The IWS denitrification process was developed as an engineered solution for reducing total nitrogen in nitrate laden effluent from advanced treatment systems. By integrating a simplified, carbon laden de-nitrification filter into an advanced treatment system where ammonia has been nitrified, the TN in the effluent stream can be reduced by an additional 75% and overall nitrogen reduced by up to 95% depending on influent characteristics. Average total nitrogen reductions of 93% have been achieved to date following Advantex treated effluent. Results are dependent on
BOD reductions required to maximize nitrification of ammonia in the waste stream.

Process Flow Diagram for IWS Upflow Filter

The IWS solution uses no chemical additives, controls, or instrumentation and involves pumping nitrified secondary treated wastewater effluent (post BOD, TSS reductions and ammonia nitrification) discharged from the primary Advantex or other advanced treatment system into a dosing basin or tank for pumping to the de-nitrification system. The nitrified wastewater effluent is pumped from the post Advantex dosing tank through the Upflow Filter. Under anoxic conditions,
heterotrophic bacteria within the carbonaceous media Upflow Filter use nitrate as an oxygen source to consume available free carbon and, thereby, convert the nitrate to nitrogen gas.

NO3 + Organic Matter > N2 + CO2 + OH + H20


The de-nitrified treated effluent gravity flows into an effluent dosing tank for disposal or, when BOD limits are required, through a secondary BOD polishing Advantex system to minimize any residual BOD elevations due to flowing through the carbon laden Upflow Filter. Post secondary treated effluent is discharged into the final dosing tank for pumping to the discharge system.