Waste Water Treatment Flashcards
Where is waste water mostly from?
Homes and agricultural systems.
Why does waste water have to be treated?
To remove organic matter and harmful microbes before it can be put into freshwater sources, otherwise the sources can become polluted.
How is waste water treated?
1) The sewage is screened by removing large materials as well as any grit.
2) The sewage is then put into a settlement tank where it undergoes sedimentation. This is when the larger and heavier materials sink to the bottom to produce sludge, and the effluent (liquid waste) floats to the top.
3) The effluent is removed and treated by biological aerobic digestion and then released back into the environment.
4) The sludge is also removed and transferred into larger tanks where it undergoes anaerobic digestion by specific bacteria.
5) The anaerobic digestion releases methane gas which can be used as an energy resource and the remaining waste can be used as a fertiliser.
