Lee Eui-Jong, Kim Young-Hoon, Kim Hyung-Soo, Jang Am
Graduate School of Water Resources, Sungkyunkwan University, Jangan-gu, Suwon, Gyeonggi-do, 440-746, Republic of Korea.
Environ Sci Pollut Res Int. 2015 Jun;22(11):8451-9. doi: 10.1007/s11356-014-3928-y. Epub 2014 Dec 30.
Currently, there is a growing emphasis on wastewater reclamation and reuse all over the world due to restricted water resources. Among a variety of wastewater reuse technologies, the use of microfiltration membranes (MF) is one of the popular processes because it has the ability to successfully eliminate particulates and colloidal matters. However, successful fouling control is not easy because effluents from the activated sludge process still contain small particulates and colloidal matters such as extracellular polymeric substance (EPS) and soluble microbial products (SMP). On the other hand, microbubbles have advantageous properties compared to common bubbles, but there hasn't been reporting of the use of microbubbles in physical cleaning instead of aeration. Encouraging results were obtained herein through the application of microbubbles for physical cleaning. In evaluation of the cleaning efficiency, the efficiency of microbubbles was observed to be twice as high as that of aeration, except during the course of the initial 30 min. Total organic carbon (TOC) concentration of the membrane tank after treatment with microbubbles was more than twice as high as that after aeration for physical cleaning. The membrane cleaned with microbubbles also had the smoothest surface, with a roughness of 42.5 nm. In addition, microbubbles were found to effectively remove EPS and make the structure of the gel layer loose. In particular, the microbubbles had the ability to remove proteins through the effect of pyrolytic decomposition. Therefore, in FT-IR spectra of the membrane surfaces taken before and after physical cleaning, while each treatment showed similar peak positions, the peak values of the membrane treated with microbubbles were the lowest. Through various analyses, it was confirmed that microbubbles can remove foulants on the gel layer in spite of their very low shear force. This means that microbubble cleaning has full potential for use as a physical cleaning method in the wastewater reclamation process.
目前，由于水资源受限，全球对废水回收和再利用的重视程度日益提高。在各种废水回用技术中，微滤膜（MF）的应用是一种流行的工艺，因为它能够成功去除颗粒和胶体物质。然而，成功控制膜污染并不容易，因为活性污泥法产生的废水仍然含有小颗粒和胶体物质，如胞外聚合物（EPS）和可溶性微生物产物（SMP）。另一方面，微气泡与普通气泡相比具有优势特性，但尚未有关于将微气泡用于物理清洗而非曝气的报道。本文通过应用微气泡进行物理清洗获得了令人鼓舞的结果。在清洗效率评估中，除了最初30分钟的过程外，微气泡的清洗效率是曝气的两倍。用微气泡处理后膜池的总有机碳（TOC）浓度比曝气物理清洗后的浓度高出两倍多。用微气泡清洗的膜表面也最光滑，粗糙度为42.5纳米。此外，发现微气泡能有效去除EPS并使凝胶层结构松散。特别是，微气泡能够通过热解分解作用去除蛋白质。因此，在物理清洗前后对膜表面进行的傅里叶变换红外光谱（FT-IR）分析中，虽然每种处理的峰位相似，但用微气泡处理的膜的峰值最低。通过各种分析证实，尽管微气泡的剪切力非常低，但它仍能去除凝胶层上的污垢。这意味着微气泡清洗在废水回收过程中作为一种物理清洗方法具有充分的应用潜力。
