Ammonia volatilization of heavily polluted rivers under simulated aeration

Quantification of ammonia volatilization is important for understanding ammonium nitrogen removal from heavily polluted rivers with aeration. Using a continuous airflow enclosure method, ammonia volatilization rates under different aeration treatments (i.e., aerating to sediments (ES), aerating to water (EW) and no aeration (EC)) from polluted urban rivers were performed in a laboratory. Polluted urban rivers showed potential capacities for ammonia volatilization, where the rate of ammonia volatilization ranged from 3.95 to 71.36 mg N.(m2.d)-1 in EC. The ammonia volatilization rate in EW was higher than that in ES, with volatilizations of 2.11 to 278.47 mg N.(m2.d) -1 and 1.69 to 205.98 mg N.(m2.d) -1, respectively. The rates of ammonia volatilization of total ammonium removal were 39.42%, 18.97% and 21.34% in EW, ES and EC, respectively. These results indicated that ammonia volatilization is a major mechanism for nitrogen removal under aeration conditions in the treatment of polluted urban rivers. © 2013 WIT Press.