HDD Used in Challenging Wisconsin Sewer Project

The cost of operating and maintaining sewer treatment facilities is an ongoing challenge for hundreds of towns and villages across the United States. Smaller communities, generally located in rural areas with sparse populations and limited tax revenues, must be diligent to carefully manage annual operating budgets, especially in supporting costs to provide municipal services. Many towns and villages are also struggling to find solutions for complying with increasing environmental regulations that create additional financial burdens.

Such is the situation for the tiny village of Rudolph, Wis.

Situated in the countryside and among pristine dairy farms smack dab in the center of the Badger State is the village of Rudolph (population 420). Rudolph is a community composed primarily of single-family residences. Each home has its own well; most with individual septic systems. A sanitary sewer system is available for all buildings, yet exists primarily to serve the collection of small businesses and municipal buildings located in the village’s downtown area.

Recent changes affecting sewer treatment facilities, enacted by the Wisconsin Department of Natural Resources (DNR), have placed officials with the Village of Rudolph in a predicament. Lacking funds that would be necessary to upgrade their present facility and comply with new requirements, village board members were forced to explore options. After identifying what they considered as the most feasible approach, officials reached out to their neighbors in Wisconsin Rapids — a community of approximately 20,000 residents and the Wood County seat —about six miles south of Rudolph.

Sewage Flows Downhill

Known for its paper-making manufacturing history, Wisconsin Rapids is also an important locale for the cranberry industry, synonymous with bogs and environmentally sensitive wetlands. So the resulting solution to Rudolph’s challenge — installing a 29,000-ft , 8-in. forced-sewer pipeline for transferring their sewage to Wisconsin Rapids’ sewage treatment facility — would present a different set of challenges for installation subcontractor Push Inc., Rice Lake, Wis.

Founded in 1974, Push Inc. got its start as a subcontractor using pneumatic air machines for road boring projects during the days when pneumatic air systems had just been introduced. The company’s core business was founded on fiber-to-the-home installations and electrical distribution projects. While horizontal directional drilling (HDD) is considered to be the company’s preferred installation method, Push Inc. is also adept in pipe bursting and auger boring. With more than 130 full-time employees and upward of 15 separate crews at any given time, Push Inc.’s trade territory extends nationally, having completed jobs in all regions of the United States

Staying on Course

Push Inc. was hired by general contractor Krucsez Construction, Green Bay, Wis.,to complete portions of the project that were specified to be completed using HDD. Located at an elevation of 1,102 ft above sea level, approximately 15,000 ft of the 5.5-mile downhill route to Wisconsin Rapids (elev. 1,027 f), were to be installed trenchless. Push operations manager Russell Johnson highlights a few of the project challenges.
“Not good,” Johnson says of the soil conditions. “We are running into sand, then swamps, followed by rock and a combination of very heavy soil types. Our crew has faced just about everything. We were familiar with the conditions, but what we didn’t anticipate was the hardness of the rock. Right now we’re running into areas of solid granite, followed by heavy clay. The abrupt change in conditions has made it a challenging job to say the least.”

According to Johnson, the dramatic and often unpredictable variance in soil types required selection of equipment with adequate power to handle anything the topography of central Wisconsin could dish out. He also needed to balance torque, pullback and horsepower with footprint, given the environmental sensitivities of the areas of wetlands. Selection of drilling fluids would also be critical for success. So Russell’s crew chose its D60x90 Navigator horizontal directional drill, manufactured by Vermeer, to confront the series of challenges. 

The route for installing the fusible PVC sewer line, prepared by engineers with Krucsez Construction, included several passes beneath wetlands in excess of 2,000 ft; a length that required Push Inc. to dissect such shots into two separate bores. The delineated wetland classification provides Johnson’s crew permission to complete minor excavation work necessary for accommodating launch and receiving pits. The longest bore completed by Johnson and crew thus far on the project has been 1,150 ft.

“We had permission to dig a pit in the middle of the longer bores, somewhere close to the middle, and splice the first half with the second,” Johnson explains. “There’s a certain approach that we have to follow for the digging and excavation component, plus other considerations due to the soggy soil and concerns for minimal disruption. The engineering plans completed by Krucsez Construction were quite specific in mapping out the bore path, including precise drilling depths required for each area along the route. Krucsez completed the plan; it was our responsibility to formulate an approach to make it all happen.”

Executing a successful drill plan requires daily study, and above all, flexibility on the part of Johnson’s entire crew. Each day begins with an in-depth overview of the engineering plan and evaluation of conditions likely to be encountered as the day’s drilling progresses. Test holes are drilled at numerous locations along the route to identify changes in soil conditions; information that allows the Push Inc. drill team to select and swap out bits accordingly.  

Fluids Critical for Securing Walls

Push Inc.’s HDD crew selected a duck bill drill bit to penetrate the tough soil conditions at an average depth of 7 ft, averaging approximately 500 ft daily. Pullback took approximately six hours using a 12-in.Vermeer-manufactured fly cutter reamer, with the 8-in. PVC fusible sewer attached and pulled back through the bore path after completion of each shot. Given the challenging and always changing conditions beneath the surface, determining the proper drilling fluid mixture was an essential component of maintaining the integrity of the bore walls.

Johnson attributes the speed and quickness of pullback with reducing the amount of fluid necessary, especially during pullback. “You’re always going to be pumping drilling fluid to any machine, no matter if it goes slow or fast,” he says. “But it only stands to reason that if you’re getting down to the end faster on pullback, you’re going to be using less drilling fluid.”

Push Inc. launched the Rudolph to Wisconsin Rapids sewer project on Oct. 29, 2011, and although the job remains ongoing, Johnson is pleased with the progress and production rates, especially given the complexity of the soil conditions and adherence to environmental sensitivities surrounding the many wetlands along the route.

“We’re running into a lot of unforeseen complications in this job, which is why it’s still in progress,” Johnson explains. “You just don’t know where the rocks are until you start the process. And then you might only get halfway through it for the day and hit 10 rocks, causing us to step back, rethink and retool. The soil conditions are going to be the biggest challenge, but nothing our crew or the equipment can’t handle. The drill is performing up to expectations, and like our company, continues to demonstrate that it’s not afraid to tackle a challenge.”

Randy Happel is a features writer with Two Rivers Marketing, Pella, Iowa.
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