Identification and characterisation of microplastics in wastewater treatment plant in Raipur, Chhattisgarh, India

Abstract

Microplastics (MPs) are worldwide pollutants in water environments, and their global presence has become a major environmental concern. Microplastics are plastic particles < 5 mm, are either purposefully made or the result of bigger plastic particles breaking apart. There is less research on MPs in IndianWastewater treatment plants (WWTPs), despite the fact that they disrupt ecosystems by destroying aquatic life, contaminating habitats, and changing food chains. WWTPs, which process urban effluents, are recognised as major point sources of microplastics into the aquatic environment. This study aims to elucidate the distribution, occurrence, and pollution level of microplastics in the WWTPs of Raipur city, Chhattisgarh. Water from the influent to the effluent stages was collected and analysed using grab sampling methods. By quantitative analysis, the mean concentration of microplastics was found to be 42±3, 25±2, 18±3 and 12±2 Particles/L from each stage influent, primary, secondary, and final treatment (effluent), respectively. Styrene butadiene rubber (SBR), polyethylene (PE), polyethylene terephthalate (PET), and polystyrene (PS) were identified as MPs as analysed by Attenuated Total Reflectance - Fourier Transform Infrared Spectroscopy (ATR-FTIR) analysis. Most frequently occurring microplastic shapes were fragments, filaments, fibres, and pellets. Black, red, blue, violet, brown, and pink were the colours of MPs present in the samples. Particle size analysis showed that the water sample contains particles in the range of 100-5000 μm for all four stages. In urban areas, industrial and domestic wastewater conveyed through drainage networks to WWTPs carries both primary and secondary microplastics act as significant sources of microplastic pollution. Therefore, assessing the occurrence of microplastics in treatment plants is essential for understanding the environmental threat. This study enhances the understanding of microplastic pollution in WWTPs and provides vital reference data essential for effective mitigation strategies.