The Town of Discovery Bay community Services District is making modifications to its wastewater treatment plants to comply with new National Pollution Discharge Elimination System (NPDES) permit changes. Changes include modifying the process to reduce effluent total nitrogen below 10 mg/l. Process improvements will take place within the existing fence line at Wastewater Treatment Plant No. 2 at 17501 Highway 4 Discovery Bay, CA 94505. Some minor piping modifications will take place at Plant No. 1 in order to accommodate the work at Plant No. 2.
Improvements will take place in areas of existing pavement and areas previously graded for future process improvements. Process improvements include adding an oxidation ditch and three new anoxic chambers in front of the existing and new oxidations ditch at Plant 2. The process changes will not result in an increase of
capacity for the Wastewater Treatment Plants. Other improvements include replacing the screen at the headworks, piping and pumping system changes to support the new process, and other maintenance items. Construction activities will include excavation to 16 feet deep, paving and grading of approximately 1.5 acres, construction of new concrete structures, modification of existing concrete structures, Civil and mechanical
piping and pumping systems, and electrical support systems. All storm water for the facility is collected and treated on site. Excavations will follow approved Storm Water Pollution Prevention Plan (SWPPP) control procedures. Construction dust control will follow standard guidelines. Construction crew size will normally vary between 5 to 10 people. There will be occasional truck deliveries of process equipment, rock, asphalt, rebar, and concrete. Total construction period is estimated to take 18 to 24 months.