The Process of Aerobic Treatment

Aerobic treatment units are today commonly used instead of the conventional septic tank systems. They are generally used in cases when the effluent from the septic tank is expected to be of higher quality and is used in leach fields and when the soil conditions are not suitable for the conventional septic tank system.
 
The waste water is treated in stages in the aerobic units. In many places the septic tank is used as a pretreatment unit. After pretreatment the flow enters the aeration chamber. Here the organic material is broken down by bacteria into carbon dioxide and water and more bacteria are produced in the process. The bacteria that are thus collected in the aeration tank form a slurry of solid matter and waste water. The flow remains in the aeration chamber for around 24-36 hours and then it moves on to the clarifier or the settling tank. The mixed slurry that is heavier than water settles to the bottom of the settling tank and returns to the aeration tank. The clear water leaves the clarifier from the top and is taken for disinfection and storage. The effluent is pumped to the irrigation system by the pumps which work on timers or level control. Ideally, all the organic matter should be consumed by the treatment process and only small amounts of inert matter is disposed by pumping. But practically, the aerobic units must be pumped out periodically. The organic and inorganic loading to the unit and the efficiency of the treatment process determine the frequency of pumping.
 
The Kerala builders are concentrating more on better ways to dispose of waste water from each of their projects.