Experimental Investigation and Modeling of Denitrification of Water in a Column Bioreactor Using Immobilized Microorganisms on Modified Zeolite

The nitrate removal efficiency of a 9.5 L packed bed column bioreactor was evaluated using different feeding strategies and initial concentrations. The bioreactor was filled with zeolite mineral particles and initially treated with Thiobacillus denitrificans. Several hydraulic retention times were examined to assess the effectiveness of nitrate removal. The most favorable scenario resulted in an 87% reduction in nitrate concentration from an influent of 400 mg/L within a three-hour period. To determine the optimal length of the bioreactor, a computational fluid dynamics model was developed. By comparing simulations with experimental results, the ideal height of the bioreactor for complete denitrification was determined to be 90 cm, 45 cm, 30 cm, and 20 cm for influents with nitrate concentrations of 400 mg/L, 250 mg/L, 120 mg/L, and 80 mg/L, respectively.