Removal of nitrogen by a sulfur-based carrier with powdered activated carbon (PAC) for denitrification in membrane bioreactor (MBR)

Abstract

In this study, the effect of the addition of powdered activated carbon (PAC) to sulfur-based carrier for autotrophic denitrification was evaluated on the removal efficiency of nitrate in MBR process for advanced wastewater treatment without any external organic carbon source. As a result of the comparative experiment with PAC 0 % and 15 % carrier, the removal efficiency of NO3−-N was enhanced up to 3 % by adding PAC to the carrier. Based on the results, the carrier was injected every seven day with 10 % of reactor volume. During the operating period of 30 days, the removal of T-N was 72.7 % and 31.8 % for the operating condition with and without the carrier, respectively. In the long-term MBR experiments, which was operated with the addition of the carrier to anoxic tank day by day, the tendency of T-N removal was relatively stable. The removal of T-N was observed at 55.80 % and 19.73 % for with and without the carrier, respectively. Based from the results, it was obvious that the removal of T-N was enhanced to around 40 % by adding the sulfur-based carrier into MBR system. The present study exhibited relatively good efficiencies so that the sulfur-based carrier will be applied for a pilot experiment.