The North Columbus Resource Facility recently completed a $12-million replacement of its settled water filtration, removing the existing Wheeler filters, their three-part media and 10-inch poured-concrete underdrains, which were no longer efficient. Prior to the filter rehabilitation, the utility’s backwash procedure consisted of a hydraulic-only backwash where the high-rate wash cycle lasted up to 20 minutes. Backwashing each dual cell filter used 150,000 to 200,000 gallons of water. The filters then operated up to an hour in rewash or filter-to-waste operation to reach the desired output of <0.09 Nephelometric Turbidity Unit (NTU).
A visit to the Leopold Product Development Center convinced Stephens to recommend the Leopold system along with other upgrades. The Wheeler filters were replaced with a state-of-the-art Leopold Filterworx® peformance filter system featuring Type SL® underdrains with I.M.S® media retainers. The new filter system also includes engineered filter media, an air-scour feature and stainless steel piping that optimizes performance and durability. The pre-engineered HDPE underdrain system employs a dual media gravelless design, yielding an increase in water depth atop the filters and adding 6 to 8 inches to the overall system freeboard.