Simultaneous Determination of COD and BOD of Waste Water by NIRS

Based on the analytical data of 120 samples of waste water obtained by NIRS,and by using the partial least square method (PLS),predictive calibration models for determination of COD and BOD were established.Discussions on methods of treatment of the NIRS data and of determination of rejection divergent values were also given.Correlation coefficients found for the predictive models for COD and BOD determinations were 0.954 2 and 0.965 2 respectively.The ranges of prediction found for COD was from 28.4-528.0 mg·L-1,and for BOD was from 16.0-305.2 mg·L-1,with values of root mean square deviation of prediction 25.24 mg·L-1 and 12.13 mg·L-1 respectively.It was found by significance test for the predictive models with the t-test at the level of significance of 0.05,no significant difference was found between the results of COD and BOD found by the present method and the results found by the standard method.