What is the Difference Between Activated Sludge and Primary Sludge?

The main difference between activated sludge and primary sludge lies in their composition and the processes they are involved in:

1. Composition: Activated sludge contains a high concentration of microorganisms, including bacteria, protozoa, and fungi, which are present as a loose, clumped mass of fine particles. Primary sludge, on the other hand, does not contain microorganisms and consists of organic matters such as faeces, vegetables, fruits, textiles, and paper.
2. Formation Process: Activated sludge is formed during the secondary sewage treatment, while primary sludge is formed during the primary sewage treatment.
3. Aeration: The formation of activated sludge requires aeration, whereas primary sludge does not require aeration.
4. Decomposition: A lot of decomposition occurs during the formation of activated sludge, whereas very little decomposition occurs during the formation of primary sludge.

In summary, activated sludge is a mixture of microorganisms formed during the secondary sewage treatment, while primary sludge is a collection of organic matters formed during the primary sewage treatment. Activated sludge requires aeration and undergoes significant decomposition, whereas primary sludge does not require aeration and has little decomposition.

Comparative Table: Activated Sludge vs Primary Sludge

Here is a table comparing the differences between activated sludge and primary sludge:

Primary sludge is generated from chemical precipitation, sedimentation, and other primary processes, while activated sludge is a process that has a high concentration of microorganisms, including bacteria, protozoa, and fungi, which are present as a loose, clumped mass of fine particles.