California Wastewater Treatment Operator Practice Exam

What should be done if a large amount of organic matter is found in the grit channel?

1. Decrease the velocity of the wastewater

2. Screen the wastewater

3. Increase the velocity of the wastewater

4. Switch to a different treatment method

The correct answer is: Increase the velocity of the wastewater

In a situation where a large amount of organic matter is found in the grit channel, increasing the velocity of the wastewater is a practical solution. This is because grit channels are designed to remove inorganic solids, such as sand and gravel, while allowing organic matter and other lighter materials to pass through. By increasing the velocity, you help to ensure that the flow is fast enough to push inorganic grit out, while minimizing the amount of organic matter that settles in that area. Maintaining an appropriate velocity helps keep the grit in suspension and prevents it from accumulating, which can lead to operational problems or inefficient treatment processes. Additionally, higher flow rates can minimize the organic load that might otherwise complicate the treatment process further down the line. Screening the wastewater or switching to a different treatment method can also be effective in other contexts. However, they might not be the most immediate or effective responses to address the organic matter issue specifically in the grit channel. Decreasing the velocity of the wastewater would likely exacerbate the problem, allowing more organic matter to settle and contributing to the accumulation of unwanted solids.