Tennessee Wastewater Operator Practice Exam

What is an indicator of good Enhanced Biological Phosphorus Removal (EBPR) performance?

1. Low pH levels

2. High phosphorous content of MLSS

3. High nitrogen concentrations

4. Low COD levels

The correct answer is: High phosphorous content of MLSS

The correct choice regarding an indicator of good Enhanced Biological Phosphorus Removal (EBPR) performance is the high phosphorus content of Mixed Liquor Suspended Solids (MLSS). This is significant because EBPR processes are designed specifically to remove phosphorus biologically by promoting the growth of specific microorganisms, namely, phosphorus-accumulating organisms (PAOs). In a well-functioning EBPR system, these organisms take up phosphorus during their growth phase, thus increasing the phosphorus content in the MLSS. The higher the concentration of phosphorus in the MLSS, the more effectively the system is functioning to remove phosphorus from the wastewater. This indicates that the PAOs are thriving, which is essential for achieving the desired reduction of phosphorus levels in the effluent. The other choices do not align with optimal EBPR performance. Low pH levels might hinder microbial activity, high nitrogen concentrations do not directly indicate phosphorus removal efficiency, and low COD levels are not a direct measure of how effectively phosphorus is being removed. Instead, they may indicate a reduction of organic matter but are unrelated to the phosphorus removal performance associated with PAOs. Thus, the phosphorus content of the MLSS serves as a clear indicator of effective EBPR operation.