Online nitrate and nitrite analysis methods in wastewater applications

In wastewater applications, existing nitrate and nitrite analysis methods can be challenging. Typically, UV absorption is used to measure both and often only using a single wavelength which is generally insufficient to be able to differentiate between nitrate and nitrite, especially in wastewater.

Only a multi-wavelength approach has been demonstrated as effective in being able to quantify nitrate and nitrite simultaneously, however, such sensors are prone to fouling in wastewater applications.

In this study, the new Aquamonitrix analyser was tested and validated by the US EPA as part of the Advanced Septic System Nitrogen Sensor Challenge, conducted at an EPA test centre in Massachusetts. The testing demonstrated that by using chromatography to separate nitrate and nitrite before conducting UV analysis yielded very high recovery rates and low relative standard deviations (i.e. high accuracy and high reproducibility).