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Item type:Publication, Access status: without files , Real-Time Monitoring and Controlling of Water Quality in Water Distribution Networks Based on Flow Cytometry and Fluorescence SpectroscopyGuaranteeing the high-quality of water in water distribution networks (WDSs) is a priority when it comes to ensuring public health. Since the majority of German water utilities (and also other EU countries) do not chlorinate, controlling of nutrients in WDSs such as assimilable organic carbon (AOC) and monitoring of microbiological activities is indispensable. Conventional methods to characterize microbiological activity and dissolved organic matter are time-consuming and labor-intensive. This study presents data on flow cytometry and fluorescence spectroscopy as leading-edge technologies for real-time analysis of drinking water quality in WDS. Flow cytometry is a sensitive method which can be applied in online modus for accurate detection of bacterial cell numbers. Furthermore, fluorescence spectroscopy is a rapid and quantitative technique for detailed characterization of dissolved organic carbon (DOC) including fractions of natural organic matter (NOM). The integration of both techniques is promising for real-time water quality analysis and as a supporting tool for quality control. In the initial step of this research, an experimental laboratory setup of simultaneous analysis is developed. Thus, the goal is to achieve knowledge about possible relations between water quality parameters, more precisely bacterial regrowth potential and the character of dissolved organic constituents. In continuous measurements, the initial state of microbiological growth is to be determined based on flow cytometric data. Due to fluorescence spectroscopy data the microbiological regrowth potential will be predicted. This will be achieved by online detecting of certain organic fractions of the DOC which can be utilized as nutrients by present bacteria. The overall project goal is the establishing of an interface between monitoring parameters and water quality simulation models for the WDSs. First promising results show the successful utilization of adapted AOC as regrowth potential parameter, which can be used for water quality simulations in a WDS.Publicationtype: Conference Paper38 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Optimal Control of Chlorine Concentration in Water Distribution SystemSupplying high-quality water is the key task of water distribution systems (WDSs). Although in Germany and some other countries chlorine is no longer used, it remains as a major disinfectant in WDSs worldwide. Therefore, chlorine concentration represents an important parameter for determining the water quality; that is, we should ensure the chlorine concentration within a reasonable range in a WDS. However, due to the complexity of the network structure and nonlinear behavior of the system, the control of chlorine concentration in WDSs imposes a challenging task. In this study, a model-based optimal control strategy is developed to address this problem. The mass and energy conservation laws are used to describe the hydraulic properties of WDSs. The one-dimensional advective transport model is simplified to describe the decay of chlorine in the pipelines. The chlorine concentration limits at the nodes are formulated as inequality constraints which will be satisfied by manipulating the flows and their directions in the pipelines. As a result, a nonlinear optimization problem is formulated and solved to achieve the specified chlorine concentration. For verifying our approach, we deliver the computed results for benchmark networks as input to the simulation model in EPANET, and the simulation gives satisfactory values of the specified chlorine concentration in the network.Publicationtype: Conference Paper26 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Establishing an Experimental and Simulation Interface for Online Monitoring and Modeling of Bacterial Growth in Water Distribution SystemsWater distribution systems (WDSs) function to deliver high-quality water in major quantities. While standard water quality parameters are monitored at waterworks, it is still a challenge to monitor water quality in the WDS network itself. Only hydraulic parameters are frequently monitored and modeled in drinking water networks in Germany. Moreover, the majority of German drinking water utilities does not disinfect when the product leaves the waterworks. This is also common practice in Northern European countries. It is thus important to monitor specific organic and bacteriological water quality parameters which define the system state. This study develops an experimental and simulation integrated framework for continuously monitoring and simulating selected organic and bacteriological water quality parameters, so abnormal deviations in water quality behavior can be detected and responded to in real time. A simple reproducible bacteria regrowth model was taken to initialize the validation of experimental values in a water quality model simulation. Batch experiment measurements from a flow cytometer are analyzed to establish an interface between laboratory values and water quality simulations. Monod kinetics are utilized to describe the bacterial growth rate according to the respective substrate for modeling the bulk species in the water network. Experimental values are incorporated in the simulations for validation. The simulation of bacterial growth is conducted firstly on a network model of a real-life test bed and on various selected distribution system models of different sizes and complexities. First results of the water quality simulations show a successful transition of experimental analysis into water quality simulations and give a promising outlook for developing an online-monitoring and prediction methodology for detecting water quality anomalies efficiently in real time.Publicationtype: Conference Paper33