(12%) Question (4-B) (4 marks each) 1. Three wastewater streams are combined at a food processing facility to equalize t

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12 Question 4 B 4 Marks Each 1 Three Wastewater Streams Are Combined At A Food Processing Facility To Equalize T 1 (225.41 KiB) Viewed 38 times

(12%) Question (4-B) (4 marks each) 1. Three wastewater streams are combined at a food processing facility to equalize the pH prior to biological treatment. The flow rate and pH of each of the wastewater streams is presented in the accompanying table. Perform a mass balance on flow and the hydrogen-ion concentration [H] so that the pH of the three combined streams may be estimated. The pH of a solution is equal to the negative logarithm of the hydrogen ion concentration (pH = -Log [H]). Wastewater Stream Flow (liters per minute) pH 1 5 5.5 2 20 6.5 3 25 8.5 II. A sanitary landfill receives 600 ft of municipal solid waste 5 days per week at a density of 500 lb/yd. If the solid waste is compacted to 1,000 lb/yd and the average depth of each cell is 10 feet, estimate the expected life of the landfill in years if 25 acres of space are still available (1 acre = 43,560 ft). Draw a materials-balance diagram to solve the problem. a II. Perform a materials balance on substrate (S) around a chemostat (completely mixed reactor without recycle) assuming a first-order removal (ds/dt = - KS) for substrate with a rate coefficient k value of 0.5 h'. The influent substrate concentration is 150 mg/L and 90% removal is desired. Determine the detention time in hours for the chemostat assuming steady-state conditions.