The issue is more common ...
Published by Giovanni Pavanello, Director at ALVIM Biofilm Monitoring Technologies
The issue is more common than you can expect - and it is usually caused by biofilm. As you know, this layer of bacteria is the ideal environment fo survival and proliferation of pathogens - biofilm is up to 1000x more resistant to chemicals than free-floating bacteria. More and more water utilities are starting to monitor biofilm, to apply chemical or physical treatments as soon as it starts to form, and thus to get the best results:
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