Aerobic denitrifiers and the application in remediation of micro-polluted water source

Abstract:

Nitrate is more stable in natural water than ammonia and thus is more difficult to be removed. Conventionally, the removal of nitrate relies on anaerobic denitrification, which is hard in natural water containing high concentration of dissolved oxygen. In this sense, aerobic denitrification is of particular importance for nitrate removal in natural water. This study reviewed the isolation, purification, microbial metabolism, and environmental influencing factors of aerobic denitrifiers. Moreover, the application of aerobic denitrification in remediation of micro-polluted drinking water sources is also introduced. Similar to their anaerobic counterparts, aerobic denitrifiers affiliate to a wide range of genera, such as Pseudomoas, Alcaligenes, Paracoccus, and Bacillus. Most of the aerobic denitrifiers have a satisfactory nitrate removal efficiency under suitable conditions (25-37 ℃, DO (dissolved oxygen)=3-5 mg/L, pH 7-8, C/N ratio=5-10). However, aerobic denitrification still has drawbacks of unstable removal efficiency and the loss of microbes. Moreover, little efforts are made in relevant study on pilot-scale and full-scale application and thus further investigation is needed.

Key words:aerobic denitrification;mechanism of nitrogen removal;micro-polluted water source bioremediation