03708nam a2200409 4500 20260817162909.0 301098s1984 th r 0000|00eng d .b10088027 AIT Thesis no. EV-84-11 Vichian Udomratanasilpa Application of horizontal flow prefiltration and slow sand filtration for small community water supply Bangkok : Asian Institute of Technology, 1984 81 p. Thesis ; no. EV-84-11 A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science, School of Environment, Resources and Development Thesis (M.Sc.) - Asian Institute of Technology, 1984 An attempt was made on a pilot scale to fi nd a simple mod el for a horizontal flow roughing prefilter used with slow sand filter a s the water treatment system for a s mall community. Three different lengths of horizontal p refilter PVC pipe model of 250 mm in diameter, i.e. 2. 0 m, 3.0 m, 4.0 m, were used in this study at the filtration rate of 1.25 m /m - h . Crushed stone , with effective size of 2-20 mm, and coconut husk fiber were used as roughing filter media in the horizontal prefilters. Slow sand filters with the filtration r ate of 0. 15 m /m-h we reused t o polish water from the horizontal prefilters. It was found that the performance of horizontal prefilters using single crushed stones was less effective than those using dual media , coconut fiber 80 cm in .length followed by crushed stones. The horizontal prefilter of 4.0 m length performs best in filtering the raw water in this study The fraction of coconut fiber in horizontal prefilter can perform effectively tor a .bout one month. Turbidity and suspended solids removal efficiencies in horizontal prefilter, when single medium was used, were a bout 28-68 % and 45-95 % whereas in the horizontal pref1lter with dual media turbidity and suspended solids removal efficiencies were about 30-68 % and 54-98 %. The reduction of fil54qgili5y indices of raw water when passing through the horizontal prefilters was about 85 % The slow sand filters can treat the water to meet the WHO standard drinking Water in terms of turbidity and completely removed suspended solids on occasions. The overall removal efficiencies of this system were about 71 -94 % and 81 -99. 6 % for turbidity and suspended solids respectively. Filters and filtration Nguyen, Cong Thanh, Chairperson Vigneswaran, Saravanamuthu, Examination Committee Samorn Muttamara, Examination Committee Carl Duisburg Gesellschaft, e.v. (COG) Government of the Federal Republic of Germany, Scholarship Donor Asian Institute of Technology. Thesis ; no. EV-84-11 Full-Text http://203.159.5.9/ait-thesis/detail.php?q=B20588 .b10088027 mnait x 240509 2 951012 m a x 0 mnait mnait mnarc 20 40 Barcode : 30050003042206 CREATED : 1994-05-16 RECORD # : i10093679 LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 Barcode : 30050003042198 CREATED : 1994-05-16 RECORD # : i10093680 LPATRON : 1016809 LCHKIN : 2004-02-27 # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 6 TOT RENEW : 6 Barcode : 30050120224638 CREATED : 2016-04-05 RECORD # : i12970293 LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 6649 6649 0 0 0 0 MAIN MAIN mnait 2026-08-17 10.00 0 AIT Thesis no. EV-84-11 30050003042206 2026-08-17 16:29:09 1 2026-08-17 20 0 0 0 0 MAIN MAIN mnait 2026-08-17 10.00 0 AIT Thesis no. EV-84-11 30050003042198 2026-08-17 16:29:09 2 2026-08-17 20 0 0 0 0 MAIN MAIN mnarc 2026-08-17 0 AIT Thesis no. EV-84-11 30050120224638 2026-08-17 16:29:09 2026-08-17 40