What aspect is NOT required for the screening of effluent in septic tanks?

The requirement for screening effluent in septic tanks primarily revolves around ensuring that solids are removed effectively before the effluent is released into the environment or processed further. A system that is fitted with a fan is not necessary for this function. The purpose of screening is to prevent larger particles from passing through and potentially clogging downstream components or harming the environment.

A fan may be used in certain plumbing or ventilation systems to aid in air movement or odor control, but it does not serve the function of screening effluent in a septic tank. Therefore, it is correct to state that a fan is not a required component of an effluent screening process in septic systems. This highlights the importance of recognizing that while various enhancements can be made to septic systems for efficiency or performance, certain basic functional requirements do not include such features.