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- Can the addition of urine to compost piles help with pathogen kill? Research in Haiti and Sweden
Can the addition of urine to compost piles help with pathogen kill? Research in Haiti and Sweden
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- joeturner
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Re: Dissertation on "Sanitisation of Faecal Sludge by Ammonia - Treatment Technology for Safe Reuse in Agriculture " at SLU, Sweden
Compost maturity is related to sanitation, stability and handling, I doubt it has anything to do with negative effects on crop growth. In some ways, immature compost may actually have more immediately available nutrients than mature compost, so one might expect better crop growth from fresh faeces than faecal compost (if one spread it at the right moment when the crops needed the nutrients). In a compost, the majority of the nutrients are going to be less available and slowly releasing to become available to the crop.
I think the conductivity and salinity is much more likely to be an issue. I had a look at the literature:
Karak give several precautions for using human urine including
higher application rates of human urine could increase the salinity and high electrical conductivity of the treated soils
from here: www.researchgate.net/profile/Tanmoy_Kara...9d113c2b59000000.pdf
This presentation from South Africa says that conductivity (salinity) is an issue at high application rates of human urine www.researchgate.net/profile/Funso_Kutu/...04cd0a6e26000000.pdf
So I think these suggest that the salinity of urine is a known issue. I wonder why some sources of urine are particularly salty.
I also wonder whether there would be a dilution (or other chemical) effect which would reduce or change the salinity of a mix of faeces and urine.
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You need to login to reply- MonikaR
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Re: Dissertation at SLU "Sanitisation of Faecal Sludge by Ammonia - Treatment Technology for Safe Reuse in Agriculture " - live streaming on 7 May at 13:00 CET
I just wanted to add in a note that at SOIL we thought that the plant stunting observed was due to the high salt content and not incomplete decomposition. The C:N ratio was around 10, indicating that it was fully decomposed but the conductivity was very high. Some of the SOIL folks would be curious to know specifically about how using urine as a means of pathogen treatment affects conductivity.
Thanks so much,
Monika
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Re: Dissertation at SLU "Sanitisation of Faecal Sludge by Ammonia - Treatment Technology for Safe Reuse in Agriculture " - live streaming on 7 May at 13:00 CET
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You need to login to reply- Elisabeth
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Re: Dissertation at SLU "Sanitisation of Faecal Sludge by Ammonia - Treatment Technology for Safe Reuse in Agriculture " - live streaming on 7 May at 13:00 CET
Interesting discussion between you and Monika, thanks a lot.
The paper that you linked to caught my attention, but then I realised it is "only" that "famous" El Salvadore paper from 2006 (which we had discussed in some length back on the old EcosanRes Discussion Forum; I just checked the Yahoo group archive for it; for example this message from Hakan Jönsson in 2006: groups.yahoo.com/neo/groups/ecosanres/co...ations/messages/1141 )
(unfortunately, the archive is not openly accessible, only to those 800 people who were members at the time; that's one of the reasons why we moved to this forum in 2011)
Mind you, I had a look if anything needs to be copied across but the discussion was mainly just around how to improve pathogen kill in UDDTs. Hakan pointed out this:
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++++Dear Shirish,
As the team of Christine Moe has shown the pathogen reduction in solar toilets is good!
Ref: Longitudinal study of double vault urine diverting toilets and solar toilets in El Salvador*
Christine L. Moe, Ricardo Izurieta (Rollins School of Public Health of Emory University, USA)
www2.gtz.de/dokumente/bib/04-5004b.pdf
Ecosan regards,
Håkan
Arno told me this:
As I recall this was a very mismanaged project and the toilets were not at all dry plus poorly maintained. I recall having met these authors and discussing this.
It's interesting because I had made a forum post earlier this year where I had asked:
Are there any studies that have shown more disease in UDDT users than in VIP users or even open defecators? This is something that I would find interesting, and alarming, but I don't think such research exists.
That post of mine is here:
forum.susana.org/forum/categories/34-uri...n-south-africa#12757
So thank you for bringing that El Salvadore study back to my attention. However, I don't think it is representative for UDDTs in general, but only for that particular case of poorly managed UDDTs in that particular project in El Salvadore.
What we'd really need is a survey of people's worm burden in several regions where UDDTs are used by many people. My hypothesis is that such a survey would show no higher rates of worm infections. But I guess we have too little research on helminth infections anyhow. We don't even yet have a clear picture on whether deworming has much of an impact on school children (something which I posted about here: forum.susana.org/forum/categories/159-in...as-much-of-an-impact)
Regards,
Elisabeth
Freelance consultant on environmental and climate projects
Located in Ulm, Germany
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Re: Dissertation at SLU "Sanitisation of Faecal Sludge by Ammonia - Treatment Technology for Safe Reuse in Agriculture " - live streaming on 7 May at 13:00 CET
Here is a link to a paper showing that prevalence of intestinal parasites was higher for UDDT users compared with non-UDDT users, due to handling and use of compost which has not reached high temperature and/or low enough moisture for ascaris inactivation.
www.ncbi.nlm.nih.gov/pubmed/17176347
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Note by moderator: Details of the mentioned paper from 2006 are:
Association between intestinal parasitic infections and type of sanitation system in rural El Salvador.
Corrales LF1, Izurieta R, Moe CL.
Trop Med Int Health. 2006 Dec;11(12):1821-31.
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You need to login to reply- MonikaR
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Re: Dissertation at SLU "Sanitisation of Faecal Sludge by Ammonia - Treatment Technology for Safe Reuse in Agriculture " - live streaming on 7 May at 13:00 CET
One question - in your 2nd paragraph when you talk about mixing the urine with mature compost in closed containers to avoid ammonia losses and ensure pathogen die-off - is this assuming that there are still pathogens left from the composting process, or that there are pathogens in the urine?
Thanks so much,
Monika
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Re: Dissertation at SLU "Sanitisation of Faecal Sludge by Ammonia - Treatment Technology for Safe Reuse in Agriculture " - live streaming on 7 May at 13:00 CET
One option is to first compost the material, and then mix it with urine when it the compost is mature. After mixing urine and compost, it should be stored in a closed storage with minimal air exchange to avoid ammonia losses. This will ensure pathogen die-off, but the storage/treatment time required depend on ammonia concentration and temperature.
I guess that the urine has slowed down the compost process in your case. When this compost was used as soil improvement it showed stunded growth, probably because the degradation/composting continued during plant growht and this requires some nitrogen, so less nitrogen was available for plant growth. I'm not an expert on these things, but this would be my guess. In a normal case, this should not be a problem when sanitizing with ammonia/urine, as the closed storage ensures a high nitrogen concentration in the final product. However, while compost can be used as soil alone more or less, ammonia sanitized material need to be mixed with soil in order to dilute it.
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Can the addition of urine to compost piles help with pathogen kill? Research in Haiti and Sweden
This post was originally in this thread about the PhD defence of Jörgen:
forum.susana.org/forum/categories/53-fae...ture-q-at-slu-sweden
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Thanks Jörgen for posting your defense slides - I'm sorry I missed your presentation.
This is very interesting work on the potential to sanitize sludge with urine. At the SOIL operations in Haiti we had tested 2 different batches of compost produced. Urine was added to one pile located in a structure with a roof. The leachate was collected and continuously re-added to this pile. The other pile had no adding of leachate or urine, and did not have a roof over it, thus receiving rain. The compost results showed high conductivity and stunted growth in a cucumber bioassay in the pile with the re-addition of leachate and urine, versus normal conductivity and cucumber growth in the control.
It seems that as you explore this topic, the quality of reused biosolids regarding the effects of urine addition could be a concern to address in the future. I (and the SOIL team) would definitely be curious to see more research on this! Thanks.
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You need to login to reply- Sanitation systems
- Treatment of wastewater, sludges, organic waste, excreta
- Composting
- Can the addition of urine to compost piles help with pathogen kill? Research in Haiti and Sweden