Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China.
Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, Xi'an 710055, China.
J Environ Sci (China). 2019 Mar;77:85-96. doi: 10.1016/j.jes.2018.06.017. Epub 2018 Jun 30.
In dynamic membrane bioreactors (DMBRs), a dynamic membrane (DM) forms on a support material to act as the separation membrane for solids and liquids. In this study, batch filtration tests were carried out in a DMBR using nylon mesh (25 μm) as support material to filtrate sludge suspensions of variable properties from three different sources to evaluate the effects on the short-term DM formation process (within 240 min). Furthermore, the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory was applied to analyze the sludge adhesion and cohesion behaviors on the mesh surface to predict quantitative parameters of the short-term DM formation process (including initial formation and maturation stage). The filtration results showed that the order of the initial DM formation time (permeate turbidity <1 NTU as an indicator) was as follows: sludge with poor settleability and dewaterability < normal sludge < sludge with poor flocculability. Moreover, normal sludge (regarding settleability, dewaterability, flocculability, and extracellular polymeric substance) showed a more acceptable DM formation performance (short DM formation time, low permeate turbidity, and high permeate flux) than sludge with poor settleability, dewaterability and flocculability. The influence of sludge properties on the initial DM formation time corroborates the prediction of sludge adhesion behaviors by XDLVO theory. Additionally, the XDLVO calculation results showed that acid-based interaction, energy barrier, and secondary energy minimum were important determinants of the sludge adhesion and cohesion behaviors. Therefore, short-term DM formation process may be enhanced to achieve stable long-term DMBR operation through positive modification of the sludge properties.
在动态膜生物反应器（DMBR）中，在支撑材料上形成动态膜作为固液分离膜。本研究采用尼龙网（25μm）作为支撑材料，在 DMBR 中进行间歇过滤试验，以过滤来自三个不同来源的不同性质的污泥悬浮液，以评估其对短期动态膜形成过程（240min 内）的影响。此外，还应用扩展的 Derjaguin-Landau-Verwey-Overbeek（XDLVO）理论来分析污泥在网表面上的粘附和内聚行为，以预测短期动态膜形成过程的定量参数（包括初始形成和成熟阶段）。过滤结果表明，初始动态膜形成时间（以浊度<1NTU 作为指示）的顺序如下：沉降性能和脱水性能差的污泥<正常污泥<絮凝性能差的污泥。此外，与沉降性能、脱水性能、絮凝性能和胞外聚合物差的污泥相比，正常污泥（关于沉降性能、脱水性能、絮凝性能和胞外聚合物）表现出更可接受的动态膜形成性能（短的动态膜形成时间、低的浊度和高的通量）。污泥性质对初始动态膜形成时间的影响证实了 XDLVO 理论对污泥粘附行为的预测。此外，XDLVO 计算结果表明，基于酸的相互作用、能垒和二次能量最小值是污泥粘附和内聚行为的重要决定因素。因此，通过对污泥性质进行积极的改性，可以提高短期动态膜形成过程，从而实现稳定的长期 DMBR 运行。
