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Sanitisation of faecal sludge by ammonia

treatment technology for safe reuse in agriculture

Fidjeland, Jörgen (2015). Sanitisation of faecal sludge by ammonia. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880 ; 2015:45
ISBN 978-91-576-8288-8
eISBN 978-91-576-8289-5
[Doctoral thesis]

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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.

Authors/Creators:Fidjeland, Jörgen
Title:Sanitisation of faecal sludge by ammonia
Subtitle:treatment technology for safe reuse in agriculture
Series Name/Journal:Acta Universitatis Agriculturae Sueciae
Year of publishing :2015
Depositing date:13 April 2015
Number of Pages:79
IFidjeland, J., Magri, M.E., Jönsson, H., Albihn, A. and Vinnerås, B. (2013) The potential for self-sanitisation of faecal sludge by intrinsic ammonia. Water Research 47(16), 6014-6023.
IIFidjeland, J., Nordin, A., Vinnerås, B. (submitted) Inactivation of Ascaris eggs and Salmonella spp. in faecal sludge by treatment with ammonia and urea. Planned submission to Journal of Water, Sanitation and Hygiene for Development
IIIMagri M. E., Fidjeland J., Jönsson H., Albihn A. and Vinnerås B. (2015). Inactivation of adenovirus, reovirus and bacteriophages in fecal sludge by pH and ammonia. Science of the Total Environment 520(0), 213-21.
IVFidjeland, J., Nordin, A., Pecson, B., Nelson, K., Vinnerås, B. (submitted) Modelling Ascaris egg inactivation as a function of ammonia and temperature. Submitted to Water Research
VFidjeland, J., Ottoson, J., Vinnerås, B. Quantitative microbial risk assessment of agricultural use of faecal sludge sanitised by ammonia. Manuscript
Place of Publication:Uppsala
Publisher:Department of Energy and Technology, Swedish University of Agricultural Sciences
ISBN for printed version:978-91-576-8288-8
ISBN for electronic version:978-91-576-8289-5
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:F Plant production > F04 Fertilizing
T Pollution > T01 Pollution
T Pollution > T10 Occupational diseases and hazards
Subjects:(A) Swedish standard research categories 2011 > 2 Engineering and Technology > 201 Civil Engineering > Water Engineering
(A) Swedish standard research categories 2011 > 2 Engineering and Technology > 207 Environmental Engineering > Other Environmental Engineering
Agrovoc terms:ammonia, disinfection, faeces, sewage sludge, waste treatment, salmonella, ascaris, viruses, pathogens, health hazards, organic fertilizers
Keywords:Ammonia sanitisation, Faecal sludge, treatment technology, Ascaris, Salmonella, virus, health risk, human excreta
Permanent URL:
ID Code:12103
Faculty:NJ - Fakulteten för naturresurser och jordbruksvetenskap
Department:(NL, NJ) > Dept. of Energy and Technology
Deposited By: Jörgen Fidjeland
Deposited On:14 Apr 2015 06:56
Metadata Last Modified:10 Sep 2020 13:41

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