Occurrence and removal of microplastics in a municipal wastewater treatment plant with conventional activated sludge process: A case study in Isfahan, Iran

IF 1.3 Q4 ENVIRONMENTAL SCIENCES
H. Sharifi, H. Movahedian Attar, B. Bina
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引用次数: 1

Abstract

Background: Microplastics (MPs) are nowadays found in the air and in various terrestrial and aquatic environments and have become emerging pollutants. These particles can absorb other chemicals and microbial contaminants and release them into the environment and food chain. Despite the high efficiency of wastewater treatment plants (WWTPs) in removing MPs, WWTPs are still one of the major sources of MPs discharge to the environment. This study was conducted to evaluate the efficiency of MPs removal in a municipal WWTP with conventional activated sludge in Iran. Methods: MPs particles were counted using a stereomicroscope after the initial preparation steps (sieving, chemical digestion with the catalytic wet peroxidation-oxidation and density separation with NaCl) and then analyzed for particle composition using a Raman micro-spectrometer. Results: MPs concentration in the influent, grit chamber, primary sedimentation tank, and effluent were 843.2±147.5, 315.5±54.7, 80.2±19.1, and 11.13±3.14 items/L, respectively. The overall MPs removal efficiency of the WWTP was 98.7%, with the grit chamber, primary sedimentation tank, and secondary sedimentation tank removed 62.6%, 27.9%, and 8.2% of the total MPs, respectively. The most abundant polymers were polypropylene (PP) and polyethylene (PE). Conclusion: Despite the effective removal of MPs in WWTP, on average 4.47×1011±1.03×1011 MPs are discharged into the receiving waters through the effluent of this WWTP annually. This means that WWTPs can be one of the major sources of MPs in the environment and efforts should be made to increase the efficiency of WWTPs and equip them with advanced technologies.
采用常规活性污泥法的城市污水处理厂微塑料的发生和去除:伊朗伊斯法罕的案例研究
背景:微塑料(MP)目前存在于空气、各种陆地和水生环境中,已成为新出现的污染物。这些颗粒可以吸收其他化学物质和微生物污染物,并将其释放到环境和食物链中。尽管污水处理厂在去除MP方面效率很高,但污水处理厂仍然是MP排放到环境中的主要来源之一。本研究旨在评估伊朗城市污水处理厂使用传统活性污泥去除MPs的效率。方法:在初始制备步骤(筛选、催化湿式过氧化化学消化和NaCl密度分离)后,使用立体显微镜对MPs颗粒进行计数,然后使用拉曼光谱仪分析颗粒组成。结果:进水、沉砂池、初沉池和出水的MPs浓度分别为843.2±147.5、315.5±54.7、80.2±19.1和11.13±3.14项/L。污水处理厂的总MPs去除率为98.7%,沉砂池、初沉池和二沉池分别去除了62.6%、27.9%和8.2%的MPs。最丰富的聚合物是聚丙烯(PP)和聚乙烯(PE)。结论:尽管污水处理厂能有效去除污水中的MPs,但该污水处理厂每年平均有4.47×1011±1.03×1011个MPs通过污水排入受纳水体。这意味着污水处理厂可能是环境中MP的主要来源之一,应努力提高污水处理厂的效率并为其配备先进技术。
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来源期刊
CiteScore
2.40
自引率
37.50%
发文量
17
审稿时长
12 weeks
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