• Question: how much energy does cleaning waste water require, and what methods of cleaning the waste water do you use?

    Asked by ands532stob63 to Lauren G, kelvinrose, Karen E, joshuadavies, Jincheng Wu, Beth C, audreyanna on 27 Feb 2026.
    • Photo: Beth Campbell

      Beth Campbell answered on 27 Feb 2026:

      This can really vary! Some techniques used for cleaning sewage are very low energy, basically just pumping water slowly through large tanks to allow contaminants to settle out, others for this purpose are higher energy, for example bubbling air through it to allow aerobic bacteria to eat the organic materials. But other techniques are much higher energy, for example methods that use electricity to cause chemical reactions degrading hard to destroy pollutants, like chemicals similar to those used in non-stick pans! I have used a number of these different techniques over the years.

Comments

  • Photo: James L

    James L commented on :

    I have never worked with waste water but my father worked in this area. He researched flocculants. Flocculants are water soluble chemicals that basically act like a net to catch the tiny particles in the water. If you’ve ever seen a chef make a clear broth, you’ll see they add the egg whites, mix it with the broth and then the egg whites will float to the top with all the impurities in the broth and then are scooped away leaving a clear soup behind. That is essentially what flocculants do with waste water. My father’s research was finding a flocculant to do that with dirty water left after coal mining, so that the water was left clear, but that the particles of coal collecting in the flocculant could be dried and hardened and used like coal again.