I know that sounds disgusting, but hear me out.
I was recently reviewing a request that had come through from one of our international offices. There was a problem during the commissioning of a new treatment plant and the site engineers had started to notice small amounts of white powdery material floating in the tanks, sticking to walls, screens and anything else.
At the same time a microbiological study had identified that there were significant concentrations of a filamentous bacteria called Thiothrix I. A bit of digging and research and a trend started to emerge... Turns out the bacteria were generating sulphur because conditions were suitable, which in turn was reacting with calcium to produce calcium sulphate (the white powdery material).
Sewage treatment is one of those areas where biology and chemistry meet, where process control, trouble shooting and operator 'feel' go hand in hand. All the while, effluent is still coming down the pipe and it needs to be treated to prevent significant negative impact on the environment.
Sewage treatment is underappreciated. Particularly in a country like Australia, but down at the "poo-plant", there is the phenomenal application of science, engineering and design to protect the environment, produce reusable water and valuable by-products (energy, fertiliser, etc.). And it's getting better.
Every now and then there are opportunities to go and visit a sewage treatment plant. Why don't you go a long next time? Maybe you'll begin to love sewage treatment like me too?.... or maybe you won't.