California Wastewater Treatment Operator Practice Exam

What is a common consequence of heavy metals in treated wastewater?

1. They aid in the purification process

2. They create a more stable sludge

3. They may cause harm to aquatic environments

4. They enhance water quality

The correct answer is: They may cause harm to aquatic environments

Heavy metals in treated wastewater pose significant environmental concerns, primarily because they can cause harm to aquatic environments. When wastewater containing heavy metals is discharged into water bodies, these metals can accumulate in the sediments and be taken up by aquatic organisms. This bioaccumulation can lead to toxic effects on fish, invertebrates, and other wildlife, disrupting ecosystems and potentially affecting human health through the consumption of contaminated fish and shellfish. In contrast, heavy metals do not aid in purification, nor do they enhance water quality. While stable sludge might be desirable in certain contexts, heavy metals generally contribute to toxicity rather than stability. Therefore, recognizing the harm that heavy metals can inflict on aquatic ecosystems is crucial for wastewater treatment practices and environmental protection efforts.