The major advantages of aerobic digestion over anaerobic digestion are:
- Volatile solids reduction meets or exceeds that of anaerobic digestion.
- The stabilized sludge is free of offensive odor and an excellent fertilizer.
- Supernatant BOD concentrations are lower than that of anaerobic digestion.
- Operation is relatively easy.
The major disadvantage of aerobic digestion is the cost of supplying oxygen to the micro-organisms.Power cost for supplying oxygen, however, may not be as significant at smaller plants.
Other disadvantages are that the stabilized sludge sometimes has poor dewatering characteristics and process performance depends strongly on temperature. Aerobic digestion is more commonly used at smaller municipal wastewater treatment plant with wastewater flows less than 5 mgd (million gallon day)
The major difference between aerobic and anaerobic digestion is that microorganisms are supplied oxygen in aerobic digestion
Aerobic digestion fundamentally follows the principles of the biological mechanism of endogenous
respiration. When little food is available to the biomass population, microorganisms consume
their own protoplasm as an energy source, thereby reducing the volatile solids concentration of the
The end products of aerobic digestion are carbon dioxide, water, and ammonia or nitrates.
However, the entire cell cannot be biologically transformed to these end products. Approximately
25 percent of the cell is typically non-biodegradable.