waste water engineering
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sample assignmentTRANSCRIPT
CHMT4013 Assignment 2The following are real data measured from a bioreactor which is being used to process a waste stream. The reactor kinetics are unknown and you are required to determine a rate constant for the degradation of the COD. An impulse-response tracer study was done on the reactor to determine what type of reactor is being considered and the rates of contaminant degradation need to be found. The effluent is from a starch manufacturing facility and due to its high COD cannot be discharged directly to sewer and must therefore be pre-treated by a biodigestor on site. The average starch concentration is 63g/L and the average COD of the effluent is 40g/L.In Table 1 data is shown where we used an inert tracer to conduct an impulse-response experiment. Table 1. Impulse response tracer experiment data.Time (min)Concentration (mg/l)
00.0000
100.0000
150.9965
202.6676
22.53.5911
253.5052
27.53.1659
302.8652
32.52.5516
352.2895
37.51.9759
401.7096
451.2715
500.9708
550.7173
600.5111
650.3822
700.2877
750.3307
900.3100
1050.2580
1200.2040
1400.1010
1600.0059
1800.0000
You are required to calculate the following (Refer to Levenspiel or Fogler for this theory).1. You will need to draw a C vs t graph[2]
2. You will need to plot an E vs t graph[5]
3. You need to find the mean of the residence time distribution [10]
4. Assume the reactor can be modelled as a tanks-in series reactor. Find a value for N, by calculating the second moment of the distribution (i.e. )[3]
5. Discuss what you found in Q3 relative to the ideal residence time which hasA value of 1.2 hours. Postulate reasons for any difference based on yourunderstanding of the residence time distribution[5]
6. Assuming that starch can be modelled as glucose, for a starting concentration of 63g/L, find the equivalent COD.[5]
7. If the final concentration of starch is 0.103g/L after treating with the bioreactor, what is the rate constant of degradation if you assume first orderkinetics? (Hint, Round N up to the nearest number and solve the TIS eqtn)[5]
8. The final COD of the effluent prior to discharge is 500mg/L. Calculate the rate ofCOD removal.[5]
9. Discuss why the rates of degradation are different as well as why the ratioOf COD to starch is vastly different in the raw effluent to the discharge.[5]