New England Waste have been providing septic pump outs for the areas of Armidale, Uralla, Glen Innes, Tenterfield, Guyra and Inverell since 1979. In that time we have become the local experts in septic services and so we have created this info sheet to help our customers understand how the older style septic systems operate.
This information applies to older style septic systems running into effluent filtration trenches, not to newer Aerated Waste Water Treatment Systems.
Septic tanks work by allowing waste to separate into three layers: solids, effluent and scum (see illustration below). The solids settle to the bottom, where microorganisms decompose them. This is called the sludge layer. Lighter matter will float to the top, where it forms the scum layer, this layer helps prevent unpleasant smells escaping from the tank.
The middle layer of effluent exits the tank and travels through underground perforated pipes into the drainage field as more water is deposited into the tank from the house.
Generally the level in the tank will always look full, this makes it hard to determine if the system needs pumping. Main reasons your tank will require pumping will be for excess sludge, the sludge layer should not be more than 1/3 the depth of the tank, at this point pumping is recommended.
The scum layer can also cause problems, most commonly blocking the outlet, preventing effluent run off into the drainage pits or trenches.
It is important to remember, that after pumping your tank will not be completely empty, as pumping is done to remove most of the sludge and scum layer, removing the entire contents of the tank is not beneficial as the microorganisms that break down solids will not be present in sufficient numbers to start the process again.
New England Waste is your local provider of septic pump out, skip bins, hook bins, commercial and residential waste removal for the areas of Glen Innes, Tenterfield, Guyra and Inverell. Call Malcolm on 0429 323 696 for a quote.