Ozonation treatments for the abatement of ammonia and organic substances

This work was aimed to test the performances of ozone in the abatement of ammonia and organic carbon from on-purpose made wastewaters. In the first part of the work solutions containing ammonia (20 mg/l), bromide (0-20 mg/l), bicarbonate (200 mg/l) and free OH- ions were employed to investigate the efficacy of ozone in the abatement of ammonia and to understand the influence of the free OH- and bicarbonate species on the ammonia oxidation rate. The experimental findings pointed out that ozone was effective in the oxidation of ammonia and its reaction rate rose as the concentration of bromide increased, with kinetics different from zero-order. The reaction rate was also affected by the presence of free OH-. In the second part of the experimentation the oxidation of organic carbon (as H5C8O4K) with ozone or bromide/ozone was investigated. Bromide had no effect on the reaction rate of the ozonation of organic carbon, but it seemed to slow down the process because of the competition between the oxidation of the phthalate and the formation of HOBr. The results obtained in the lab tests may be useful for the full scale design of an oxidation treatment with ozone which has effect on both ammonia and organic carbon.