Which test typically yields results more quickly than the BOD test?

• A. BOD test
• B. TOC test
• C. TSS test
• D. COD test

Answer: (D)

The speed difference comes from how the test measures organic load. BOD relies on microbes consuming oxygen over a set period, typically five days, so it naturally takes days to get a final result. COD uses a chemical oxidation with a strong oxidant to break down organics quickly, usually in a few hours, so you get results far faster. TOC can be quick with the right instrument, and TSS requires filtering and drying, which takes some hours, but the key point is that COD doesn’t depend on biological activity and is designed for rapid estimation, making it the fastest among these options relative to BOD.