Plastic waste has become a global environmental concern. One type of plastic waste is microplastics (MPs), which can spread easily in the environment. Wastewater effluent is one of the land-based sources of MPs. This study investigates the amount of microplastic (MP) pollution in an urban wastewater treatment plant (WWTP) in Thailand. Water samples were collected and examined to find the types, morphology and sources of MPs. Wastewater was filtered through a set of sieves ranging from 5 mm to 0.05 mm. Sludge samples were also collected to find the potential risk from the application of dried sewage sludge. Fourier-transform infrared spectroscopy (FTIR) was used to confirm the types of MPs. The amount of MPs in the influent was 26.6 ± 11.8 MPs/L. More than one-third of MP particles were removed after a grit trap, followed by 14.24% removal in the secondary treatment. If the peak flow rate of the WWTP is reached, 2.32 × 10⁹ MP particles can be released daily. The amount of MPs in a sludge sample was 8.12 ± 0.28 × 10³ particles/kg dry weight. Dry sludge is one of the potential sources of MP contamination in agricultural soil. Most MPs in the liquid fraction and sludge sample were fibres. Results from FTIR analysis showed that the major types of MPs in the WWTP were polyester fibres, followed by polypropylene, polyethylene, silicone polymer and polystyrene. This finding indicates that a conventional WWTP may act as a path by which MPs enter the environment.

塑料废料已成为全球关注的环境问题。一种塑料废物是微塑料（MPs），可以在环境中轻松传播。废水是MPs的陆上来源之一。这项研究调查了泰国城市污水处理厂（WWTP）中的微塑料（MP）污染量。收集水样并检查以发现MP的类型，形态和来源。废水通过一组5 mm至0.05 mm的筛网进行过滤。还收集了污泥样品，以发现使用干污泥产生的潜在风险。傅里叶变换红外光谱（FTIR）用于确认MP的类型。进水中的MP量为26.6±11.8 MPs / L。砂砾捕集后，去除了三分之一以上的MP颗粒，然后去除了14。在二级治疗中去除率达24％。如果达到污水处理厂的峰值流速，则为2.32×10 每天可以释放⁹ MP颗粒。污泥样品中的MP含量为8.12±0.28×10 ³颗粒/ kg干重。干污泥是农业土壤中MP污染的潜在来源之一。液体馏分和污泥样品中的大多数MP是纤维。FTIR分析的结果表明，污水处理厂中MP的主要类型是聚酯纤维，其次是聚丙烯，聚乙烯，硅酮聚合物和聚苯乙烯。该发现表明，常规的WWTP可以充当MP进入环境的路径。