Increasing the life of membrane-based water filters

    Posted on Monday, Nov 18, 2019
    So, unfortunately, I didn’t make it to the final rounds of the 3MT thesis competition. However, as communicated in my last blog, it was altogether an enjoyable learning experience. I would like to use this blog to test my learning. You see, 3MT is all about communicating your research to a lay audience in a brief time of 3 minutes. In this blog, I am going to try to explain my research in a similar fashion and would really be glad if I could get some feedback.

    Here is the content of my speech for the preliminary competition.

    I like to think of myself as a doctor of water filters or, more precisely, membrane filters. Even my twitter handle is @waterfilterDoc. You see, membranes have increasingly become an essential component in providing us clean drinking water. But while working for us, they kind of get sick and eventually die. This is where my research comes in. In my research, I try to understand the reasons that led to the membranes getting ill and eventually die.

    I wish I was like Dr. Doolittle, and the membranes talked to me, but alas, they don’t. So, just like a regular doctor, I run diagnostic tests, I look at their performance, and then suggest medicines. Since I know how the prescribed medication works, I am able to figure out the reason for the disease. As you can understand, the process is very iterative. To accomplish all this, I have a lab rat. Basically, I have developed my own lab-scale filtration system that emulates a real-world filtration setup. Using this setup, I would, on purpose, make the membrane sick with different diseases and then test a variety of medicines, and the iteration continues.

    What I have found so far, is (1) there are some specific type of contaminants in water that have a particular affinity to the membranes, (2) these specific contaminants are not just themselves disease-causing but also help other contaminants to cause other diseases, (3) and the worst are the ones that can enter the pores of these filters. However, in my research, I have found two simple solutions: (1) make the size of contaminants bigger and therefore prevent them from entering the pores or (2) kill the contaminants before they reach the membrane by something as simple as household bleach. My research is still ongoing to further understand the mechanisms leading to the sickness and eventual death of the membranes, and I hope that I can provide solutions that would lead to the increased life of these membranes.

    Based on the critique by the judges, here are a few things that should give more context to the speech and hopefully make the research clearer.
    1. Membranes are inanimate objects (somehow, I made one of the judges to question herself that it was living thing). The membranes that I use in my research can be thought of as a sieve with pores of the size 1/100th of the thickness of human hair (~80 micrometers).
    2. The disease or sickness of membranes is basically clogging of the pores while filtration happens (we call it fouling). As you may have experienced, the smaller the pores, the more difficult it is to remove things congesting it.
    3. The eventual death of the membrane, i.e. when membranes need to be replaced due to inefficient performance. This happens that all our efforts to decongest the membrane pores are futile. Typically, the lifetime of a membrane is around 7-8 years but may reduce if not correctly operated.
    4. Diagnostic tests are the different types of analytical instruments that can be used to identify the clogging agents, and different clogging agents need different medicines.
    5. Medicines are cleaning agents. For example, acids for metals, bases for carbon compounds (organic matter, this is what gives color to natural water bodies like rivers, lakes, and ponds).
    I think that the outcome of my research was well communicated without any jargon, and I hope that the above contextual definitions of the analogies and the metaphors used would make more sense now. One more thing that I would like to add is the broader impact of my research outcome. The most crucial benefit of membranes is their consistency in terms of water quality, and with the increasing shortage of water worldwide, we will have to rely on unconventional sources of water. The role of membranes in the utilization of these sources is vital. The current issue with the application of membranes is the expense associated with their setup; however, my research aims at increasing the life of these membranes and therefore offset the high cost. The cost is especially detrimental to the application of these membranes in developing countries that continuously struggle with providing their citizens with clean drinking water.

    I look forward to your comments, feedback, and questions. Water is a necessity for life, and we need clean water for everyone.

    ---Kunal Gupta
    Kunal Gupta is a doctoral student in the Department of Civil and Environmental Engineering

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