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    DVGW project: Removal of dissolved organic carbon from groundwater containing humic acids (decolorization) – possible applications and limits of treatment processes (COL_EX)
    Both in the laboratory and at selected waterworks sites, three technologies (flocculation / precipitation, oxidation, adsorption) are examined for their decolorization efficiency and the respective performance limits. As an innovative method, ozonation with downstream biofiltration is used. This technique is used almost exclusively in surface waters for other treatment purposes (disinfection, odorants, pre-flocculation). Ozone selectively attacks chromophoric molecules and is therefore well suited for decolorization. In contrast to other technologies, no residues (sludge, concentrates) are generated. However, questions about the resulting DOC bioavailability and the formation of bromate depending on technical parameters and water quality have to be answered. The participating water suppliers offer access to their plants and previous experience in dealing with the problem. Thus, the application possibilities and limitations of the considered methods become clear. The evaluation of the results of the analyzed treatment processes is carried out with the aim of developing recommendations for action in the DVGW set of rules, as well as minimizing the use of energy and chemicals and the entire life cycle costs.
      318
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    BMWi-cooperation project: Treatment of groundwater with increased sulfate concentration: innovative options and limits of resource and energy efficient drinking water management (SULEMAN)
    Water suppliers have to deal with increasing sulfate concentrations in ground water and bank filtrate used for drinking water production. There are several reasons for the increase of sulfate concentration. - Shut-down and flooding of open brown coal pits cause increased sulfate concentration in surface water. From the surface water, sulfate can migrate into near-surface groundwater that is used for drinking water production - Increasing concentrations of nitrate and the related oxidation of pyrite in pyrite dominated extraction sites result in oxidation of sulfide to sulfate with consequential effects on the ground water quality - Deep groundwaters, as present in northern German extraction sites, are partially in exchange with salt domes (especially gypsum) and therefore enrich sulfate The limit value for sulfate in drinking water is at 250 mg/L as prescribed in the German Drinking Water Regulation and must be strictly adhered by all drinking water suppliers. Within the project commercially available technologies (low pressure reverse osmosis LPRO, ion exchange process CARIX) are tested regarding energetically optimized, sustainable sulfate removal for the treatment of different raw waters for drinking water application. In Hamburg, deep and salty ground waters (anaerobic before and aerobic after deferrization) are tested, in Berlin near-surface bank filtrate is treated. Results from semi-technical scale (plant capacities ca. 1 m³/h) are extrapolated regarding available literature data and are compared through ecological (life cycle assessment) and economical assessment. Evaluation criteria are amongst others specific energy consumption, application behavior and sustainability of each technology under varying raw water compositions. Beyond the industrially available technologies LPRO and CARIX a commercial Polymer-UF-Membrane is post modified by a novel coating process and thus optimized for the target substance sulfate. This innovative technology of Capillary-NF runs at low operating pressures compared to the state of the art processes and will therefore be able to realize operation at lower energy demand for the treatment of waters with increased sulfate concentration. The experiments are run in parallel to the LPRO and CARIX trials in technical scale. The operation data of the Capillary-NF are regarded in the ecological assessment and are critically compared with results of LPRO and CARIX.
      938
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    Further development and validation of flow cytometry as a fast detection method for bacteria in raw water and drinking water
    Flow cytometry (FCM) is a powerful method for the quantification of all bacteria in a water sample (total cell count, TCC). After staining with a DNA-specific fluorescent dye every single cell is excited by a laser beam and its light scattering and fluorescence intensity is detected by optical sensors. The combination of different signals gives a specific fingerprint of a water sample showing e.g. the proportion of small cells with a low DNA content (LNA) to big cells with a high DNA (HNA) content. The measurement of a TCC takes only a few minutes. In contrast culture methods detect only 0.01 to 0.1 % of the TCC and the determination of colony counts according to the german drinking water ordinance require at least 48 hours. The time saving and the availability of mobile and recently also of online-instruments are important arguments for a promising application of FCM in water analysis. Additionally, FCM can differentiate between live (membrane intact) and dead (membrane damaged) cells which allows the detailed investigation of the efficacy of disinfection methods. Several publications propose the general application of FCM for the surveillance of disinfection methods. However, this has to be regarded critically due to different mechanisms of action of disinfectants - especially with regard to UV-disinfection. The objective of the project is to determine the potential and the frontiers of this forward-looking method. The FCM should be further developed and validated for different fields of application: - Fast measurement of total cell counts (TCC) in different matrices - Fast characterization of raw water and drinking water - Specific detection of fecal indicators - Surveillance of the efficacy of disinfection The comparison of the results from FCM with classical culture methods should reveal the relevance of FCM data for the assessment of the hygienic quality of the water. For an as far as possible close-to-practice development of flow cytometry real water samples of preferably different compositions from water utilities will be analyzed. The DVGW-Forschungsstelle TUHH performs the following work program in the overall project: - Participation in interlaboratory tests for the determination of TCC, LNA/HNA-ratio and proportion of live (membrane intact) cells - Analysis of the microbial dynamics in treatment processes of different raw waters and during distribution (long-distance water main) - Surveillance of disinfection: investigation of the effect of chlorine dioxide on the live/dead differentiation of cells in laboratory experiments with different drinking water qualities - Measurement of the effect of different water matrices (e.g. particles, dissolved compounds) on bacterial FCM-signals - Hygienic relevance of the data: interpretation of FCM-data and evaluation of their hygienic relevance by comparison with the results from routine culture techniques - Adaptation of standard operation procedures (SOPs) for sampling, sample fixation, instrument settings and quality control
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