Differentiate between BOD and COD and discuss their importance.
In short
BOD measures the oxygen microbes need to decompose biodegradable organic matter over five days, while COD measures the oxygen needed to chemically oxidise all organic matter, within hours. BOD shows the risk to aquatic life, COD the total pollution load, and their ratio shows whether effluent can be treated biologically.
Model answer
Ghissu Editorial · Verified 4 Oct 2026 · 305 words
BOD Explained
Measures oxygen demand by aerobic bacteria to degrade biodegradable organics over five days at 20°C, indicating biological pollution load.
COD Explained
Measures total oxygen needed to chemically oxidize all organics, including non-biodegradable, using strong oxidants, providing a comprehensive pollution metric.
Testing Agencies
Andhra Pradesh Pollution Control Board (APPCB) uses BOD and COD to monitor rivers like Godavari and Krishna, crucial for irrigation and drinking water.
Testing Methods
BOD involves biological incubation; COD uses chemical reagents for rapid results.
Pollution Scope
BOD targets biodegradable organics; COD includes resistant pollutants, critical in Visakhapatnam industrial zones.
Time Efficiency
BOD requires 5 days; COD results come within hours, enabling faster management decisions.
Environmental Impact
High BOD causes oxygen depletion affecting aquatic life; COD helps identify total organic load for comprehensive pollution control.
Monitoring Gaps
Rural Andhra Pradesh faces lab infrastructure shortages, delaying water quality management in Rayalaseema and coastal areas.
Policy and Awareness
APPCB enforces BOD and COD standards under Water Act; community education in cities like Vijayawada improves compliance.
Future Steps
Expand accredited labs, integrate BOD-COD data for targeted pollution control in Visakhapatnam and Krishna delta, and promote citizen engagement via apps.
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Question from the official APPSC Group-I Mains 2012 paper. Answer written by Ghissu's engine and checked against our editorial standards. Found an error? Tell us and we correct it within 48 hours.