| Summary: | 碩士 === 國立成功大學 === 環境工程學系 === 89 === Drinking water in southern Taiwan often received complains for its unpleasant odors. Musty/earthy, fishy and chlorine odors are the three major odor groups in the area. Among the three odor groups, musty/earthy odor is known to be the most difficult one to be removed. As powered activated carbon (PAC) is used to mitigate the musty/earthy odor problems in many countries, there is a need to understand the adsorption of odorous compounds onto PAC in the raw water of south Taiwan.
In this study, kinetic and equilibrium adsorption of a typical odorous compound, 2-methylisoborneol (2-MIB) onto PACs was studied. Three different types of commercially available PACs were used for the adsorption experiments. Raw water of Feng-Shen Waterworks (FSW) was chosen for the representative source water. The equivalent background compound (EBC) model was combined with the Freundlich isotherm to describe the equilibrium of 2-MIB on PAC in the raw water, while the homogeneous surface diffusion model (HSDM) was employed to simulate the adsorption kinetics. The models followed the experimental kinetic data very well, and equilibrium and kinetic parameters were extracted. Based on the extracted parameters, the models were able to predict the adsorption kinetic curves at different 2-MIB concentrations under different PAC dosages. Accounting for the isotherm exponent range commonly observed for 2-MIB on activated carbon, only one kinetic experiment is needed for predicting the adsorption kinetic curves. This observation further reduces the experimental effort required for estimating PAC dosage.
In addition, PAC dosage was also linked to the weather condition in FSW. A strong correlation was observed between 2-MIB concentration in the raw water of FSW and corresponding water temperature at sampling time. The correlation was used to predict 2-MIB concentration in the raw water, while the flavor profile analysis was employed to estimate the 2-MIB concentration in the finished water at accepted level. Based on the removal efficiency of 2-MIB needed in the treatment processes, the PAC dosage may be calculated according to the contact time of PAC in the water works. Experimental data showed that PAC dosage eatimated from this approach was able to remove the odorant to the predetermined levels. The approach provides a simple way to substantially reduce the experimental effort needed for determining PAC dosage in FSW.
|
|---|
