Estimation Method of Denitrification Rate Constant in Aquifer

The concentration variation of the nitrate ion in aquifer is influenced by not only the denitrification, but the recharge dilution, sorption of aquifer, etc, thus it is difficult to calculate the denitrification rate directly. In this paper, the methods of identifying the denitrification and estimation of denitrification rate constant were proposed using the field data in aquifer. Chloride ion, which is more conservative than others ions, was selected as reference ion to indicate the variation of nitrate ion concentration only caused by the denitrification. Accordingly, using the variation of chloride and nitrate concentration can identify the denitrification. In the paper, three concentration variation conditions about two kind of ion were presented. In addition, initial concentration of nitrate can be obtained by linear interpolation with the concentration of chloride ion; Furthermore denitrification rate constant can be estimated by the first-order kinetics equation. The results of case study show that it´s an effective method for identifying the denitrification and estimating the denitrification rate constant.