What condition is created by oxygen present in an anaerobic digester?

In an anaerobic digester, the presence of oxygen creates a condition that is contrary to its design, which is to function without oxygen. The key purpose of an anaerobic digester is to promote anaerobic conditions, allowing specific types of microorganisms to thrive, particularly those that produce methane as a byproduct of the digestion process.

When oxygen is introduced into an anaerobic digester, it poses a significant risk of explosion. This is because anaerobic processes generate methane, which is highly flammable. The introduction of oxygen can lead to a mixture of gases that, when ignited, can result in an explosion. Therefore, the correct answer highlights the potential for a hazardous situation when oxygen is inadvertently introduced into an anaerobic system designed to operate without it.

The other options are not conducive to the functioning of an anaerobic digester when oxygen is present. A stable environment and high production of methane would not occur under oxygenated conditions, as aerobic bacteria would outcompete the anaerobic bacteria, disrupting the intended biological processes. Similarly, while bacteria growth may occur, it would not be beneficial growth relevant to the anaerobic digestion process, as aerobic and anaerobic bacteria require different conditions to thrive.