Activated sludge process is a suspended growth process in wastewater treatment.

Suspended Growth Process
- In a suspended growth process, microorganisms are suspended in the wastewater and form a mixed liquor. This mixed liquor contains both the microorganisms and the organic matter that needs to be treated.
- The microorganisms in the mixed liquor feed on the organic matter, metabolizing it and converting it into carbon dioxide, water, and new microbial cells.
- The suspended growth process is commonly used in wastewater treatment because it is effective in removing organic matter and nutrients from the wastewater.
- The activated sludge process is one type of suspended growth process used for wastewater treatment.

Activated Sludge Process
- The activated sludge process is a biological treatment process that uses aeration and agitation to promote the growth of microorganisms in the wastewater.
- In this process, wastewater is mixed with a culture of microorganisms called activated sludge, which contains a mixture of bacteria, fungi, and protozoa.
- The microorganisms in the activated sludge feed on the organic matter in the wastewater, removing it through a process of oxidation.
- Aeration is provided to the wastewater to ensure that there is enough dissolved oxygen for the microorganisms to carry out their metabolic processes.
- Agitation is also provided to keep the microorganisms in suspension and to promote contact between the microorganisms and the organic matter in the wastewater.

Other Processes in Wastewater Treatment
- In addition to the activated sludge process, there are other processes involved in wastewater treatment:
1. Preliminary Treatment: Involves the removal of large solids and grit from the wastewater through processes such as screening and grit removal.
2. Primary Treatment: Involves the removal of settleable solids and floating materials from the wastewater through processes such as sedimentation and flotation.
3. Secondary Treatment: Involves the biological treatment of the wastewater to remove organic matter and nutrients. The activated sludge process is one of the common secondary treatment processes.
4. Tertiary Treatment: Involves the further treatment of the wastewater to remove any remaining contaminants, such as pathogens and nutrients. This may include processes such as filtration, disinfection, and nutrient removal.
5. Sludge Treatment and Disposal: Involves the treatment and disposal of the sludge that is generated in the wastewater treatment process. This may include processes such as thickening, dewatering, and digestion.