Hello Greta! I have just come across your posts and love what I read; - so much so, that I had to read on,... and on...everything you posted:" ) -
Having helped build some sustainable homesteads
with alternative building techniques, (among them an earth ship), as well as
done a lot of restoration with environmental retrofitting - all of them with with extensive water- and resource recycling,
I found, after all personal experience
toilets as well as black water
plant beds with prepended 3-chamber separator/digester/decanter tanks,
that, with the abundant amount of free water available - even in arid areas - through good water management and recycling,
the only remaining compelling argument for dry composting toilets over grey-water toilets with treatment in black water planters
was the need to have sedimentation tanks emptied out periodically by a contractor, - which would so totally not fit in with the aim for self-sufficiency.
So I kept searching for an alternative that would combine "the best of all worlds": - the ease and convenience of a (grey-)water flushed toilet
which could use ubiquitously existing toilet and sewer pipe installations, plus "living machine" black water treatment in planted beds,
with the simplicity, ecology, sustainability and self-sufficiency of a composting system for the residues of human manure.
I finally found the perfect, most simple, hygienic, and virtually maintenance-free solution here:
The manufacturer of these rotting devices is a German company, who specializes in small to medium scale sewage treatment,
especially with planted black-water clearing beds. There seems to be no translation on their web site, but the essence of what it says is this:
- the sensible alternative
Instead of an anaerobic three-chamber digester/decanter tank, these rotting units use an aerobic two chamber strainer,
which acts as a separator for solids too, but also as an integrated composting bin with plenty of oxygen,
- without any additional technical or energetic input - while eliminating the costly need to have sediments pumped out .
While one chamber is being filled for about a year, the material can complete its two year composting cycle in the other chamber.
The fluid phase drips out and is being directed via pipes into the planted black water bed.
Thereby, the black water remains in an oxygen-rich state (4-6 mg/l O2), which enhances the cleaning action of the planted black water beds
and also inhibits the development of undesirable odors.
Because it is a closed system, this procedure is - contrary to complete sewage processing on reed beds -
hygienically unobjectionable. (Actually, the output after the post-treatment of the liquid phase
in planted backwater beds easily meets and often far surpasses the stringent requirements for swimming lakes.)
With gravity feed
pipes or a solar pump
the operating costs are virtually zero; and
apart from taking out a small amount of ripe compost
once every two years, this system is virtually maintenance free.
The ready processed compost has the consistency and smell of fresh woodland soil and can be used as
an instant high quality fertilizer in landscaping,
The container model, employs sturdy, non-rotting compost sacks.
The manufacturer can also supply custom made sacks according to your specifications for existing units.
Further pictures are here:
or from different sources here:
Something like this can relatively easily be self-built and installed. The essentials are just an enclosure such as a concrete pit/cistern
with two perforated inserts, hanging above or standing on a filter medium (such as scoria,..) above the floor of the enclosure.
This could relatively easily be improvised such as with a discarded laundry machine.... or any other perforated container...
This rotting double-chamber is connected near the top to an incoming sewage pipe which can be moved between the two inserts.
the outlet needs to be on the bottom, and can either be realized simply as a pipe with continuous flow into the planter beds,
or - a little more elaborate for better efficiency - a pipe into an intermediate fluid collection container, which is being emptied periodically,
controlled e.g. by a siphon with swimmer, and gravity fed into lower black water plant beds, - or by a (mechanically triggered) (solar) pump.
In equation of efficiency, hygienic aspects, comfortability, low to no maintenance requirements, and environmental impact,
this kind of solution for human manure treatment is from my experience simply unsurpassed - perfect permaculture design
(- No, I have no affiliation to any of the manufacturers of this kind of systems: ) -
If you think it's not for you, - maybe it still gives you some fresh ideas...
Blessings to you!