Which of the following is true about secondary treatment in wastewater management?

Secondary treatment in wastewater management is primarily characterized by biological treatment processes, making it essential for the removal of organic pollutants. This stage of treatment aims to degrade organic matter using microorganisms, which feed on the waste, thereby reducing the levels of biological oxygen demand (BOD) and total suspended solids (TSS) in the effluent.

The biological processes involved can vary, including activated sludge systems, trickling filters, and sequencing batch reactors, all of which rely on the metabolic activities of bacteria and other microorganisms. These processes are effective at significantly reducing the organic load, converting harmful substances into less harmful byproducts that can be further processed or safely discharged.

The other options do not accurately represent secondary treatment. For example, it is not primarily a physical treatment method, as that would pertain more to primary treatment, which involves processes such as screening and sedimentation. Moreover, secondary treatment is highly effective in organic material removal, as its main purpose is to address this very issue. Finally, monitoring discharge is critical in wastewater treatment to ensure compliance with environmental standards and regulations, making it a necessary component of secondary treatment practices.