도시림, 생활림, 가로수, 도시공원 등 국민들의 일상생활을 하는 구역이나 장소에 위치한 생활권 수목 식재지에서의 농약 살포는 농약 살포자의 농약 노출 문제뿐만 아니라 농약의 살포 후 생활권 수목과 접촉하는 불특정 시민들도 지속적인 농약 노출이 문제가 될 수 있다. 본 연구에서는 생활권 수목의 관리를 위해 관행적으로 가장 많이 사용 살포되는 살충제인 Fenitrothion을 회양목에 살포하고 일정시간별로 손 노출량, 잎 잔류량, 호흡 노출량을 측정 한 뒤, 위해성 평가 수식(MOS; margin of safety)을 이용하여 체중별 안전 노출시간을 분석하였다. 그 결과, 살포된 Fenitrothion의 손을 통한 전이량이 급격하게 떨어지고 호흡노출량이 측정되지 않는 48시간 이전 까지는 농약노출에 대한 주의가 필요할 것으로 판단되었다.

Dinitrophenol is preventing cells from making energy for growth and it has been suggested that pH may be important in mitigating effects of uncouplers. The effect of pH on toxicity of dinitrophenol at high concentration was investigated, over a pH range of 5.7 to 8.7. DNP inhibition was found to be strongly dependent on mixed liquor pH. The DNP degradation rate was highest in the pH range of 7.0 to 7.8; at pH 6.0 degradation of 0.41 mM dinitrophenol was significantly inhibited; at pH <5.7, dinitrophenol degradation was completely inhibited after approximately 25% of the dinitrophenol was degraded. However no significant effect of pH variation was seen on glucose uptake by the activated sludge mixed culture.

This study was performed to evaluate the inactivation and microbial regrowth of heterotrophic and nitrifying bacteria using chloramine as a secondary disinfectant for drinking water distribution system. Three sets of the three reactors filled with the Cl2/NH3-N ratio of 3:1, 4:1 and 5:1 were used in these experiments. Chloramine concentration were applied to each set of the reactors with 1㎎/ℓ, 2㎎/ℓ and 3㎎/ℓ, respectively. For the set with 1㎎/ℓ was applied, all the reactors showed that the residual chloramine concentration gradually decreased with elapsed time and reached to zero level after 7 days. Heterotrophic bacteria remarkably increased and nitrification occurred after 11 days. For the sets with 2㎎/ℓ and 3㎎/ℓ, however, the residual chloramine was maintained through the experimenatal period (21 day). Furthermore the regrowth of heterotrophic bacteria and nitrification were not found. More than 2㎎/ℓ of chloramine with Cl2/NH3-N ratio of 3:1, the nitrification could be inhibited by 2 days of contact time.

Kinetic data for the acid phase anaerobic digestion were presented in this study and the constants were determined with acid production rate and gas production rate. Process models based on continuous culture theory were used to describe the characteristics of the acid forming microorganisms and to enable further development toward utilization of the process in a more rational manner. Acid phase digestion can be separated with appropriate manipulation of hydraulic retention time in anaerobic digestion. Kinetic analysis of data from the various hydraulic retention times using a phase specific model obtained from the acid phase indicated maximum specific growth rate of 0.40/h, saturation constant of 2,000㎎COD/ℓ, yield coefficient of 0.35 ㎎VSS/㎎COD utilized and decay constant of 0.04/h for the acid production rate. Similar analysis of data for the gas production rate indicated maximum specific growth rate of 0.003/h, saturation constant of 2,200㎎COD/ℓ, yield coefficient of 0.0035 ㎎VSS/㎎COD utilized and decay constant of 0.06/h.