Located in Belgrade,  Aqua Interma Engineering  manufactures and install solutions for drinking water purification and waste water treatment. They select the right-sized PLC + HMI controller, Samba, Jazz or Vision430 to  create applications that dose water with chlorine to eliminate micro-organisms and test the residual levels of chlorine in order to ensure water purity. 

Read about it here:
https://unitronicsplc.com/testemonials-category-carrousel/?category=waterwaste-water&tid=10833