The Hidden Role of Potassium Dichromate in BOD Testing: Practical Applications and Real-World Insights

Water is life, but when polluted, it can quickly become a harbinger of disease and environmental damage. Testing for water quality is vital, and the Biochemical Oxygen Demand (BOD) test is a cornerstone method, measuring the oxygen consumed by microorganisms breaking down organic pollutants over five days. While potassium dichromate (K₂Cr₂O₇) is better known for its use in Chemical Oxygen Demand (COD) tests, its story doesn’t end there. This powerful chemical has a subtle yet important role in understanding water pollution, especially when BOD and COD results are analyzed together.

Why Potassium Dichromate Matters in Water Analysis

Think of potassium dichromate as the "detective" of water testing. In COD tests, it reveals the full extent of pollution by chemically oxidizing both biodegradable and non-biodegradable substances. The BOD test, on the other hand, measures oxygen demand due only to biodegradable organic matter, giving insight into what microorganisms can naturally break down. Together, these tests offer a complete picture of water quality, with potassium dichromate playing a key role in exposing hidden pollutants.

Real-World Scenarios: Decoding Water Pollution with BOD and COD

1. Uncovering Pollution in Rivers

In a study of river water downstream from a city, researchers used both BOD and COD tests: