Dear Chris,

I agree with your suggestions that the cover material include some percentage of the finished treated feces, after whatever the treatment is done (long storage, lacto-fermentation, vermicomposting, thermophilic composting, etc.) to inoculate the new feces and break them down efficiently.

The pressmud from the sugar factory is a good option as a cover material in UDDTs. It will add to odor reduction, the faeces are sticking to it, becoming a homogenous mass, which is easy to decompose. In Moldova press mud does not have any uses, it is just piled around the sugar factory, occupying a big portion of potentially good land. Also there is lot of waste from charcoal produced from grilling which again uses land with potential value. The pressmud itself is not good to apply alone, since it is dusty, can be inhaled by the toilet users, but in combination with charcoal is an excellent cover, since if we wish to do vermicomposting of faeces afterwards, the earthworms will just devour it. The press mud can also be added to lacto-fermented material since that is too moist and not that good to be applied to the soil.

Kind regards,
Nadia

Dear all,

I'm very happy to announce that Nadia submitted her thesis...!!
However, as she is still busy submitting her papers to journals, we are at this stage not yet ready to share the PDF. This will happen in a couple of weeks though.

Thanks all for the interest and support! Nadia did a tremendous amount of field work, it's great she'll be soon sharing this with all of you. Wish her luck for the defense early next year..

Nice weekend in advance, best regards, Mariska.


_____
Dr.ir. Mariska Ronteltap
Senior Lecturer in Sanitary Engineering
Environmental Engineering and Water Technology Department
UNESCO-IHE Institute for Water Education
Westvest 7, 2611 AX Delft, The Netherlands
T: +31 15 215 1767 | E: This email address is being protected from spambots. You need JavaScript enabled to view it.
NB. Not in the office on Wednesdays

Dear Nadia, Carol, and everyone,

My suggestion is that the cover material include some percentage of the finished treated feces, after whatever the treatment is (long storage, lacto-fermentation, vermicomposting, thermophilic composting, etc.). This would create a biological feedback loop, in which the soil microbes (esp. bacteria and fungi) that decompose feces can inoculate the new feces and break them down efficiently with less smell and fewer flies. There could even be microbes that attack fly larvae.

In this interview, I cite scientific studies that show that finished compost is excellent cover material for controlling smell:
www.chekhovskalashnikov.com/human-waste-disposal/

This percentage could be so small as to be imperceptible for the users, since microbes reproduce so quickly in the right substrate and conditions. Most of the treated feces + cover material could go to agriculture. In an inner city or isolated location, where agricultural recycling is not practical or desired, almost all of the treated feces + cover material could be used as cover material again, remembering that feces are mostly water that evaporates and microbes that each other, with the small excess going to landscaping and urban agriculture or being trucked to rural agriculture. This inoculates the new feces and largely eliminates the need to transport anything long distance.

The pressmud from the sugar beet factory sounds like a good, abundant cover material. Is it dry and fibrous? I think this is important in any of these treatments, so more air can filter into the pile. This is another reason that it is great that you are adding biochar, which does not biodegrade and keeps fulfilling this function year after year. I also like to mix in egg shells and rice hulls, as they also help air to filter in and they do not break down quickly.

I know that most of the users will consider dirt to be dirty, but where would we be without soil? People want to believe that they live on a cloud, but they need to recognize and celebrate that they live on Planet Earth. It is also feasible to add the cover material mechanically. Plus, if users are worried about using dirty cover material, this will encourage them to wash their hands.

In future studies, it may be worthwhile to look at the effect of the pressmud on its own in corn production. And it should be mentioned as an ingredient in the lacto-fermented mix of feces.

Congratulations on the important work being done in Moldova. Keep up the good work, inform us of new advances, and please let us know how we can help.

Best wishes,
Chris Canaday

Thanks, Chris, for the reminder about your earlier post. This makes sense. Any new reports or studies since? I appreciate your conscientious study which seems to put you ahead of the usual learning curve.

Yes, I agree, we need experimentation. Grassroots. In the field. Among kindred practitioners using scientific processes to monitor, measure, and document results. Why is this so hard to do in many places? Like North America. Particularly the CSZ earthquake zone where we need to plan for climate change AND a seismic disaster.

Dear Chris,
In the experiments on lacto-fermentation of faeces in UDDT, I have used few types of cover materials: sawdust, a mixture of sawdust and pressmud (a waste product from sugar factory) in a proportion of 3:1 and a mixture of sawdust:charcoal and pressmud. Pressmud is easily available and is very good feedstock for earthworms if treatment of faeces in UDDT will be consider integrated lacto-fermentation and vermicomposting. Sawdust is a better cover material if lacto-fermentation will be combined with thermophilic composting. All these are only preliminary observations and would require further research. As regarding the odour reduction, both pressmud and charcoal contribute to odour reduction when used as cover materials.

We have not reused stored faeces, since wanted to see if faeces can be treated right after collection, without preliminary storage. However, for field experiments, since we needed a lot of material we have used stored faeces from school UDDTs. Reuse of dried faeces probably will add with beneficial microbes, however, field studies have shown that drying of faeces may not contribute to a complete sanitization or composting. Lacto-fermentation can be applied as a secondary treatment of faeces, where it can be combined with kitchen waste (a study suggested by Asrat Yemaneh at Hamburg University). Normally, lacto-fermentation does not last long (10-14 days). After that, for soil application, it is better to do additional treatment as vermicomposting or thermophilic composting since the obtained lactic acid material is anaerobic, not good for plants.
Some general information can be found on this link www.wecf.eu/english/publications/2015/terrapreta-handbook.php
Concerning the urine application, in our case it was sprayed on the soil by a sprinkler, during spring, before sowing, other equipment was not available at the local level.

Kind regards,
Nadia Andreev

Dear Nadia,

Congratulations on this important work.

Are the methods you are applying published anywhere on the internet? I look forward to reading your dissertation and papers. Please let me know if you would like me to help proofread your English texts.

What cover material are you currently using with the faeces? Have you tried using the finished, treated faeces as cover material?

In 2011, I wrote the following on this Forum:

I suggest that our best reuse of cover material with a small percentage of dried feces (after approximately 6 months in tropical countries or 12 months in temperate countries) is to use it again as cover material. Advantages include
--Not needing to ever search for more cover material, after the initial 7 or 13 months (this is key since many UDDTs fail due to lack of cover material).
--Containment of any potential lingering pathogens.
--Fewer smells and flies (at least according to my subjective experience).
--Innoculation of the beneficial soil microbes that decomposed the feces of previous cycles.

I have been doing this since the beginning of 2011 and it is very effective at controling smell and flies. The treated faeces themselves have no smell and, if the users are worried about germs, this will help to remind them to wash their hands, which we want them to do anyway.

In places with dispersed settlement, it may be worthwhile to experiment with distributing urine into the soil via perforated hoses buried in the soil. Burying would reduce the likelihood of freezing, right? Urine should also freeze at a lower temperature than water. This might be worthwhile at least during the summer.

Best wishes,
Chris Canaday

Dear Elizabeth,

Thanks for your comments for the article. I am currently working in Moldova the Laboratory of Hydrobiology and Ecotoxicology, also collaborating with Research Institute of Field Crops from Balti. Additionally, I work in WiSDOM association.

Currently our NGO is implementing a small project in the South of Moldova and hope we can include lacto-fermentation as an approach for treatment and reuse of excreta for horticultural activities (for example willow plantation and decorative plants).

As regarding the PhD thesis I am currently at the stage of finalization, the thesis is currently under examination before it will be sent to the Examination Committee.

I found quite interesting to apply lacto-fermentation of urine and faeces at a larger scale in Moldova. Indeed, as Claudia mentioned we already have a good number of UDDT spread all over the country to start from and it is nice that the code on construction and operation of UDDT was approved.

The UDDT technology is well accepted, however I think Moldova still lacks some good examples of sustainable reuse of products. Here I find lacto-fermentation as a good example in trying to improve the efficiency of nutrient and carbon matter recycling, speed up sanitization and reduce odor.

For faeces fraction lacto-fermentation it would probably economically feasible if it is combined with manure or kitchen/food industry waste. Among the main limitations at the moment I see it is that we need molasses, which for example during cold time you cannot buy it due to solidification. Also, there is the biochar, however, our experiments showed that waste charcoal (small pieces and charcoal dust) also works.

Regarding faeces from UDDT, I have used in the experiments faeces from school UDDTs but also from household. We have found that for an effective faeces lacto-fermentation it is important to consider the type of cover material. We also have obtained interesting results for urine lacto-fermentation, at the moment they are not yet published, it is quite tough to publish research based on laboratory scale, at the same time, there are nice results suggesting good practical applications for improving UDDTs.

I consider that such an approach would be easy to implement and it not costly for urine treatment. In Moldova, from my experience, odor is a big issue, especially from the urine tanks. At the same time, considering the quantity of urine accumulated, its fertilizing value, it would be nice to apply lacto-fermentation, it considerable decrease odor and ammonia volatilization and has better germination than the stored urine. The results are at the incipient stage, but I think quite promising. I hope that some ideas could be soon implemented at the local level.

Regards,
Nadia

Dear Elisabeth,

to answer to your second question: Moldova as the poorest country in Europe is really a model country where UDDT are successful, especially for school sanitation. Now around 55 rural schools have been equipped with UDDT and meanwhile the municipalities contribute up to 50% while the Swiss programme Apasan finance the other 50% of the implementation.

I have been consulting the Moldovan ministries during the last 3 years on technical standards for small water and sanitation systems. The outcome is among others:
a national code of practice on construction and operation of UDDT and
one on construction and operation of constructed wetlands.
Both of them were approved by the Ministry of Construction and Regional Devlopment and the English translation is almost ready, we can share it very soon.

Best regards
Claudia

Dear Nadejda,

Thanks for posting your article here. Are you already finished with your PhD? If yes, could you post it here as well?

I found it interesting to see the organizations involved in this research, apart from UNESCO-IHE, which are:

• Research Institute for Field Crops, Selectia, 28 Calea Ieȿilor str., MD 3101 Baltsy, Moldavia
• Laboratory of Hydrobiology and Ecotoxicology, Institute of Zoology, Moldova Academy of Sciences, 1 Academiei str., Chisinau, Moldavia

Do you work for one of them?

Some questions:

1. What are the next steps for this research in Moldavia? Do you see an opportunity to apply this at a larger scale?
2. What was the source for your input materials, i.e. which UDDTs in Moldavia did you use? Are there many UDDTs there?
3. How do the costs look, i.e. the costs to prepare this kind of fertiliser from materials collected in UDDTs compared to fertilisers bought on the market?

Regards,
Elisabeth


P.S. Good that you made the article freely accessible for a while, however of course I missed the 50 day deadline. Was it much cheaper to make it only available for 50 days compared to making it available for free forever? Just wondering.

Resource oriented sanitation improves the efficacy of excreta treatment schemes, reduces the environmental pollution from their disposal and improves soil fertility. A recent study was carried out in Moldova, within a PhD study at Unesco-IHE Institute for Water Education, the Netherlands. In a two year field experiment, the effects of the stored source separated faeces and bio-waste treated via lactic acid fermentation and supplemented by urine charged biochar were investigated on the growth and yield of corn as well as on the soil quality.

The study found that the lacto-fermented mix supplemented by biochar significantly improved plant height compared to all fertilizers during the first production year and compared to the control, stored faeces and vermicompost during the second year. This fertilizer also achieved a significantly higher corn yield compared to all other fertilizers during first and second production year, except for the lacto-fermented mix without biochar and the mineral fertilizer, which showed no significant yield difference during the second year only.

The final version of the article with full bibliographic details is now available online, with free access valid for 50 days, until October 5, 2016
authors.elsevier.com/a/1TZ0-cA-IOO32


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Link to article: www.sciencedirect.com/science/article/pii/S0167880916304066

Title: Lacto-fermented mix of faeces and bio-waste supplemented by biochar improves the growth and yield of corn (Zea mays L.)

Abstract:

Resource oriented sanitation has emerged as a need to improve the efficacy of excreta treatment schemes, reduce the environmental pollution from their disposal and improve soil fertility. In urine diverting dry toilets, the storage alone is inefficient for faeces treatment due to poor hygienization, incomplete decomposition, as well as high losses of organic matter and nutrients. The purpose of this study was to assess the effect of stored faeces and bio-waste treated via lactic acid fermentation and supplemented by urine charged biochar on the growth and yield of corn as well as on the soil quality in a two year field experiment. Lacto-fermentation of faeces and bio-waste was performed under microaerobic conditions in earth pits covered with plastic foil, by the addition of microbial innoculum and molasses. The fertilizer was compared to an unfertilized control, a lacto-fermented mix (faeces, bio-waste, molasses and microbial innoculum) without biochar, stored faeces, cattle manure, urine and mineral fertilizer. In addition, during the second year, a vermi-composted lacto-fermented mix and biochar was applied as well. Differences of means among the treatments concerning corn growth parameters, yield and soil quality were evaluated using the Dunnet test of multiple comparisons. The lacto-fermented mix supplemented by biochar significantly improved plant height (p < 0.05 and confidence interval CI with both negative values) compared to all fertilizers during the first production year and compared to the control, stored faeces and vermicompost during the second year. This fertilizer also achieved a significantly higher corn yield compared to all other fertilizers during first and second production year, except for the lacto-fermented mix without biochar and the mineral fertilizer, which showed no significant yield difference (p > 0.05, CI with both positive and negative values). The bulk density was reduced during both years while the soil potassium content increased only during the first production year.