A STICKY SITUATION
The Village of Hartland’s Arlene Drive sanitary lift station serves a high-end residential community adjacent to a golf course. Many of the homes that are served by this submersible lift station use a cleaning service. Unfortunately, “disposable” wipes and other cleaning materials that are frequently used by these cleaning services are often flushed down the toilet, clogging the lift station pumps. Before this issue was resolved, the Village utility staff were sent out several times a week to pull the pumps from the wet well and unclog them.
WORKING TOGETHER TO FIND A SOLUTION
The Village partnered with R/M to find a way to prevent their pipes from such frequent clogging.
First, the Village implemented an educational program targeting nearby residents and mailed out flyers explaining the problems associated with flushed cleaning supplies. The Village noticed a slight improvement following the educational campaign, but clogged pipes continued to create serious issues in the community.
The Village decided that it was necessary to replace the pumps with another manufacturer that uses a backswept, semi-open, impeller. This impeller was designed to be more resistant to clogging than the conventional submersible pump impeller thanks to its unique geometry and the design of how wastewater enters the eye of the impeller.
OVERCOMING UNIQUE CHALLENGES
This project presented a special challenge since the Village needed to provide continuous pumping service at the lift station. R/M coordinated an individualized approach with the Village where construction would take place overnight from 10 pm to 5 am; the time period when the flow rates were the lowest going to the lift station.
In addition to the pumps themselves, the pump bases located at the bottom of the wet well had to be replaced in order to accommodate the new pumps. All of the necessary construction materials were inventoried and delivered to the site beforehand. The wet well was isolated by blocking off an upstream manhole. During the construction in the middle of the night, a rotation of pumper trucks drew wastewater from the upstream manhole and discharged it to the nearby wastewater treatment facility. The flow rates in the middle of the day would have been too high to use this method, but by completing the work overnight, this method of wastewater conveyance was feasible.
OPTIMAL RESULTS
The contractor performed well, and the project was completed by dawn the next morning. The new pumps’ clog resistance performance exceeded expectations. The pumps still clog occasionally, but the frequency has been reduced from several times per week to several times per year. As an added benefit, the Village has seen an approximate 40% energy usage reduction at the lift station because rags no longer accumulate on the edge of the impeller.
If you’d like inquire as to whether or not your community can benefit from similar lift station upgrades, please contact an expert at R/M today.
About the Author
David W. Arnott, P.E.
Team Leader/Senior Project Manager
Dave has extensive experience in the planning, design, and construction project management of wastewater treatment facility renovation and upgrade projects. Areas of expertise include treatment processes, hydraulics, mechanical equipment, and wastewater disinfection. He also has experience in sanitary and water pumping station design and sanitary sewer wet weather facilities.
