Treating landfill leachate by electrocoagulation.

Area of Science:

• Environmental Engineering
• Water Treatment Technologies
• Chemical Engineering

Background:

• Landfill leachate poses significant environmental risks due to high pollutant concentrations.
• Effective treatment methods are crucial for mitigating leachate's impact on water bodies and public health.
• Electrocoagulation (EC) is a promising technology for wastewater treatment, but optimal conditions require investigation.

Purpose of the Study:

• To determine the optimal operating conditions for electrocoagulation treatment of landfill leachate.
• To investigate the influence of key parameters (current density, pH, time, conductivity) on turbidity removal.
• To evaluate the efficiency of electrocoagulation in removing various pollutants, including aluminum, iron, and total Kjeldahl nitrogen.

Main Methods:

• Surface response methodology with a central composite design was employed.
• Four independent variables (current density, pH, time, fluid conductivity) were analyzed.
• A second-order polynomial model was utilized to predict turbidity removal efficiency.

Main Results:

• Current density was the most significant factor (60.1% contribution) influencing turbidity removal.
• Optimal conditions determined were: 38.8 min, pH 7.6, current density 109.9 A m⁻², and 2.9 g L⁻¹ NaCl.
• Achieved 96.9% turbidity removal, with significant reductions in Al (97.0%), Fe (99.5%), and 66% total Kjeldahl nitrogen removal.

Conclusions:

• Electrocoagulation, under optimized conditions, effectively removes turbidity and heavy metals from landfill leachate.
• While effective for many pollutants, total Kjeldahl nitrogen removal did not meet discharge regulations.
• The study provides valuable insights for optimizing electrocoagulation processes for leachate treatment, highlighting areas for further improvement.