This SBIR Phase I project will improve operation of deep-bed filter biological denitrification through a number of modifications to the current process. These include (i) Replacement of air usage with compressed Nitrogen gas for bump, scour, and airlift. (ii) Elimination of nuisance biological growth on weir walls by dosing carbon right over the filter bed using Venturi eductor principles. (iii) Inclusion of alkalinity buffering rock materials in bed media. The broader/commercial impact of the project will be more efficient treatment of municipal wastewater in order to reduce total nitrogen concentrations entering the nation's waters. A secondary benefit is reduction in the use of methanol that is currently used as a carbon source in the filtration process