Home hygiene, safety: Septic tank functionality

Without a proper soak pit, a septic tank becomes like any ordinary pool in the ground. Storing water for a short time, waiting to be drained.

This means that the soak pit is of great importance if the sewerage system on any property is to properly function.

John Mugerwa, who has developed a niche in pit-digging, says the soak pit has to be deeper in length for it to properly absorb water. “It must be dug to the level of the brown-marrum soil because it absorbs water. Any other type of soil simply becomes water-logged,” explains Mugerwa.

He also cautions property owners to steer clear of the water table; the underground water because if you dig to that level, it means the underground water (ensulo za mazzi) will be coming up into the soak pit draining pipe, making it hard for the water from the septic tank to soak as it will not have where to flow.

Once the desired depth has been attained, then the pit has to be filled with hardcore stones, which direct the water in the tank to flow and consequently be absorbed. Unlike in the past, where the stones would be heaped in the pit, today the practice has changed. A perforated pipe is placed in the centre of the soak pit to allow for easy draining when the pit gets filled up with water.

Soak pits get filled once the stones get too coated with dirt or when the ground that has been absorbing water gets saturated. However, a well-connected septic tank should start draining water to the soak pit when the required level has been reached. This draining can go on for months before a cesspool truck can be called in to empty the septic tank.

How do you unclog the soak pit?

Unblocking or unclogging the soak pit is done by excavating the stones, Mugerwa says. It means you have to dig up the soak pit, remove the stones and clean them. Widen or if need be, deepen the soak pit before adding the hard core stones. However, it is when you have opened up the soak pit, that you see a clear picture of where the problem is; which could be saturated soil or dirt-coated stones.

A suitable septic tank that can handle sewerage for at least three apartments, should measure 12X10feet; 12feet wide and 10feet deep. That said, something smaller will require that the property owner empties the septic every six months, depending on water usage. Mugerwa says the soak pit technology is evolving and there is talk of biodigesters taking over.