I am sharing information about a novel biodegradable septic tank system.
It is a significant innovation for micro waste-water treatment. In this case for 5 adolescents.

My company is planning a boarding school in Kasama, Zambia which requires the
best possible waste-water treatment. It must be as cheap as possible, as
practical, reliable and multi-functional as possible.
As construction engineer, I have never been satisfied with current solutions
for underground septic tanks because they are too resource intensive, in
production and construction, to be an option for large parts of the population
in Zambia. They are too heavy on maintenance and they require removal of sludge
(there is no access for de-sludging trucks to the remote area of the school,
neither on the campus itself which is a super-dense tropical wilderness park
without roads).

Therefore, I will establish a company that will build simplified barrel-like timber
containments on-site. The barrels will be built from Paulownia wood and Bamboo,
cultivated on the premises of the campus. Traditional charring is used for
water-proofing of the barrels. The barrels of the anaerobic stage will be full
after 4 years and start decaying after 5 years or more. They will not have to
be emptied, or removed. The sludge will dehydrate while finishing decomposition
and be fully engulfed by roots right in place. Barrels of the aerobic stage
will be built to last longer.
The location for the barrels is on top of a 2m high earthen mount inside a close ring of trees, not
visible from the outside. The soil below the treatment system provides about
1000 cubic meters of roots. The space inside the ring of Banyan trees, which
grow for many centuries, is more than 100 cubic meters. Therefore, the system
can be operated for several hundred years, considering the minimized volume of
the sludge after full de-composition and de-hydration.
A central barrel for the final clarification stage might be built with the hard-woods available to
make it last much longer. I plan to use hard-wood nails for the soft Paulownia
wood and charred Bamboo pipes for the conducts.
 
The further development of this new faecal sludge management system is open-source. Please copy,
patent, or do with it what you want. Collaboration, investment or partnerships
are welcome as well. The eye is on the goal to provide what the children need,
nothing else.