Imhoff tanks used for sewage disposal are primarily dependent upon the action of:

Imhoff tanks are designed for the treatment of sewage, utilizing a combination of settling and anaerobic treatment processes. The primary mechanism in these tanks is bacterial decomposition, where microorganisms break down organic matter in the sewage.

In this anaerobic environment, specific bacteria thrive and facilitate the decomposition of organic material, turning it into biogas and residual solids. The design of an Imhoff tank allows for effective settling of solids, enabling the separation of sludge from the liquid effluent, which is then subjected to further treatment processes if necessary. This reliance on the natural biological processes of bacteria is crucial for reducing pollutants and organic content in wastewater, making it a highly efficient method in sewage treatment.

High temperatures contribute to the efficiency of bacterial processes but are not the main functional element of an Imhoff tank. Similarly, while chemical disinfectants play a role in the final stages of wastewater treatment, they are not intrinsic to the function of the Imhoff tank itself. Water dilution can assist in wastewater treatment but does not pertain specifically to the mechanical and biological processes that Imhoff tanks utilize for effective sewage management. Thus, the action that primarily drives the operation of Imhoff tanks is indeed bacterial decomposition.