| Summary: | 碩士 === 國立暨南國際大學 === 土木工程學系 === 94 === In the study, the sludge obtained from the pilot-scale A2O system and full-scale SBR were used to test the adsorptions of heavy metal (Pb, Ni and Cd) by the activated sludge and the impacts of heavy metal on the nitrification and denitrification abilities of the activated sludge. The aim of the study was to investigate the feasibility of the treatment combination of municipal wastewater and lower level heavy metal wastewater. Results showed that the influence degree of these three kinds of heavy mentals was Ni>Cd>Pb for SAUR and Cd>Ni>Pb for SNUR. The inhibition occurred at the situation of 2 mgl-1 Ni or Cd. However, no significant inhibition occurred even though 40 mgl-1 Pb was added. When combining three metals at different concentration, no synergistic effect was found and the inhibition effect was based on the highest toxicity heavy metal. Furthermore, comparing with two systems, the result indicated that the tolerance of SBR sludge to heavy metals was better than that of A2O sludge. Both the regression equations of inhibition rate of SAUR and SNUR were first order kinetic reaction for both systems, as below: SAUR = ( SAURmax – SAURmin )‧ + SAURmin and SNUR = ( SNURmax – SNURmin )‧ + SNURmin.
The adsorption ability of activated sludge to heavy metals was Pb≒Cd>Ni for both systems. And, the adsorption capacity (q) of activated sludge for heavy metal was increased with the increase of the heavy metal concentration and with the decrease of the MLVSS concentration. Experimental results also showed that the adsorption capacity of the SBR sludge was larger than that of the A2O sludge.
The unculture bacteria and Beta-proteobacteria were the predominant bacteria population for both systems. In the A2O system, the floc forming bacteria Zoogloea oryzae was the only one microbial group that had been mentioned to the ability of adsorption of heavy metals by extra-cellular polysaccharide. However, Acidovorax temperans found in SBR system possesses the extra-cellular protein and can combine silver. It is possible that this bacterial group can be tolerant to the heavy metals and accumulate them. All the results of this study demonstrate that the tolerance and adsorption abilities of the SBR sludge to heavy metals was better than those of the A2O sludge. Therefore, it was suggested that the Acidovorax temperans in the SBR system played a significant role to the adsorption and tolerance of heavy metals.
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