Which test pair are commonly used to assess organic content in wastewater besides BOD?

• A. COD and TOC
• B. TSS and VSS
• C. pH and alkalinity
• D. Nitrates and phosphates

Answer: (A)

The main idea is that wastewater’s organic content is measured with tests that capture different aspects of organics beyond what BOD shows. Chemical Oxygen Demand and Total Organic Carbon together give a broader picture: COD estimates how much oxygen would be needed to chemically oxidize nearly all organic matter in a sample, providing a quick, overall gauge of organic strength (including stuff that isn’t easily biodegradable). TOC directly measures the amount of carbon contained in organic compounds, giving a direct mass-based view of organic load. Used together, they complement BOD by covering both the oxygen-demanding potential of organics and the actual organic carbon present, which is why this pair is commonly used to assess organic content in wastewater.

The other options don’t fit as well. Suspended solids (TSS and VSS) relate to particle content, not the organic material in solution. pH and alkalinity speak to acidity and buffering capacity, not organic load. Nitrates and phosphates are nutrients, not measures of organic content.