Question

Which process is commonly used in secondary treatment to break down organic matter?

• A. Filtration
• B. sedimentation
• C. Chlorination
• D. Activated sludge process

Hint:

• Secondary treatment aims to remove dissolved and fine suspended organic matter using biological processes.
• The Activated Sludge Process is a common aerobic biological method where microorganisms in an aerated environment consume organic pollutants.
• Other secondary treatment methods include trickling filters and rotating biological contactors.
• Filtration and sedimentation are physical processes; chlorination is for disinfection.

Answer 1

The Correct Option is D

To answer the question, let's explore the process commonly used in secondary treatment to break down organic matter in wastewater.

1. Understanding the Concepts:

- Secondary Treatment in Wastewater Treatment: Secondary treatment is a crucial step in the wastewater treatment process that focuses on breaking down and removing organic matter, such as dissolved and suspended solids, that were not removed during primary treatment. This stage typically involves biological processes where microorganisms degrade organic pollutants.

- Common Processes in Secondary Treatment: The main goal of secondary treatment is to biologically treat wastewater, typically by using bacteria and other microorganisms to break down organic pollutants. This is usually done in aeration tanks or through other biological processes that promote the activity of microorganisms.

2. Breakdown of the Given Options:

• Option 1: "Filtration": Filtration is generally a physical process used in primary treatment to remove large particles from the wastewater, but it is not typically used in secondary treatment to break down organic matter. Secondary treatment focuses on biological methods.
• Option 2: "Sedimentation": Sedimentation is a physical process used primarily in primary treatment to settle out large particles. While it may also be used in secondary treatment to remove sludge, it does not play a major role in breaking down organic matter.
• Option 3: "Chlorination": Chlorination is a chemical process used in the disinfection stage, typically during the final stages of wastewater treatment, to kill harmful pathogens. It does not break down organic matter in the secondary treatment process.
• Option 4: "Activated Sludge Process": This is the correct answer. The activated sludge process is the most commonly used method in secondary treatment. In this process, air or oxygen is pumped into aeration tanks where bacteria and microorganisms break down organic matter in the wastewater. The treated water is then separated from the remaining sludge through sedimentation.

3. Conclusion:

The activated sludge process is the key method used in secondary treatment to biologically break down organic matter, making the water cleaner and safer for further use or discharge.

Final Answer:

The process commonly used in secondary treatment to break down organic matter is the activated sludge process.