Dissertation on "Sanitisation of Faecal Sludge by Ammonia - Treatment Technology for Safe Reuse in Agriculture " at SLU, Sweden

  • Vinneras
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Dissertation on "Sanitisation of Faecal Sludge by Ammonia - Treatment Technology for Safe Reuse in Agriculture " at SLU, Sweden

Jörgen Fidjeland will defend his PhD thesis on May 7 at 1300h CET.
The title is: "Sanitisation of Faecal Sludge by Ammonia - Treatment Technology for Safe Reuse in Agriculture "

The defence will be streamed at: epi-resurs.slu.se/avs/stream/Fidjelands

The thesis are awailable at pub.epsilon.slu.se/12103/

Thesis and presentation slides available here: www.susana.org/en/resources/library/details/2266

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Abstract:

Faecal sludge contains valuable plant nutrients and can be used as a fertiliser in agriculture, instead of being emitted as a pollutant. As this involves a risk of pathogen transmission, it is crucial to inactivate the pathogens in faecal sludge. One treatment alternative is ammonia sanitisation, as uncharged ammonia (NH₃) inactivates pathogens. The aim of this thesis was to study how the pathogen inactivation depends on treatment factors, mainly NH₃ concentration, temperature and storage time, and based on this to make treatment recommendations that ensure pathogen inactivation.

Salmonella inactivation was rapid and could be eliminated within a few days. Reovirus and adenovirus were inactivated more slowly than that, but more rapidly than bacteriophages PhiX174, 28B and MS2. Ascaris eggs were generally inactivated more slowly than the other studied organisms, especially at low temperatures (<20 °C). Ascaris egg inactivation was modelled as a function of NH₃ concentration and temperature, which enabled the prediction of required treatment time. An assessment of health risk associated with consumption of crops eaten raw indicated that a 4.5 log10 reduction of Ascaris eggs and a 7.5 log10 reduction of rotavirus were required for unrestricted use of ammonia-treated faecal sludge as a fertiliser.

Faecal sludge contains some ammonia mainly due to the ammonia in urine, but the concentrations can be low due to dilution with flushwater and losses to air. Mixing source-separated urine and faeces from urine-diverting dry toilets will give a high enough NH₃ concentration for pathogen inactivation. Estimations of NH₃ concentrations in faecal sludge from vacuum, pour-flush and low-flush toilets indicated that the ammonia concentrations required for stable pH may not be reached without the addition of ammonia. The addition can be urea, which is a common mineral fertiliser that hydrolyses to ammonia and carbonate through the enzyme urease found in faeces.

Ammonia sanitisation of faecal sludge is a simple and robust technology enabling a high degree of pathogen inactivation. This can considerably reduce the health risk for farmers, food consumers and downstream populations. It is important to minimise flush water volumes in order to reduce the treatment costs.
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  • muench
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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

The Swedes really are leading the way...! I am very impressed that defences of PhD theses are being streamed live and plan to attend this one. I wonder if questions from the floor (worldwide!) might even be taken? (probably not) ;-)

The title of this thesis is a little bit misleading. It says "faecal sludge" but it also deals in quite some detail with the (dry) faecal matter from urine-diverting dry toilets. So: all the UDDT enthousiasts on this forum might be interested in this part!

I think Joe Turner might enjoy the section about QMRA (qualitative microbial risk assessment), see p. 51. ;-)

And I copy here something that jumped at me and wants me to read more:

While the mixing of urine and faeces from UDDT toilets showed considerable
potential for self-sanitisation using only the intrinsic ammonia, the estimation
of intrinsic NH3 in sludge from other toilets indicated that the addition of urea
may be required to achieve sanitisation within a practical treatment time (<0.5
year).

In addition, there is a risk of biological degradation causing a fall in pH
in sludge from vacuum, pour-flush and low-flush toilets if urea is not added, as
the treatments in Paper II with initial NH3 concentrations below 20 mM
experienced a fall in pH. The low intrinsic NH3 concentrations in faecal sludge
from toilets using water were mainly due to the high number of urinations,
which were estimated to be four, six or eight times per day for the different
scenarios.


At the beginning of the thesis, the papers are also listed that Jörgen authored on this topic. Very impressive work!

Regards,
Elisabeth

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  • jorgenfidjeland
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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

muench wrote: I wonder if questions from the floor (worldwide!) might even be taken? (probably not)


The plan is to have a email address to my college at the webpage of the streaming, so that people can email questions to her and she will ask them. Usually there is an opening for questions from the audience in the end of the session after the evaluation committee are done asking quetions, so this will be possible then, if technology works.
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  • Vinneras
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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

You will be able to post questions to This email address is being protected from spambots. You need JavaScript enabled to view it. and she will ask them in the end of the session.
Welcome to listen.
Björn
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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 am now in the room (1 pm Germany time), the internet streaming is working, I can listen to Jörgen's PhD defence. Ah, technology at its best!
If you want to be there live, here is the link again:
epi-resurs.slu.se/avs/stream/Fidjelands/

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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

Hi,

The slides from my presentation are available on the link below:

Slides
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