Sani Solar, designed as a dry sanitation system for rural areas with hot climate

  • jscheerer
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Solar treatment of feces?

Dear Kevin,

I just read your post regarding the possibility of killing pathogens in faeces generated in a UDDT ( forum.susana.org/comparisons-of-various-...in-the-feces-quickly ). In that context I would like to draw your attention to Sani Solar, designed as a dry sanitation system for rural areas with hot climate ( 3psanitation.de/the-product-sani-solar/?lang=en ).

Sani Solar consist of a functional unit based on solar radiation and convectional air- flow, which can be combined with any kind of cabin structure.

It would be good to know more details about your project in order to evaluate the feasibility of using this technology.

Best regards,

Jochen Scheerer

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  • hajo
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Re: Solar treatment of feces?

Hello Jochen,

Thanks for drawing attention to your technology which seems so far only be promoted in Asia and Southern America. In Africa I haven't heard of you. Some few remarks and questions:
  1. I assume that your users prefer using toilet paper for anal cleansing. What about 'washers', they could possibly over-strain the drying capacity in the containers?
  2. Don't you have problems with men standing and peeing into the faeces compartment? We therefore use recommending the installation of an urinal.
  3. How about the emptying? Users get used doing it by themselves or would rather prefer an emptying service?
  4. How many units have you installed so far and what is the ex-factory price (let's say for a full container)?
  5. Do you face problems of vandalism, especially with the urine vaporiser sitting on the ground?
  6. Do you have a special reason why the system is promoted for rural areas? Is it not also applicable in peri-urban areas of cities where sewers and water supply are lacking?
  7. You link your posting to the question about pathogen removal in UDDT but you do not make any statement regarding pathogen removal in the SaniSolar!?

Looking forward to your responses,
ciao
Hajo

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  • jscheerer
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Re: Solar treatment of feces?

Dear Hajo,
Thanks for your interest in our technology.
Indeed, we have started to work with Sani Solar in Brazil, Chile and Mexico. However, we have a pilot site operating at Guinea Bissau since more than one year and three more units just had arrived in Africa, two of them in South Africa and one in Kenya.
In the following I will try to answer your questions:

1. The system is based on a drying process driven by the sun and climatic conditions in warm and arid regions. Any extra water introduce into the system will interfere with this drying process and should be avoided. For that reason the system is not suitable for “washers’” in its current configuration.

2. As in any UDDT, men standing (and not aiming well) would spoil the separation process and therefore this is not a desired practise. However, in all the pilots we had no significant problem with this issue after explaining the concept to the users and make them understand the benefits of changing habits. We experimented with a urinal, but it turned out to be a source of odours, something we wanted to avoid in any case.

3. The original approach of our system was to provide a sanitation solution for remote rural areas suffering from water scarcity and lack of all kind of infrastructure or service. In those terms the user himself can perform emptying in a hygienic safe way without the need of special equipment or training. According to our experience emptying was generally accepted, however there where differences related to gender, culture and socioeconomic status. In case an emptying service can be provided surely it would be preferred, however depending on the related cost.


4. So far we have installed 16 units in different parts of the world (Brazil, Chile, Mexico, Guinea Bissau, Singapore, Spain). The current Ex works price from Germany is 2.550 €/ complete unit (with cabin structure) and 1.500 €/ functional unit. In a 40 “ Sea Container we could ship 16 complete units or 32 functional units.
Our future concept for Sani Solar is aiming for local production in order to reduce cost according to the local market.
It is important to consider that we are talking about a system that needs neither external service nor commodities.


5. So far we did not have any problem with vandalism. For sure that has to do with the fact that the systems are operating in a rural environment with good relations between the neighbours.

6. The focus on rural areas comes from the beginning of the Sani Solar project, which was initiated in the context of a governmental project in rural Northeast of Brazil (“Agua para Todos”). Also the system is designed for autonomous operation in remote areas, it could be used in urban or peri-urban areas as well. In any case different criteria, as for instance the vandalism aspect, or possible shading by higher buildings, have to be considered.

I hope that I could answer your questions in an adequate way and looking forward to receiving you comments/considerations.

By the way, I saw you are located in Lusaka! We are currently working with Raise a Smile and Terra Nova Children's home on a interesting sanitation project in the Luapula province in Zambia.


Best,

Jochen Scheerer

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Re: Solar treatment of feces?

Hello Jochen,

thank you for your comprehensive response. I see the advantage of the SaniSolar compared to a standard UDDT in the 'turntable' which probably speeds up the drying process and in the immediate drying of the urine in the evaporator.

While it has similar limitations as the UDDT (not for washers, wrong use by men) and some additional (vandalising of the evaporator).

Is it possible to get a bit more technical details about the evaporator? How does it function? How is the 'fresh' incoming urine separated from the 'old' already dried urine? What is its capacity? What is the end product? What are the properties of the end product? Did you do any chemical analysis what is the fertiliser value of the dried urine?

What is the difference in delivery between the complete unit and the functional unit?

You mention considering local production. You may get in contact with ENVIROSAN/Durban or KENTAINERS/Kampala/Nairobi who both produce sanitation components in the region from PVC/PE as a possible partner.

ciao
Hajo

We can't solve problems by using the same kind of thinking we used when we created them.
Albert Einstein
Any intelligent fool can make things bigger and more complex... It takes a touch of a genius - and a lot of courage to move in the opposite direction.
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Everything should be made as simple as possible, but not simpler. :-)
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Re: Solar treatment of feces?

Hello Hajo,

Thank you for your comments and information’s regarding potential partners for local production.

Please find my answers to your questions below:

Function of urine treatment:
After usage the urine is conducted into the urine treatment unit outside the cabin where it accumulates on the steel plate (see image 1 attached).
During the day, the accumulated urine is heated up (depending on the climatic conditions up to 80°C) and stabilized. Further more the water evaporates.
For the harvesting, please have a look at our homepage under the following link:

3psanitation.de/videos/?lang=en
The video is called collection and disposal.

Eventual overflow is conducted into a small reservoir (10 – 15 l) in order to facilitate eventual emptying (see image 2 attached).
In the recommended climatic conditions, the evaporation capacity is approx. 3L/ d.

A sample of the dried residue has the following characteristics:
Dry matter: 79,35 %
Total N: 181.000 mg/ l
Nitrate: 55.740 mg/l
Total P: 20.250 mg/l



Functional unit:

We call the functional unit, the core part of the system, which can be installed in combination with any kind of cabin.
Please se pdf attached.



Best,

Jochen Scheerer
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Re: Solar treatment of feces?

Hello Jochen,

thanks again for the again open and detailed information! I didn't always find commercial suppliers so open with information on the forum.

Since you have a 'chemical heavy-weight' behind you, you can easily provide figures how the dried urine-fertiliser compares with industrial NPK fertiliser. I could possibly find out by myself but for you it is much easier... ;)

We have not yet talked of the pathogen removal in the SaniSolar. Do you have any information regarding this matter? In 'standard' UDDT sometimes ashes are added lowering the pH and killing pathogens... except for helminth eggs which can only be killed by temperatures > 700C. This aspect is of relevance if the dried faeces shall be used in agriculture.

Just a quick observation: these small washers and wing-nuts holding the windows will easily get lost, and cannot easily be replaced by a local household.

ciao
Hajo

We can't solve problems by using the same kind of thinking we used when we created them.
Albert Einstein
Any intelligent fool can make things bigger and more complex... It takes a touch of a genius - and a lot of courage to move in the opposite direction.
E.F. Schumacher
Everything should be made as simple as possible, but not simpler. :-)
Albert Einstein
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  • JKMakowka
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Re: Solar treatment of feces?

hajo wrote: Just a quick observation: these small washers and wing-nuts holding the windows will easily get lost, and cannot easily be replaced by a local household.


Yes some sort of durable clip-on solution would be much more practical.

In general: have you thought about / experimented with a more simple set of plastic moulds that would allow stackable parts for easier distribution?

Microbiologist & emergency WASH specialist
WASH news aggregator at: news.watsan.eu
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Re: Solar treatment of feces?

hello Jochen,

In the recommended climatic conditions, the evaporation capacity is approx. 3L/ d.


I forgot in my last posting to ask about the capacity of the toilet. I read somewhere it is meant for 5-6 people, but they produce between 5 to 6 L of urine in a day. Thus the evaporator cannot handle that quantity and the 'balance' reservoir will always fill up, or?

ciao
Hajo

We can't solve problems by using the same kind of thinking we used when we created them.
Albert Einstein
Any intelligent fool can make things bigger and more complex... It takes a touch of a genius - and a lot of courage to move in the opposite direction.
E.F. Schumacher
Everything should be made as simple as possible, but not simpler. :-)
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  • jscheerer
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Re: Solar treatment of feces?

Hello Hajo,

it' a pleasure trying to answer you questions/ doubts.
Regarding the comparison with a comercial fertilizer we did some theoretical studies, however a representetive field test was not yet performed. I'll look for the theoretical numbers.

Regarding the reduction of microbiological load we did some analysis, however I wouldn't call them representative. In any case I can share the information we have at the moment.

Currently I'm travelling and have no access to my data base. I'll come back with this issues at the beginning of next week.

Best
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Re: Solar treatment of feces?

Thank you for this usefull information. We will consider corresponding modification within future adaptions of the system.

Best,

Jochen
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Re: Solar treatment of feces?

Hello Hajo,

looking at those numbers you are right. However, according to our experience in the field evaporation capacity results sufficient in case of 5 member family under normal living conditions, which means that not all 5 members of the family stay all day at home every day.
For unfavorable conditions (bad weather, visits, etc.) we implement the overflow device.

Jochen
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Re: Solar treatment of feces?

Hello Hajo,

back from my trip I would like to reply on your questions related to nutrients and pathogenic load.

As I mentioned before, the analysis we did are far from begin complete. However, we came to the conclusion that the nutrient load in the dried urine is quite significant compared to conventional fertilizer.

The problem with a direct comparison is the fact that the treated urine's consistency is not as defined as in the case of a industrial fertilizer. This is true not only for its composition (depending on the diet of the users and other factors) but also of its density, which depends on the drying grade and which we did not determined so far. So if we assume for instance that the average density of the urine is about 1, the content of nitrogen is about 18 % according to the previously mention analytical result of 181.000 mg/l. Compared to comercial NPK fertilizer this is in a good range considering corresponding values in the range of 7 to 14 %. In comparison to industrial urea fertilizer (about 46 % N) however it is lees than half .

Doing the same calculation on P, the content in our dried urine was about 2% (20.250 mg/l). Commercial NPK-Fertilizers are in the range between 3 and 8 % total P.

Pathogene reduction:
Accompanying our pilot sites, we took some samples for analysis related to pathogens with the following results:
Endolimax Nana cysts: negative
Blastocystis hominis cysts: negative
Fecal coliforms: < 10 ufc/g

I really want to point out that we do not consider such results as representative as the number of samples and analysis is limited so far and the sampling method is not standardized. Nevertheless from our point of view such results indicate that our treatment concept presents considerable improvement compared to traditional technologies in terms of hygiene, safety environmental protection.

In terms of future analysis I would like to take the opportunity to ask if you have any information regarding sampling procedures (where and how to take the samples) and relevant parameters to analyze.

Thanks.

best

Jochen
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