In this study, the performance of powdered activated carbon(PAC) contactor located in the Hakya water treatment plant(WTP) was evaluated. The result of tracer tests showed that the plug flow portion was more than 70 %. According to the total organic carbon(TOC) data of target WTP, there were no clear evidence that the addition of PAC contributed to the removal of organics. However, the results of jar test, conducted with the raw water taken from the Hakya WTP, proved that PAC could remove dissolved organic carbon(DOC) to some extent when the proper velocity gradient was maintained. It was estimated that the production rate of Hakya WTP, defined as the ratio of the operating flow rate to the design flow rate, was only 50 %. Because of this lower production rate, the mixing intensity in the contactor is much less than the designed value and, finally, the performance of PAC contactor was much less than what was expected.

Algae-related taste and odor problems are recognized by the water community worldwide to be major causes of consumer complaints and a loss in confidence of drinking water safety by the general public. Such problems can be arisen by natural and anthropogenic means, even by drinking water treatment processes. Microorganism is a common cause of naturally produced taste and odor. In this connection, the role of microorganisms and their metabolites are reviewed in the viewpoint of taste and odor in drinking water supplies.

Analysis of design parameters of residual treatment process at eight model water treatment plants, which were located in the four major watersheds, showed that there were large differences between those design parameters and the actual conditions. In this background, a new procedure was proposed and applied to the Chungju water treatment plant as an example of the optimum design of residual treatment process based on the characteristics of raw water. In this design example, a filter backwash recycle system consisting of a surging tank and sedimentation basin was newly proposed for more safe recycle of spent backwash water. It is expected that the design procedure proposed in this study would be estimated as a meaningful attempt to develope new design procedure for the domestic water industry.

연안오염퇴적물에 함유된 유기물질과 PAHs의 현장정화를 위한 생물활성촉진제의 효능을 파일럿 규모의 현장실험을 통하여 1년간 평가하였다. 실험 해역의 수온은 계절적인 요인으로 인해 16.5°C에서 21°C까지 변화가 있었으나, 파일럿 반응조의 오염퇴적물의 pH는 8.4-8.5로 서 비교적 일정하였다. 파일럿 실험종료 후 바탕시험구와 초산, 황산이온, 질산이온을 함유한 생물활성촉진제를 주입한 오염퇴적물의 화학적 산소요구량은 각각 39% 및 79%까지 감소하였으며, 휘발성고형물은 초기 약 15 g/kg에서 7 g/kg 및 2.5 g/kg까지 각각 감소하였다. PAHs는 2- ,3- ,4- ,5-ring 과 6-ring 16PAHs를 평가하였으며, 생물활성촉진제를 주입한 오염퇴적물에서 2-ring 화합물인 나프탈렌은 실험시작 2개월 후 100%(바탕시험구의 감소율 55.6%)까지 감소되어 가장 빨랐고, 12개월 후 3-ring 및 4-ring PAHs의 감소율은 모두 100%(바탕시험구의 감 소율 46%-100%)에 달하였다. 5-ring과 6-ring PAHs의 12개월 후의 감소율은 바탕시험구와 생물활성촉진제를 투여한 오염퇴적물에서 각각 26%-87% 및 77%-100%로 평가되었다. 연안오염퇴적물에 투입한 생물활성촉진제는 유기물질 및 난분해물질인 PAHs의 제거속도를 향상시킬 수 있는 것으로 평가되었다.

Pollutants generated by the biodegradation of livestock carcasses have the potential for contamination of the environment. Hence, livestock mortalities burial has been banned in the EU. In spite of the hazard, research on the biodegradation of livestock carcasses is lacking. In this study, five lysimeters were used to evaluate the enhanced biodegradation of organic materials in livestock mortalities burial. Lysimeter 1(control), lysimeter 2(grinding of livestock carcass), lysimeter 3(anaerobic microorganisms), lysimeter 4(Corynebacterium glutamicum in anaerobic condition) and lysimeter 5(Corynebacterium glutamicum in aerobic condition) were operated with temperature control. The degradation efficiencies of livestock carcass in the lysimeters were evaluated based on total organic carbon balance. The degradation efficiencies of ground livestock carcass were 1.9 times more than those of livestock carcass without grinding. In anaerobic condition, anaerobic microorganisms were more effective compared with Corynebacterium glutamicum on the biodegradation of livestock carcasses. However, the degradation efficiencies with Corynebacterium glutamicum in aerobic condition were significantly influenced on the biodegradation of livestock carcasses. Even if it would be helpful to degrade the livestock carcass in aerobic condition in terms of stabilization, potential risks on the environment by odor and bioaerosol must be solved.