It is important for a plumber to understand how a septic tank works. Basic working principles are listed below:
- Wastewater from building is discharged into the septic tank through a T-shaped inlet pipe.
- Heavy solids settle at the bottom of the tank.
- Lighter solids such as grease, oils and fats, rise to the top and form a scum layer. Solids that are not decomposed remain in the septic tank.
- Bacteria grow in the septic tank and digest the solids and reduce the solids into liquid, fats and grease, and insoluble particles.
- A T-shaped outlet pipe prevents the sludge and scum from leaving the tank and clogging the drain field area.
- A relatively clear waste water flows out of the septic tank through the T-shaped outlet pipe.
Limitations of a septic tank
Because of the unsatisfactory quality of the effluent from the septic tank and also the difficulty in providing a proper effluent disposal system, septic tanks are recommended only for individual homes and small communities and institutions whose contributory population does not exceed 300.
For larger communities, septic tanks may be adopted with appropriate secondary effluent treatment and disposal facilities.
In such cases soak pit (Leech pit is also known as soak pit) is not recommended. The plumber should go in for other secondary treatments.