Standard Biochemical Oxygen Demand (BOD) test is performed in a 300 ml BOD bottle at:

Correct option is C

The correct answer is (c) 20°C after 5 days.
The Standard Biochemical Oxygen Demand (BOD) test measures the amount of oxygen consumed by microorganisms while decomposing organic matter under aerobic conditions. The standard conditions for this test are:
· Temperature: 20°C
· Duration: 5 days
· Volume: 300 ml bottle
These conditions are standardized to provide consistent and reproducible results for water quality assessments.
Information Booster: 1. Biochemical Oxygen Demand (BOD): Measures the amount of dissolved oxygen needed by aerobic microorganisms to break down organic matter in water.
2. Standard Conditions: 20°C for 5 days is used worldwide to compare the organic pollution level in water bodies.
3. BOD₅: The BOD measured after 5 days is referred to as BOD₅.
4. 300 ml Bottle: The standard size used for BOD testing to allow for proper oxygen measurement and microbial activity.
5. Water Quality Indicator: BOD is a critical parameter for assessing the level of pollution in wastewater, rivers, and lakes.
Additional Knowledge: · High BOD Values: Indicate high levels of organic pollution, which can lead to oxygen depletion in water bodies.
· Low BOD Values: Suggest cleaner water with lower levels of biodegradable organic matter.
· Factors Affecting BOD: Temperature, microbial activity, and the nature of the organic matter.
· BOD vs. COD:
· BOD (Biochemical Oxygen Demand): Measures biologically degradable matter.
· COD (Chemical Oxygen Demand): Measures total organic matter, including non-biodegradable substances.