Septic Tank Treatment Process (Primary System)
3,000 L Polymer Septic Tank with Ankers attached ready for backfilling
Septic Tanks are waterproof tanks, usually installed into the ground, they receive all waste water generated on a property.
Cross Section of a Septic Tank
Septic Tanks provide Primary Treatment to the entire waste stream by allowing oils and fats to float to the top to form a scum layer and the solids to settle to the base of the tank as sludge.
The tank must be large enough to provide some “settling” time of the waste stream for this to occur.
Anaerobic (in the absence of oxygen) and Aerobic bacteria digest some of the retained solids, however because of accumulation over-time, the tank must be regularly pumped out “desluged”.
Desluging should be done about every four years to prevent clogging of the tank and carry-over solids with the waste water stream to other components of the system, but the frequency depends on how heavily the system is used and the design of the tank.
Septic Tanks do not remove nutrients or other pollutants, the waste water is not disinfected and because it is highly infectious it must be disposed of below the ground via specifically constructed ETA Beds or Trenches.
This type of Primary Treatment System can only be used on non environmentally sensitive sites, for an environmentally sensitive site the waste water must undergo a Secondary Treatment stage.
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Layout of a Septic Tank |
Outlet Filter for Polymer and Concrete Septic Tanks |
You should not use heavy chemicals such as bleach or industrial washing powders when connected to a Septic Tank, as it will kill the essential bacteria making the Septic Tank work, if you lose the bacteria in your tank you can help to re-establish it by adding enzymes (living bacteria).