Cool Water High-Rate Full-Scale Denitrification in Deep Bed Filters

The Littleton-Englewood Wastewater Treatment Plant has new strict daily nitrogen limits that change during the year. The Plant has begun using eight new deep bed denitrification filters to remove nitrate from a portion of the water the plant discharges to the South Platte River near Denver, Colorado. The filters were designed with individual carbon source feeds for denitrification and variable influent flow splitting for maximum flexibility.The filter biological startup occurred successfully when wastewater temperatures were near their yearly minimums in April 2008 with snow still on the ground. The filters later passed their formal performance test conducted at maximum design flow and maximum nitrate removal.Now the operators are using the flexible features of the filter plant design to meet the variable plant permit while minimizing carbon source feed. Some filters are used for simultaneous denitrification and solids filtration, while others operate for solids filtration only.