Microplastic removal in managed aquifer recharge using wastewater effluent.

Area of Science:

• Environmental Science
• Water Resources Management
• Environmental Chemistry

Background:

• Microplastic (MP) pollution poses a significant environmental and potential human health risk.
• Managed aquifer recharge (MAR) systems utilize reactive barriers to treat wastewater effluent, but their efficacy in retaining MPs is not fully understood.

Purpose of the Study:

• To investigate the presence, distribution, and characteristics of MPs in the soil of a MAR system.
• To assess the influence of different reactive barrier materials on MP retention.
• To evaluate the performance of MAR systems in mitigating MP pollution in freshwater resources.

Main Methods:

• MP extraction using density separation and oxidant digestion.
• Visual and chemical characterization of MPs via Fourier-Transform Infrared Spectroscopy (FTIR).
• Quantification of MP concentration, morphology, color, and polymer type in soil samples.

Main Results:

• MPs were widely detected in MAR soil, with concentrations ranging from 60 to 236 n kg⁻¹.
• Fragments and fibers were the dominant morphologies, with white and transparent MPs being most abundant.
• Polypropylene (PP) and polyethylene (PE) were the most prevalent polymers; compost and woodchip barriers showed superior MP retention.

Conclusions:

• The MAR system demonstrates effective MP retention, particularly in outer barrier layers and with compost/woodchip materials.
• Findings contribute to understanding MP dynamics in soil and wastewater treatment.
• This research supports the development of improved wastewater management strategies to protect water resources from MP contamination.