Low Tech Water Testing Incubator
In developing countries, clean water sources are sacred and scarce. It is estimated that 1 billion people in the world lack access to a source at all. For those who are lucky enough to be able to draw from the precious spring of life (no pun intended), water quality testing is key.
This creation is an attempt to find a simple-to-make yet comfortable incubator to hold water samples close to the body. Since testing must take place over the course of 24 hours, the incubator must be comfortable to work, play, and sleep in. Although putting a tube in a vest pocket or sock while on the field has been accepted practice in the past, there has been an evolution of many formalized technologies that has led me to this “design” conclusion.
A water test is done using a small water sample is a bottle that is incubated over 24-hours at body temperature. The idea is that the vial of water from the drinking source may or may not be full of bacteria. At the lab (or right after collection in the field), a “food” is added so that the bacteria can be encouraged to grow. The samples that I have in class are for coliform e.coli and sulfur-producing salmonella strains. Immediately afterwards, the samples need to be put at body temperature for 24 hours. The idea is that you can give the water body-like conditions in order to “grow” any possible infections.
There have been a multitude of technologies used for incubation. The first are the many large, mechanical heaters used to keep samples at a constant temperature. The second is Amy Smith’s phase change incubator which is a collection of small packets that are distributed throughout a large cooler of samples. Three is no electricity necessary. The third was a revolutionary design that took advantage of the idea that the samples only needed to be at stable, constant body temperature: the waistbelt incubator. It is a fanny pack with about 20 pouches for vials. It has the advantage of being able to hold a formidable number as well as being incredibly low-tech.
However, the waistbelt is not easy to work or sleep with. Additionally, it is a formalized product, manufactured for this sole purpose. I tried to make something that would address both this issues. I used fishing line, an ace bandage, and part of a bicycle inner tube to create the product. I had rural Peru in mind where all these materials are readily available. Additionally, the way that the incubator ties around the mid-section allows it to move with the body as it goes about its daily chores.
After speaking with Susan Murcott, the inventor of the waistbelt incubator, I’ve had a few realizations:
1. The design needs to have an added cloth between the flesh and samples as the body temperature is 37 C while the samples are usually tested at 35 C. Additionally, the incubator has space for many samples but more would be better.
2. Although I was originally shy about making a formal item such as a vest, I think that some sort of iteration needs to be attempted in order to accommodate more tubes.
3. The inner tube becomes loose after extensive use and becomes prone to tearing. Another material should be considered.
