03322nam a2200397 4500 20260818090310.0 241297 th eng .b10192657 AIT Thesis no. 643 Yau, Chap Hoi Design parameters for oxidation ditches in the tropics Bangkok : Asian Institute of Technology, 1974 56 p. Thesis ; no. 643 A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science of the Asian Institute of Technology,Bangkok, Thailand. Thesis (M.Sc.) - Asian Institute of Technology, 1974 A pilot scale oxidation ditch was built to evaluate whether the design parameters recommended by PASVEER (1969) could be improved under tropical conditions. While nutrient and D.O. were maintained at non-limiting levels, 8 different organic loadings of Pepsi-Cola waste, ranging from F/M = 0.07 to 0.78, were studied at a common detention time of 48 hours. Results showed that the effluent COD, increased with increasing loading. But the COD removal efficiency remained above 96% throughout the whole organic loading range. Ash content of the sludge was about 24% at loadings below F/M = 0.2, but decreased down to 13% at higher organic loadings. Keeping the organic loading with F/M about 0.38, the results. of 3 tests with different detention times showed that the change of hydraulic retention time from 48 hours to 17.5 hours did not change the COD removal rate, nor. the ash content of the sludge. However, at the same organic loading, a low influent COD lowered effluent COD and SVI . In a separate test, laboratory scale aeration units were set up to find out the chemicals which can restore the settling properties of a bulking sludge, once it occurs in an oxidation ditch, by changing its microbial composition. It was found that addition of calcium acetate at a concentration of 0.6 g per litre of bulked sludge, with NaN03 at a concentration of 0.5 g per litre of bulked sludge, suppressed the growth of Sphaerotilus, and selectively promoted to growth of other desirable bacteria so that the bulking problem was completely eliminated in a period of 8 days. Water Pollution Oxidation Pescod, M.B., Chairpeson Yang, Yi Ping, Co-Chairperson Asian Institute of Technology. Thesis ; no. 643 Full-Text http://203.159.5.9/ait-thesis/detail.php?q=B24197 .b10192657 mnait v 260525 3 951012 m a v 0 mnait mnait mnarc 20 40 Barcode : 30050003033015 CREATED : 1995-10-13 RECORD # : i10230920 LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 Barcode : 30050003033049 CREATED : 1995-10-13 RECORD # : i10230932 LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 Barcode : 30050160093356 CREATED : 2016-04-22 RECORD # : i12946941 LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 27584 27584 0 0 0 0 MAIN MAIN mnait 2026-08-18 0 AIT Thesis no. 643 30050003033015 2026-08-18 09:03:10 2 2026-08-18 20 0 0 0 0 MAIN MAIN mnait 2026-08-18 0 AIT Thesis no. 643 30050003033049 2026-08-18 09:03:10 1 2026-08-18 20 0 0 0 0 MAIN MAIN mnarc 2026-08-18 0 AIT Thesis no. 643 30050160093356 2026-08-18 09:03:10 2026-08-18 40