रिवर्स ऑस्मोसिस (RO) तकनीक का उपयोग मुख्य रूप से इनमें से किसमें से घुले हुए लवणों और खनिजों को हटाने के लिए किया जाता है?

Which of the following elements is most commonly used as a disinfectant in municipal water purification?

Water containing high salt concentration (saline water) can be purified and desalinated by which process?

Which process is primarily used to remove suspended solid particles like dirt and sand from wastewater?