South Plant gets to the heart of energy efficiency

Crossposted from Clean Water Stories

Water is heavy, and moving it around takes a lot of energy. King County’s Wastewater Treatment Division (WTD) is responsible for 54 percent of total energy use for all King County facilities, so even small energy savings make a big difference. The pumps are vital to plant operations and vital to energy efficiency, and after 50 years of service, it was time for three pumps to be replaced.


While the pumps were reliable and easy to operate throughout their lifespan, they were also inefficient. These pumps liked to take it slow and steady, like power walkers on a level surface. Because people use the most water in the morning and evening, flows into the plant vary. Just like a power walker, the pumps have to work harder when the terrain gets steep. The pumps can throttle up and down as flows vary, but this wastes energy as heat. Since energy efficiency was a primary objective for the project team, they enlisted the WTD energy team to get involved.

Read more at Clean Water Stories