Optimization of Backwash Operation of the Sand Filters by Concentration Profiles Examination

Document Type : Research Paper

Authors

Chemical Engineering Faculty, Tarbiat Modares Universityو Tehran, Iran

Abstract

The importance of filters in drinking water systems is increasing because it can remove considerable percentage of bacteria and diseases-causing microorganisms with minimal cost. In this context, the use of sand filters to removes water turbidity is common. The backwashing of sand filters remove deposits which are formed on the sand bed. Optimization of the backwash operation has a particular importance due to the volume of water used for backwashing sand filters (about 2-3% of the volume of filtered water). The measurement of wastewater turbidity in the operations can be an appropriate criterion for evaluating the effectiveness of Backwash operations. In this study, the Backwash operation of three sand filters are optimized by examination of the plots of turbidity versus time during the backwash of filter. In this study, backwash operation of three sand filter beds made of quartz sand particles has been studied. The results show that the optimized pattern of backwashing operation can be proposed by changing the air blowing time of backwash operation.
 

Keywords


[1]. Eckenfelder W. W. Jr., “Industrial Water Pollution Control,” 2nd ed., McGraw-Hill., 1989.##
[2]. Cheremisinoff N. P., “Hand book of Water and Wastewater Treatment Technologies,” 2nd ed., Butterworth-Heinemann., 2002.##
[3]. Cornwell D. A. and Lee R. G., “Waste stream recycling:its effect on water quality,” JAWWA., 1994.##
[4]. Ratnayaka Don D., Malcolm J. K. and Johnson M, “Water Supply,” 6th ed., Elsevier, 2009.##
[5]. Cleasby J. L. and Logsdon G. S. “Granular Bed and Precoat Filtration, Chapt.8 in Water Quality & Treatment,” 5th ed., AWWA & McGrawHill,1999.##
[6]. Hall D. and Fitzpatrick C. S. B., “Suspension concentration profiles during rapid gravity filter backwashing,” Chemical Engineering J., Vol. 80, pp. 197–201, 2000.##
[7]. Elbana M., Ramírez de Cartagena F. and Puig-Bargués J., “Effectiveness of sand media filters for removing turbidity and recovering dissolved oxygen from a reclaimed effluent used for micro-irrigation,” Agricultural Water Management Journal, Vol. 111, pp. 27-33, 2012.##
[8]. Cornwell D. A., “Landfilling of Water Treatment,” AWWARF., 1992. ##
[9]. Norman P. A., Backwash Instability in Rapid sand filters. M.Sc Dissertation, University of NewSouth Wales, Australia, 1970.##
[10]. Hudson  H. E., “Water Clarification Processes,” 2nd ed., Van Nostrand Reinhold, 1981.##
[11]. Kawamura S., “Desing and Operation of high-rate Filter,” JAWWA5, Vol. 67, No. 10, pp. 535-544, 1975.##
[12]. Graham N. J. D., “Slow sand Filteration,” Ellis Horwood,1st ed, 1988.##
[13]. Monk R. D. G., “Desing options for water Filteration,” J. AWWA, Vol. 79, No. 9, pp 93-106, 1987.##
[14]. Weber W. J., “Physicochemical Processes,” 1st ed, Wiley-Interscience, 1972.##