Thomas Township Collection System Upgrades
Upgrades Include New Pump Stations, 15,000 Feet of Forcemain, and New Sanitary Sewer
Thomas Township, MI - Located in Saginaw County, Thomas Township is a primarily residential community of approximately 12,000 residents. The area is also home to commercial and industrial activity, most notably Hemlock Semiconductor (HSC), a global leader in producing hyper-pure polysilicon for the semiconductor and solar industries.
HSC’s operations require large volumes of drinking water and generate significant volumes of wastewater, which places considerable demand on the Township’s infrastructure. In 2021, HSC announced a $375 million expansion to its facility, adding around 100 jobs and enhancing its competitiveness in the semiconductor industry. The expansion would also more than double its wastewater discharge—from 420,000 gallons per day to 1 million gallons daily. This increase is necessary for long-term growth at HSC and within the Hemlock community. HSC’s average drinking water use is 2.0 million gallons per day, more than twice the Township’s average of 0.96 MGD.
To address these demands, HSC approached Thomas Township with a request for infrastructure improvements. In response, the Township hired Spicer Group in late 2021 to evaluate the existing wastewater system and develop solutions. The Township also began to negotiate multiple agreements between Saginaw Township, HSC, and themselves, which were essential to move the project forward. Spicer Group conducted a comprehensive analysis and determined that substantial upgrades were necessary to support the increased wastewater flow and avoid overburdening the current system.
At the time, the entirety of HSC’s sanitary flow was routed through the Township’s Pump Station #12 into the M-46 corridor, a section already operating at capacity. The additional flow posed a serious risk of sanitary sewer overflows, prompting engineers and the Township team to consider either expanding the current interceptor or rerouting the flow.
The most feasible solution was to construct a new larger-capacity Pump Station #12 and redirect the discharge to the northern section of the collection system, where more capacity was available. A planned 21-inch gravity sewer connection point was created during the original development of the Township’s sanitary sewer collection system, which was initially built to support future development and identified as a key connection point. A 3,750-foot gravity sewer extension was planned to reach the connection point, both to shorten the new forcemain and to offer future development potential. Redirecting the flow northward also required upgrades to Pump Station #4, which was aging and too small for the projected new volumes.
This comprehensive plan helped alleviate the hydraulic bottleneck along M-46 and positioned HSC for future growth by shifting its flows to an area of the collection system that had room for growth. To achieve this, a 15,000-foot stretch of 14-inch high-density polyethylene (HDPE) forcemain was installed under Geddes Road, crossing Swan Creek, using precision directional drilling to minimize environmental impact. The new main is connected with a gravity sewer at Kennely and Geddes Roads, enabling further system flexibility.
Pump Station #4, first built in 1972 and located in a residential neighborhood called Rambling Acres, presented additional challenges. Expansion space was limited at the existing pump station location, and the area was governed by a restrictive covenant that mandated residential use. Due to cost and community disruption concerns, the Township chose to purchase a nearby residential property to build a new station at the corner of Sue and Madeline Streets.
Upgrades at this location included the installation of a new wet well and pump station capable of handling both HSC’s increased flow and anticipated residential growth. Approximately 100 feet of 30-inch gravity sewer, 3,000 feet of 12-inch forcemain, and 1.5 miles of new road surfaces were also installed.
To maintain the neighborhood’s aesthetic and adhere to the restrictive covenant, the pump station was designed to look like a house. The generator was housed in a garage-style section of the building with noise-reducing features, and the wet well was fenced off to blend in with the surroundings. Sound attenuation materials were included in the design, and the generator’s exhaust was directed vertically to further reduce street-level noise.
Throughout the project, the Township prioritized transparency and public engagement. When the restrictive covenant was discovered, Spicer Group and Township officials held a town meeting to explain the necessity of the upgrades and sought support from residents. For those unable to attend, staff went door-to-door to explain the project and obtain signatures on waiver forms. The building’s design, modeled after the original house it replaced, helped secure community buy-in. After construction was completed, an open house was held to invite residents to see the new station and learn about the improvements firsthand.
Environmental protection was also a key focus, particularly during the Swan Creek crossing. Swan Creek is a critical drainage route for Saginaw County, and its surrounding wetlands are environmentally sensitive. To minimize disruption, directional drilling was used to install the 2,000-foot section of forcemain, eliminating the need for open trench excavation. The project team worked closely with the Michigan Department of Environment, Great Lakes, and Energy (EGLE), the U.S. Army Corps of Engineers, and the Saginaw County Public Works Commissioner to secure the necessary permits.
The project was designed with long-term sustainability in mind. Both Pump Stations #4 and #12 were upgraded, nearly doubling the capacity of each to pass flow through the new route. This allows the Township to retain its initial capacity in the stations, while accommodating the growth of HSC.
Pump Station #12 now features three pumps, allowing greater capacity without increasing energy usage. Noise control measures and careful site planning ensured the upgrades remained unobtrusive to local residents. Moreover, the Geddes Road pipeline upgrade enhanced system efficiency by utilizing previously underused infrastructure, enabling further development in key industrial and residential areas.
The Thomas Township sanitary sewer project exemplifies successful collaboration between industry, local government, and the community. HSC achieved the infrastructure capacity needed for expansion, the Township resolved critical system bottlenecks, and residents benefited from infrastructure improvements, increased service reliability, and environmental safeguards. Through thoughtful planning, community outreach, and strategic design, the project not only met immediate needs, but also laid the foundation for sustainable growth well into the future.
