Situation: | Low-pressure membrane techniques in water treatment, like microfiltration (MF) and ultrafiltration (UF) offer many advantages compared to conventional purification processes due to a small footprint, reliability in operation and high water quality effluent independent of the available raw water source. One of the main limitations of UF and MF systems is membrane fouling, which is the undesirable deposition and accumulation of particulate matter, microorganism, colloids, and solutes on and within the membrane matrix. Fouling is undesirable because it reduces membrane performance, increases operating costs, and shortens membrane lifetime.
The objectives of this project are to estimate the impact of different water constituents on the fouling layer formation during the filtration process by analyzing the composition of the feed water, to identify new analytical approaches to predict the fouling potential of varying raw water sources and, based on this, to develop suitable and sustainable strategies to stabilize the filtration process. |
| Methodology: | Lab-scale as well as pilot-scale systems are available for filtration and fouling experiments. The dissolved fraction of natural organic matter is quantified and characterized by methods of the analytic chemistry, like the Liquid Chromatography with Organic Carbon Detection (LC-OCD) and the Fluorescence Spectroscopy (EEM). Image analysis techniques like the Nanoparticle-Tracking-Analysis (NTA) are used to investigate the colloidal and particulate water constituents. A promising option to enhance this technique is the application of fluorescence marker for a further discrimination of specific colloidal groups. The impact of individual water constituents, as well as their complex interactions, on the membrane filtration behavior is investigated by tests with model waters. The results are verified by and critically compared to filtration performance with real waters of varying raw water sources. Using a statistical data analysis, fouling relevant substances shall be identified and – depending on the water composition – be reduced by means of different pre-treatment strategies (e.g. coagulation, adsorption or oxidation) in order to identify conditions, which allow an energy and cost efficient application of this technique.
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