The diagram provides how water is filtered by using a slow sand filter.
Overall, this process includes 3 main steps from the entrances of water then it is filtered by sand before becoming fresh water.
Taking the initial step, the raw water is going through the tube then it is contained by a break pressure tank. After that, the water flows to the second tank, where filtration mainly takes place. At this stage, it separates into two layers, first of which is sand with a thickness of 60-90 cm. For the better effect, after going through the sand layer, dirt and particles are purified by the gravel layer with a thickness of 20-30 cm.
Having been filtered, clean water is collected in underdrains connecting to another tank. This tank connects to a tube which allows filtered water to flow out. There, the water is stored waiting for users to obtain.
