What does aerobic biological treatment of effluent primarily involve?

The primary focus of aerobic biological treatment of effluent is the breakdown of organic matter using oxygen. This process utilizes aerobic bacteria, which require oxygen to survive and thrive. During treatment, these bacteria metabolize organic materials present in wastewater, converting them into carbon dioxide, water, and cellular biomass. This not only helps in reducing the organic load of the effluent but also improves its quality before it is discharged into the environment.

In contrast, the other options involve different methods that do not specifically match the aerobic biological treatment process. For instance, using plants to filter water relates more to phytoremediation, while choosing marketing techniques is entirely unrelated to biological waste treatment. Adding chemical disinfectants, while a common practice in treating effluent, does not involve the biological breakdown of organic matter with the emphasis on oxygen that characterizes aerobic treatment. Thus, the selected answer accurately captures the essence of aerobic biological treatment in effluent management.