Enhancing total nitrogen removal from wastewater of a science and industrial park using entrapped biomass

Abstract

This study employed entrapped biomass technology to augment the conventional activated sludge process with anoxic–oxic (AO)/anaerobic–anoxic–oxic (A2O) functions for the removal of total nitrogen (TN) from wastewater of a science and industrial park in Taiwan. The entrapped biomass unit was fabricated in the format of carrier plates on which microbial cells were entrapped. Due to mass transport limitations, anoxic and anaerobic conditions were created within the bioplates that enabled denitrification to occur. The treatment basin incorporated an equivalent amount of 1300–2400 mg MLSS/L of activated sludge on the bioplates at packing ratios of 10–30% (volume ratio of bioplates to basin) operating with the addition of sodium carbonate for alkalinity and methanol for the electron donor. The results showed nearly 90% of ammonia nitrogen being converted to nitrate and 63% of TN removal, in comparison with typically 10% of TN removal in traditional activated sludge process of domestic wastewater plants.

Keywords:

• entrapped biomass
• anoxic/anaerobic
• nitrification
• denitrification
• total nitrogen removal