Download Bacteria-Detecting Water Sensor

BACTERIA-DETECTING WATER
SENSOR
COLLABORATION OF WATER TECHNOLOGY ACCELERATOR AND RICE
TECHNOLOGY
CO-AUTHORS: MARCIA SILVA, DAVE RICE, DAVID GARMAN
PURPOSE:
•
Today, microbial drinking water quality is monitored through time-consuming
laboratory. There is no real-time technology for microbial measurements. Results are
thus either delayed or insufficient to support proactive action.
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Reducing the rate of measurement is essential to reduce theoretical distribution of
contaminated water supplies
•
Creating an efficient and accurate device which calculates specific amount of
bacterial contaminants present
NEW TESTING METHODS
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RAS (Returned Reactivated Sludge) gathered from a local wastewater
treatment plant
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E. coli cultivated through streaking modMTEC plates
Inoculations preformed with e. coli colony and LB growth media
Dilution and filtration preformed to gather cfu/ml (colonies formed per
milliliter) counts of bacteria
NEW TESTING METHOD
Figure 1: Novel Sensor
Figure 2: Closed System for Detection
NEW TESTING METHOD
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CFU/ML calculated from samples
taken during sensor readings
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Comparing readings to counts though
trials in order to calibrate the system
Figure 2: Example of a trial run
RESULTS
Figure 4: Two sensors when salt added, after 24 hours
Figure 5: Two sensor when salt added (expanded
at the introduction of salt)
• one sensor had slightly delayed clock due to
inaccuracies in its microcontroller
DISCUSSION OF RESULTS
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When two sensors were placed in the same closed system, less than .3%
deviation between each device
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A few grains of salt sprinkled creates a step in the results (see Figure 4,5)
The sensor is sensitive to the smallest changes in contamination
CONCLUSION
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Device shows repeatability
Low or negligible instrumental error noted
Accurate readings
Can generate readings in less than ten seconds
Through more trials, the output will be calibrated to directly display in
CFU/ml(colonies formed per milliliter)
Sample rate set at one minute
REFERENCES
1.
2.
<http://www.nature.com/articles/srep23935>
Bo Højris, Sarah Christine Boesgaard Christensen, Hans-Jørgen Albrechtsen, Christian
Smith & Mathis Dahlqvist
Scientific Reports 6, Article number: 23935 (2016)
Rice Technology LLC
QUESTIONS?