During what condition should effluent samples preferably be collected?

Effluent samples should preferably be collected during routine operational periods because this allows for the sampling of water under stable and predictable conditions. Collecting samples during these times ensures that the data reflects typical operating conditions of the facility. This is crucial for establishing a reliable baseline for compliance monitoring and helps in accurately assessing the performance of the treatment processes.

Sampling during peak flow conditions or during unexpected changes may often result in higher variability in the data, which can obscure the true performance of the system. Peak flow may dilute contaminants and lead to lower concentrations being measured, while unexpected changes could be related to temporary anomalies that do not reflect normal operations, making the data less useful for compliance purposes. Hence, focusing on routine operational periods helps achieve consistency in sampling efforts and enhances the reliability of compliance assessments.