The adsorption behavior of Eosin Y on activated carbon (AC) in batch system was investigated. The adsorption isotherm could be well fitted by the Langmuir adsorption equation. The kinetics of adsorption followed the pseudo-second-order model. The temperature variation was used to evaluate the values of free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°). The positive value of enthalpy change ΔH° for the process confirms the endothermic nature of the process and more favourable at higher temperature, the positive entropy of adsorption ΔS° reflects the affinity of the AC material toward Eosin Y and the negative free energy values ΔG° indicate that the adsorption process is spontaneous. With the increase of the amount of AC, removal efficiency of Eosin Y was increased, but adsorption capacity was decreased. And adsorption capacity was increased with the decrease of particle size. With the increase of the amount of AC, removal efficiency of Eosin Y was increased, but adsorption capacity was decreased. And adsorption capacity was increased with the decrease of particle size.

Biosorption of Pb was evaluated for plants, Persicaria chinensis, Oenanthe javanica and Salvinia natans. The adsorption equilibrium was reached in about lhr for Pb and the highest adsorption capacity was 150㎎ Pb/g biomass at S. natans. Pb adsorption process showed a pseudo second order irreversible reaction. The highest initial adsorption rate was 2000㎎ Pb/g biomass/hr at O. javanica. In spite of pH variation, Pb adsorption capacity by P. chinensis was maintained uniformly. When light metals concentrations were increased in the solution, Pb was selectively adsorbed. The selectivity of mixture solution showed the adsorption order of Pb>Cu>Cr>Cd. The Pb adsorption capacity of P. chinensis pretreated with NaOH was increased by 30% in comparison with that of no treatment.

Immobilized nitrifier bead in airlift bioreactor were used to remove high levels of ammonia nitrogen from synthetic wastewater. Polyvinylalcohol (PVA) bead for immmobilization of nitrifier consortium were prepared by PVA-boric acid method by varying concentration of PVA and nitrifier consortium. By determining viscosity, sphercity and tailing, the characteristics of prepared beads were investigated and the continous immobilization process was developed. Synthetic wastewater containg 25g/㎥ of ammonia nitrogen could be treated within 0.5 hour and the highest removal rate of ammonia nitrogen was 934.2g/㎥ ·day.

Nitrifier consortium immobilized in polyvinyl alcohol was used for the removal of ammonia nitrogen from synthetic aquaculture water in the airlift bioreactor. At the aeration rate of 0.15 vvm and bead packing volume fraction of 20%, airlift bioreactor was operated effectively for a removal of ammonia nitrogen and for a stability of operation. Ammonia nitrogen removal rate by airlift bioreactor was continuously increased with decreasing hydraulic residence time. At the HRT(hydraulic residence time) of 0.3 hour, ammonia nitrogen removal rate was 84.3 g/㎥·d and the highest ammonia nitrogen removal rate was 130.8 g/㎥·d when HRT was 0.1 hour.

Pb2+ and Cr3+ uptake capacity by Sargassum horneri was 185.5㎎ Pb2+/g biomass and 102.6㎎ Cr3-/g biomass, respectively. An adsorption equilibria were reached within about 0.5 hr for Pb2+ and 1 hr for Cr3+. The adsorption parameters for Pb2+ and Cr3+, were determined according to Langmuir and Freundlich model. With an increase in pH values of 2 to 5, Pb2+ uptake was increased, however Cr3+ uptake was constant. The selectivity of mixture solution showed the uptake order of Pb2+>Cu2+>Cr3+>Cd2+. Pb2+ and Cr3+ adsorbed by S. horneri could be recovered from 0.1M HCl, 0.1M HNO3 and 0.1M EDTA by desorption process, and the efficiency of Pb2+ desorption was above 98%, whereas the efficiency of Cr3+ desorption was below 34%.

Nitrifier consortium entrapped in Ca-alginate bead were packed into aerated packed bed bioreactor and non aerated packed bed bioreactor and the performances of two bioreactors were evaluated for the removal of ammonia nitrogen from synthetic aquaculture water. Total ammonia nitrogen(TAN) removal rate was decrease in aerated packed bed bioreactor below 0.3hr of hydraulic residence time(HRT), but increased in non aerated packed bed bioreactor until 0.5hr of HRT. At HRT of 0.05 hr, TAN removal rate of non aerated packed bed bioreactor was about 335g TAN/㎥/day and the optimum ratio of packing height and inside diameter of reactor (H/D) was 4. The performance of two bioreactors indicated that non aerated packed bed bioreactor was better than aerated packed bed bioreactor in ammonia removal from synthetic aquaculture water.

Marine algaes are capable of binding a large quantity of heavy metals. We have investigated the uptake capacity of Pb and Cu by using 22 species of marine algae, collected from Korean coast. Among a variety of different marine algae types for biosorbent potential, Kjellmaniella crassifolia showed the highest uptake capacity of Pb. Metal uptake of Pb and Cu by Kjellmaniella crassifolia increase as the initial concentration rises, as long as binding sites are remained. The metal uptake parameters for Pb and Cu had been determined according to Langmuir and Freundlich model. By increasing pH. Pb uptake was increased and Cu uptake was constant. The maximum uptake capacity of Pb and Cu by Kjellmaniella crassifolia was 437 ㎎/g and 129 ㎎/g, respectively.

The feasibility of foam separation to remove protein in aquacultural recirculating water was investigated. From the results of batch foam separation on protein removal, superficial air velocity and initial protein concentration in bulk solution were found to be important operational factors in determining removal rates of protein. The protein removal rate by batch foam separation was proportionally increased with the superficial air velocity. Performance characteristics of continous foam separator were highly dependent upon the operating parameters of superficial air velocity, hydraulic retention time(HR) and foam height. Removal efficiency of protein increases with increasing superficial air velocity and HRT, and independent on foam height. As DO concentration was increased with superficial air velocity, foam separator is also used for oxygen addition. It could be confirmed that foam separator might offer better perspective for protein removal in aquacultural recirculating water

In order to investigate the possibility as a simple technique of wastewater treatment for recirculating aquaculture system, the experiment by a biofilter unit was carried out. The high and stable removal efficiency of nitrogen could be obtained by selecting the optimum recycle ratio and DO concentration. It was found that the proper combination of nitrification and denitrification step in the reactor would be required for increasing the removal efficiency. The extent of nitrogen removal gradually decreased with the rise of recycle ratio since the depression of denitrification by the lack of hydrogen donor. The depression of nitrogen removal was overcome by increasing the C/N ratio in the wastewater. The extent of phosphorus removal was increased slightly with the increase of DO concentration and recycle ratio, but high removal efficiency was not observed. However, the extent of COD removal was not affected by recycle ratio and DO concentration and showed the stable removal of above 90%.

This study was conducted for the efficient utilization of a scoria, which is abundantly found in Cheju island, as adsorbent and the scoria was examined for its performance in clarification of adsorption of heavy metal ions. The order in heavy metal ions adsorbed on scoria was; Pb^+>Cd^2+>Cu^2+>Ag^+>Co^2+>Zn^2+>Cr^3+>Cr^6+. This tendency was relatively consistent with the decreasing order of radius of hydrated metal ion. Also, the smaller scoria size and the larger amounts of scoria showed higher removal efficiency for heavy metal ions. The same scoria size showed more effective removal efficiency for heavy metal ions at lower initial concentration than at higher initial concentration. The adsorption abilities of original scoria and chemically treated scoria were compared. Adsorption isotherm of scoria was generally obeyed to Freundlich formula than Langmuir formula and Freundlich constant, 1/n was obtained in the range of 0.2∼0.4.

The waste biomass of Saccharomyces uvarum, used in fermentation industries to produce ethanol, were studied for their ability to absorb various heavy metal ions. Heavy metal ions studied in this research were Cd, Co, Cr, Cu, Ni and Pb. The order of the sorption capacity was Pb>Cu>Co=Cr=Cd>Ni. The living Saccharomyces uvarum exhibited higher metal-uptake capacity than the dead Saccharomyces uvarum. After we compare the uptake capacity of the Saccharomyces uvarum for individual metal ions with for a mixture of them, the following was observed: in the mixed heavy metal solution the uptake capacity was decreased than the one heavy metal solution. The selective uptake was observed when all the heavy metal ions were dissolved in a mixed solution. The adsorption isotherm modelling was decribed with the Langmuir and Freundlich model. The results were in good agreement with the Langmuir model.

The treatment performances of anaerobic-aerobic activated sludge process were investigated under various operation conditions. The treatment system proposed in this study gave a relatively stable performance against hourly change of the flow rate and showed a satisfactory removal of nitrogen and phosphorus compounds under experimental conditions. The recycle ratio of mixed liquor from aerobic to anaerobic region and peak coefficient primarily controlled the extent of nitrogen removal. The recycle ratio had the optimum values which were determined by the microbial activities of nitrification and denitrification. The behavior of the treatment unit could be simulated by using the kinetic equations and reactor models which considered the treatment units as complete mixing tanks.