Answer:
The correct option is;
B. Remove the organic materials from the sewage
Step-by-step explanation:
In water treatment plants, floating the and settling solid wastes (by gravity) materials are removed and further process of sedimentation, screening grit removal are performed, to segregate and remove form solid wastes. Sedimentation tanks known as primary clarifiers are used to remove suspended solid wastes.
The soluble organic materials that pass through primary treatment are removed in the secondary treatment
The reduction and removal of the soluble and insoluble organic matter serves to preserve the amount of oxygen available in the final destination of the treated sewage waste water including a lake or stream.