Inactivation of pathogenic bacteria in concentrated urine Laboratory on Engineering For Sustainable Sanitation, Hokkaido University Oishi, W., Tezuka, R., Higikata, N., Ito, R., Ushijima, K., Funamizu, N. 12 th Specialized Conference on Small Water and Wastewater System & 4 th Specialized Conference on Resources Oriented Sanitation November 2-4, 2014 Muscat, Sultanate of Oman
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Inactivation of pathogenic bacteria in concentrated urine · Inactivation of pathogenic bacteria in concentrated urine ... Estimation of damaged parts ... – Non-hydrolyzed urine
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Inactivation of pathogenic bacteriain concentrated urine
Laboratory on Engineering For Sustainable Sanitation,Hokkaido University
Oishi, W., Tezuka, R.,Higikata, N., Ito, R., Ushijima, K., Funamizu, N.
12th Specialized Conference on Small Water and Wastewater System & 4th SpecializedConference on Resources Oriented Sanitation November 2-4, 2014 Muscat, Sultanate of Oman
WHO recommends urine storage at least6 months to avoid infection(WHO,2006)
Pathogenic risk originate fromfecal contamination
INTRODUCTION 2
• Space for urine is limited in urban slum• Storage time should be shortenedBut
Combined effect of osmotic pressure and pHwas the key factor
【Examination of the key factor】 RESULTS AND DISCUSSION
NH3 : 1200mM
Without NH3
0
0.05
0.1
0.15
0.2
0.25
0.3
4 5 7 10
k e[h
-1]
Concentration level
TSA DESO C-EC
16
Damaged part was unclear
Non-hydrolyzed urine
【Investigation of inactivation mechanism】
4
RESULTS AND DISCUSSION
17
Hydrolyzed urine
E. coli was damaged on enzyme activity
【Investigation of inactivation mechanism】
0
1
2
3
4
5
6
1 3 5 10
k e[h
-1]
Concentration level
TSA DESO C-EC
RESULTS AND DISCUSSION
CONCLUSIONS 18
1. 5 folds concentration was best for inactivation– In hydrolyzed urine, combined effect of pH and osmotic
pressure caused rapid inactivation
2. Urea hydrolysis reduced required storage time tocollect urine safely– Non-hydrolyzed urine needs space for 1 week storage
3. Enzyme activity was predominantly affected inhydrolyzed urine
Thank you for your attention.
MATERIAL AND METHODS 19
Media CharacterAssumed damages
when result innon-detection
Tryptic Soy Agar(TSA)
Non-selective(bacteria growth media)
Nucleic acid and/orMetabolism
Desoxycholate Agar(DESO)
Selective for E.coli whichhave outer membrane
Membrane and/orNucleic acid and/or
Metabolism
Compact Dry EC(C-EC)
Selective for E.coli whichcan produce beta-
glucuronidase
Enzyme activity and/orNucleic acid and/or
Metabolism
3 media
ScenarioRISK ANALYSIS 20
• Dose-response assessmentModel: Beta-Poisson mode【Ingested pathogen and probability of infection】
P: probability of infection, α,β: parameter, D: number of ingested pathogen
Pinf,year : annual probability of infection, n: frequency of infection
DDP 11)(
n,year P)(P 11inf
ScenarioRISK ANALYSIS 21
• Exposure assessment9.1 mg feces/L urine( Schönning et al., 2002)Infected human feces contain 109 pfu/g feces
– Assumption• 4 member family (infected by rotavirus)• Each of them excretes 1L/day• A collector collects 30 family‘s urine• Urine is concentrated before collected
– Infection route• Urine attach to hand (2.8mL) → oral intake
9.1×103 pfu/Lurine
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Synthetic urine
N[times] 1 2 3 4 5 6 7 8 9 10 Average
Attached[mL]
2.5 3.0 2.8 3.3 2.5 2.1 2.4 3.3 3.1 3.2 2.8
Result
Exposure: when pour urineUrine attach on collector’s hand.
RISK ANALYSIS
Collection tank
23
Spike E. coli
E.colisolution
…
Tenfold dilution
TSA
DESO
C-EC
Incubate (37oC) Count colony
24h
105-106 cfu/mL-urine
1mL
1mL
1mL
Phosphate buffer 9mL
200mL
Preparesynthetic urine
10 102 ・・・・
MATERIAL AND METHODS
24
ReagentsCompounds in each concentration level [mM]