10.6 Hexachlorocyclohexanes (HCHS) are organochlorine pesticides frequently found in lakes and oceans. HCH compounds have been shown in laboratory tests to undergo a first-order base hydrolysis reaction. Measurements of HCHS in a small impoundment with a hydraulic retention time of 20days indicate 30% removal. This impoundment behaves like two CMFR Sin series. What would be the expected removal in another impoundment of the same pH which has a hydraulic retention time of 90 days and behaves like three CMFRS in series?Answer: 83%.

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