1) Waste treatment technology
Found on
https://www.crosswordclues.com/clue/sludge-bulking
In treatment of sewage one process used is the activated sludge process in which air is passed through a mixture of sewage and old sludge to allow the micro-organisms to break down the organic components of the sewage. Sludge is continually drawn off as new sewage enters the tank and this sludge must then be settled so that the supernatant can be ...
Found on
http://en.wikipedia.org/wiki/Sludge_bulking
No exact match found.
