What factor is essential for the effectiveness of secondary sewage treatment?

The effectiveness of secondary sewage treatment heavily relies on the presence of adequate bacteria to decompose waste. In this stage of sewage treatment, biological processes are employed to break down organic matter present in the wastewater. Bacteria play a crucial role as they metabolize the organic pollutants, converting them into carbon dioxide, water, and new cellular biomass through the process of digestion. The health and populations of these bacteria determine how well the wastewater can be treated; if bacterial levels are low or if the bacteria are not functioning optimally, the overall effectiveness of waste decomposition is compromised, leading to insufficient treatment.

While other factors, such as the size of the treatment facility, sunlight, and temperature, can influence specific aspects of the treatment process, they do not directly reflect the core purpose of secondary treatment, which is the biological breakdown of contaminants. Adequate bacterial presence ensures that this essential degradation process occurs efficiently, making it the fundamental requirement for successful secondary sewage treatment.