 250 mils thickness was maintained throughout. This precision not only met stringent specifications but also provided a durable and seamless surface.
The team installed new piping, guide rails, and refurbished pumps, restoring the lift station with enhanced performance and longevity. The innovative use of advanced materials and quality-focused execution exemplified modern engineering excellence.
The force main rehabilitation employed trenchless techniques to address both non-pressurized and pressurized sections, ensuring durability and efficiency.
For the non-pressurized section, the team utilized a steam-cured CIPP liner. A boiler truck introduced steam to cure the resin, enabling the liner to conform to the pipe and create a seamless, durable new pipe within the existing infrastructure.
The pressurized sections upstream required the FFRP liner. The liner was pulled into the ductile iron force main using a winch, and compressed air was used to inflate it. Food-grade oil lubricated the process, ensuring smooth installation. Special coupling connectors secured the liner, with resin applied only at the couplings to lock them in place.
This project tackled significant hurdles in stakeholder coordination, bypass operations, and access constraints within a high-traffic industrial zone. The bypass system, accounting for over half of the project’s cost, required precise planning to maintain service continuity during the rehabilitation of the lift station and force main. Stakeholder negotiations balanced industrial users’ operational needs with bypass staging logistics and extended operational periods.
Access constraints required strategic site planning to streamline construction activities and mitigate impacts. Surface preparation was another critical element, as the structures, heavily corroded by H2S, demanded thorough sandblasting and cleaning for proper adhesion of the applied linings. Structural lining in key areas provided enhanced durability, ensuring the infrastructure’s long-term performance.
The project used a hybrid trenchless rehabilitation approach, combining CIPP for the gravity section and FFRP for the pressurized force main. This strategy successfully addressed the structural and hydraulic deficiencies of the system. Extensive cleaning and pigging of the force main removed severe tuberculation buildup, improving hydraulic performance and restoring smoothness.
Force Main Tuberculation Buildup
This innovative approach extended the infrastructure’s service life, minimized service interruptions, and provided a cost-effective solution to complex urban challenges. By leveraging multiple trenchless technologies, the project demonstrated the versatility and efficiency of modern rehabilitation techniques in addressing aging infrastructure.
The project underscored the importance of a proactive approach to aging infrastructure. Over time, lost records can create uncertainty, making pre-construction assessments and inspections critical. Techniques like hydro excavation prior to bidding were instrumental in reducing unknowns, accurately locating buried infrastructure, and understanding pipe profiles. This upfront knowledge enabled more precise budget forecasting, competitive pricing, and mitigation of unforeseen construction issues, offering a replicable model for future urban infrastructure projects.
