Recent UV–visible spectrometers deliver on line and in situ absorbance spectra in wastewater or stormwater transported in urban drainage systems. After calibration with local data sets, spectra can be used to estimate pollutant concentrations. Calibration methods are usually based on PLS (Partial Least Squares) regression. Their most important difficulty lies in the identification of the number of both i) the latent vectors and ii) the independent variables. A method is proposed to identify these variables, based on an exhaustive tests procedure (Jackknife cross validation and matrix of prediction indicator). It was applied to estimate TSS (total suspended solids) or COD (chemical oxygen demand) concentrations at the inlet of a storage-settling tank in a stormwater separate sewer system, and compared to three other calibration methods used either for turbidity meters or UV–visible spectrometers. With the available calibration data set: i) the spectrometer gives results with better prediction quality than the turbidity meter, ii) for the spectrometer, local calibration gives better results than global calibration, iii) the proposed PLS method gives results with a similar order of magnitude in uncertainties as the manufacturer local calibration method, but is more open and transparent for the user. Similar results were obtained for a second data set.
Skip Nav Destination
Article navigation
Research Article|
March 01 2008
Partial Least Squares local calibration of a UV–visible spectrometer used for in situ measurements of COD and TSS concentrations in urban drainage systems
A. Torres;
1INSA-Lyon, LGCIE, F-69621 Villeurbanne, cedex, France E-mail: jean-luc.bertrand-krajewski@insa-lyon.fr
E-mail: andres.torres@insa-lyon.fr
Search for other works by this author on:
J.-L. Bertrand-Krajewski
J.-L. Bertrand-Krajewski
1INSA-Lyon, LGCIE, F-69621 Villeurbanne, cedex, France E-mail: jean-luc.bertrand-krajewski@insa-lyon.fr
Search for other works by this author on:
Water Sci Technol (2008) 57 (4): 581–588.
Citation
A. Torres, J.-L. Bertrand-Krajewski; Partial Least Squares local calibration of a UV–visible spectrometer used for in situ measurements of COD and TSS concentrations in urban drainage systems. Water Sci Technol 1 March 2008; 57 (4): 581–588. doi: https://doi.org/10.2166/wst.2008.131
Download citation file:
Sign in
Don't already have an account? Register
Client Account
You could not be signed in. Please check your email address / username and password and try again.
Impact Factor 1.915
CiteScore 3.3 • Q2
13 days submission to first
decision
1,439,880 downloads in 2021