The purpose of this study was to effectively purify U-contaminated soil-washing effluent using a precipitation/distillation process, reuse the purified water, and self-dispose of the generated solid. The U ions in the effluent were easily removed as sediments by neutralization, and the metal sediments and suspended soils were flocculated–precipitated by polyacrylamide (PAM). The precipitate generated through the flocculation–precipitation process was completely separated into solid–liquid phases by membrane filtration (pore size < 45 μm), and Ca2+ and Mg2+ ions remaining in the effluent were removed by distillation. Even if neutralized or distilled effluent was reused for soil washing, soil decontamination performance was maintained. PAM, an organic component of the filter cake, was successfully removed by thermal decomposition without loss of metal deposits including U. The uranium concentration of the residual solids after distillation is confirmed to be less than 1 Bq·g−1, so it is expected that the self-disposal of the residual solids is possible. Therefore, the treatment method of U-contaminated soil-washing effluent using the precipitation/distillation process presented in this study can be used to effectively treat the washing waste of U-contaminated soil and self-dispose of the generated solids.

A new model and resultant equation for the coagulation of acrylonitrile monomers in precipitation polymerization are suggested in consideration of the surface tension (γ) and cohesive energy density (ECED). The equation was proven to be quite favorable by considering figure fittings from known surface tensions and cohesive energy densities of certain organic solvents. The relationship between scale value of surface tension (γ/M) and cohesive energy density of monomers can be obtained by changing the coagulation bath component for effective precipitation polymerization of acrylonitrile in wet spinning.

홍수가 발생하기 전에 위험을 진단할 수 있는 기법이 다음의 절차를 따라 마련되었다. 현존 가용 수자원이 평균치 보다 많은 지 여부를 결정한다. 평균치보다 많은 날의 연속기간을 계산한다. 연속된 기간동안 강수량을 누적한다. 누적된 강수량 중에서 일별 감소량(유출 및 증발산등에 의한)을 감한 다음 다시 하루강수량으로 환산한 것이 유효강수량이다. 유효강수량을 다시 계절적, 지역적 평균치와 비교하여 일반화된 수자원의 집중정도 즉 유효강수지수를 구한다. 유효강수