If the feces have been in storage for 6 months they have dried and most of the pathogens have died.  As stated earlier people do not want to handle human waste.  This is especially true with feces.  Once the feces has dried it no longer looks or smells like feces and it is easier to convince the local population that it has changed and is now a soil conditioner/fertilizer.  If there is a concern for acaris eggs then putting this soil  conditioner in a box with a window for a day is easy.  Since it is dry it is easier to heat and achieve a temperature above 160F so all is dead.  I would recommend wearing a mask and gloves since the material is a dry ash that has a tendency to fly everywhere.  Remember it no longer looks, smells, or acts as feces so rename it to a more local acceptable term.

Linda, If you are doing an experiment I would recommend building a simple box with a glass window and take temperatures.  Also put in some 6 month old soil conditioner and check the temperature at various depths.  The thinner the depth the more certain you can be that the temperature has been reached.  I have a chart in my book that shows time/temperature relationship to achieve total death though the acaris is especially hard to kill.

Remember: Don't let the perfect become the enemy of the good!

To all who have contributed, thank you so much.  Tore and Hajo, this latest advice is very timely as we have a meeting this afternoon to plan some experiments!All best,Linda

Dear all,

You would not need more than a single sunny day to kill any remaining pathogens and make the dried feces usable for agriculture.

This remark by Tore in his above posting, motivates me to raise a proposal again, which had been shortly discussed between Chris Canady and me in this thread earlier (page 1).

Chris recommended that in UDDTs which are used by unknown numbers of users (or numbers beyond the design capacity), the vault could be replaced by sacks in containers. When a sack is full, it can be taken off the container and be replaced with an empty one, while the full sack can be stored for treatment.

I had recommended to place the sack in the full sun of a sunny day (we talk of a project on the Ghana coast!), turning it around so all sides get 2 hours bright sunshine and are heated up to 50⁰C killing all pathogens within 2 hours (each side).

Chris warned that the UV would destroy the sacks. I felt that it was a misunderstanding in such that he assumed the exposure to sun would go on for longer time. I assumed it would be a day's job following the same information as Tore (above) that few hours of high temperature is enough to kill ascaris (and all other pathogens).

Of course this has to be investigated a bit: how thick can be sack, so that also the core is heated to 50⁰C (chef's thermometer!)? Protection against rain and moisture from ground? How long will it take to reach the temperature? What additional assistance can we give to reach sufficient temperature (sun reflecting material under, heat-absorbing material above the sack)? But these are all aspects which do not require a university laboratory, but just some innovative ideas and can be done on site by DBG.

ciao
Hajo

The acaris eggs are always the last to die and you are restricted to time and temperature.  Elevating either will help destroy the eggs.  In most cases it is easier to increase the temperature to quickly kill the eggs and use the product.  Since you still have viable eggs after 6 months of storage and the product is totally dry then the volume is not very large.  I would suggest making a box with a glass window facing south.  In the past I have constructed passive water heaters which was simply and insulated box with a glass window to the south and a water storage tank inside.  On a sunny day I would achieve air temperatures of between 250 and 300 degrees F. which is more than adequate to kill any remaining acaris.  You would not need more than a single sunny day to kill any remaining pathogens and make the dried feces usable for agriculture.

Dear Heiner,
I agree that we need to consider life cycle costs of interventions and changes in our consumption habits. Also agree that the costs need to be calculated on multiple dimensions - financial, water footprint, carbon footprint, etc. and it makes more sense to concentrate nutrients in urine if it needs to be transported over distance.

I was sure you had already seen Scott's work but wanted to build a link to that thread for other members and for future reference.

regards
paresh

Heiner's point about transport costs  and contaminated urine are valid, but of course if the Toilets are Urine diverted and  urine collected on site, the problem of contaminated urine falls away, but still leaves transport costs.  If we can re-use on site  where the urine is created, then we have a much better solution.

Dear Paresh,

we are well aware of Scottchen's work and it is a great one! But when it comes to questions of transport and logistic, it has never been a good idea to drive water around the bloc. I would prefer the other way round like Jenna or EAWAG suggest: we have to concentrate rather than dilute. There is no over all ecological approach to this topic, as far as I know. There is always the economical one of costs and benefits and this can lead to very false conclusions. How will you judge the ecological costs for one liter Diesel? Just by the price at the petrol station and perhaps added price for CO2? 
Perhaps it is even better to drive the fresh urine out of town by truck even if there is 95% of water load. The ecological benefit can be: this urine will not end up in the rivers and oceans and pollute the environment. But by logic it would be more clever to take the water out of urine to reduce the truckloads by 90%.
Here in my country we calculate a lot.....but very often the wrong way. But there was one good calculation about the benefit of organic food compared with conventional  food in the supermarket . In this study the found out there are some advantages for the organic production line. But then, at the end, the advantage got completely lost when the customers decided to drive miles to the farm or far away little whole food store to grab the organic super food with their petrol car. This phenomenon they call "the big loss of the last mile".
So whatever we do here, I think, we should always be very aware of the whole system. Starting at the sanitation and ending withe the yields in the fields.

Have a nice evening or morning, where ever you are!

Heiner

Dear Jenna,

every transformation starts with a demonstration plant. So I hope you start soon. If I remember right you will do so in SA too? That would be great because of the need and the so different conditions. We in the rich countries could even choose very sophisticated  high tec solutions. Even if the results and ecological benefit over all are usually poor (think of all the "improvements" of the last decades which lead to a speed up of climate change because of all the rebound effects). But in the poorer countries we need the low tec simple ones.  And as far as I can judge you work on one. 
Wish you much success and we will follow the progress, not to say I keep a sharp eye on your work!  

Cheers,
Heiner

Dear Hajo

You said

The idea with the direct pipe from the toilet to the garden/field works where the toilet can be next to a garden and the output and requirement in quantity is not large. How to resolve transport of urine from a peri-urban high-density settlement to a farm 10 kms out of town?

I'd like to bring to you notice another discussion that may answer your question:  Bamboo charcoal with urine shows us immediate effectiveness
in the video shared by user: Scottchen in their post dated 27th of December, they have set up system to collect urine from a school and transport it to their apple orchards in tankers. I assume similar arrangements can be made at public urinals/toilets as well as large public and private institutions. 

Regards
paresh

Dear Heiner, Glad you like our approach! The system is not on the market yet, but we are working on it and will have our first demonstration system installed in Sweden this spring - I will share pictures on SuSanA when it is installed. About the smell, we have worked a lot with this (and continue to do so). In chemically stabilizing the urine, we can keep the odours to being the smell of fresh urine, which for most people is still not appealing so ventilation is needed at all times to keep the bathroom from smelling (or seal the box when there is no ventilation). The best alkaline media we have worked with so far is wood ash as it has a high initial pH. Biochar has too low of a pH and even when we increase the pH (with KOH for example) we had problems with odours. I hope the concept can be of use.

Cheers,
Jenna

hi Heiner,

 I am happy  you as an organic farmer participating here on a sanitation forum. Please stay here, as you can be one of those helping to bridge the gap between sanitation and agriculture. You know what you need on the field (humus, natural fertilizer, ...) and what to consider (ph, ...) and can alert us sanitation workers how to provide the inputs.

The idea with the direct pipe from the toilet to the garden/field works where the toilet can be next to a garden and the output and requirement in quantity is not large. How to resolve transport of urine from a peri-urban high-density settlement to a farm 10 kms out of town?

good luck in your collaboration with Chris, Linda and many others who try closing the loop..
ciao
Hajo

Dear all,

following the link in Jennas post I'm really happy about the simplicity of their invention. When I saw the little grey box beside the toilet....If that is all we need and harvest a not smelling concentrated sludge or even dry powder.....good for an Uexküll price! We have to realize this installation could save 60-80% of the flush water. And flush water is usually potable water in our countries.
I love it simple and this would be a very good example! And the relation of the macro nutrients (N9, P1, Potas. 4) shows they have no N loss. For me as an organic farmer the most important thing. 
Jenna is your system on the market here in europe? I shift our washing machine then......
And in Ghana this system of urine processing should work perfect if a concentration is needed for logistic purpose.

wish you all a nice weekend!

Heiner