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- Fidjeland, Jörgen, et al.
(author)
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The potential for self-sanitisation of faecal sludge by intrinsic ammonia
- 2013
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In: Water Research. - : Elsevier BV. - 0043-1354 .- 1879-2448. ; 47, s. 6014-6023
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Journal article (peer-reviewed)abstract
- Faecal sludge has the potential to be used as a sustainable fertiliser in agriculture, but the sludge must be sanitised due to its content of pathogenic microorganisms. The intrinsic ammonia from the urine may be sufficient for sanitisation of the sludge if it is not too diluted by flush water or lost by ventilation. To evaluate the potential for this sanitisation method, inactivation of Enterococcus faecalis, Salmonella typhimurium and Ascaris suum eggs during treatment were assessed. The inactivation was studied at different storage temperatures (10-28 degrees C) and in several sludge mixes with different contents of urine, faeces and flush water, and with ammonia concentrations from 40 to 400 mM. All pathogens were inactivated by the ammonia, and ascaris eggs were the most persistent. Lower flush water volume and higher urine content favoured inactivation, mainly due to increased uncharged ammonia (NH3) concentration. The lag phase in ascaris inactivation was shortened by increasing temperature and NH3 concentration, while post-lag phase inactivation was not influenced by NH3 concentration. Faecal sludge can be sanitised by airtight storage without the use of additives when flush water volumes are sufficiently low. For temperatures of 23-28 degrees C, a 3 log reduction of ascaris egg viability can be achieved within 1-6 months depending on ammonia concentration and temperature. (C) 2013 Elsevier Ltd. All rights reserved.
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| 3. |
- Lalander, Cecilia, et al.
(author)
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Faecal sludge management with the larvae of the black soldier fly (Hermetia illucens) - From a hygiene aspect
- 2013
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In: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 458-460, s. 312-318
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Journal article (peer-reviewed)abstract
- Inadequate and lacking sanitation and wastewater treatment systems can lead to the spreading of diarrhoeal diseases. One contributing factor in the lack of such treatment systems is the lack of economic incentives for stakeholders throughout the service chain. However, the organic fraction of the waste is high in valuable plant nutrients and could be reused in agriculture and as animal feed. For example, grown larvae of the black soldier fly, Hermetia illucens L (Diptera: Stratiomyidae), make an excellent protein source in animal feed, while the feeding activity of the larvae substantially reduces the dry mass of the treated material. This study examined the effect of black soldier fly larvae on the concentration of pathogenic microorganisms in human faeces and found a 6 logic, reduction in Salmonella spp. in human faeces in eight days, compared with a <2 log(10) reduction in the control. No increased reduction was observed for Entero coccus spp., bacteriophage phi X174 or Ascaris suum ova. (C) 2013 Elsevier B.V. All rights reserved.
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| 4. |
- Magri, Maria elisa, et al.
(author)
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Inactivation of adenovirus, reovirus and bacteriophages in fecal sludge by pH and ammonia
- 2015
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In: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 520, s. 213-221
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Journal article (peer-reviewed)abstract
- The aim of this study was to evaluate the inactivation of adenovirus, reovirus and bacteriophages (MS2, Phi X174, 28B) in a fecal sludge. We conducted two experiments. In the first, we tested different compositions of the fecal sludge by mixing different amounts of water, feces and urine, totaling nine combinations which were kept at temperatures between 10 and 28 degrees C. In the second study, urea was added to the mixtures, which were kept at temperatures from 5 to 33 degrees C. The inactivation was based on a combination of temperature, pH and uncharged ammonia concentration. The increase in pH and ammonia was provided mainly by urine content (Experiment 1) and by urine and added urea (Experiment 2). The inactivation of bacteriophages was slower than the AdV and ReV. At 23 degrees C and 28 degrees, reasonable treatment times were obtained when pH was higher than 8.9 and NH3 concentrations were higher than 35 and 55 mM respectively. With those conditions, the maximum time for a 3 log reduction in viruses, according to this study, would be 35 days (23 degrees C) and 21 days (28 degrees C). However, in most applications where helminth eggs are present, the treatment time and NH3 for sanitization will be the scaling criteria, as they are more persistent. Concerning the sanitization of effluents from latrines, vacuum toilets or dry toilets in developing countries with tropical and sub-tropical climates, the use of intrinsic ammonia combined with high pH can be effective in producing a safe and highly valuable liquid that can be used as a fertilizer. In the case of the fecal sludge with very intrinsic ammonia concentration (< 20 mM), sanitization could still be achieved by the addition of urea. (C) 2015 Elsevier B.V. All rights reserved.
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