03879cas|a2200421 i 4500 20260817162954.0 230399s1993 th uzm rtt 00| a1eng d .b10089238 AIT Thesis no.EV-93-26 Werellagama, D. R. Induka B. Application of the floto filter unit for contact flocculation filtration of surface waters Bangkok : Asian Institute of Technology, 1993 141 leaves + 1 online resource Thesis ; no. EV-93-26 A thesis submitted in partial fulfillment of the requirement for the degree of Master of Engineering Thesis (M.Eng.) - Asian Institute of Technology, 1993 Laboratory scale experiments were carried out in contact flocculation filtration using a dual media filter. The objective of the research was to find an optimum synthetic media combination which would give acceptable quality water under varying conditions while maintaining a low headloss. The media was lighter than water hence the bed was floating. Since coarse media remained at the bottom the flow direction was upflow which had the added advantage that the flow was in the direction of grain compression. Polypropylene and Polystyrene were selected as the optimum combination of media which due to their large . density difference did not intermix even under severe agitation. Spherical fine media performed better than angular fine media giving lower headloss and better effluent quality. The dual media combination and the higher rates of filtration are in line with the current trends in the water industry. The influent concentrations were kept constant and the flow velocity and filter media size were varied. The headloss variation along the filter, the influent quality to the two filter layers and the effluent quality were studied. The filter performed for over 40 hours producing acceptable quality water at conventional rapid sand filtration rates, also having low headloss development. Another major advantage was the ease and economy in backwashing. The filter media did not mix even during or after backwashing, thereby eliminating the most common problem encountered in conventional multi media filters. The Floto Filter operation was compared with upflow sand filtration. The headloss development curves for Floto filter showed a characteristic shape easily identifiable from that for sand. The existing mathematical model was able to predict the headloss profile but the concentration profile was not predicted. The necessity of particle size data for mathematical modelling of filtration of heterodisperse suspensions is emphasized. Water Purification Filtration Visvanathan, C., Chairperson Fujii, Shigeo, Examination committee Samorn Muttamara, Examination Committee Swedish International Development Agency (SIDA), Scholarship donor Asian Institute of Technology. Thesis ; no. EV-93-26 Full-Text http://203.159.5.9/ait-thesis/detail.php?q=B16676 .b10089238 mnait x 240411 2 951012 m a x 0 mnait mnait mnarc 20 22 40 Barcode : 30050120806087 CREATED : 1994-05-16 RECORD # : i10095366 LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 Barcode : a CREATED : 1995-10-13 RECORD # : i10095378 LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 Barcode : 30050160055728 CREATED : 2016-11-05 RECORD # : i12975187 LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 6880 6880 0 0 0 0 MAIN MAIN mnait 2026-08-17 10.00 0 AIT Thesis no.EV-93-26 30050120806087 2026-08-17 16:29:54 1 2026-08-17 20 0 0 0 0 MAIN MAIN mnarc 2026-08-17 0 AIT Thesis no.EV-93-26 30050160055728 2026-08-17 16:29:54 2026-08-17 40