The diagram given in the image shows the constuction and the function of a simple water filter that is used to produce clean drinking water. It seems to be an ancient technique which is oudated to be of the modern use.
The filter mechanism consists of two tanks – one to filter the impure water and the other to store the filtered drinking water. The filtering tank is connected to the drinking water storage tank via a hose or a pipe.
The filtering tank consists of mainly four resources: gravel, charcoal, sand and impure water. the tank is first levelled with a layer of gravel which is followed by a layer of charcoal. This is then toppped up by a layer of sand which is the topmost and the last layer. The tank is then filled with impure water and the lid is closed.
The impure water then gradually flows through each of the layers of the filter, leaving behind various kinds of impurities at each layer. As a result of this, by the time the water reaches the gravel layer, it becomes filtered or purified. This purified or filtered water is collected into another tank via a piece of hose or pipe. This tank is used as the drinking water storage tank.