Dear Carl,

You may have miss-interpreted my post. I fully agree with you that our primary aim should be sustainable sanitation and not best compost.

But my concern is, that the composting especially with regard to the shrinkage may not work if the worms do not find conducive conditions. Then you end up with an anaerobic degradation process stinking worse than a pit latrine. And it will not reduce to 2% volume after 6 years.

Therefore my questions also to other experts whether they believe/know that the worms will survive the conditions in the Smart Toilet – against what I read in the books – and even if only the fittest together with their ‘helpers’ (bacteria, fungi, …).

I do not want the users regret having switched to Smart Toilet because the toilet is stinking and overflowing after 3 years – against our full-bodied promises.

Ciao Hajo

Dear Hajo,
When we call it a new strategy it means that the emphasis is not on the composting but on the containment, shrinkage and preparation for use as a broad-spectrum (macro- and micro-nutrients) fertilizer. The one thing I have learnt from half a century of composting processing is to not optimize the process for any particular thing, requiring specific conditions, since we are in and out of different conditions all the time and want to favor diversity rather than maximizing anything (focusing on only one parameter and letting everything else become dependent parameters).
So we want survival of many "active composting helpers - worms, bacteria, fungi etc." especially those who can wake up and get going again if the pile gets too something (wet,dry tall etc.). So the process we want, is slow and steady rather than a thorougbread

The final stages might be different where you want to make sure that the result is a safe fertilizer for agriculture, handeled by professionals. So we don't want to make the users, ever regret that they switched to a "Smart Toilet" ... it must be felt that the new toilet is easier and more pleasant to USE and free of worries. Most people want WCs for a reason of NOT being responcible for the endresult. Small scale homestead farmers all have their tricks to make "best" compost soil and if we want to have a product for toilets users focusing on ease of use and a sense that we have a clean toilet, not offending any of our senses (sight, smell, hearing, touch), but that does not do harm to to the environment like sewers do.

When you offer long term processing the issues you bring up with carbon/nitrogen etc. also take care of themselves over time. Worms do not go into fresh feces and they usually wait for the "waste" to get older and mature ... Eisenia Foetida can be seen (to the extent that they are seen, around the toilet pile like airplanes around a terminal. Anyway give it time, which means give it size ...

Dear Carl, Dean and other specialists on vermin-composting,

The ‘SmartToilet’ (ST) (or CompostEra or Clivus Multrum as it was called before) is built on vermi-composting (VC). The 2m2 tank receives a 600L starter bed containing the compost worm Eisenia Foetida.

The system seems to work as it has been used since 45 years. Nevertheless I have some questions regarding aspects where the technique of SmartToilets seems not in line with what I have read (Appelhof, Pilkington) about vermi-composting:

1. I read that VC requires good aeration, containers should be provided with side holes to ensure this. The ST has no side holes and the fan only let air pass over the surface of the pile in the container. Is it possible that this together with the worms working through the pile still ensures aerobic conditions in the pile?

2. Worms prefer ‘wide’ piles rather than ‘deep’ piles which is different with the ST which is 1.2 x 0.8 m2 wide and 1.8m high. I can imagine that at a certain point when all ‘food’ is worked up, the worms vacate the lower strata and move upwards where ‘fresh’ food can be found. But what happens in the vacated area? Does it not turn into anaerobic conditions if not ‘harvested’ more often than every 40 years?

3. VC seems to require a bit of observance by the user with regard to the well-being of the worms (food, temperature, moisture, air, urine dilution). How can I ensure this in a 1.8m deep container under a toilet where I rather prefer not to look into?

4. I cannot remember having read to which % of volume worms can reduce their ‘food’. The ST claims that faeces and toilet paper are reduced to 2% of their original volume after 6 years. Is that realistic acc. to your experiences with worms?

5. Which just brings me to another question: VC requires carbon through addition of paper, cardboard or wood chips to otherwise organic ‘waste’. If the user uses toilet paper that may be Ok, what about washers who only add water which rather may cause anaerobic conditions clogging any voids?

I find the ST a very appealing sanitation solution because acc. to the website it requires little maintenance and needs only be emptied after 40 years if designed correctly for the number of users. But what do vermin-composting experts say? Please comment!

Ciao Hajo

Feces is the primary source of disease through bacteria, virus, parasites, prions and medicin recidue. A new SmartToilet strategy, contains, shrinks and concentrates plant nutrients for future recovery ... see the strategic description at www.smarttoilet.se

Composting toilets have been around for many centuries and have not had much success, mostly because no one has had any luck with ensuring that the final product is usable, safe and attractive enough to go back on the land as it was intended. Sometimes it fails because of no maintenance of too small tanks, sometimes because of creative maintenance that creates more problems than they were meant to solve ... a new, simpler paradigm is needed and has inadvertently been tried successfully with old large composting toilets that were just left alone. By designing them for long term processing, we can make them simpler, less complicated to build and leave it to natures most reliable procedures: time and natural decay ...