A review of denitrification in on-site wastewater treatment systems

The literature on denitrification and its relationship to on-site wastewater systems was reviewed. Denitrification is an important nitrogen removal mechanism in some alternative on-site wastewater systems. Nitrogen removal rates for conventional septic tank systems may vary from 0% to 35% but should be increased by pressure dosing. Denitrification rates for conventional on-site wastewater systems will depend upon loading rate, soil types and the height of the water table below the soil adsorption bed. Some alternative on-site wastewater systems may remove 70% to 80% of the nitrogen if a supplemental carbon source is used. Methanol and household wastes have been used as carbon sources. Crust formation in a soil adsorption bed may improve denitrification.