Severn Trent Services offers the TETRA® Denite® system that combines the denitrification and filtration process for the removal of nitrate-nitrogen (NO3-N) and suspended solids (SS) in a single treatment step. Denite is a fixed-film biological denitrification process that also serves as a deep bed filtration system capable of removing suspended solids to virtually any final effluent requirement. The system integrates well with other plant treatment processes to provide superior total nitrogen (TN) and phosphorous removal. Denite is used as the final treatment step in the total nitrogen removal process to help each facility meet stringent TN discharge limits of 3 mg/l.
Effective removal of nitrate-nitrogen is undertaken by introducing a carbon source, such as methanol, using the proprietary TETRAPace® automatic dosing control for savings of up to 30% in carbon consumption. The Denite system employs a patented SpeedBump® operation to remove or purge accumulated gas – nitrogen or CO2 – that can build up in the filter media that can be accomplished without removing the reactor from service.
TETRA Denite offers consistent and proven performance - even with low water temperatures – all in a footprint one tenth of the size of a conventional suspended growth system. Percent of return of wastewater is less than 4% (<2% typical) of the plant’s forward flow.