陳柏寓 - Roger

- Thesis topic: Performance Analysis of Various Wastewater Treatment Processes for Microplastic Removal

- Doi: https://doi.org/10.6840/cycu202301426

- Abstract: 

        Plastic products have become indispensable in our daily lives. However, due to human overreliance on plastic products and the lack of proper storage, disposal, and management practices, plastic products have gradually emerged as a new and concerning pollutant of this generation. The resulting contamination from microplastics has also become a prominent issue of concern. Therefore, this study aims to sample and conduct experiments in wastewater treatment plants to understand the removal efficiency of microplastics in such facilities. As there is currently no standardized testing method for microplastics, this study utilizes stainless steel or glass equipment for sampling. Wet hydrogen peroxide digestion is employed to digest organic matter in the samples, and density separation using a saturated sodium chloride solution is used to isolate microplastics. Finally, microscopic observation is performed to determine the concentration of microplastics in different units of the wastewater treatment plant. The experimental results reveal that wastewater treatment plants have a significant effect on the removal of microplastics. In the overall removal process, the activated sludge method and activated sludge membrane filtration (MBR) in the secondary treatment exhibit an average removal efficiency of up to 95%. The tertiary treatment using reverse osmosis (RO) achieves a removal efficiency of up to 97%. However, wastewater treatment plants employing the contact aeration method in the secondary treatment show a relatively lower removal rate, reaching only 85%. Nevertheless, they still contribute significantly to the removal of microplastics. The biological treatment method in the secondary treatment utilizes activated sludge to purify the water, effectively adsorbing impurities, including microplastics. Subsequently, sludge sedimentation in the secondary clarifiers significantly reduces the microplastics content in the wastewater. Based on the aforementioned results, wastewater treatment plants can effectively remove microplastics, with the activated sludge method and membrane treatment method demonstrating high removal rates. However, it is important to consider the contamination of microplastics within the sludge when addressing the issue of sludge reuse, in response to the sustainable development concerns of our society in the future.

Keywords: Wastewater treatment plant, Microplastic, Grit chamber, Secondary treatment, Sedimentation tank, Removal rate