02801nam a2200253   450000500170000000800410001703500150005810000280007324500660010126000520016730000100021949000270022950001520025650200570040852017250046565000190219065000430220970000380225270000370229070000430232771000530237081000590242385600650248220260817172714.0120399s1988    th      r    0000|00eng d  a.b101390720 aKrerkpong Charnpratheep10aChromium removal in attached-growth waste stabilization ponds  aBangkok :bAsian Institute of Technology,c1988  a86 p.1 aThesis ;vno. EV-88-12  aA thesis submitted in partial fulfilment of the requirements for the  degree of Master of Science, School of Environment, Resources and Development  aThesis (M.Sc.) - Asian Institute of Technology, 1988  aWaste stabilization ponds (WSP) installed with attached- growth  media are called attached-growth waste stabilization ponds (AGWSP).  Research was conducted to investigate chromium (Cr) removal efficiency  in the laboratory-scale and the pilot-scale WSP and AGWSP units after  subjected to one-day Cr shock loading. The laboratory-sea 1 e ponds,  operated at the hydraulic retention times (0) of 5, 10 and 15 days, were  fed with synthetic waste containing Cr concentrations of 5, 10, 20 and  30 mg/L while the Cr concentration of 20 mg/1 mixed with AIT sewage was  introduced to the pilot-scale ponds operated at e = 10 days.  Data from the laboratory-scale and pilot-scale AGWSP units showed a  better Cr removal than that of the WSP units. The attached biomass in  AGWSP were found to retain the applied Cr from 30 - 65 % while 10 - 91 %  were overflowed in the effluents of the WSP units. Particulate Cr was a  predominant fraction of total Cr concentration in the effluents.  Physico-chemical mechanisms, particularly adsorption, was found to be a  significant mechanism in removing soluble Cr from the pond water. An  empirical model was developed to predict the total Cr removal ~h reas a  mass transfer through the adsorbing-porous media model was applied to  predict the soluble Cr removal.  The significant effects of the Cr shock loadings on the pond  performance in terms of total dissolved organic carbon (TDOC) removal and  ammonia nitrogen (NH3-N) removal were not obvious. However, most of the  AGWSP units showed a better performances than the WSP units after the Cr  shock loadings. Decreasing of chlorophyll ~ and suspended solid  concentrations in the effluents of all units were generally observed.  0aSewage lagoons 0aSewagexPurificationxChromium removal0 aChongrak Polprasert,eChairperson1 aI, Fude, eExamination Committee1 aAhn, Kyu-Hong, eExamination Committee2 aThe Government of Australia, eScholarship Donor2 aAsian Institute of Technology.tThesis ;vno. EV-88-12  3Full-Textuhttp://203.159.5.9/ait-thesis/detail.php?q=B18882