The sewage from the residences is led into a below ground Sewage collection sump after screening through bar screen for removal of large solid or floating particles.
From the sewage collection sump the sewage is pumped to the Aeration Tank where the reduction of organic pollutants in the sewage occurs. The high surface Area of the HDPE media inside the Aeration Tank will ensure high concentration of Aerobic Bacteria, thus leading to faster processing time of the sewage. The compressed air required for the aeration system is supplied through fine or medium bubble diffusers placed at the bottom of the Aeration tank. The air is diffused so that Oxygen in the air is efficiently transferred to the Effluent water in the Aeration tank thereby maintaining sufficiently high dissolved Oxygen levels inside the tank.
In the subsequent step, the wastewater + sludge mixture from the Aeration Tank is allowed to overflow into the secondary settling tank. Here, the sludge being heavier, will slowly settle to the bottom of the tank from where it is removed periodically and the clear supernatant on top will overflow into the clarified water tank. Liquid Alum is introduced at the secondary settling tank inlet to enable faster settling of the Sludge.
The treated water from the Clarified water tank is put through a tertiary treatment process comprising of Pressure sand filter and an Activated carbon filter or a Dual Media filter as the case maybe, for fine polishing of the treated water. Sometimes, UV filter is also incorporated in the tertiary treatment process so that the water can be safely reused for Toilet Flushing.