Question

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3) Practice tice problem 1. When drinking water treatment plants chlorinate water, the chlorine must remain in contact with the water for at least 30 minutes before being delivered to customers. A water plant operator wishes to know i his existing 10,000-gallon storage tank can provide this HRT. He does a wash-out tracer test with fluoride salt (conservative). The initial concentration is i2 mg/L and after an hour of feeding non-fluoridated water through the tank at 20 gpm, the concentration has dropped to 2 mg/L. Does the tank have the required HRT? Answer: Yes, the HRT is 33.5 minutes. Practice problem 2. Upstream of a pond (75,000 m2 with a downstream outlet stream) a factory has discharged XYZ to the creek feeding the pond for many years. A new wastewater treatment system is installed which removes XYZ totally from the factory wastewater. If the creek flowrate is 0.5 m'/s and there is no other source of XYZ in the system, how long will it take for the pond concentration to drop to 10% of its original value? Answer:

Answer 1

Hormone replacement therapy is used to help balance estrogen and progesterone in women around the time of menopause. Also known as hormone therapy (HT) or menopausal hormone therapy (MHT),hormone replacement therapy (HRT) can help relieve sweating, hot flashes, and other symptoms of menopause.