What is the purpose of a "lead-lag" configuration in wastewater treatment processes?

In wastewater treatment processes, a "lead-lag" configuration is utilized primarily to enhance efficiency and maintain capacity. This configuration involves two or more treatment units where one unit (the lead) operates while the other (the lag) is on standby or used as a backup.

The purpose of this arrangement is to ensure continuous treatment, as the lag unit can be brought online seamlessly when the lead unit is either undergoing maintenance or is overloaded. This not only helps in managing varying inflow rates but also ensures that efficient treatment can occur at all times without risking violations of discharge standards. This setup maximizes operational reliability by allowing for flexibility in responding to fluctuations in wastewater volume or quality, thereby maintaining overall treatment capacity without downtime.

While increasing the number of treatment units may be a consideration in some scenarios, the primary goal of a lead-lag system is to optimize the performance of existing units. Additionally, while operational costs may be influenced by such configurations, the main advantage lies in enhancing the efficiency and effectiveness of the treatment process itself. Manual operation of each unit is not a purpose of this configuration, as the focus is on automated and dynamic management of treatment units to provide continuous service.