Green Total Nitrogen Test Method – A Simple Alternative for TKN Analysis in Wastewater

Over one thousand wastewater dischargers in the US are required to monitor Total Kjeldahl Nitrogen (TKN) and report results to regulatory agencies. The typical TKN procedure consists of heating a mixture for several hours with strong acid and hazardous materials, manually adding strong base to strong acid, followed by a distillation and quantitative measurement of an analyte. TKN is one of the most challenging, dangerous and labor intensive tests performed at wastewater treatment plants. The s-TKN method changes this, allowing any laboratory to quickly and easily run the test. Equally important, the s-TKN method does not suffer from the same performance limitations as the traditional TKN test, particularly with documented nitrate interference. Not only does this allow for more frequent and accurate testing for process control purposes, but the methodology is intrinsically safer for operators to perform, and eliminates hazardous reagents and waste such as mercury. Benefits of the s-TKN may be summarized as:
• Green chemistry – Less hazardous
• Simplicity
• Comparable performance to other reference methods
• Speed of analysis
• Low cost
• Does not suffer from nitrate interference
The primary goal of this project was to develop a green alternative analysis system for TKN that provides comparable analytical results while using significantly less hazardous reagents. In addition, the method must be simple enough for use by current wastewater treatment plant staff with the potential to significantly reduce expenditure of time and analysis costs. Source: WEFTEC 2009 Proceedings