05247cas|a2200457 i 4500 20260818213953.0 181197s1991 th uzm rtt 00| a1eng d .b10601272 AIT Diss. no. EV-91-3 Verapong Chaiperm Side-stream chemical precipitation to enhance efficiency and stability of anaerobic/aerobic activated sludge process for biological phosphorus removal Bangkok : Asian Institute of Technology, 1991 204 p. Dissertation ; no. EV-91-3 Thesis (Ph.D.) - Asian Institute of Technology, 1991 A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Engineering, School of Environment, Resources and Development Anaerobic/ Aerobic Activated SIudge Process Is widely used to remove phosphorus from wastewater. In this process, the microorganisms capable of taking up higher amount of phosphorus than those observed under conventional activated sludge process are responsible for high phosphorus removal performance. This process sometimes faces a problem of poor stability in phosphorus removal. Many factors have been claimed to influence phosphorus removal performance such as organic loading, nitrite, nitrate, sludge age, etc. The objectives of this study are : (1) To Investigate the effect of organic loading on · phosphorus removal performance and stability. (2) To evaluate the effectiveness of the Introduction of side- stream chemical precipitation. (3) To investigate contribution of each factor to phosphorus removal through material balance consecrations of phosphorus. (4) To experimentally find out substances which give adverse effects on phosphorus removal performance. Lab-scale continuous flow experiments are conducted In order to Investigate the effect of organic loading and the effectiveness of side-stream chemical precipitation. The organic loadings are varied from 1.61 to 1.17 and 0.46 kgCOD/(m3.d). The side-stream flow ratios are 0%, ~0% and 45% for each organic. loading condition. The results show that phosphorus removal performance Is affected when the organic loading decreases. Also, the unit with 45% side-stream flow clearly shows Improvement In phosphorus removal performance and stability. From material balance considerations of phosphorus, the Improved phosphorus removal performance Is dued to the Increased amount of phosphorus In chemical precipitated sludge. An semi - empirical model Is proposed In order to perform sensitivity analysis. The results show that the changes of phosphorus content of sludge, side-stream flow ratio, organic loading and performance of chemical precipitation tank In side--stream are highly sensitive to phosphorus removal performance of the process. Batch experiments are performed In order to find out substances which give adverse effects on phosphorus removal performance. Nitrite affects biological phosphorus uptake at concentration exceeding 5 mg/I as N. Nitrate does not show any effect on aerobic phosphorus uptake upto concentration of 80 mg/I as N. Also, sulphate and aluminum do not show any effect to phosphorus release and uptake characteristics upto concentrations of 900 mg/I and 100 mg/I , respectively. The effect of nitrite Is again tested with lab-scale continuous flow anaerobic/aerobic activated sludge process. The results show that biological phosphorus uptake in the aeration tank is affected by nitrite when nitrite concentration exceeds 1 O mg/I. As side-stream chemical precipitation unit is convenient for being applied with anaerobic/aerobic activated sludge process, the app li cation of this modified process is useful when the stable phosphorus removal efficiency is required. Sewage Purification Activated sludge process Sewage Purification Phosphate removal Mino, Takashi, Chairperson Chongrak Polprasert, Co-Chairperson Tran, Francis T., Examination Committee Verink, Johan, Examination Committee Bhattacharya, Sribas C., Examination Committee Henze, M., Examination Committee The Government of Australia, Scholarship Donor Asian Institute of Technology. Dissertation ; no. EV-91-3 Full-Text http://203.159.5.9/ait-thesis/detail.php?q=B17432 .b10601272 mnait y 240410 2 951012 m a y 0 mnait mnait mnarc 20 40 Barcode : 30050003058251 CREATED : 1995-10-15 RECORD # : i10761585 LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 Barcode : 30050003058244 CREATED : 1995-10-15 RECORD # : i10761597 LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 Barcode : 30050160004999 CREATED : 2016-01-02 RECORD # : i12876070 LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 106778 106778 0 0 0 0 MAIN MAIN mnait 2026-08-18 0 AIT Diss. no. EV-91-3 30050003058251 2026-08-18 21:39:53 1 2026-08-18 20 0 0 0 0 MAIN MAIN mnait 2026-08-18 0 AIT Diss. no. EV-91-3 30050003058244 2026-08-18 21:39:53 2 2026-08-18 20 0 0 0 0 MAIN MAIN mnarc 2026-08-18 0 AIT Diss. no. EV-91-3 30050160004999 2026-08-18 21:39:53 2026-08-18 40