Osterhus S, Azrague K, Leiknes T, Odegaard H
Department of Hydraulic and Environmental Engineering, University of Science and Technology, S.P.Andersensvei 5, Trondheim, Norway.
Water Sci Technol. 2007;56(10):101-8. doi: 10.2166/wst.2007.780.
With the process combination Ozonation-Biofiltration-Membranefiltration (the OBM-process) an average removal of 63% for UV-absorbance (UV(254)), 79% for color, and 28% for DOC was obtained treating NOM containing surface water. In this paper, focus has been made on the removal of particles after the ozonation and biofiltration treatment steps, using a submerged hollow fiber ultrafiltration membrane reactor. For this purpose the membrane performed adequately. The ultrafiltration step did not have a significant impact on the removal of color, UV(254), and DOC. However, the SS and the heterotrophic plate count (HPC) was almost completely removed, and the turbidity was reduced by 65% by the membrane filtration, even at very high fluxes. Fouling occurred during operation, and operational factors of both the ozonation/biofiltration and the membrane reactor were important for controlling this. The experiments at pH 6.5 gave a higher permanent fouling than at pH 8.5, which was caused by the different oxidation pathways and consequently by the change in size and hydrophobicity of the by-products. On the other hand, the reversible fouling was less important at low pH. The mechanical cleaning was efficient, however, it seemed that the air scouring participated to the formation of submicron particles which favored the fouling.
采用臭氧化-生物过滤-膜过滤工艺组合（OBM工艺）处理含天然有机物的地表水时，对紫外线吸光度（UV(254)）的平均去除率为63%，对颜色的去除率为79%，对溶解性有机碳的去除率为28%。本文重点研究了在臭氧化和生物过滤处理步骤之后，使用浸没式中空纤维超滤膜反应器去除颗粒的情况。在此过程中，膜的性能表现良好。超滤步骤对颜色、UV(254)和溶解性有机碳的去除没有显著影响。然而，悬浮物和异养平板计数（HPC）几乎被完全去除，并且即使在非常高的通量下，膜过滤也使浊度降低了65%。运行过程中出现了膜污染现象，臭氧化/生物过滤和膜反应器的运行因素对控制膜污染都很重要。在pH值为6.5时进行的实验比在pH值为8.5时产生了更高的永久性污染，这是由不同的氧化途径以及由此导致的副产物尺寸和疏水性变化引起的。另一方面，在低pH值下可逆污染不太严重。机械清洗是有效的，然而，空气冲刷似乎促进了亚微米颗粒的形成，这有利于膜污染。
