The design and usage of a portable incubator for inexpensive in-field water analysis

  • Department of Material Science, University of Texas, USA

  • PLH Advanced Engineering

  • Department of Material Science, University of Texas, USA
  • Modular, Inc.
  • Mechanical Engineering Graduate, University of Texas
  • Public Invention http://orcid.org/0000-0003-4749-7045
Keywords: Bacterial analysis, off-grid functionality, Petrifilm, water quality, portable instrumentation, E. coli

Abstract

Humanitarian engineers need an inexpensive, fast, visually compelling way to assess bacterial water quality in remote locations. One way to do this is with 3M Petrifilm E. coli/Coliform (EC) Count Plates to detect E. coli in water samples. These require incubation at close to body temperature. To meet this need, we provide a free, open-source design of a battery-powered incubator capable of maintaining 35°C ± 1°C for up to 65 hours in ambient temperature of 25°C. Our incubator, called the Armadillo, can be replicated by an ordinarily skilled person in five hours for under USD $200.00 in materials cost. This paper summarises the reference documentation for construction, sample handling, inoculation, and incubation using Petrifilms and the Armadillo. Colony-forming unit (CFU) counts generated by the Armadillo are compared side-by-side with a laboratory-grade incubator. Incubation performance at ambient temperatures of 25°C and 4°C shows that a single battery charge reliably powers a full incubation period of 48 hours under normal ambient temperatures.

Author Biography

, Public Invention

Founder, Public Invention

PhD, Computer Science

Presidential Innovation Fellow

References

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Published
2019-01-14
Section
Articles