05888nam a2200481 a 4500 20260817162843.0 .b10087503 En AIT Thesis no. EV- 88-28 Casiano, Visitacion Legaspi Application of coarse-media slow sand filtration and rapid sand filtration in aquaculture Bangkok : Asian Institute of Technology, 1988 136 p Asian Institute of Technology. Thesis ; no. EV-88-28 Thesis ; no. EV-88-28 A thesis submitted in partial fulfillment of the requirement for the degree of Master of Engineering, School of Environment, Resources and Development Thesis (M. Eng.) - Asian Institute of Technology, 1988 Laboratory experiments were carried out with pilot-scale experimental units of coarse-media slow sand filter and rapid sand filter. Coarse-media slow sand filter was operated with a 0.56 m diameter and 2. 7 m high filter column, filter media size of 1 - 2 mm and media depth of 1.0 mat filtration rates of 0.5 and 0.2 m 3/m2 h . Experiments on rapid sand filtration were carried out with two different sizes of filter column. Tests using the 10 cm diameter and 1. 9 m high filter column were conducted with media size of 1.0 mm and media depth of 1.0 m at filtration rates of 7 . 5 and 5 .0 m 3/m2h. Another experimental run was carried out with 0.56 m diameter and 2.1 m filter column with filter media size of 1 - 2 mm and media depth of 1.0 m at filtration rate of 1 . 0 m 3/m2 h. One circular concrete fish tank with 1.16 m diameter was used for each experimental unit. A 1.5m x 1.0m x 1.0m existing biological filter was operated with 0.45 m filter media depth which consists of t he following sizes of crushed stones: 15 cm depth of 2 cm diameter, 20 cm depth of 0.95 cm diameter and 20 cm depth of 0.51 cm diameter. A filtration rate of 1.92 m 3 ;m 2h was implemented. Eight concrete fish tanks were used with the existing biological filter. Different parameters were measured in order to monitor the water quality as well as to be able to compare the performance of the filters. Experimental results showed that the coarse-media slow sand filter (CMSSF) has a comparatively higher removal efficiency than the existing biological filter (EBF). EBF has a mean removal efficiency of 20.6, 2.31, 61.7, 57.66 and 20.37% for turbidity, total phosphorus, ammonia, nitrite and chemical oxygen demand, respectively with 6.85% nitrate production. CMSSF at high filtration rate resulted to a removal of 55, 6.23, 81.18, 74.23 and 36.42% for turbidity, total phosphorus, ammonia, nitrite and chemical oxygen demand, respectively with 17.98% nitrate production. On the other hand, CMSSF was operated at lower filtration rat e which showed a mean difference of 52 .13 4.72, 92.54, 87.65 and 31.71%, respectively with a corresponding nitrate production of 41.68% at lower filtration rate . It was a lso evident that the coarse-media slow sand filter at 0.20 m 3 /m2 h filtration rate has slightly higher removal efficiency compared to its performance at 0.50 m 3/m2h filtration rate . Furthermore, dissolved oxygen has decreased by 34.7 an 48.79% (mean values) after 57 and 33 days of filtration run for CMSSF at high and low filtration rates , respectively. Dissolved oxygen of the filtered water from EBF has a mean increase of 9. 8% due to the constant flushing of the overflow from the header tank which was returned back to the c l ear water tank. A similar arrangement in CMSSF can overcome the problem of DO depletion, which is not favorable to fish. Rapid sand filtration carried out with a 10 cm diameter filter 3 2 column at filtration rates of 7 . 5 and 5 . 0 m /m h has only 12 and 9 hours 3 2 filtration run, respectively . Whereas, the filter operated at 1.0 m /m h has a filtration run of 6 . 75 days. Results showed that removal efficiency was higher at the lowest filtration rate implemented. Percentage weight gain of individual fish for all the systems were found to be increasing but it started to decline after 63 days in the case of EBF. Likewise, daily weight gain and specific growth rate of indi vidual fish used for all systems was observed to be increasing except for EBF in which it started to decrease after 21 days of experimentation. Water Purification Filtration Vigneswaran, Saravanamuthu, Chairperson Samorn Muttamara, Examination Committee Lin, Chang Kwei, Examination Committee Kriengsak Udomsinrot, Examination Committee Wee, Kok Leong, Examination Committee German Academic Exchange Scholar (DAAD) Federal Republic of Germany, Scholarship Donor Full-Text http://203.159.5.9/ait-thesis/detail.php?q=B18898 .b10087503 mnait u 240410 2 951012 m a u 0 AIT Thesis no. EV- 88-28 mnait b m 099 3005000019848x mnait 30050000198498 2 mnait mnait mnait mnarc 20 40 Barcode : 30050003044657 CREATED : 1994-05-16 RECORD # : i10092900 LPATRON : 1018969 LCHKIN : 2006-02-28 # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 1 TOT RENEW : 0 Barcode : 30050003044665 CREATED : 1994-05-16 RECORD # : i10092912 LPATRON : 1018969 LCHKIN : 2006-01-26 # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 7 TOT RENEW : 8 Barcode : 30050120223382 CREATED : 2016-10-05 RECORD # : i12973634 LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 6516 6516 0 0 0 0 MAIN MAIN mnait 2026-08-17 10.00 0 AIT Thesis no. EV- 88-28 30050003044657 2026-08-17 16:28:43 1 2026-08-17 20 0 0 0 0 MAIN MAIN mnait 2026-08-17 10.00 0 AIT Thesis no. EV- 88-28 30050003044665 2026-08-17 16:28:43 2 2026-08-17 20 0 0 0 0 MAIN MAIN mnarc 2026-08-17 0 AIT Thesis no. EV- 88-28 30050120223382 2026-08-17 16:28:43 2026-08-17 40