6. 25% Design a rapid sand filter system to treat 72,000 m3 per day using the following criteria: The filtration rate is

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6 25 Design A Rapid Sand Filter System To Treat 72 000 M3 Per Day Using The Following Criteria The Filtration Rate Is 1 (58.35 KiB) Viewed 43 times

6. 25% Design a rapid sand filter system to treat 72,000 m3 per day using the following criteria: The filtration rate is 240 m/d but should not exceed 280 m/d when operating with two filters out of operation. Size of filter unit is set at 30m2 (5m x 6m). Effective size of the sand is 0.5mm and the uniformity coefficient is 1.5 The density of the sand is 2.65 and the density of the anthracite 1.5 The operating temperature is 15°c and the viscosity (u) of the water is 0.00113 N.s/m2 The grain sphericity and the porosity for both sand and anthracite is 0.8 and 0.5, respectively Total time needed for backwash operation is 30 minutes where backwash duration is 15 minutes and filter to waste is 10 minutes and the air wash is 5 minutes. a. How many filter units are needed to carry out the filtration under normal operating conditions and what would be the operating filtration rate. b. What would be the size of anthracite to be used if it is decided to use dual media. (assume the difference in weight between sand and anthracite to be equal to 20%). (Volume of a sphere is 4/3nr). c. What is the backwash rate and the size of the backwash water tank. d. What would be the water lost due to backwashing and filter to waste per day assuming that each unit will be backwashed twice a day. Is it acceptable? How much water will be delivered at the end of the day?