Uncertainties of spectral in situ measurements in wastewater using different calibration approaches.
Three calibration methods were applied to UV/VIS spectra recorded in the influent of six wastewater treatment plants (WWTPs) to measure total COD (CODtot), filtered COD (CODfil), nitrate and nitrite nitrogen (NO(x)-N) and total suspended solids (TSS). It could be shown that a calibration of the sensor using data sets from four Swiss WWTPs leads to an improvement of the precision in comparison to the global calibration provided by the manufacturer. A calibration to the specific wastewater matrix always improves the results and gives the highest accuracy. For CODtot a mean coefficient of variation CVx of 12.5% could be reached, whereas for NOx-N only weak results were achieved (average CVx = 36%).
Rieger
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L
Ecole Polytechnique de Montréal, Environmental Engineering, Department CGM, c/o Biodôme de Montreal, 4777 Av. Pierre De Coubertin, Montreal QC, H1V 1B3, Canada. leiv.rieger@polymtl.ca
Langergraber
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G
Siegrist
H
H
D002138:Calibration / Q000592:standards; D016014:Linear Models; D012680:Sensitivity and Specificity; D013056:Spectrophotometry, Ultraviolet / Q000592:standards; D014867:Water / Q000032:analysis*; D018508:Water Purification / Q000592:standards
D014867:Water