Tennessee Wastewater Operator Practice Exam

What is the purpose of injecting diffused air into aerated grit chambers?

1. To increase temperature

2. To lower the specific gravity of water

3. To reduce pressure

4. To enhance chemical reactions

The correct answer is: To lower the specific gravity of water

Injecting diffused air into aerated grit chambers primarily serves to enhance the settling properties of grit and promote the efficient removal of solids. The introduction of air into these chambers helps to create a controlled environment that maintains a specific level of turbulence. This turbulence enables heavier particles, such as grit, to settle out more effectively while keeping lighter organic materials in suspension. While the choice of lowering the specific gravity of water might seem plausible, the key function of the air injection is not about changing the specific gravity. Instead, it focuses on optimizing the conditions for solid removal by ensuring that dense materials can settle at a faster rate without the interference from buoyant or lighter materials, thereby enhancing the overall treatment process. This important role of air injection helps ensure that the grit chamber operates efficiently and effectively in the preliminary treatment stages of wastewater management.