Where to use UV in river water treatment
In river water treatment to drinking water you usually apply chemical treatment steps (coagulation, flocculation, sedimentation) followed by sand-filters and membrane technologies (UF, RO etc) – the setup can vary from case to case.
In the final treatment before sending the water out to pipeline (if this is the case), a 2 step disinfection is normally applied. Traditionally, chlorination has been used for this; Step 1 to remove all pathogens efficiently and step 2, chlorine is added to ensure that pathogens cannot develop while the water is traveling throughout the pipeline system.
Chlorination is however not very environmentally friendly and it creates a lot of unhealthy byproducts after reacting with the target microorganisms and organics in the water. Some of the byproducts are even carcinogenic. Disinfection using UV creates no byproducts and will hence be much healthier and doesn’t have the same negative impact on the environment.
In a system as described above a UV could be applied as a primary disinfection step, but if you are pumping into a pipeline system, where you know there is a risk of microorganism development, you will still need to add some chlorine before pumping out the water. Alternative a UV can be applied downstream as well at tapping point(s) – then chlorination can be totally be avoided.