"We knew our biggest problem was [our] lift stations, we just didn't know exactly what to do about it."
The words of Jon Brown, sewer system supervisor for Idaho’s Fremont County Public Works Department, no doubt resonates with many of his peers. Lift stations—or pump stations—operate as critical components in a collection system as they keep water flowing.
For Brown and his staff, a litany of issues gradually emerged over time as their collection system expanded, including the number of lift stations. The county operates a wastewater collection system in the Island Park region of rural Idaho, near Yellowstone National Park. The area is made up of a vast expanse of accessible forest comprised of private and public lands. Because the region is a popular vacation destination for outdoor enthusiasts, many of the county’s lift stations operate in forested locales and other remote areas only accessible by off-road-type vehicles.
A network of 47 lift stations conveys more than 175,000 gallons per day to two treatment plants. Despite being spread over an actual area of more than 24 square miles, only five public works technicians cover the entirety of the wastewater system including the treatment plants. Therefore, conducting preventative operation and maintenance (O&M) or emergency repairs for lift stations became both time-consuming and difficult.
“Island Park is so spread out, it makes it tough,” Brown said. “There’s all these little cabins and properties [feeding the wastewater collection] spread across the forest.”
Increasing recreational activity also led to frequent pump clogging events—consistent with the pandemic flushable issues occurring nationwide—and ultimately required the technicians to patrol on busy weekends and holidays.
Further complicating matters, the county had been operating and maintaining lift stations with 16 different manufacturer pump brands with many different models, configurations and ages, requiring a large and unwieldy spare parts inventory. This made it difficult to apply common troubleshooting practices, anticipate problems or conduct repairs without the use of outside contractors.
Developing Tiers & Templates
The county contacted consulting engineering firm Keller Associates to seek solutions to improve operational efficiency. Keller Associates proposed a tiered standardization program that would reduce the number of lift station types and manufacturer brands to three standard types based on size and capacity: (1) shallow, household-type pumping systems with less than 5-horsepower (hp) motors; (2) mid-range lift stations with 5- to 50-hp motors; and (3) large regional and/or influent lift stations with 50-hp motors or larger and typically deeper wet wells.
Fremont County selected preferred manufacturers based on extensive experience with a variety of systems: a grinder pump manufacturer was selected for the small household pumping systems; a packaged above-ground pump stations manufacturer for the mid-range lift stations; and a submersible manufacturer for the large lift stations.
“We’ve had so many different types of pump stations in the ground that we’ve figured out some of our likes and dislikes,” Brown said. “First and foremost, I want serviceability out of my pumps.”
Brown emphasized the need to access and perform maintenance on the pumping equipment more safely and easily. The county standardized on packaged above-ground lift stations for the mid-range station applications, which makes up most of the lift stations. These packaged stations arrive pre-assembled with all pumps, valves and controls aligned on a common base with a quick-access enclosure, allowing quick and easy installation on the wet well after basic suction pipe and electrical connections were completed.
Immediate and safe ground-level access to the controls, valves and pumps means these systems significantly reduce the time and personnel required to perform regular O&M.
Confined space entry and associated requirements are virtually eliminated, including permitting, harnesses, gas monitoring equipment, and other Occupational Safety and Health Administration (OSHA) and Class 1 Division 1 requirements. Routine tasks like pulling a pump to change a seal or impeller can be completed in minutes by a single operator.
Standardization in Action
First, the county’s professional engineering consultant undertakes the lift station’s design and sizing. Plans and specifications are then developed for the station with the county public works staff. They collectively review the necessary site-specific design details such as freeze protection and specialized impellers that prevent potential clogging.
The design template is applied to the specific location, and the developed plans and specifications are submitted to the Idaho Department of Environmental Quality (IDEQ). After IDEQ approval, a bid package is released for station pricing by the standardized lift station vendor, and the quotation and submittal process begin.