Every spring, the wastewater municipality in Dalarna, Sweden, experienced melting snow and heavy rainfall that caused a dramatic increase in pump station inflow. To handle this seasonal volume, the station had oversized pumps that consumed more energy than needed during drier months. This case study illustrates how the installation of a variable-speed pump controller decreased energy consumption by almost 50 percent while allowing for variations in flow.
Energy costs have become an increasing contributor to pumping systems Total Cost of Ownership (TCO). In fact, energy cost represents 40% of the TCO of a typical pump. It is possible to reduce the electrical consumption by at least 30% utilizing Variable Speed Drives while decreasing maintenance costs associated with the mechanical driven system. This paper explains how to reduce TCO with a limited investment focused on three key areas: energy efficiency management, asset management, and energy cost management.
Ypsilanti’s pumps, originally put into service in 1982, became priority candidates for replacement after operating ten years beyond their expected 20 year service life. The Ypsilanti Community Utilities Authority (YCUA), included the project in the utility’s Master Plan.
As with many plants modified for activated sludge treatment, the existing infrastructure at the Adams Field Wastewater Treatment Plant in Little Rock, AR, allowed rags and other debris to clog the impellers of the submersible pumps. One of the plant’s two 15-horsepower pumps was replaced with an 18-horsepower RAS submersible pump with a self-cleaning impeller, virtually eliminating the clogging problem by simply pumping away any debris that reaches the pump intakes.
Undersized original construction and gradual equipment deterioration led to recurring pump station failures and overflows for the Valley Rural Utilities Company’s wastewater collection system in Lawrenceville, Indiana.
Aging pumps at Jackson Energy Authority’s Rolling Acres Lift Station (Jackson, Tenn.) resulted in frequent clogging and outages that required costly maintenance and repair.
After anticipated growth of the New Jersey casino industry fell short, Atlantic City Sewerage Company’s Baltic Avenue Pump Station was left with grossly-oversized long-shaft sewage pumps that operated inefficiently and were prone to cavitation.
Lift stations are remote pumping facilities that move wastewater from lower to higher elevation. Monitoring lift stations is important to collection system operators.
Wastewater can be both corrosive and abrasive. To ensure reliable and cost-effective pump operation, it is important to select a wastewater pump made from the most suitable material for your wastewater.
If one debate over a specific design feature stands out amongst all the others in the submersible waste water pump field, it must be, “Which is better, air-filled or oil-filled motors”? With The introduction of premium efficient motors by several manufactures, this topic has come to the forefront once again.
When a motor is operated on a variable frequency drive, unexpected voltage can be induced on the rotor and shaft.
When the discussion turns to requirements for “explosion-proof” pumps, many people rely on word of mouth, past practices or even old wives tales it seems. By Kevin Clemons