What is an advantage of using low-rate or extended aeration tanks in small plants?

Using low-rate or extended aeration tanks in small wastewater treatment plants is particularly beneficial because they can effectively combine the roles of primary clarifiers and nitrogen removal processes. This integration allows for more efficient treatment within a compact system, which is especially advantageous in smaller facilities where space and resources may be limited.

The extended aeration process promotes prolonged microbial activity, which not only facilitates the breakdown of organic matter—similar to what occurs in primary clarification—but also enhances nitrogen removal due to the longer retention time of sludge. This extended contact time enables better nitrification and subsequent denitrification, essential steps in treating nitrogen compounds found in wastewater.

This capability to fulfill multiple functions in a single tank design can simplify the overall treatment process, minimize the need for additional infrastructure, and optimize operational efficiency. Consequently, the combination of roles improves the effectiveness of the treatment system while meeting regulatory requirements for nutrient removal.