Determination of Ammonia Nitrogen in Wastewater Using Electronic Nose

A low cost, fast and convenient method based on electronic nose for determination of ammonia nitrogen in wastewater is developed in this study. The pH of the sample is adjusted to higher than 11 by adding saturated sodium hydroxide solution, through which most of the ammonium ions transform into ammonia and volatilize to the gas phase following Henry's law. A sensor array consist of four metal oxide semiconductor gas sensors responses to the headspace gas of the sample. Response data is analyzed using BP neural network. The result shows a robust relationship between the responses patterns of the electronic nose and the wastewater ammonia nitrogen concentrations.