Which of the following is added during water or sewage treatment to promote flocculation?


a. sludge
b. PHA
c. BOD
d. alum

Verified step by step guidance

1. Step 1: Understand the context of the problem, which is about water or sewage treatment processes and the role of flocculation in these processes.
2. Step 2: Define flocculation. Flocculation is a process where fine particulates are agglomerated into a floc, which can then be easily removed from liquids.
3. Step 3: Review the options provided: a. sludge, b. PHA, c. BOD, d. alum.
4. Step 4: Identify which of these options is commonly used as a flocculant in water or sewage treatment. Flocculants are substances that promote the clumping of particles.
5. Step 5: Recognize that 'alum' (option d) is a well-known flocculant used in water treatment to promote the aggregation of particles into larger clumps, making them easier to remove.

Key Concepts

Flocculation

Flocculation is a process in water treatment where fine particulates clump together into a floc, which can then be removed from the water. This process is essential for clarifying water and is often enhanced by the addition of chemical agents that promote the aggregation of particles.

Alum

Alum, or aluminum sulfate, is a commonly used coagulant in water treatment processes. It works by neutralizing the charges on suspended particles, allowing them to aggregate and form larger flocs that can be easily removed from the water during sedimentation.

Sewage Treatment

Sewage treatment involves the removal of contaminants from wastewater to produce an effluent that can be returned to the water cycle with minimal environmental impact. This process often includes physical, chemical, and biological methods, with flocculation being a key step in the clarification phase.