Nitrates/nitrites concentration estimation in wastewater samples using transmittance curve models optimized by evolutionary computation techniques

This paper presents an application of evolutionary computation algorithms in the estimation of the concentration of nitrates/nitrites in water. Specifically, we start from the measured transmittance curves of a water sample and a model of the curve consisting of a mixture of polynomial, Fermi and Gaussian functions. An evolutionary programming algorithm is then used to obtain the optimal parameters of the model which minimize the distance between the measured and the modeled transmittance curves. This process allows us to separate the modeled transmittance curve into several components, one of them associated with the nitrate/nitrite concentration. We can extract the nitrate/nitrite concentration of the water sample using this component of the transmittance model. We test our proposal on several laboratory samples and on three real samples measured in different locations around Madrid, Spain.