Which of the following statements is true regarding wastewater treatment efficiency?

When evaluating the efficiency of wastewater treatment systems, it is important to understand the differences in how gravity and pressurized systems operate. Pressurized systems often provide better distribution of wastewater throughout the treatment area, which can lead to improved oxygenation and filtration. This increased aeration helps in breaking down organic materials more effectively compared to gravity systems, which may struggle with distribution and can lead to settling issues.

Furthermore, pressurized systems can effectively mitigate issues such as ponding or backups that dilute treatment efficacy. The flexibility in design and distribution that pressurized systems offer typically shows greater overall treatment efficiency, particularly in varying soil conditions or where surface water infiltration is a concern. In this context, stating that gravity systems are generally less efficient than pressurized systems aligns with established observations regarding wastewater treatment performance.