Municipal Wastewater Treatment Practice Exam

Secondary treatment processes in wastewater treatment primarily focus on the biological removal of organic matter. The correct choice emphasizes key monitoring parameters that directly relate to the efficiency of biological treatment methods.

Biochemical Oxygen Demand (BOD) is a critical indicator of the organic pollution in wastewater. It measures the amount of oxygen that microorganisms will consume while decomposing organic matter under aerobic conditions. Monitoring BOD helps to assess the effectiveness of the biological treatment process, as lower BOD levels indicate successful removal of organic contaminants.

Total Suspended Solids (TSS) is another essential parameter. It measures the solids present in the wastewater that can be trapped by a filter, which reflects both the physical presence of particulates and the potential for biological activity in the treatment stage. High TSS levels can impair treatment efficacy and reduce the quality of effluent.

Dissolved Oxygen (DO) levels are critical for aerobic biological treatment processes. Sufficient dissolved oxygen is necessary for aerobic microorganisms to break down organic substances effectively. Monitoring DO ensures that conditions remain favorable for these microorganisms, promoting the efficient degradation of organic pollutants.

Together, BOD, TSS, and dissolved oxygen levels comprehensively characterize the biological process's performance and are integral to controlling and optimizing secondary treatment operations.