What is the structure called? Briefly describe how the organic matter decomposes in the structure - NSC Civil Technology Woodworking - Question 3 - 2017 - Paper 1

Organic matter decomposes in the septic tank through the action of anaerobic bacteria and other biological organisms. These microorganisms break down waste, facilitating the digestion and liquefaction of solid waste into liquid effluent, which is then discharged into the drainage system.

The inlet pipe at 3.1.B serves the purpose of allowing wastewater to enter the septic tank. This pipe is essential for directing the incoming effluent from the household plumbing into the tank where it will undergo treatment.

The inflow at 3.1.B must be lower than the liquid level to prevent surface water contamination and to ensure that the wastewater is adequately treated within the anaerobic environment of the tank. If the inflow exceeds the liquid level, it could lead to overflow and potentially allow untreated waste to escape.

The effluent at 3.1.D is typically discharged into a drainage field or a leach field, where further treatment occurs through soil filtration before the water reaches the groundwater.