Where, oh Where, DOES all the Crap Go?

This is a very important subject on our minds at the moment, OK it may sound crude or something,but it is REALLY important. Why I hear you ask. Well one of the major tasks this year is to convert the old water tank in to a new bathroom. We now have a roof on the tank and a opening into the house, the next job is to start the pluming, and one of the tasks, as part of that is to lay new drains. Now for you who live in the UK and most major towns this is not hard - find the nearest man hole and connect the new drains to that. Well it is not quite that simple here....
We in the country don't have main drains.. So what do we have? We have what is called a Poso Negro, the direct translation of that is "Black Well", and up to last week we did not know where it was and in what condition it was in. We had some idea that it was located close to the current bathroom, (which is a 1m x 2m concrete hut in the garden). We thought that it might be under about half a meter of soil that was dumped in front of the loo to bring the ground up to the level of the house. Well last week I started clearing a space behind the loo to hold the tank for gray water recycling. while doing so I notest that there appeared to be a concrete wall below the loo....
After some work with a hammer, there was a hole and behold we have the Poso Negro, and what is the poso negro? A large hole in the ground, about 1 meter square and 2 meters deep, (well to the serf ice of the water, I am not going to find out how deep that is!!!!), With the loo on top of it.
So now all I have to do is put in the new pipes and close up the hole and we have somewhere for the new loo to empty into.