Gauteng Smallholder July 2015 | Page 43

SEWERAGE And finally, why it sometimes goes stinky T wo factors will result in your septic system malfunctioning and backing up: Either it is too small for the job it is expected to do and is simply unable to cope with the volume of effluent it receives daily. Or you are putting into it substances that are harmful to the microbes that make it function. Households often outgrow their septic systems, by the addition of members of the family, staff and guests, or by the addition of granny flats, etc. Moreover, ignorant builders often simply miscalculate the size tank required for a household when building the dwelling in the first place. Assuming your tank is the correct size and is not overloaded, malfunction is most likely the result of killer substances being poured down the drain. Just as they clog drainpipes, fats, oils and greases are also killers in the septic system, particularly if they get into the drain-field. In the tank they take an inordinately long time to be destroyed by the bacteria in the septic tank and if the system overflows and allows the oil layer into the drain field it coats the media (the rock, old tyres or brick that fills the soakaway) surfaces and stops the bacteria in the drain-field working. A smell around the drain-field indicates that the media is becoming blocked. Next, the fats and oils will then coat the trench soil surfaces, preventing the fluid from soaking away into the soil. As the liquid cannot escape it rises to the surface or backs up into the septic tank. Apart from the fact that there are health reasons why one should limit the amounts of fat and grease one eats, one should also limit the amount that ge