Public Works Director Charles Swimley proposed upgrades to the White Slough treatment plant’s outdated aeration blower system during Tuesday’s shirtsleeve meeting at Carnegie Forum.
The installation of two new variable speed blowers is expected to cost the city $750,000, according to Swimley. The blowers are used to separate water and sludge in the beginning stages of the filtration process, making them critical in the treatment of wastewater.
“A substantial amount of energy is needed in water supply and treatment systems to convert the unprocessed water before its safe for use or discharge,” Swimley said.
The new blowers will be energy efficient and help reduce electricity costs for the treatment plant, Swimley said.
In the treatment of wastewater, the blowers must deliver varying airflow under different environmental conditions with a relatively narrow pressure range. The blowers can consume a large amount of electricity, and make up a large portion of the electricity costs at the treatment plant, Swimley said.
Aeration blowers are used in the oxygenation process to filter the water that comes through the plant and separate the sludge from the water. The water then undergoes tertiary treatment in cloth media filters and UV disinfection, according to Swimley.
“Is the water safe enough to drink?” Councilman Alan Nakanishi asked Swimley.
In order for the water to be consumed, it would need to undergo additional filtration, Swimley said.
“The water filtered at White Slough is expelled into the Delta or it used for irrigation,” Swimley said.
The filtration of water at White Slough removes enough water annually to irrigate an estimated 700 acres of land leased to local farmers for crop production and fill a 300 acre-foot storage pond. This allows the city to expand its recycled water opportunities, Swimley said.
“The storage pond has allowed us to minimize discharge into the Delta and has allowed us to license our recycled water. Caltrans has taken an interest in the recycled water to irrigate the highway embankments,” Swimley said.
The Public Works Department will go before the Lodi City Council on July 17 and request the city adopt a financial plan for the aeration blowers and planned other capital projects at White Slough.