The Wallace R. Knox Wastewater Treatment Plant in Texas City, Texas, operates one of two belt presses seven days a week during normal work hours, dewatering an average of 72,000 gpd of feed sludge.
Every three to four weeks, however, the spring-loaded check valve in the aging emulsion blending system became caked with polymer. It took the staff one day to dismantle the chemical feed pump and clean the mixing chamber with polymer solvent.
“We had capacity to store sludge in the digester for a day or two, but interrupting the dewatering process wasn’t very efficient,” says wastewater superintendent Calvin Bremer. “Neither
