Study of the generation and diffusion of bioaerosol under two aeration conditions
Study of the generation and diffusion of bioaerosol under two aeration conditions
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DOI：
10.1016/j.envpol.2020.115571
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发表时间：
2020-12-01
影响因子：
8.9
通讯作者：
Liu, Junxin
中科院分区：
文献类型：
--
作者：
Han, Yunping;Yang, Tang;Liu, Junxin
鉴于对实际污水处理厂的研究经常受到环境条件的影响，清楚地了解曝气过程中相关的生物气溶胶的产生和扩散特性具有挑战性。因此，为了加深对这方面的认识，本研究采用生物气溶胶发生器模拟气泡底曝气和刷面曝气两种曝气模式下生物气溶胶的产生和扩散。气泡底曝气和刷面曝气产生的生物气溶胶中可培养细菌的总浓度范围为300-3000 CFU/m(3)。在气泡底部曝气下，产生的生物气溶胶对称分布在源点周围，而在刷面曝气下，产生的生物气溶胶主要分布在旋转刷表面的向前方向。这些来自气泡底部曝气的生物气溶胶主要由尺寸低于 3.3 毫米的颗粒组成，特别是尺寸在 1.1-2.1 毫米范围内的颗粒。相反，通过刷子表面通气产生的生物气溶胶主要由尺寸大于3.3毫米的颗粒组成。两种通气模式下的种群结构分布特征与相应模型中的浓度分布特征一致。此外，结果表明，当曝气过程不受环境条件（颗粒物、风直达、风速等）影响时，生物气溶胶成分主要来源于母体污水或污泥，不会扩散到远离源点的地方。因此，可以推荐源头减少（加盖或密封）作为污水处理厂生物气溶胶的主要控制策略。采取此类措施将显着限制生物气溶胶的扩散，从而减少与人体暴露相关的潜在风险。 (C) 2020 Elsevier Ltd. 保留所有权利。
Given that studies on actual sewage treatment plants are often affected by environmental conditions, it is challenging to clearly understand the associated bioaerosol generation and diffusion characteristics during the aeration process. Therefore, to enhance understanding in this regard, in this study, bioaerosol generator was used to simulate bioaerosol generation and diffusion under two aeration modes, i.e., bubble bottom aeration and brush surface aeration. The total concentration range of culturable bacteria in the bioaerosol produced by bubble bottom aeration and that produced by brush surface aeration were 300-3000 CFU/m(3). Under bubble bottom aeration, the generated bioaerosol was symmetrically distributed around the source point, whereas under brush surface aeration, it was primarily distributed in the forward direction of the rotating brush surface. These bioaerosols from bubble bottom aeration predominantly consisted of particles with sizes below 3.3 mm, particularly those with sizes in the range 1.1-2.1 mm. On the contrary, the bioaerosols produced via brush surface aeration predominantly consisted of particles with sizes above 3.3 mm. The distribution characteristics of population structure in the two aeration modes were consistent with the distribution characteristics of concentration in the corresponding models. Additionally, the results showed that when the aeration process is unaffected by environmental conditions (particle matters, wind direct, wind speed, etc.), the bioaerosol components originate primarily from the parent sewage or sludge, and do not diffuse far from the source point. Therefore, source reduction (capping or sealing) can be recommended as the primary control strategy for bioaerosols in sewage treatment plants. The adoption of such measures will significantly limit the diffusion of bioaerosols, thereby reducing the potential risks associated with human exposure. (C) 2020 Elsevier Ltd. All rights reserved.