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Microbial contaminants in water distillation

  1. May 20, 2013 #1
    Hello all,

    I have a few questions regarding purification of water of microbial contaminants by boiling.

    1. If water containing microbial contamination is boiled, and the vapor is collected, is the condensed vapor going to be free of microbes? I would think so because if the microbes don't die during boiling, they probably aren't going to be boiled into vapor along with water. But am I missing any pieces? Would microbes somehow find a way to stay onto the water vapor particles?

    2. Are there any studies that discuss how microbes in water affect its properties? In other words, what is the ebullioscopic constant of microbes, how microbes affect heat capacity and enthalpy of vaporization of water, etc? I couldn't find anything on this.

    Thank you.
  2. jcsd
  3. May 20, 2013 #2


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    1. A single microbe is many orders of magnitude larger than a water molecule. After all, microbes are composed of water and other organic compounds.

    2. Like most living things, microbes are more water than anything else. I don't think you are going to find any physical data on water chock a block with microbes because only pure water is used in heat generation or manufacturing processes. For instance, if the feed water for a boiler contained a sizable fraction of organic material, the boiler would become clogged with the scale formed from this material and possible fail.
  4. May 20, 2013 #3


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    1. It is entirely possible that microbes become aerosolised and carried upward with the vapour (and end up condensing on whatever you're collecting the vapour on or in). However, practically all vegetative cells of human pathogens die when exposed to boiling temperatures under conditions of normal atmospheric pressure. The exception is with spore-forming organisms, that can survive ordinary boiling very easily. The spores can be borne aloft in the vapour and condense, as I've already mentioned. The spores can then revive to become active vegetative cells when they're cooled. If you're boiling a suspension of highly pathogenic Bacillus anthracis, for instance, this is a real concern.

    The vegetative cells of some extremophiles can survive boiling, but these are not usually considered human pathogens (they're free-living saprophytes for the most part).

    The concern with aerosolisation is the main reason why microbiology laboratories working with human pathogens use biosafety cabinets.

    2. I am not aware of any data, per se, for microbial suspensions. I agree with SteamKing's answer. If you really want data, I guess you have to take the empirical approach.
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