Pathogens in septage in Vietnam
ABSTRACT Septage is widely acknowledged as a major source of infectious pathogens while disposal of septage, and the operation and maintenance of septic tanks, is not regulated in many developing countries. Twenty untreated septage and septage sludge samples were taken from Can Tho City, Vietnam to examine their pathogen content, and indicator micro-organisms. Escherichia coli and Enterococcus spp. were detected in all samples, regardless of sludge storage time. Phages were detected in 80% of samples. Salmonella spp. were detected in 70% of the untreated septage and 60% of septage sludge samples. Concentrations of phages and bacteria tested in septage sludge after many years of tank storage were much higher than the expected levels. Helminth ova were present in 95% of untreated septage samples with an average of 450 oval(-1), and were detected in all septage sludge samples with an average of 16,000 oval(-1). Twelve varieties of helminth ova were identified. More helminth ova varieties in higher concentrations were found in septage than those reported from stool samples. The varieties' frequency ranged from 10% to 50% and Ascaris lumbricoides predominated. Results show that pathogens and indicator micro-organisms, especially helminth ova, accumulate in sludge. Thus helminth ova should be considered when septage sludge is treated and used for agriculture. Proper health protection measures must be applied for people handling septage.
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ABSTRACT: We reported on the transit and survival of 6 potentially pathogenic bacterial populations in a schist aquifer beneath the Etueffont landfill (France). Total coliforms, Escherichia coli, Enterococci, Pseudomonas aeruginosa, Salmonella and Staphylococcus aureus were monitored for 15 months in groundwater and leachate and coupled to tracer tests in an attempt to identify the source of contamination. The results showed the absence of S. aureus and Salmonella. The monitoring of piezometer 30 (PZ30) located downstream from the landfill highlighted leachate infiltrations into the substrate. Groundwater analysis showed high levels of faecal bacteria in the underground environment (20,000 CFU 100 mL− 1 for total coliforms, 15,199 CFU 100 mL− 1 for E. coli and 3290 CFU 100 mL− 1 for Enterococci). Data from tracer tests indicated that bacteria originated from the septic tank of the transfer station and part of these bacteria transited through waste. Bacterial density was lower in leachates than in groundwater sampled from PZ30, except for P. aeruginosa which seemed to take advantage of adverse environmental conditions. The landfill, closed since 2002, was not a source of faecal bacteria which appeared to be able to survive in the schist substrate, and may be considered as good markers of recent faecal contamination.Desalination 10/2010; 261(1):162-168. DOI:10.1016/j.desal.2010.05.007 · 3.96 Impact Factor
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ABSTRACT: Ecological sanitation technologies can be effective in providing health and environmental pollution control if they can efficiently reduce the pathogenicity of microorganisms carried in faecal material to safe levels. This study evaluated the sanitising effect of different additives for dry treatment of faeces from urine-diverting dry toilets, based on inactivation of Enterococcus faecalis, Salmonella Typhimurium, bacteriophages MS2 and ΦX and Ascaris suum. The additives, ash (A) and oyster shell (O) in different amounts and urea (U) to optimise the process, were compared with no additive, solely urea and sawdust as controls (C) and covered [X%O:A] or uncovered X%O:A. The main inactivation factors found were desiccation, ammonia content and pH. S. Typhimurium and E. faecalis were more affected by the ammonia content. A combination of neutral to high pH and desiccation was most effective for inactivation of MS2 and desiccation for inactivation of ΦX and A. suum. Inactivation rate was modelled in all combinations studied. The most promising treatments were [150%O:A+U], 150%O:A+U and 150%O:A. According to the models these could inactivate, for example, 7log(10) of all bacteria and bacteriophages within 83, 125 and 183 days, respectively. The inactivation of A.suum was modelled, albeit the measured decay in eggs viability was low.Applied and Environmental Microbiology 01/2013; 79(7). DOI:10.1128/AEM.03920-12 · 3.95 Impact Factor
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ABSTRACT: Surface water samples were collected from rivers which fed into large urban areas within Vietnam, Indonesia, Cambodia, and Thailand and were processed to enumerate Escherichia coli. Selected isolates were further characterized using PCR to detect the presence of specific virulence genes. Analyzing the four countries together, the approximate mean cfu/100 ml for E. coli counts in the dry season were log 4.3, while counts in the wet season were log 2.8. Of the 564 E. coli isolates screened for the presence of pathogenic genes, 3.9 % possessed at least one virulence gene. The most common pathogenic types found were Shiga toxin-producing E. coli isolates. These results reinforce the importance of monitoring urban surface waters for fecal contamination, that E. coli in these water environments may serve as opportunistic pathogens, and may help in determining the impact water usage from these rivers have on the public health of urban populations in Southeast Asia.World Journal of Microbiology and Biotechnology (Formerly MIRCEN Journal of Applied Microbiology and Biotechnology) 05/2013; DOI:10.1007/s11274-013-1376-3 · 1.35 Impact Factor