Simultaneous Determination of Chemical Oxygen Demand (COD) and Biological Oxygen Demand (BOD5) in Wastewater by Near-Infrared Spectrometry

To rapidly determine the pollution extent of wastewater, the calibration models were established for determination of Chemical Oxygen Demand and Biological Oxygen Demand in wastewater by partial least squares and near infrared spectrometry of 120 samples. Spectral data preprocessing and outliers’ diagnosis were also discussed. Correlation coefficients of the models were 0.9542 and 0.9652, and the root mean square error of prediction (RMSEP) were 25.24 mg·L and 12.13 mg·L in the predicted range of 28.40~528.0 mg·L and 16.0~305.2 mg·L for Chemical Oxygen Demand and Biological Oxygen Demand, respectively. By statistical significance test, the results of determination were compared with those of standard methods with no significant difference at 0.05 level. The method has been applied to simultaneous determination of Chemical Oxygen Demand and Biological Oxygen Demand in wastewater with satisfactory results.