Optimizing microplastic treatment in the effluent of biological nutrient removal processes using electrocoagulation:...

Area of Science:

• Environmental Science and Engineering
• Water Treatment Technologies
• Pollution Control

Background:

• Microplastic (MP) pollution is a critical global environmental issue, particularly in aquatic ecosystems.
• Wastewater treatment plants (WWTPs) are a significant pathway for microplastic release into the environment.
• Effective and efficient methods for microplastic removal from WWTP effluent are urgently needed.

Purpose of the Study:

• To investigate the efficacy of the electrocoagulation (EC) process for removing microplastics from biological WWTP effluent.
• To optimize EC process parameters (pH, current density, reaction time) using Taguchi design and ANOVA.
• To evaluate the cost-effectiveness and feasibility of EC for microplastic removal in real wastewater.

Main Methods:

• Electrocoagulation (EC) process utilizing aluminum electrodes.
• Taguchi experimental design to systematically evaluate process variables.
• Analysis of Variance (ANOVA) to determine the significance of parameters.
• Visual analysis of microplastic morphology before and after treatment.

Main Results:

• Current density was identified as the most significant parameter influencing microplastic removal efficiency.
• Optimized conditions (pH 9, 1.905 mA/cm², 15 min) achieved 99% microplastic removal.
• The developed model demonstrated high accuracy with an R² value exceeding 98%.
• The process cost was determined to be approximately $0.049/m³.
• EC treatment predominantly removed fiber-shaped microplastics.

Conclusions:

• Electrocoagulation is a highly efficient and cost-effective alternative for microplastic removal from WWTP effluent.
• The EC process can be integrated into existing WWTPs to significantly reduce microplastic discharge.
• The study confirms the applicability of EC for microplastic removal in real wastewater matrices.