A challenge issued by the Snohomish County (Wash.) Public Utility District (PUD) No. 1 to reduce energy consumption by 10 percent in three years motivated the Edmonds Wastewater Treatment Plant team to process solids more efficiently and offset escalating electric bills.To evaluate energy savings for the challenge, plants must select a baseline representing typical energy use and develop dashboard indicators against which to measure changes. “The main energy indicator for most wastewater facilities is kilowatt-hours per million gallons treated,” says Pamela Randolph, plant manager. “However, our main indicator is kilowatt-hours per ton of dry solids processed, because we process solids
