02359nas a2200229   450000500170000000800410001703500150005810000250007324500650009826000520016330000220021549000270023750001020026450200570036652014390042365000480186270000350191070000360194570000450198171000440202681000590207020260818214646.0301098s1983    th      r     000| 0eng d  a.b106184170 aPinthita Mungkarndee10aSolving "sludge bulking" problem in activated sludge process  aBangkok :bAsian Institute of Technology,c1983  a66 leaves :bill.1 aThesis ;vno. EV-83-17  aA thesis submitted in partial fulfillment of the requirements for the degree of Master of Science  aThesis (M.Sc.) - Asian Institute of Technology, 1983  aSludge bulking often occurs in the completely-mixed activated sludge  processes treating carbohydrate waste. Hydrogen peroxide was selected as  the chemical for sludge bulking control in this study. The effect of hy-  drogen peroxide was studied first in the batch study. It was evident that  the optimum effective doses of hydrogen peroxide were 40 and 60 g H202/kg  MLSS·d at the SVI of 150-300 mt/g and 300-450 mt/g respectively. And it  was also observed that after shock loading from 0.3 to 0.5 kg BODS/kg MLSS·d  in the batch system SVI increases from 180-200 to 300-450 mt/g. The second  doses of hydrogen peroxide of 60 and 70 g H202/kg MLSS·d could reduce the  SVI to 150 mt/g in such unit within 3 and 2 days, respectively. While the  second doses of hydrogen peroxide of 40 and 50 g H202/kg MLSS·d were needed  to overcome sludge bulking within 4 days.  For the continuous completely-mixed system study, the organic loading  of 0.4-0.5 kg BODS/kg MLSS·d was found to be optimum with no sludge bulking  occurred. In this system the effective dose was found to be 60 g H202/kg  MLSS·d in both units operated under different SVI values (800-1,100 mi/g  and 300-50 mg/i). The frequency of hydrogen peroxide feeding and contact  time exhibit the similar effect in both units. The most effective of hydro-  gen peroxide feeding and appropriate contact time were found to be single  dose and more than 5 hours, respectively.10aWater quality managementxNepalxPhewa Lake0 aSamorn Muttamara,eChairperson1 aNguyen, Cong Thanh,eCo-Advisor0 aPakit Kiravanich,eExamination Committee2 aJapanese Government,eScholarship Donor2 aAsian Institute of Technology.tThesis ;vno. EV-83-17