*Please don't copy the other chegg answer. The answer is wrong.
Question 1 (40 marks) Hazardous radioactive waste X is biodegraded into innocuous compound via biological microbial treatment feeding on methanol, ammonia and mineral salts in a 100 liter chemostat operating at steady state. The maximum specific growth rate is 0.4hr' and the half substrate saturation constant for methanol and ammonia are 0.05 g/l and 0.0017 g/l, respectively. The yield coefficients for the two substrates are 0.7 g cell/g methanol and 18 g cell/g ammonia. The feed of methanol is obtained from a byproduct of chemical plant and is supplied at 40 l/hr and 20g/l. The methanol feed is then supplemented with salts and ammonia and fed into the chemostat. Due to the environmental regulations, the methanol concentration in the effluent stream from the chemostat must not exceed, and thus will be at 0.05 g/l (hypothetically). To ease the operation, one and only one substrate (eg. methanol) will be used as a limiting substrate. To ensure that only methanol is limiting, the concentration of each of the other substrate in the culture must be at a level of ten times of its half saturation constant. Under such conditions, the specific growth rate can be considered dependent only on methanol concentration. Apparently, one way to meet these constraints is to employ cell recycle. A cell settling separator is used. It separates the effluent from the bioreactor into two streams; the concentrated stream has a cell concentration 7 times of that in the dilute stream. The concentrated stream is recycled while the diluted stream is purged. a) Sketch a diagram of your system and label clearly any symbols you use in your explanation. b) Estimate the operating conditions (specific growth rate, dilution rate, recycle stream/feed stream ratio) that are sufficient to define the system. c) Analyse the cell concentration in the chemostat. d) Evaluate the throughput (g cells/hr) of the chemostat. e) Evaluate the feeding rate of ammonia (g ammonia/liter-hr). Neglect the volume increase caused by the addition of ammonia on the dilution rate. Question 1 (40 marks) Hazardous radioactive waste X is biodegraded into innocuous compound via biological microbial treatment feeding on methanol, ammonia and mineral salts in a 100 liter chemostat operating at steady state. The maximum specific growth rate is 0.4hr' and the half substrate saturation constant for methanol and ammonia are 0.05 g/l and 0.0017 g/l, respectively. The yield coefficients for the two substrates are 0.7 g cell/g methanol and 18 g cell/g ammonia. The feed of methanol is obtained from a byproduct of chemical plant and is supplied at 40 l/hr and 20g/l. The methanol feed is then supplemented with salts and ammonia and fed into the chemostat. Due to the environmental regulations, the methanol concentration in the effluent stream from the chemostat must not exceed, and thus will be at 0.05 g/l (hypothetically). To ease the operation, one and only one substrate (eg. methanol) will be used as a limiting substrate. To ensure that only methanol is limiting, the concentration of each of the other substrate in the culture must be at a level of ten times of its half saturation constant. Under such conditions, the specific growth rate can be considered dependent only on methanol concentration. Apparently, one way to meet these constraints is to employ cell recycle. A cell settling separator is used. It separates the effluent from the bioreactor into two streams; the concentrated stream has a cell concentration 7 times of that in the dilute stream. The concentrated stream is recycled while the diluted stream is purged. a) Sketch a diagram of your system and label clearly any symbols you use in your explanation. b) Estimate the operating conditions (specific growth rate, dilution rate, recycle stream/feed stream ratio) that are sufficient to define the system. c) Analyse the cell concentration in the chemostat. d) Evaluate the throughput (g cells/hr) of the chemostat. e) Evaluate the feeding rate of ammonia (g ammonia/liter-hr). Neglect the volume increase caused by the addition of ammonia on the dilution rate
