microbiological testing of a community- based , …...2018/11/02 · microbiological testing of a...
TRANSCRIPT
COLLEGE OF ENGINEERING
Microbiological Testing of a Community-
Based , Biomass-Fueled Water Pasteurizer and Procedures for Cleaning Household Water Transport Containers
Grace Burleson1, Catherine Mays2, Nordica MacCarty1,
Tala Navab-Daneshmand2, Kendra Sharp1
1. Mechanical, Industrial, and Manufacturing Engineering, Oregon State University, Corvallis, OR
2. Chemical, Biological, and Environmental Engineering, Oregon State University, Corvallis, OR
10/30/2018
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At least 2 billion people rely on a fecal-contaminated
water source (WHO/UNICEF, 2017)
Boiling remains the most common method of household water treatment (WHO, 2016)
Image sourced from Pixabay
Major Concerns of Boiling• Huge fuel cost to bring water to a boil
• Inefficient use of resources and time
• Open fires cause major degradation of air quality
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Water pasteurizer insertWater pasteurizer insert in 60 L pot
Photo/diagram provided by InStove
The InStove Water Purifier
A. Inlet pipe
B. Heat exchanger
C. Heating coil
D. Thermostatic valve
E. Kill chamber
F. Outlet pipe
G. Fuel Input
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G
Purifier Studies
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InStove Water Purifier
Capacity ~400 L/hr
Fuel usage 5.5 g/L
Microbial Reduction Potential ??
800% improvement to traditional boiling
97% less fuel than traditional boiling
US-EPA standards: • 6-log removal of bacteria • 4-log removal of viruses
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Drinking Water Collection
Water collected from InStove Purifier
Transported back to the home
Stored until useDistributed amongst the family
7Images sourced from Pixabay
Objectives
1. InStove Water Quality
Efficacy of the InStove Water Purifier in removing fecal indicator microorganisms
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2. Container Cleaning
Efficacy of 5 recommended and/or commonly practiced container cleaning methods
OBJECTIVE 1
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1. Efficacy testing of the InStove Water Purifier in removing fecal indicator microorganisms
InStove Microbial Reduction
Methods
• Common fecal indicator organisms were inoculated into an inlet water source– Bacterial Indicator: Escherichia coli
– Viral indicator: Bacteriophage MS2
• Water was pasteurized under standard operating conditions
• Samples were collected at the outlet at multiple time points
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InStove Microbial Reduction
Results
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E. Coli (ATCC 25922)Colony Forming Unit (CFU)
Bacteriophage MS2 (ATCC 15597-B1)Plaque Forming Unit (PFU)
InStove Microbial Reduction
Results
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6-log (99.9999%) reduction of both E. coli and MS2 bacteriophage
Source Water with E. coli6.1 (± 0.05) Log CFU/mL
Source Water with MS26.5 (± 0.15) Log PFU/mL
Treated WaterBelow Detection Limit
(<1 CFU/100 mL)
Treated WaterBelow Detection Limit
(<10 PFU/mL)
OBJECTIVE 2
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2. Efficacy testing of 5 recommended and/or commonly practiced container cleaning methods
Container Sterilization Methods
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1. Water rinse
2. Two Oxfam recommended procedures
3. Two CDC recommended procedures
(1) Water Rinse
Container Sterilization Methods
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1 Liter6.4 (± 0.1)
Log CFU/mL
1 LiterClean drinking
water
2.0 (± 0.58) Log CFU/100mL
Inoculation Method Testing
Container Sterilization Methods
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(2) Oxfam – Soap/Water Rinse
(5) CDC – Emergency Container Protocol
(3) Oxfam – Bleach Rinse
(4) CDC – Personal Container Protocol
Oxfam. (2012). Hygiene Promotion for Household Water Treatment and Safe Storage in Emergencies
CDC. (2016). Cleaning & Preparing Personal Water Storage Containers CDC. (2017). Cleaning and Sanitizing with Bleach after an Emergency.
Conclusion
InStove Water Quality
The InStove Water Purifier is capable of removing at least 6 logs of E. coli and MS2 bacteriophage, while reducing fuel requirements 97%.
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Container Cleaning
CDC/Oxfam recommended container cleaning procedures are an effective practice to remove 6 logs of E. coli, while a simple water rinse is not.
Acknowledgements
Material Support– InStove staff members Nicholas Moses, Damon Ogle, and
Fred Colgan
Funding– Damon Ogle
– Tom Carter, Agua Pura Para el Pueblo
– InStove
– Oregon State University start-up funding
– Venturewell
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