Wastewater Treatment Operator Certification Practice Test

Which process is commonly used to reduce nutrient loading in wastewater treatment?

1. Filtration

2. Activated sludge process

3. Calcium carbonate precipitation

4. Chlorination

The correct answer is: Activated sludge process

The activated sludge process is widely recognized for its effectiveness in reducing nutrient loading, particularly nitrogen and phosphorus, in wastewater treatment. This biological treatment method involves aerating wastewater in a mixed environment containing microorganisms. These microorganisms, primarily bacteria, consume organic matter and nutrients as food, facilitating their breakdown and conversion into biomass. As the process continues, these microorganisms grow and reproduce, forming flocs that can settle out of the treated water during the subsequent clarification phase. The settled sludge can then be recycled back into the aeration tank, enhancing the system's efficiency in nutrient removal. Additionally, because this process supports the growth of specific bacteria capable of assimilating nutrients, it directly contributes to minimizing nutrient concentrations in the final effluent, thus mitigating issues related to eutrophication when the treated water is discharged into natural water bodies. In contrast, the other options present different functions or are less effective for specifically addressing nutrient loading in wastewater.