What does the BOD test measure in wastewater treatment?

The BOD test, or Biochemical Oxygen Demand test, is a critical measure used in wastewater treatment that quantifies the amount of biodegradable organic matter present in a sample. By assessing how much oxygen microorganisms will consume while decomposing organic materials under aerobic conditions over a specified period (typically five days), the BOD test provides insight into the organic pollution in wastewater.

This measurement is essential because it helps operators understand the potential impact of the wastewater on receiving waters. Higher BOD values indicate a greater level of organic pollution, which can lead to oxygen depletion in aquatic ecosystems, harming aquatic life.

The other options focus on different parameters within wastewater treatment. Total dissolved solids reflect the concentration of all dissolved substances but do not specifically measure organic matter. The concentration of harmful bacteria concerns microbiological safety rather than organic content, and chemical oxygen demand relates to the total oxygen required to oxidize both biodegradable and non-biodegradable substances, not exclusively organic matter. Thus, the BOD test specifically targets and quantifies the biodegradable portion, making it a vital tool for monitoring and managing wastewater treatment processes.