Massachusetts Wastewater Practice Exam

What might be one effect of unregulated industrial waste discharged to a municipal wastewater treatment plant?

1. Reduction in operational costs.

2. Improved plant performance.

3. Better cooperation from regulatory agencies.

4. Anaerobic digester upset.

The correct answer is: Anaerobic digester upset.

Unregulated industrial waste discharged to a municipal wastewater treatment plant can lead to an upset in the anaerobic digester, which is a crucial component of the treatment process. Anaerobic digesters rely on a specific balance of microorganisms to break down organic material in the absence of oxygen. When unregulated industrial waste, which may contain toxic substances or chemicals that are incompatible with the treatment processes, is introduced, it can disrupt the microbial balance. This upset may result in decreased efficiency in digestion, leading to problems such as increased odors, reduced biogas production, and potential sludge accumulation. The microorganisms may struggle to adapt to the sudden influx of unfamiliar materials, causing a decrease in their population or activity. This can ultimately impair the overall effectiveness of the wastewater treatment facility, resulting in violations of discharge permits and potentially harming the environment. In contrast, reduction in operational costs, improved plant performance, or better cooperation from regulatory agencies are unlikely to occur as a direct consequence of unregulated waste because these outcomes typically rely on consistent, regulated practices that ensure the plant operates within its design parameters and maintains a healthy relationship with its regulatory framework.