What is a traditional fosse system?

The conventional “fosse toutes eaux” with filter bed works by collecting all waste water in the fosse itself where it is separated and the lighter suspended solids are digested by aerobic bacteria and the heavier sludge waste digested by anaerobic bacteria. As this only results in a reduction of pollutants, some germs and pathogens still remain which could pose a real threat of contamination or disease if released directly into waterways. As such the effluent then needs to pass through a filtration process where the remaining waste and toxic particles are removed before the resulting liquid is either allowed to soak away or be siphoned off .