Oversizing systems can have positive and negative results, depending on the final treatment system selected. On the other hand, some oversizing is desirable for soil-based treatment systems. Oversizing allows a treatment system s parts to be rested periodically, creating more flexible operation and extending system life. From a regulatory view, oversizing also reduces the need for monitoring and maintenance. Both of these are positives for individual systems, where it is hard to get individuals to perform such simple maintenance tasks as the regular cleaning of septic tanks.
Flow is a critical piece of the puzzle.
Keep in mind that basic decisions made early in designing a wastewater system carry through the construction and operating phases, and can have a large impact on system performance. When estimating flows, it is important to strike a balance among three considerations the desired treatment, the level of monitoring, and costs. After identifying the site and flow characteristics, the type of system can be selected. There is a wide variety of choices and they all offer advantages and disadvantages. The key is understanding each system's requirements and having a plan in place that will ensure the system's long-term operation.