Objective: To learn about wastewater and sewage, their sources and the process of treatment of water. Learning outcomes - students will be able to: 1. Predict how wastewater and sewage are formed 2. List the different sources of wastewater 3. Illustrate the working of a sewage system 4. List some housekeeping practices to avoid water pollution 5. Define potable water 6. Memorise various methods of purifying water 7. Explain UV purification, chlorination and reverse osmosis 8. Describe the process of water treatment in water-treatment power plants