What does the five-day biochemical oxygen demand test primarily measure in wastewater?
Correct answer: A. Oxygen used by microbes to decompose biodegradable organic matter
- A. Oxygen used by microbes to decompose biodegradable organic matter
- B. Oxygen dissolved in water after complete physical treatment
- C. Chlorine needed to destroy disease-causing organisms
- D. Suspended solids removed during sedimentation
Explanation
BOD5 measures the dissolved oxygen consumed by microorganisms while decomposing biodegradable organic matter over five days at a specified temperature. It does not directly measure chlorine demand or suspended solids concentration.
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About Environmental Engineering
Environmental engineering examines water supply, water quality, treatment processes, wastewater collection and treatment, solid waste management, air pollution and public health protection. It covers sedimentation, coagulation, filtration, disinfection, biological treatment and disposal methods, while distinguishing drinking-water treatment from sewage treatment and BOD from COD.
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