Chemistry 10.1.4 Flashcards
Where does Water end up when it is run down the Drain?
It passes through the Sewers into Sewage Treatment Plants.
Why does both Domestic & Agricultural Sewage need to be Processed?
To Remove Organic Matter, Harmful Microbes, Particulates, & Toxins.
Where does Water go after is has been Treated & Purified?
It is Returned back to Freshwater Sources, eg Lakes & Rivers.
What are the Stages of ‘Sewage Treatment’? Explain them. (4)
-Screening & Grit Removal: Remove Large Materials by Screening.
-Sedimentation: Water in a Tank. Heavier Solids Sink to the Bottom. Creates Sewage Sludge. Lighter Materials Float, & Create Effluent.
-Aerobic Digestion: Effluent is Removed, & Treated by Aerobic Digestion. This Involves Pumping Air into the Water to Encourage the Breakdown of Organic Matter & Other Microbes by Aerobic Bacteria.
-Anaerobic Digestion: Used to Break Down the Sewage Sludge from the Bottom of the Settlement Tank. Firstly Broken Downs, then Placed in Larger Tanks, Where Bacteria Break it Down. Releases Methane Gas, which is Used as an Energy Source. Digested Waste is Used as a Fertiliser.
What is a Common Method Used to Cleanse Water of Toxic Substances?
UV Radiation.
