Abstract
Nitrogen removal performance of a polyethylene glycol (PEG) gel carriers with entrapped heterotrophic denitrifying bacteria was evaluated at room temperature (20℃). Methanol was used as hydrogen donor for denitrification. A lab-scale reactor for the denitrificatnion process was operated for the treatment of synthetic nitrite and nitrate wastewater. First, nitrite was used as a nitrogen source in order to evaluate the nitrogen removal performance on the start-up periods. As a result, nitrite removal activity increased gradually, reaching 1.4 kg-N m-3 d-1 on day 46. After that, high-loading test was conducted using synthetic nitrate wastewater. A maximum nitrogen removal rate of 3.6 kg-N m-3 d-1 was confirmed. However, nitrite accumulation was observed when nitrogen loading was exceeded the capacity of the reactor. It was suggested that the denitrification rate was decreased by accumulated nitrite.
