Domestic Tertiary Filtration
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Plant History: The wastewater treatment plant has operated for many years as a lagoon treatment process. Through the years, the facility has used adjacent property to the hospital and treatment plant as a spray field. It has recently become necessary to filter the final lagoon discharge to meet these more strict requirements of spray field discharge.
Plant Description: The facility operates as a five stage lagoon operation. The operators have aeration capability in the first three ponds. The plant flow rates vary during the year with average flows being in the 200,000 gallons per day range with peak flows being up to 250,000 gallons per day. Chemical addition is designed to be injected prior to filtration to enhance the filtration process. The feed to the tertiary filters is pumped from the final lagoon via centrifugal pumps. Flow is regulated with manual valves and monitored with inline flowmeters. The filtrate flows to a chlorine contact tank for disinfection before being discharged to the spray field pumping system.
Tertiary Filters: Two (2) Centra-flo Gravity Sand Filter Model CF-25’s are designed to remove algae and suspended solids from the plant discharge stream. The plant has the ability to add chemicals to aid in the removal of solids.
Filter Startup: The Centra-flo was installed in April 1999. Equipment startup was completed and the filter system was put online in November of 1999. The filter has been in continuous operation since startup at a flow rate of 175 gpm. The operation has been uneventful with only normal operator attention required. Initial operation was begun without the addition of chemicals.