1. Oxygen Supply:
- Aeration tanks are designed to provide a sufficient supply of dissolved oxygen to the bacteria present in the water. Oxygen is essential for the metabolic processes of aerobic bacteria, which are responsible for breaking down organic pollutants.
- The oxygen demand in an aeration tank is high due to the abundance of bacteria and the organic matter they are consuming. By continuously supplying oxygen, the environment is maintained aerobic, ensuring efficient biodegradation.
2. Bacterial Growth and Metabolism:
- Bacteria added to the aeration tank are responsible for the biological removal of pollutants. These bacteria consume organic compounds as a source of carbon and energy for growth and reproduction.
- The addition of oxygen enhances bacterial growth and metabolic activity. Aerobic bacteria require oxygen to carry out cellular respiration, which generates energy in the form of ATP. With sufficient oxygen, bacteria can reproduce rapidly and maintain a high population density, leading to efficient wastewater treatment.
3. Biodegradation of Organic Matter:
- The primary function of bacteria in the aeration tank is to degrade organic pollutants present in the wastewater. Organic compounds, such as carbohydrates, proteins, and fats, are broken down into simpler substances like carbon dioxide, water, and microbial biomass.
- Oxygen serves as the electron acceptor in the respiratory processes of bacteria during the biodegradation of organic matter. Without adequate oxygen, the biodegradation process would be limited, and organic pollutants would remain in the wastewater.
4. Nitrification and Denitrification:
- In addition to organic matter degradation, the aeration tank also facilitates nitrification and denitrification processes, which are essential for nitrogen removal.
- Nitrifying bacteria convert ammonia into nitrates and nitrites, while denitrifying bacteria convert nitrates into nitrogen gas. These processes contribute to the removal of nitrogen from wastewater, preventing eutrophication in receiving water bodies.
By providing a controlled environment with sufficient oxygen and the necessary bacterial populations, aeration tanks play a crucial role in the activated sludge process for effective wastewater treatment and the removal of pollutants.