County highlights small-footprint upflow filters to cut nitrogen and phosphorus

John described commercially available small-footprint upflow filter systems intended for locations where large constructed wetlands are not feasible; he said the media in these devices is engineered to target nitrogen and phosphorus removal.

Courtney offered a numerical example during the discussion: "if my calculations are correct, that would be about 334 pounds of total nitrogen per year and 234 pounds of total phosphorus per year." John agreed that the systems can increase nutrient-removal performance in constrained sites compared with traditional small devices.

County staff framed these technologies as tools to increase nutrient removal in urban or confined areas where larger treatment areas would not fit, enabling better performance in retrofit or small-footprint projects.