During the physical treatment process of wastewater, what is the correct order of following operations to be followed?

(A) Flocculation

(B) Filtration

(C) Screening

(D) Sedimentation

Choose the correct answer from the options given below :

Wastewater treatment

• Wastewater treatment is a process used to remove contaminants from wastewater or sewage and convert it into effluent that can be returned to the water cycle with acceptable impact on the environment, or reused for various purposes.
• Processes like screening, sedimentation, and skimming are used to remove the solids. No chemicals are involved in this process.
• One of the main techniques of physical wastewater treatment includes sedimentation, which is a process of suspending the insoluble/heavy particles from the wastewater.
• Water treatment is any process that improves the quality of water to make it appropriate for a specific end-use. The end use may be drinking, industrial water supply, irrigation, river flow maintenance, water recreation, or many other uses, including being safely returned to the environment.
• The primary treatment works on sedimentation, where solids separate from the water through several different tanks. In contrast, the secondary treatment uses aeration, biofiltration, and the interaction of waste throughout its process.

Key Points

• Primary or Physical Treatment: It is the process of removal of small and large, floating and suspended solids from sewage through two processes of filtration and sedimentation. The first floating and suspended matter are removed through sequential filtration with progressively smaller pore filters.
• These include: (1) Collection; (2) Screening and Straining; (3) Chemical Addition; (4) Coagulation and Flocculation; (5) Sedimentation and Clarification; (6) Filtration; (7) Disinfection; (8) Storage; (9) and finally Distribution.

Let's examine these steps in more detail                                                    

Therefore Option 2 is the correct answer.