Final answer:
Filtration is used to remove dissolved and finely divided suspended solids from wastewater, which may include physical filtration through sand, biological treatment with microorganisms, and chemical processes such as coagulation and flocculation.
Step-by-step explanation:
Filtration is the process used to remove dissolved and finely divided suspended solids from wastewater. During this process, water is typically filtered through substances such as sand and rocks.
This physical treatment method effectively reduces turbidity, color, odors, and the levels of iron content and organic matter in the wastewater, thereby removing most bacteria and solids.
Another key stage in wastewater treatment is the secondary treatment, which targets dissolved and suspended biological matter. This often involves the use of microorganisms in a controlled environment, such as aerobic bacteria that consume organic components of the sewage.
To support bacterial growth, the sewage is mixed with air, facilitating the decomposition process.
Additionally, coagulation and flocculation are chemical processes used to remove iron oxide particulates and organic matter, giving water a clearer appearance. After coagulation, the wastewater moves to a sedimentation tank where the flocculated particles settle, and the clear water flows to further filtration units.