A biological process that uses microorganisms in presence of dissolved oxygen to break down organic pollutants is called an aerobic digestion process. An aerobic digestion process may involve a single or a consortium of microorganisms that work together to degrade complex organic matter.
The microorganisms break down the organic pollutants producing carbon dioxide, water, and energy.
Biological units are the most important component of wastewater treatment plants as more than 50 to 90% of the reduction in pollution happens in a biological unit. Most of the aerobic units face issues related to their effectiveness and efficiency.
Poor microorganism performance is one of the major issues. Inadequate mixing and aeration further add to the problem as it cannot maintain an optimum environment for microorganisms.
pH variation, shock loads in hydraulic and organic loading, external factors such as changes in temperature, changes in the composition of wastewater, and influxes of toxic pollutants can further upset conditions that can reduce the performance of the biological units.
Excess build-up of sludge in biological units can reduce their efficiency and effectiveness, requiring regular removal and disposal.
