Welcome to EnviroDIY, a community for do-it-yourself environmental science and monitoring. EnviroDIY is part of WikiWatershed, an initiative of Stroud Water Research Center designed to help people advance knowledge and stewardship of fresh water.
New to EnviroDIY? Start here


  • Diatrix posted an update in the group Sensor Developers 4 years, 11 months ago

    Hello everyone.
    I’m slowly developing a water quality sensor to monitor water pollution in underground krastic river systems. The main pollutant in these waters is fecal matter from lack of proper water treatment, and sewer systems. This pollution drains on the ocean, where it damages local reefs and it also pollutes local cenotes. Both of these have a great impact to the local economy, which is based on tourism.

    Anyways, I’m currently stuck on a way to monitor in real time the amount of fecal matter in the water. I’ve talked to a local hydro-biologist, and he tells me that the way to monitor fecal matter in water is by taking samples and measuring the fecal coliform bacteria in the water. I don’t see a way to do this with a real time sensor. I’m wondering if someone here knows of a sensor to monitor the fecal matter in real time.

    The environment i work in is underground, slow-flowing rivers with two distinct layers of water: a salt water layer, and a fresh water layer. Some times they mix, and the level of the edge is not constant, and changes depending on the weather and tides.

    I thank you all in advance for your help.

    • Hello Diego,
      That is an interesting project. Is it in Yucatan Peninsula?
      I think that the advice that you have been given is correct. I don’t know of any sensor that can measure fecal matters real time. The usual way is to monitor the water at fixed intervals, and take the samples to the lab where they can tell you if the bacteria is present.
      What if you can measure another variable that can serve as proxy for the water quality? e.g. Turbidity or Dissolved Oxygen
      Or maybe some new technology can be tested in your system, see e.g.

      Luis Andres

      • That’s what I was thinking. I’ve been researching fluorescence spectroscopy to make a meter, but I feel like the optical filters would not be cost effective. Although I’ve seen some other comercial products that use them. (See: https://youtu.be/0uipKkfs1rs). The idea is to have a large array of sensors, to find the sources of the pollution.

        Yes, it’s the Yucatan Peninsula. I’m based in Tulum. Here is what the problem looked like 8 years ago, I can only imagine what it looks like now.

        Perhaps I can do the Dissolved Oxygen, Turbidity, Salinity and temperature. How do you measure the DO?
        Thank you for your reply.

    • No such sensor yet exists. The best you can do is correlate turbidity from a sensor with measurements from water samples.