Semi-pilot Scale Feasibility Test of Sulfur-Based Bio-barrier System and Effect of Alkalinity Sources on Autotrophic Denitrification

Biological autotrophic denitrification into permeable reactive barrier (PRB) system to reduce nitrate concentration in bank filtrate was implanted. The objectives of research are to investigate effect of inoculation, alternative alkalinity sources, and effect of flow rate on the performance of semi-pilot PRB system. Also, the effect of various alkalinity sources, (i.e., calcite, dolomite, and oyster shell) was investigated through the batch test. Nitrate was reduced by indigenous microorganisms in oyster shell as well as by inoculating microorganisms isolated in this study. Oyster shell as well as limestone can be used as an alkalinity source. As the flow rate in the system increased from 66 to 132 ml/min and nitrate removal efficiencies decreased from 75 to 58% at the fixed thickness of 80 cm of PRB. In the test for effect of various alkalinity sources, only 1.6 and 5% of initial nitrate remained in seven days for oyster shell and calcite, respectively, but about 15% still was detected when dolomite was used.