PRIMARY TREATMENT PROCESS
Sand, pebbles, and soil sink to the bottom of the grid chamber because of the slow 몭ow of sewage during
the 몭rst treatment process.
When wastewater enters the settling tank or sedimentation tank, where solid wastes like faeces are
permitted to settle, wastes like soap, oils, and grease rise to the surface. Sludge and scum are the names
for the waste material that sinks to the bottom and 몭oats to the surface. After that, scum and sludge are
removed every several days using the scraper and skimmer, respectively. Clari몭ed water is the term for
the water that is not used.
SECONDARY TREATMENT PROCESS
Organic or biological wastes are eliminated during the secondary treatment procedure. The process is biological. This is
performed by transferring the puri몭ed water to an aeration tank equipped with air blowers that create bubbles of air to
encourage the growth of aerobic bacteria that consume organic pollutants including food waste, faeces, and other creatures.
Activated sludge then gravitationally separates out of the mixture as it moves from the aeration tank into the clari몭er.
The digester is where anaerobic bacteria break down the activated sludge that has been created together with the sludge
from the primary phase. The remaining water in the activated sludge drains through the sandpits after some of it evaporates
from the mixture. The remaining dried sludge is then left behind and can be used to create compost or fertilisers.