Use of faecal pollution indicators to estimate pathogen die off conditions in source separated faeces in Kathmandu Valley, Nepal

Anjali Manandhar Sherpa, Denis Byamukama, Roshan R. Shrestha, Raimund Haberl, Robert L. Mach, Andreas H. Farnleitner

Research output: Journal article (peer-reviewed)Journal article

12 Citations (Scopus)


As the introduction and promotion of dehydrating toilets progresses, the safety of handling and reuse of their biosolids remains a question. A detailed study to understand the storage conditions and the fate of selected faecal indicators was conducted on four urine diverting dehydrating toilet units, using ash as a major additive, in Kathmandu Valley, Nepal. Presumptive Escherichia coli, total coliforms, enterococci and different fractions of Clostridium perfringens were investigated under field storage conditions. In addition, chemo-physical and chemical (carbon, nitrogen, phosphorous content) parameters were investigated. Observed temperature was low in all the four toilets with a median of 24.0°C, which was in the same range as the ambient temperature. pH was below the desired range of >9 and moisture level was very high (>60%). No single factor of the studied chemo-physical and chemical parameters could be found by statistical analysis to have accounted for the reduction of the indicators in any of the toilets. By time series analysis of the investigated strata in the faecal heaps (n = 96), the determined reduction rate showed increasing persistence characteristics for E. coli, coliforms and enterococci with respective average log10 reduction of -0.4, -0.3 and -0.2 per month ( p < 0.001). No significant reduction was observed for the different fractions of C. perfringens determined for the non-pasteurised and pasteurised fraction at 60°C and 85°C. 72% of randomly selected and analysed samples (n = 36) were found to contain helminthes eggs. The used 6 months storage time did not prove sufficient to reach appropriate safety levels for handling and reuse of the biosolids.

Original languageEnglish
Pages (from-to)97-107
Number of pages11
JournalJournal of Water and Health
Issue number1
Publication statusPublished - Mar 2009
Externally publishedYes


  • Chemo-physical and chemical factors
  • Indicator microorganisms
  • Microbial die-off
  • Sanitation
  • Urine
  • Urine diverting dehydrating toilets
  • Helminths/isolation & purification
  • Temperature
  • Enterococcus/isolation & purification
  • Escherichia coli/isolation & purification
  • Humans
  • Animals
  • Time Factors
  • Clostridium perfringens/isolation & purification
  • Feces/microbiology
  • Toilet Facilities
  • Agriculture
  • Nepal
  • Hydrogen-Ion Concentration

ASJC Scopus subject areas

  • Water Science and Technology
  • Waste Management and Disposal
  • Public Health, Environmental and Occupational Health
  • Microbiology (medical)
  • Infectious Diseases


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