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Grøn Dyst 2016

310 84 Detection of microbial outbreaks in water distribution networks with an ATP based monitoring system Mathias R. Hjorth Environmental Engineering, Technical University of Denmark The frequency of assessing microbial drinking water quality in Danish water distribution networks is fairly low, ranging from once every second year to 37 times a year depending on the distributed amount of water. Although microbial water quality assessments take place, it happens quite often that microbial outbreaks occur. 105 and 102 occasions of severe microbial outbreaks took place in 2010 and 2011 respectively. Conventional methods of assessing drinking waters microbial quality typically relies on heterotrophic plate counts (HPC) and fecal indicators such as the Colilert-18. These tools are very precise in their assessment and are able to differentiate between pathogens and apathogenic microorganisms, but results can first be interpreted after days of incubation. A more rapid way of assessing microbial drinking water quality is through measurements of adenosine 5´-triphosphate (ATP) concentrations. ATP is an energy-carrying molecule present in all living cells, which makes it a great parameter for identifying microbial activity. The department of environmental engineering at DTU is currently in charge of designing a remote controlled real time monitoring system for drinking water, using ATP as microbial water quality indicator. The project is a part of the Aquavalens framework, which main purpose is to protect European citizens health from contaminated drinking water. Measuring ATP takes a matter of minutes and is therefore well suited for a real life monitoring system, however it’s not possible to differentiate between pathogen and apathogenic microorganisms with this method. The system can be used to identify sudden uprising bacterial activity, which typically indicates contamination. Real time monitoring of our drinking water using an ATP based monitoring system, would allow for proactive actions instead of reactive ones. Implementation of the system would give the ability to manage microbial infected water properly, thus minimizing the frequency of diseases caused by microbial contaminated water. Measurements of microbial ATP rely on extraction of ATP through cell lysis. Cell lysis is typically performed using a chemical lysing reagent and is a proven, effective and reliable method of extracting ATP from cells. Despite being a reliable method of extraction, chemical lysing has shown undesirable properties when used in the microfluidic system designed to measure ATP due to precipitation of particulates; these are capable of compromising the self-sustainability and reliability of the platform. Thermal lysing has been proposed as a substitute to chemical lysing, since no particulate matter is formed in this process. The properties of thermal lysing have been investigated throughout this bachelor project. Thermal lysing has shown great characteristics and the method has proved to be up to 29.6 % better at extracting ATP than chemical lysing. Results have shown that an exposure time between 5-7.5s at temperatures of 90-100 °C yield the highest extraction of ATP. This project’s main purpose has been to identify whether or not thermal lysing could act as a substitute to chemical lysing. The promising results obtained through laboratory experiments strongly suggest that it could and have therefore taking the ATP based monitoring system one step closer to implementation and safer drinking water. WATER POSTER CONCEPT BACHELOR FINAL ASSIGNMENT


Grøn Dyst 2016
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