Tennessee Wastewater Operator Practice Exam

What effect does an increase in temperature generally have on wastewater treatment processes?

1. It decreases gas production

2. It increases biological activity

3. It decreases solubility of gases

4. It increases sludge volume

The correct answer is: It increases biological activity

An increase in temperature in wastewater treatment processes typically enhances biological activity. Microbial organisms, such as bacteria, are crucial in breaking down organic material in wastewater, and their metabolic rates generally rise with temperature. Warmer temperatures can lead to faster growth rates and increased enzymatic activity among these microorganisms, promoting more effective digestion of organic pollutants. This can lead to improved treatment efficiency as bacteria metabolize waste more rapidly, which is particularly important in processes like activated sludge systems or biofilters where microbial action is a primary mechanism for removing contaminants. In contrast, while temperature affects other parameters such as gas solubility and sludge production, the most notable and direct impact is the acceleration of biological processes. Higher temperatures can indeed reduce the solubility of gases like oxygen, which can be critical in aerobic treatment processes, but the overall benefit regarding treatment efficiency lies in the increase in biological activity. Additionally, while higher temperatures can lead to increased sludge volume due to enhanced microbial growth, this increase often relates back to the biological activity rather than being a primary objective of temperature increases.