What are the advantages and disadvantages of aerobic treatment of liquid manure instead of anaerobic treatment?

Aerobic treatment requires supplying enough oxygen to support aerobic bacteria. The amount of aeration needed (in increasing order) depends on whether it is desired to just reduce odor, or completely remove the oxygen demand of the organic matter, or to supply enough oxygen for nitrification of ammonia to nitrate.

Advantages of aeration can be reduced odor, nitrification of ammonia to nitrate (thus potentially reducing ammonia emissions and also having a nitrogen form that is readily crop-available but also more prone to leaching), and reduction of greenhouse gases (especially methane) compared to anaerobic treatment.

Disadvantages include higher capital cost for aeration equipment, higher operating cost (particularly energy for pumps or aerators), higher maintenance requirements, and possibly monitoring requirements for checking the dissolved oxygen level in the liquid. There are various methods and types of equipment for aeration, and selecting the most efficient equipment and methods may be difficult. Consultation with knowledgeable professionals is advisable. Aeration has not been used much in treatment of liquid manure primarily because of the increased expense.

For more information on aerobic treatment and other treatment options, see:
LPES Lesson on Biological Processes for Controlling Emissions

Author: Phil Westerman, North Carolina State University