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Microbial fingerprint of water

DNA fingerprinting: powerful monitoring tool in water management

Next Generation Sequencing (NGS) is a technique that determines the microbial composition of water (streams) on the basis of DNA. Each specific type of water, such as surface water, WWTP effluent and wastewater, has its characteristic DNA fingerprint. This helps water managers trace the water’s origin. DNA techniques can therefore be employed in monitoring and managing problems arising in water- and wastewater management. But the boundaries of the techniques’ utility are not yet known. This TKI project research was therefore carried out, in collaboration with Water Authorities and municipalities, to determine the extent to which NGS can offer solutions to concrete questions faced in the water sector.

Power of DNA fingerprinting

The power of DNA fingerprinting was studied in a variety of cases. The technique was shown to be suitable in determining whether WWTP effluent or wastewater has been discharged into the surface water. The water is traceable, since each of the two sources has a typical composition of microorganisms. A further application is the demonstration of leakages of WWTP water into groundwater. Based on the microbial profile, one can determine what the situation is right into the monitoring wells. The monitoring of the switching of surface water sources between different locations is another matter. DNA fingerprinting is (still) unable to accomplish this, because the micro-life in different surface waters is very similar. Lastly, the research studied the degree to which a connection can be made between process changes in WWTPs, and what role microorganisms play in this.

Outlook

Follow-up research should clarify the degree to which NGS can be linked to existing parameters, such as bacterial colony counts, as an indicator of water quality. Once the boundaries for the use of NGS as a monitoring tool are known, the technique can then possibly contribute to answering the question about what microbial composition ecologically healthy water should have, in accordance with the Water Framework Directive. It is expected that more knowledge about the microbial population will lead to targeted recommendations to improve the performance of WWTPs.