Question

Your engineering firm has been asked to determine whether the secondary clarifier (labeled“SECONDARY") downstream from the aeration basin (labeled “AERATION") is leaking at your local wastewater treatment plant. You conduct

measurements over 45 minutes. During this time,you determine the average inflow rate Qin= 4.5 m³/min, the average outflow rate Qout = 4.0 m³/min, and the change in volume in the secondary clarifier is AV= 2.2 m³. You also determine that the fluid removed from the aeration basin is 90% water and 10% air by volume,since the fluid contains air bubbles. These bubbles rapidly dissipate in the secondary clarifier. Is the secondary clarifier leaking, and if so, at what rate? [kg/min]

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