Site visits were made to installations of various nitrogen removal systems operating in the country. Thirteen nitrogen removal systems were identified and reviewed. A numerical ranking system, based on selected criteria, was developed to determine which of the systems had the greatest potential for single family home application. Blackwater holding tank Extended aeration package plant Trickling filter Ion exchange, reverse osmosis and the mound with a constructed wetland system had insufficient data to rank. The technology for nitrogen removal as applied to individual onsite systems is relatively untested.
Few data exist regarding removal efficiency, reliability, consistency and costs.
The total cost versus the nitrogen removal efficiencies of the various technologies are not known. Further testing and demonstration is still needed for all of these systems. Ion exchange technology is a technology that has not been tested, yet has promise because of its simplicity and potential for low operating costs. In addition, it would likely be a vendor type service which could result in consistent and reliable performance. The systems should be constructed to allow the demonstration of several process flow scheme alternatives.