Which parameter is often used to assess the quality of treated wastewater?

Treated wastewater quality is assessed using multiple parameters, each serving a different purpose in determining the safety and environmental impact of the discharge. Dissolved oxygen is critical because it indicates the water's ability to support aquatic life; higher levels signify better water quality. The pH level is also crucial, as it affects chemical reactions and the solubility of nutrients and metals in water, influencing the overall ecosystem health. The concentration of heavy metals is essential for assessing potential toxicity, as these contaminants can have harmful effects on both human health and the environment.

Since all these parameters provide valuable information regarding the quality of treated wastewater, the correct choice highlights the comprehensiveness of wastewater quality assessment, recognizing that a single parameter alone cannot fully represent the overall situation. Each one addresses different aspects of water quality, which is why a holistic approach is employed in evaluating treated wastewater.