The Pit

Ok, so lets start aat the bottom..(hahaha the first of many lame jokes) the pit is where the faeces goes, and the size of this pit can be whatever you want it to be. A sensible figure for how much faeces people produce in a year is about 65L. If we take an average 6-person family in Kwa-zulu Natal, and we want the pit to last, say 6 years, then you need a pit that is...65x6x6 = 2340L=2.34m3.

Now you don't really want to dig too dep a hole, as there is a danger that it might collapse when you are digging it, so I'll specify a depth of 1.6m. This means that the pit has dimensions of 1.2m x1.2m and 1.6m deep.

The sides of the pit can be lined with bricks to stop all the earth filling the pit in. How strong this lining is depends on the soil in which the hole is dug. For unstable, sandy soil the walls of the pit you are digging will tend to collapse easily, so you want a stronger lining whilst for more stable, rocky soil you want a weaker lining, or perhaps even no lining at all.

Irrespective of this, the bottom of the pit is unlined, as you want the liqiuds to soak away into the soil.

For the loo factory loo, we will use Textile Concrete panels for the lining. Since they do not need to be watertight, I'll try to make the panels interlocking, so that the pit lining is easy to put together. Of course it might be a good idea to offer customers the choice of not having a pit lining, if it turns out that the soil in the place where they dig the pit is sufficiently stable. In really rocky soil, on the other hand, it might be easier to to drill a narrow, deep hole using a hand-auger, if one is available.