Optimisation of electrochemical oxidation process with boron doped diamond (BDD) for removing COD, colour, ammonium, and phosphate in landfill leachate

ABSTRACT

This study investigated the electrooxidation (EO) of mature landfill leachate from the Brady Road Resource Management Facility, Winnipeg (Canada). EO using boron-doped diamond (BDD) electrodes were applied to treat real landfill leachate using a batch reactor. Response surface methodology (RSM) was used to determine the optimum process parameter levels. This research mainly focused on how different current densities (64, 95, and 125 mA/cm²) and operational time (30 min, 1, 1.5, 2, 2.5, and 3 hr.) influenced the optimisation of parameters such as chemical oxygen demand (COD), colour, ammonium, and phosphate removal in mature landfill leachate at varied pH. To attain a high percentage of removal for the parameters mentioned above, the optimal conditions were found to be a current density (J) of 125 mA/cm² and a pH of 8. The optimum conditions resulted in removal percentages of 95.47%, 80.27%, 71.15%, and 47.15% for colour, NH₄⁺, COD, and PO₄^3- respectively, with an energy consumption of 0.05 kWh/dm³. The removal is related to a mechanism of the decomposition of water molecules to hydroxyl radicals and by direct anodic oxidation where the pollutants are transformed to CO₂ and H₂O. The novelty of this research lies in the optimisation of BDD electrode-based treatment for the simultaneous removal of COD, ammonium, phosphate, and colour from mature leachate collected from a severely cold climatic region of Canada. The BDD electrode showed excellent removal efficiencies for the targeted contaminants with lower energy consumption, making it a feasible method for on-site landfill leachate treatment.

GRAPHICAL ABSTRACT

KEYWORDS:

• Mature landfill leachate
• electro-oxidation
• phosphate
• BDD electrode
• energy consumption

Acknowledgments

The authors acknowledge Daniel Dankewich and Dr. Victor Wei for their help in some experiments in the lab and are thankful to the previous master’s student, Mr. Mofizul Islam for his knowledge sharing regarding landfill leachate treatment.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The datasets used and/or analyzed during the current study are available from the corresponding author upon reasonable request.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.