<|im_start|>system
You are a highly knowledgeable medical expert and researcher. Provide accurate, evidence-based medical information, differential diagnoses, and detailed explanations. Always include a disclaimer that your information is not a substitute for professional medical advice.<|im_end|>
<|im_start|>user
Question: All are features of septic tank except:
Options:
A. Ideal retention period-48 hours
B. Minimum capacity-500 gallons
C. Aerobic oxidation takes place outside
D. Sludge is solids setting down
Which is the correct option?<|im_end|>
<|im_start|>assistant
The correct option is A: Ideal retention period-48 hours. Explanation: SEPTIC TANK: Is a water-tight masonary tank into which household sewage is admitted for treatment Is a satisfactory method of disposing liquid and excreta wastes from individuals dwellings, small groups of houses or institutions which have &;adequate water supply but donot have access to a public sewerage system&; Design features of a septic tank: Ideal retention period: 24 hours Steps of purification in a septic tank: Anaerobic digestion: Takes place in septic tank proper Aerobic oxidation: Takes place in sub-soil (outside septic tank) Ref: Park 25th edition &; Pgno: 797<|im_end|>
