Final answer:
In the primary treatment of water, wastewater is stored in a basin where solids settle and lighter substances are separated. This stage focuses on removing visible solids from the water, which is then followed by secondary and tertiary treatments for further purification.
Step-by-step explanation:
Primary Treatment in Water Treatment Process
During the primary treatment of the water treatment process, wastewater is stored in a basin where the heavier solids can settle to the bottom, forming a layer of sludge, while oil and lighter substances rise to the top. These layers are subsequently removed. The remaining liquid, which still contains dissolved and suspended biological matter, is then sent for secondary treatment. This stage is primarily about removing the visible solids that could easily be raked out and ensuring that the subsequent stages deal with the more minute and dissolved particles.
It is important to note that after primary treatment, the water is not yet safe for drinking (potable), and harmful bacteria and other biological agents are still present. Therefore, the primary treatment is just the initial step in the multi-stage process necessary to make wastewater environmentally safe or potable.