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Faecal coliform bacteria is a class of microorganisms found in the excreta or waste produced by all warm blooded animals & humans.

|
Parameter |
Biochemical Oxygen Demand (BOD) |
Chemical Oxygen Demand (COD) |
|
Definition |
Measure of oxygen consumed by microorganisms breaking down organic matter in water. |
Measure of total oxygen needed to chemically oxidize all organic matter in water. |
|
Scope |
Only measures oxygen consumed by microbial activity. |
Measures oxygen needed for complete oxidation (biodegradable and non-biodegradable). |
|
Focus |
Biological breakdown of organic pollutants. |
Total oxidation of organic matter (both biodegradable and non-biodegradable). |
|
Timeframe |
Measured over a 5-day period at 20°C (BOD5). |
Measured within hours using a strong chemical oxidizing agent. |
|
Relevance |
Indicates organic pollution that is biodegradable. |
Indicates total pollution, including non-biodegradable substances. |
|
Method of Measurement |
Typically involves microbial activity in a water sample. |
Involves chemical reagents, often potassium dichromate, to oxidize organic matter. |
Source: Livelaw
|
PRACTICE QUESTION Q. Biological Oxygen Demand (BOD) is a standard criterion for a) Measuring oxygen levels in blood b) Computing oxygen levels in forest ecosystems c) Pollution assay in aquatic ecosystems d) Assessing oxygen levels in high altitude regions Answer : c Explanation: Biological Oxygen Demand (BOD) is a standard criterion for pollution assay in aquatic ecosystems. It measures the amount of oxygen required by microorganisms to break down organic matter in water, which helps assess the level of pollution in water bodies. |
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