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 biosorption of heavy metals has received a lot of attraction for application of metal ions treatment. In this work, we studied with Arthrobactor sp., screening from a wastewater containing heavy metals. The Pb uptake capacity of Arthrobactor sp. was nearly 146.9 ㎎ Pb/g dry biomass(initial concentration, 500 ㎎/L), whereas the Pb uptake capacity of Saccharomyces cerevisiae and Saccharomyces uvarum were only around 39.40 and 35.65 ㎎ Pb/g dry biomass, respectively. The Pb and Cr were removed from metal solution much more efficiently than were the other metals(Cd and Cu). The Pb uptake capacity of Arthrobactor sp. increased with increasing in pH(1.8, 3.0 and 4.0) and decreased with increasing of biomass concentration. At pH 4.0, the Pb uptake capacity reached 244 ㎎ Pb/ g dry biomass in Pb initial concentration of 1000 ㎎/L. The Pb uptake capacity of Arthrobactor sp. treated by KOH and CaCl_2 were increased above values obtained with untreated Arthrobactor sp. However, the Pb uptake capacity of Arthrobactor sp. treated by NaOH was decreased. The removal efficiency of Pb was kept above 99% before the breakthrough points were reached.

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%.

Heavy metal adsorption by microbial cells is an alternative to conventional methods of heavy metal removal and recovery from metal-bearing wastewater. The waste Saccharomyces cerevisiae is an inexpensive, relatively available source of biomass for heavy metal biosorption. Biosorption was investigated by free and immobilized-S. cerevisiae. The order of biosorption capacity was Pb>Cu>Cd with batch system. The biosorption parameters had been determined for Pb with free cells according to the Freundlich and Langmuir model. It was found that the data fitted reasonably well to the Freundlich model. The selective uptake of immobilized-S. cerevisiae was observed when all the metal ions were dissolved in a mixed metals solution(Pb, Cu, Cr and Cd). The biosorption of mixed metals solution by immobilized-cell was studied in packed bed reactor. The Pb uptake was investigated in particular, as it represents one of the most widely distributed heavy metals in water. We also tested the desorption of Pb from immobilized-cell by using HCl, H_2SO_4 and EDTA.