Abstract

The primary objective of this research was to search for an effective method of industrial wastewater treatment containing a high amount of Total Kjeldahl Nitrogen (TKN). Photographic process wastewater is one of them. Traditional approaches, e.g. biological, filtration, carbon absorption are often ineffective in the degradation of persistent organic nitrogen. Thus, this study included four phases of investigation for an effective simultaneous removal of organic nitrogen and ammonia. In Phase I the electrochemical oxidation was performed under different operating conditions to determine the ability of this process to mineralize organic nitrogen and to determine operating ranges for the further investigation. In Phase II conventional electro-Fenton oxidation was implemented. The most successful results were obtained in Phase III, when enhanced electro-Fenton oxidation (EEFO) by additional of an oxidation agent was applied. The best removal efficiency of TKN, ammonia and organic nitrogen reached 92.4 %, 95.2 % and 81.4 % respectively. Also, it was demonstrated that enhanced electro-Fenton process with pretreatment from the ammonia can remove TKN and organic nitrogen by 95.8% and 97.2% respectively in a shorter residence time of 24 hours. In Phase IV the system was tested with a series of electrodes implemented in parallel. The results showed that the removal of organic nitrogen in a single cell and in series was similar. The developed process demonstrated an acceptable level of TKN removal while an insignificantly low amount of chemicals was added. The developed enhanced electro-Fenton oxidation method can be applied to other industrial wastewaters with a similar composition of pollutants.