• Journal of the Korean GEO-environmental Society
• /
• v.13 no.4
• /
• pp.37-44
• /
• 2012

This study investigated on the adsorption of nonpoint pollution source using the Sand, hydroxyapatite(HAP), Zeolite and mixed culture. The adsorption of nonpoint pollution source on Sand, hydroxyapatite(HAP), Zeolite and mixed culture was investigated during a series of batch adsorption experiments. After the batch absorption experiments analysed COD, T-N, T-P on adsorption water. The experimental data was analysed using the pseudo-first-order adsorption kinetic models. Langmuir and Freundlich isotherm models were tested for their applicability. The maximum adsorbed amount $(Q_{max})$ of COD were found to be sand 0.0511mg/g, HAP 0.1905mg/g, Zeolite 1.0366mg/g and Mixed media 0.7444mg/g. The maximum adsorbed amount $(Q_{max})$ of T-N were found to be sand 0.0159mg/g, HAP 0.0537mg/g, Zeolite 0.5496mg/g and Mixed media 0.1374mg/g. The maximum adsorbed amount $(Q_{max})$ of T-P were found to be sand 0.0202mg/g, HAP 0.1342mg/g, Zeolite 0.0462mg/g and Mixed media 0.1180mg/g. As a result, the mixed media was effective to remove nonpoint pollution source.

• Korean Chemical Engineering Research
• /
• v.43 no.3
• /
• pp.360-365
• /
• 2005

SMB (simulated moving bed) is a continuous chromatographic process by shifting periodically port position. Binary of mixture, Blue dextran and Orange G, was separated by SMB. These components have unique color individually, that is, Blue dextran is blue and Orange G is orange. It is easy to understand SMB process by observing the shift of color changes in SMB. These components was not adsorbed to stationary phase and isolated by difference of size exclusion factor. Mass transfer coefficient was determined by single pulse test under several flow rate conditions. Operation condition was obtained by standing wave theory and optimized for high purities in extract and raffinate streams. Experiment was performed in open loop 4 zone (2-2-2-2) SMB. There are several advantages in open loop SMB, where extract is product for high purity. It is also easy to control flow rate and monitor experimental state during operation. Experimental, extract and raffinate history is well fitted with simulation results, however, column concentration profile is a little different from simulation results. Purities were 99.5％ for extract and 98.9％ for raffinate and extract and raffinate yields were obtained as 98.9％ and 99.4％ respectively.

• Korean Chemical Engineering Research
• /
• v.56 no.1
• /
• pp.73-78
• /
• 2018

The main objective of this study was to evaluate the effects of acetate on the cultivation of anabena under mixotrophic condition. Four different types of acetates were used for the anebena cultivation. Among them, ethyl acetate was found to be the most effective and the growth rates linearly increased as the amount of ethyl acetate increased. When 40 mM of ethyl acetate was used, the highest values of specific growth rate of $0.979day^{-1}$ and maximum biomass productivity of $0.293g\;L^{-1}\;d^{-1}$ were obtained. On the contrary, input of acetic acid and butyl acetate inhibited the growth of anabena. For aeration tests, 0.54 vvm was optimum for anabena cultivation. For a semi-continuous cultivation test, ethyl acetate was used after 0.54 vvm test was finished. Then, test continued under 0.54 vvm and 40 mM of ethyl acetate. Lower specific growth rate and maximum biomass productivity were obtained compared to those from batch cultivation tests. However, the greatest maximum concentration of 5.91 g/L was obtained during the semi-continuous cultivation test.

• Journal of Korean Society of Environmental Engineers
• /
• v.30 no.8
• /
• pp.781-788
• /
• 2008

This study shows how to find out optimum co-substrate conditions and continuous operating parameters for maximum acidification of three different organic wastes - livestock wastewater, sewage sludge and food waste. Design of experiments and statistical analysis were revealed as appropriate optimization schemes in this study. Analyses of data obtained from batch tests demonstrated the optimum substrate mixing ratio, which was determined by maximum total volatile fatty acids(TVFA) increase and soluble chemical oxygen demand(SCOD) increase simultaneously. Suggested optimum mixing ratio of livestock wastewater, sewage sludge and food waste was 0.4 : 1.0 : 1.1 based on COD, respectively. Response surface methodology(RSM) contributed to find out optimum operating parameter - hydraulic retention time(HRT) and substrate concentration - for the semi-continuous acidogenic fermentation of mixed organic wastes. The optimum condition for maximum TVFA increase was 2 days of HRT and 29,237 mg COD/L. Empirical equations obtained through regression analysis could predict that TVFA increase would be 73%. To confirm the validity of the statistical experimental strategies, a confirmation experiment was conducted under the obtained optimum conditions, and relative error between theoretical and experimental results was within 4%. This result reflects that using statistical and RSM technique can be effectively used for the optimization of real waste treatment processes.

• Korean Journal of Microbiology
• /
• v.34 no.3
• /
• pp.126-131
• /
• 1998

Reduction of hexavalent chromium to its trivalent form by leachate microorganisms was studied in batch and bench-scale continuous stirred tank reactor. The inoculum was a culture of microorganisms in leachate and capable of providing up to 90% chromate reduction during 72 h batch assay with $20mg\;Cr(VI)\;L^{-1}$ in minimal media containing different levels of leachate (10 to 60%) and glucose (50 to 200 mM). Addition of glucose increased the efficiency of chromate reduction, but adverse effect was observed with increase of leachate probably due to the competitive inhibition between chromate and sulfate ions. The continuous culture experiment was conducted for 124 days using synthetic feed containing different levels of chromate (5 to $65mg\;L^{-1}$) at room temperature. With a hydraulic retention time of 36 h, chromate reduction efficiency was mostly 100% when Cr(VI) concentrations in the reactor were in the range of 5 to $50mg\;L^{-1}$ Specific rate of Cr(VI) removal was calculated as $3.492mg\;g^{-1}\;protein\;h^{-1}$ during the period of 101~124 days from the start-up which showed 81.2% of average reduction efficiency. The results indicate the potential application of using leachate microorganisms for detoxification of hexavalent chromium in various chromium-contaminated wastewater from landfill or tannery sites.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.10 no.3
• /
• pp.127-136
• /
• 1990

In this paper, the experimental study was carried out for the removal of olive oil in wastewater by the use of Biological Fluidized Bed(BFB) with the reticulated polypropylene sheets as media. The nonbiodegradable olive oil, one of the animal and vegitable oil, was used bacause of the relative simplicity of constitution. Biological degraciability and removal characteristics of emulsified olive oil were studied by batch and continuous experiments respectively. From the results of batch experiments, it was observed that the emulsified olive oli used in BFB reactor was absorbed by media and sludge in about 12 hours, and degradation of the absorbed olive oli was mostly completed for 24 hours. The functional relationship of Michaelis-Menten's Enzyme reaction equation exists between oil concentration and maximum specific rate of olive oil. From the continuous experiments for the removal of olive oil using BFB reactor, it was proved that the substrate removal rate coefficient $k=0.004d^{-1}$, which is the first order kinetics. It was apperared that oxygen utlization coefficients for synthesis(a') and endogeneous respiration(b') of microorganisms in the reactor are respectively 0.85mg $O_2/mg$ $COD_{cr}$ and 0.011mg $O_2/mg$ BVS. day.

• KSBB Journal
• /
• v.18 no.5
• /
• pp.418-423
• /
• 2003

A laboratory jar fermenter was modified to measure the duration for cooling water supply and the temperatures of the coolant at the inlet and outlet of water jacket. Successful operation of temperature control and on-line measurement was achieved by adjusting optimum parameters of the Proportion-Integral-Derivative temperature controller. The variables measured on-line were used to estimate cooling rates from empirical equations comprised of the time period of cooling water supply and the temperatures of coolant. The measured cooling rate showed a good correlation to the specific growth rate during batch cultivation of E. coli. Cooling rate was measured and applied to programmed cell growth in a fed-batch cultivations. Three fed-batch cultivations were demonstrated by feeding substrate to follow the programmed cooling rates increasing exponentially.

• Journal of the Korean GEO-environmental Society
• /
• v.4 no.3
• /
• pp.61-67
• /
• 2003

A new precess which consists of pre-dewatering device, post composting for solid phase and post sequencing batch reactor(SBR) for liquid phase was designed. Nitrogen in supernatants of dewatering device was removed by sequencing batch reactor. Experiments were carried out to investigate the SBR operation modes such as fill ratio, SRT, and operation cycle. The optimum fill ratio, SRT and aeration/non-aeration time were 1/12, 15days, and 2hr aeration / 1hr non aeraion, respectively. Methanol as an external carbon source increased denitrification when step feeding method was applied, not single feeding method.

• Journal of Korean Society of Environmental Engineers
• /
• v.22 no.7
• /
• pp.1193-1203
• /
• 2000

In this study, in order to remove Cd(II) from aqueous solutions, strongly acidic cation exchange resin(SK1B) by Diaion Co. was employed as an adsorbent. Experiments were mainly performed in two parts at room temperature($25{\pm}5^{\circ}C$) : batch tests and adsorption kinetics tests. In batch tests adsorption equilibrium time, pH effects, temperature effects, several adsorption isotherms, and finally desorption tests were examined. In differential bed tests, an optimum flow rate and an overall adsorption rate were obtained. In the batch experiment, adsorption capability increased with pH and became constant above pH 6 and adsorption quantity increased with temperature. Batch experimental data found that Freundlich and Sips adsorption isotherms were more favorable than Langmuir adsorption isotherm over the range of concentration (5~15ppm). The desorbent used in the desorption test was hydrochloric acid solution with different concentrations(0.01~2N). The degree of regeneration increased with concentration of desorbent and decreased slightly with the number of regeneration. In the continuous flow process using a differential bed reactor, the optimum flow rate was $564m{\ell}/min$ above which the film diffusion resistance was minimized. The overall adsorption rate for the removal of Cd(II) by cation exchange resin was found as follows ; $r=1.3785C_{fc}^{1.2421}-2.0907{\times}10^{0.0746C_i}\;q_e^{0.0121C_i-0.0301}$

• Journal of Korean Society of Environmental Engineers
• /
• v.31 no.7
• /
• pp.541-548
• /
• 2009

Iron coated media (activated carbon, sand and starfish) were prepared at pH 4 and applied for the treatment of landfill leachate containing organic compounds and soluble metal ions such as $Zn^{2+},\;Cu^{2+},\;Mn^{2+}$ in batch and column experiment. The amount of iron coated in media was analyzed with EPA 3050B method. The removal efficiency of metal ions and phenol was compared with iron coated media. The amount of iron coated in Fe-AC and ICS(iron coated sand) were 1,612 mg/kg and 1,609 mg/kg, respectively, while it was higher with 1,768 mg/kg in ICSF(iron coated starfish). The result of batch study represent the highest removal efficiency in the treatment of wastewater using iron coated starfish. In column study, the removal efficiency of phenol and metal ions was higher in multi-layered system of ICS, Fe-AC and ICSF compared to single layered system. Breakthrough time in the effluent was relatively enhanced for $Cu^{2+}$ and $Zn^{2+}$ in multi-layered system while the removal efficiency of $Mn^{2+}$ were not varied much. Therefore, multi-layered system was identified as the better system for the treatment of wastewater containing of metal ions and organic compound.