The steps involved in getting clarified water from wastewater are as follows :
(i) Firstly all the physical impurities like stones, plastic bags, cans, etc. are to be removed. It is done by passing the water through bar screens.
(ii) Then, the water is filtered through the layers of sand, fine gravel, and medium gravel. Filtration makes the wastewater clean from various types of pollutants. The water is filtered continuously until it becomes clear.
(iii) Solid impurities and feces etc. are collected from the bottom of the water. These impurities collected are called sludge.
(iv) Then any disinfectant such as chlorine tablet is added to the filtrate and stirred to obtain completely clear water.