Question

CIEG 328 HOMEWORK7 Homework 7 (Suspended growth) Due: 4/112019 Design an activated sludge biological treatment system for a typical medium-strength domestic wastewater with a design daily flow of 2.9 million gallons per day. Assume the plant effluent criteria are 10/10/1" This means that the plant must produce an effuent with average BODS and TSS concentrations of 10 mg/Leach year round, and an effluent ammonia concentration of 1 mg/L as N during the winter months. The layout of the plant will be such that the SRT will be held constant throughout the year. Assume a peaking factor of 2.1 Use the process parameters given below. The influent BOD,COD ratio 0.86, the primary effluent BODs/COD ratio 0.78, and the effluent BODCOD ratio 0.43. Wintertime wastewater temperatures reach as low as 13 C and summertime reach 28"C, Determine the following for design: a. Select a design SRT ad justify your selection. b. Calculate summe and winter effiuent substrate concentrations (COD and NHI-N) c. Assming an average influent concentration of 200 mg COD/L, determine a reasonable reactor volume in order tohit target HRTs and biomass concentrations. Does summer or winter temperature control this decision? d. Assuming an average influent NH3-N concentration of 30 mg N/L. Determine the mixed liquor total suspended slids (MLSS) concentration in the bioreactor for winter and summer e. Calculate the required oxygen (kg/d) for winter and summer f. Calculate the amount of biomass produced per day (kg COD/d]. E. Determine the wastage flow rate (m'fd, asming that a conventional wastage strategy is deployed and a typical underflow suspended solids concentration is 8,000 mg/L TSS Parameter values at 20°C Parameter Parameter Value 0.04 0.47 On KNI mg CODimg COD my CODimg N

Answer 1

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