Which organisms play a lesser role in reducing sewage to "soil," liquids, and gases?

The role of anaerobic bacteria in the reduction of sewage material is indeed significant; however, when considering the broader ecosystem involved in processing waste, anaerobic bacteria play a more specialized role compared to the other organisms listed.

Anaerobic bacteria primarily thrive in environments devoid of oxygen and are involved in the breakdown of organic matter under such conditions. While they are effective at digesting sewage and converting it into simpler substances, their contributions often result in the production of gases like methane and carbon dioxide rather than solid organic matter or soil.

In contrast, earthworms, protozoa, and aerobic bacteria engage in processes that are more directly aligned with converting waste into soil and enriching it. Earthworms, through their physical activity and digestion, improve soil structure and nutrient content, facilitating the conversion of organic waste into a fertile substrate. Aerobic bacteria operate in oxygen-rich environments and are highly efficient at decomposing organic material, thus transforming sewage into liquids and nutrients that can be absorbed by plants. Protozoa also contribute to this process by consuming bacteria and organic matter, helping to maintain a balance in the ecosystem involved in waste degradation.

Therefore, the role of anaerobic bacteria is necessary but can be seen as less comprehensive in the overall transformation of sewage into soil, liquids