Problems - Complete the following problems located in the text: Howe, K. J., Hand, D. W., Crittenden, J. C., Trussell, R. R., & Tchobanoglous, G. (2011). Principles of Water Treatment (1st ed.). Hoboken, New Jersey, USA: John Wiley & Sons.
1. RSSCT columns were used to determine the bed life of a fixed-bed adsorption system for the removal of methyl-tert-butyl ether (MTBE) from a raw water source. The RSSCT column had a media particle diameter of 0.19 mm, superficial velocity of 45.0 m/h, and EBCT of 27 s. Under those conditions, breakthrough of MBTE occurred in 12.28 d. If the full-scale adsorber is designed with a media particle diameter of 1.10 mm, calculate the appropriate EBCT and superficial velocity of the full scale column, and the predicted operating time before breakthrough of MBTE occurs.
2. Calculate the minimum air-to-water ratio for a countercurrent packed tower for 95 percent removal of chloroform and benzene at 10oC.
3. A treatment plant has been designed to achieve 99 percent inactivation of C. parvum using ozonation. The engineer used data on ozonation of C. parvum at 20oC for the design, but the plant operates in a northern climate and the water temperature will be 0.5?C in winter. Estimate how much inactivation the plant will actually achieve when the water is at that temperature, assuming the plant will achieve the same Ct value, inactivation of C. parvum follows the Chick-Watson model (Eq. 13-31), and that disinfection kinetics follow the Arrhenius' equation (Eq. 4-33). Use an Ea value of 76 kJ/mol.
4. Determine the mass and volume of sludge produced and the volume of sludge as a percentage of the total flow from the use of alum [Al2(SO4)3•6 or 14 or 18H2O] for the removal of turbidity. Assume the following conditions apply: (1) flow rate is 0.05 m3/s, (2) average raw-water turbidity is 45 NTU, and (3) average alum dose is 40 mg/L, sludge solids concentration is 5 percent with a corresponding specific gravity of 1.05, and temperature is 10?C. Assume the ratio between total suspended solids and turbidity expressed as NTU is 1.33 and 0.3kg of alum sludge is produced per kilogram of alum added. Assume 1 mg/L of a coagulant aid will also be used. Value of bound water to be selected by instructor.