Efficient removal of ammoniacal nitrogen from textile printing wastewater by electro-oxidation considering the effects of NaCl and NaOCl addition

Water Sci Technol. 2021 Aug;84(3):752-762. doi: 10.2166/wst.2021.261.


In this study, an electro-oxidation (EO) process using graphite electrodes as electrode pairs was used for the removal of chemical oxygen demand (COD), ammoniacal nitrogen (NH4+-N), and color from real textile printing wastewater. The effects of solution pH, sodium chloride (NaCl) dosage, sodium hypochlorite (NaOCl), which is the oldest and still most important chlorine-based bleach, dosage, and oxidation time were investigated on the removal efficiencies. Operating conditions for the EO reactor were applied to current density 1 mA/cm2, distance between the electrodes: 2 cm, 150 min operation time, and stirring speed of 500 rpm. At optimum conditions: pH 9.5, applied current density 1 mA/cm2, NaCl dosage of 8 g/L, NaOCl dosage of 44.4 mg/L and 150 min electro-oxidation time, the obtained removal efficiencies were 86.5% and 91.1% for chemical oxygen demand (COD) and ammoniacal nitrogen, respectively. Efficiency was increased to 91.1% for ammoniacal nitrogen from 21.7% after applying EO combined with NaOCl addition compared to individual NaOCl addition.

MeSH terms

  • Biological Oxygen Demand Analysis
  • Electrodes
  • Nitrogen
  • Oxidation-Reduction
  • Printing, Three-Dimensional
  • Sodium Chloride
  • Textiles
  • Waste Disposal, Fluid
  • Wastewater*
  • Water Pollutants, Chemical* / analysis


  • Waste Water
  • Water Pollutants, Chemical
  • Sodium Chloride
  • Nitrogen