Anytime we flush something from our sinks and toilets, it goes down into the sewer. Used Water contains organic matters which can be useful if treated correctly. It can be recycled to make fertiliser. (1. Screening to remove wipes, toilet paper, mobile phones, etc. 2. Primary settlement - organic solids sink to the bottom of the tank and are removed. 3. Biological treatment: Either biological filter beds Or aeration ditch: both systems use micro-organisims. 4. Final settlement. 5. Outfall)