Electro-Fenton assisted sonication for removal of ammoniacal nitrogen and organic matter from dye intermediate industrial wastewater

The intricacy in the treatment of effluents from the textile sector attracts the researchers since 20th century. Dye intermediate manufacturing industries are responsible for producing the toxic pollutants such as nitro-aromatics, benzene, toluene, phenol, heavy metals etc. with intense colour. The present study focuses on the performance of combined Electro-Fenton (EF) and sonication for the removal of ammoniacal nitrogen and COD from dye intermediate manufacturing wastewater. Batch experiments of EF were performed using graphite electrodes and sonication was applied to the EF treated wastewater to enhance the treatment performance. A number of experiments were executed to discover the influence of pH, applied voltage, Fenton catalyst dosage and time of electrolysis on the removal efficiency of EF batch process was scrutinized. The pH was varied between 2 and 4, applied voltage from 1 to 4V, Fenton catalyst dosage between 50 and 200 mg L−1 and time between 15 and 180 min. At optimum condition i.e. pH 3, applied voltage 3V, Fenton catalyst dosage of 100 mg L−1and 120 min electrolysis time, the percentage removal obtained for ammoniacal nitrogen and COD were 59.4% and 79.2% respectively. The removal efficiency was increased to 65.5% for ammoniacal nitrogen and 85.4% for COD after applying sonication to the EF treated wastewater. The removal of ammoniacal nitrogen and COD can be achieved in a scientific and feasible way by combining EF process with sonication. •EF for removal of ammoniacal nitrogen and COD.•Treatment of highly acidic dye intermediate wastewater with very low BOD5,20/COD ratio.•Influence of sonication on the EF for the removal of COD and ammoniacal nitrogen.•EF after sonication leads to 65.5% of ammoniacal nitrogen and 85.4% of COD removal.•Chlorine species can possibly lead to indirect oxidation of pollutants.