Dear Hajo - thank you for your comments, which we truly appreciate.  Yes, we have seen the previous discussions of this issue here on the Forum. Dr Tore Knos also spoke with us about the importance of reaching the correct temperatures to destroy the ascaris eggs, and shared his design for toilets with a window in the chamber to allow more heating from the sun. However, this design is somewhat beyond our means.  It's certainly becoming clear to me that there is no clear international evidence to underpin best practice, but a range of expert opinion. More research evidence would be very helpful for us small, grass roots NGOs.  I will relay your comments to the team on Ghana as we continue to work on this issue and try to find a solution that suits our context. With thanks and best wishes, Linda

Dear Linda, dear DBG team,

I want to comment on your last discussion re pathogen safety of the dehydrated faeces from an ECOSAN/UDDT toilet. Beware, I am not a bio-chemist researcher and also can only report from what I have read. But maybe it helps a bit further in the discussion.

That the lab in Accra found only 3-4 eggs per gram of dehydrated faeces does not indicate that the dehydration and storage has reduced the ascari load. It can be that only one user was infected with ascari, the treatment did not reduce the load (or only marginally) which is why the load is low now. You have no test result of the same fresh faeces regarding ascaris for comparison, or do you?

What I have read, it is only heat which can destroy ascaris. There has been a discussion about this on this forum, I can try trace it and refer to you. If I remember well, I read that 70 degC for 10 min or 50degC for 30 min will destroy ascaris, therefore thermophilic composting will do so and the infra-red treatment in the LaDePa machine in Durban does so. I also read somewhere that you can concrete in asacari eggs, break the concrete after 3 years ... and revive the eggs. Thus I am skeptical whether just (dry) storage will destroy them . It needs to be researched properly. 

I guess that also 3-4 eggs per gram can infect a person when getting in contact. Because you report that about 25% of the dehydrated faeces are used by other farmers than the 'producers', there is a possibility that the ascaris are transmitted from the 'producers' to the 'users' which we do not want to induce by ‘safe sanitation’. And the load can be higher than 3-4 eggs per gram! What can be done?

The multi-barrier approach is widely recommended: Persons handling the dehydrated faeces must wear gloves and/or handle the faeces only with tools not with bare hands. Further, the dehydrated faeces must not come in direct contact with fruits or vegetables (lettuce, carrots, potato, ...) but preferably be used on produce growing on a stem (trees, maize, bushes, ...). My doubt is whether this can be ensured in your project environment. Users of the dried faeces may easily be misguided by the inoffensive look of the material, the ascari eggs cannot be seen and people may become careless.

Unfortunately, I cannot yet give you a hint which second step treatment (and which is easily applicable in your project environment) can ensure the safety of the material avoiding the multi-barrier approach. Even the long-time (dry) storage recommended to you by SEI to my knowledge has not yet been researched in detail (please SEI: if you have research results, please make them public here!). Since this is a problem for all on-site sanitation technologies, maybe some other reader on the forum can give some advice in this direction!

While I agree that ‘the perfect must not become the enemy of the good’, I wonder whether the open defecation by one family carries more or less risk of ascari transmission than the same family providing their dehydrated faeces (with 3-4 eggs per gram) to the neighbourhood as soil conditioner?

ciao
Hajo

Hi Kimgerly, and thank you so much for responding to our post.  You are quite right, the issue of testing is not addressed in our report.  If I can share a little of our history... We began our work in Dzita in 2010 or thereabouts, and took the design for the toilets from the international WASH charity 'Sanitation First'.  We were concerned about pathogens from the get-go, but were advised by an expert that the design, sandy soil and high temperatures in Ghana would make the process safe. We have matured as a Ghanaian-registered NGO and supporting UK charity, but we are still very small (the UK charity is run entirely by the volunteer Trustees). We are not, and do not claim to be, WASH experts. However, we have recently (since this report was written) had samples from our toilets tested at a lab in Accra.  Everything was OK except for helminth eggs, which were in the region of 3-4 viable eggs per gram.  As this exceeds the WHO limit of <1 egg per gram, we sought advice from WASH experts. A colleague at the Stockholm Environmental Institute suggested a way forward that we are currently trialling, which is storing the dehydrated faeces in large bags for an additional 6 months once the chamber is emptied. We will re-test at the end of this period and hope this will do the trick. However, in a village where 50% of the population is still forced to practice open defecation we don't want to let the perfect become the enemy of the good! (3-4 viable eggs per gram is, I believe, way less than you would find in infected fresh faeces.)

I have been known to be 'blind', but I did not see any quantitative data reporting how the participants tested their humanure compost to ensure it was safe to use as a solid amendment. Without this kind of information, how can one ensure it is truly safe to use to sell and/or produce compost to improve the quality of the sandy soil? 

I searched on 'pathogen', 'thermophilic', 'test', and 'heat' and was not returned any reasonable, quantitative data. Is testing of the quality of the compost for safety and pathogen reduction going to be an on-going consideration? I enquire, because I did not see this mentioned in the conclusion.

We are delighted to share our latest report on the Dream Big Ghana NGO family Ecosan toilet programme. We carried out a survey exploring how satisfied our families are with the toilets and identifying where there is room for improvement.  We are pleased to report that nearly all of the 97 households surveyed reported being 'very satisfied', even though our toilets are usually shared between more than one household and are being used by an average of 12 people. The toilets are being managed and maintained well, and are producing compost to improve the quality of the sandy soil. The report describes how our approach to Ecosan works and how Dream Big Ghana NGO manages its sanitation programme.  Comments, ideas and advice would be very welcome!