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Read the following statements w.r.t. bio...

Read the following statements w.r.t. biological treatment of sewage. Br a. Involves removal of sewage through sequential filteration. Br b. BOD of waste water is directly proportional to its a polluting potential. Br c. Constant agitation of primary effluent is carried out in large aeration tanks. Identify the incorrect statement(s)

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To identify the incorrect statements regarding the biological treatment of sewage, let's analyze each statement step by step. ### Step 1: Analyze Statement A **Statement A:** "Involves removal of sewage through sequential filtration." - **Explanation:** The biological treatment of sewage primarily involves the use of microorganisms to decompose organic matter. The removal of sewage through sequential filtration is not a part of biological treatment; rather, it is a part of physical treatment or primary treatment. In primary treatment, solid waste is separated from liquid waste through filtration and sedimentation. Therefore, this statement is **incorrect**. ### Step 2: Analyze Statement B **Statement B:** "BOD of wastewater is directly proportional to its polluting potential." - **Explanation:** Biological Oxygen Demand (BOD) measures the amount of oxygen that microorganisms will consume while decomposing organic matter in water. A higher BOD indicates a higher level of organic pollution, meaning more oxygen is required for microbial decomposition. Thus, BOD is indeed directly proportional to the polluting potential of wastewater. Therefore, this statement is **correct**. ### Step 3: Analyze Statement C **Statement C:** "Constant agitation of primary effluent is carried out in large aeration tanks." - **Explanation:** In biological treatment, aeration tanks are used to mix the primary effluent with microorganisms and provide oxygen for aerobic respiration. While agitation is important, the statement implies that constant agitation is the primary function of aeration tanks. The main purpose of aeration tanks is to supply oxygen to the microorganisms, not just to agitate the effluent. However, since the statement does not accurately describe the primary function of aeration tanks, it can also be considered **incorrect**. ### Conclusion The incorrect statements are: - **Statement A**: Involves removal of sewage through sequential filtration (incorrect). - **Statement C**: Constant agitation of primary effluent is carried out in large aeration tanks (incorrect).
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