Agronomic characteristics of transgenic herbicide-resistant rice lines were evaluated under field condition. Differences in agronomic traits and rice quality were observed between transgenic plants and the corresponding untransformed controls. Transgenic Ilpumbyeo lines flowered earlier than untransformed controls, whereas transgenic Nagdongbyeo flowered at the same time as untransformed control. With regard to the yield and rice quality, most of the transgenic lines showed lower yield than control except some selected transgenic lines. Selected Nagdongbyeo transgenic line also showed good eating quality comparable to the control although most selected Ilpumbyeo transgenic lines showed slightly lower eating quality and increased white center/belly in the rice grain. In order to find the main factor leading to somaclonal variation among transgenic lines, Tos17, a rice retrotransposon activated by prolonged tissue culture period was investigated. Although the transgenic lines carried only one or two of transformed bar gene, the copy number of Tos17 increased in most transgenic lines compared with control. The activation of Tos17 was not detected in selected promising transgenic lines such as ND115-15-1-B and IP23-3-3, suggesting that the increased copy number of Tos17 may have negatively affected agronomic characteristics of transgenic rice.

This study was conducted to investigate anoxic-RBC (rotating biological contactor) and its application in advanced municipal wastewater treatment process to remove biologically organics and ammonia nitrogen. Effluent COD and nitrogen concentration increased as the increase of volumetric loading rate. But, the concentration changes of NO2--N and NO3--N were little, as compared to COD and NH4+-N. When the volumetric loading rate increased, COD removal efficiency and nitrification appeared very high as 96.7～98.8% and 92.5～98.8%, respectively. However, denitrification rate decreased to 76.2～88.0%. These results showed that the change of volumetric loading rate affected to the denitrification rate more than COD removal efficiency or nitrification rate. The surface loading rates applied to RBC were 0.13～6.01g COD/㎡-day and 0.312～1.677g NH4+-N/㎡-day and they were increased as the increase of volumetric loading rate. However, the nitrification rate showed higher than 90%. The thickness of the biofilm in RBC was 0.130～0.141㎜ and the density of biofilm was 79.62～83.78㎎/㎤. They were increased as surface loading rate increased. From batch kinetic tests, the kmaxH and kmaxN were obtained as 1.586 g C/g VSS-day, and 0.276 g N/g VSS-day, respectively. Kinetic constants of denitrifer in anoxic reactor, Y, ke, Ks, and k were 0.678 ㎎ VSS/㎎ N, 0.0032 day-1, 29.0 ㎎ N/ℓ, and 0.108 day-1, respectively. P and Ks values of nitrification and organics removal in RBC were 0.556 g N/㎡-day and 18.71 g COD/㎡-day, respectively.

This study was carried out to obtain the operating characteristics of SMMIAR process for biological nitrogen·phosphorus removal. SMMIAR was operated at HLR(Hydraulic loading rate) of 39.6, 52.8, 63.4 and 79.2ℓ/㎡/d respectively and the operating parameters such as intermittent aeration time ratio of aerobic/anoxic, DO and microorganism concentration were changed to confirm the optimum operating condition. The concentrations of the wastewater BOD, TN(Total nitrogen) and TP(Total phosphorus) were 150, 30 and 7.5㎎/ℓ respectively. Achieving better removal efficiencies of BOD, TN and TP up to 90, 85.4 and 95.4% respectively, we must keep in operation condition of SMMIAR by 0.75 of time ratio of aerobic/anoxic and by minimum 45 minutes of oxic period simultaneously.

Improvement of water quality and Investigation of bacterial characteristics have been conducted in a pilot plant using biological activated carbon (BAC) in water treatment process at the downstream of the Nakdong River. Most of water control parameters were highly improved after passing through BAC. Approximately 54% of dissolved organic carbon was removed in coal-based BAC process. Bacterial biomass and bacterial production appeared 9.8×108 CFU/g and 7.l㎎-C/㎥·hr in coal-based BAC, respectively. Predominant bacteria species grown in BAC were identified as Pseudomonas, Flavobacterium, Alcaligenes, Acinetobacter and Aeromonas species. Particularly Pseudomonas vesicularis was dominant in both coal-based and coconut-based BACs, while Pseudomonas cepacia was dominant in wood-based BAC.

The combined wastewater of municipal landfill leachate and municipal sewage was treated using several sets of bench-scale aerated circulating system including porous media. Investigated items in this experiment were the dominant protozoa and metazoa in this system, the variation of microfauna relationship between operating condition and dominant genera. Also considered the factors determining dominant genera and their role. The outcome of this research is as follows; 1. Aspidisca, Vorticella, Trachellophyllum, Lecane, Philodina, Cyclops were mainly appeared prior to combinding leachate, while Trachelocerca, Bodo, Glaucoma were the dominant genera after combinding leachate. 2. As to metazoa, Nematode and Philodina were not influenced by 5% leachate mixing ratio, meanwhile Crustacea has high sensitivity for increased leachate mixing ratio and it was not appeared in 5% leachate mixing ratio. 3. The appropriate treatability could`nt be expected at the above 10% leachate mixing ratio. Especially, in the condition of 20% leachate mixing ratio, all of the microfauna were affected damage seriously on their existence. Meanwhile hydraulic retention time, substrate loading rate and sludge production rate didn`t give notable influence on increasing the number of microfauna. 4. As to protozoa, saprozoic and holozoic species were appeared commonly and polysaprobic species were dominent. 5. Filamentous organsms were nearly not affeced by leachate mixing. It seems that they could live without any trouble at the 10% leachate mixing ratio, if the substrate is sufficient. 6. Diversity of microfauna had a reducing trernd as the sewage was mixed with leachate.

In order to research the adsorption removal characteristics of trace organic by-products in disinfection of drinking water by biological activated carbon(BAC), water samples disinfected with Cl_2, O_3 and ClO_2 after treatment by fluidized-bed system with water added with humic acid(l0㎎/L) were investigated the formation and the removal of trihalomethanes (THMs), and the trace organic by-products by gas chromatography(GC) & gas chromatography/mass selective detector(GC/MSD). Control was used by activated carbon(AC) and water added with hurnic acid(HA). The results were summarized as follow ; The THMs removal effect of BAC by chlorination was in lower 90 % than that of control(HA), the sorts of oxidants formed by Cl_2, O3 and ClO_2 were that O_3 was very fewer than Cl_2 or ClO_2 and that ClO_2 was fewer than Cl_2 The trace organic by-products were esters and phthalates etc. Based on results above, it is concluded that BAC was appeared the more desirable adsorption-degradation removal characteristics than that of AC.