In this study, ibuprofen(IBP) degradation by the photochemical (UV/S2O8 2-) and sonochemical (US/S2O8 2-) processes was examined under various parameters, such as UV (10~40±5 W/L) and US (50~90±5 W/L) power density, optimum dosage of persulfate ion (S2O8 2-), temperature (20~60℃) and anions effect (Cl-, HCO3 -, CO3 2-). The pseudo‐first‐order degradation rate constants were in the order of 10-1 to 10-5 min-1 depending on each processes. The synergistic effect of IBP degradation in UV/S2O8 2- and US/S2O8 2- processes could investigated, due to the generation of SO4 - radical. This result can confirm from the produced H2O2 and SO4 2- concentration in each processes. IBP degradation rate affected by the S2O8 2- dosage, temperature, power and anion existence parameters. In particular, IBP degradation rate increased with the increase of the temperature (60℃) and applied power density (UV:40±5 W/L, US:90±5 W/L). On the other hand, anions effect on the IBP degradation was negative, due to the anion play as a the scavenger of radical.

현재 우리나라의 슬러지 발생량은 지속적으로 증가하는 추세이며, 해양매립이 금지됨에 따라, 슬러지의 처리방법과 활용방안이 시급해져 새로운 방법을 모색할 필요가 있다. 이 연구에서는 하수 처리 시 발생하는 잉여슬러지의 탈수성을 증대시켜 슬러지 케이크를 감소시키기 위해 초음파를 적용하였다. 초음파를 액체에 발사하면 액중에 수축과 팽창이 교대로 일어나며 수 만개 이상의 미세한 공동이 발생된다. 이 공동이 폭발하면서 발생한 에너지를 슬러지의 입자 파괴에 이용하여 슬러지의 탈수성을 증대시키고자 하였다. 이번 연구에서 사용된 슬러지는 김포하수처리장에서 채취한 탈수 전 슬러지이며 하수슬러지 7L에 초음파 조사시간(5min, 10min, 20min, 30min, 50min, 60min)에 조사강도 154W, 308W를 가하였다. 일반적으로 초음파 조사시간이 길어질수록 CST가 증가하는 경향을 보였다. 그러나 조사한 슬러지에 응집제를 첨가시 초음파 강도와 조사시간에 따른 CST 결과 154W에서 조사시간 5분, 10분일 때 CST가 가장 낮게 측정되었다. 또한 초음파 조사시간에 따른 원심분리실험을 실시하였다. 조사시간 5min, 10min일 때를 조사하지 않은 슬러지와 실험을 실시한 결과, 초음파에 조사된 슬러지가 초기 침하되는 속도가 더 빠르며, 최종침하량도 더 빨리 도달했다. 연구결과 초음파조사시간과 초음파 강도가 탈수성에 큰 영향을 주었다. 탈수성의 직접적 효과를 보기 위하여 조사시간 5~10min, 초음파 강도 154W를 가해야한다. 이를 잉여슬러지의 탈수능 향상에 도입시 유용하게 사용될 수 있을 것으로 기대된다.

PAHs are major pollutants that are widely distributed in soil and groundwater environment, so that may be regarded as carcinogens. We investigated the degradation kinetics of PAH in aqueous solution when low pressure UV energy and ultrasonic irradiation were applied. Phenanthrene and pyrene were used as model compounds. The degrees of degradation of these compounds with time were analyzed with a GC/MSD (SIM-mode). UV photolysis experiments showed that phenanthrene was reduced by 90～67% at initial concentrations of 1 ppm to 8ppm whilst it decreased to 50% at 10 ppm. Under the same conditions pyrene was degraded up to about 75% at lower initial concentrations but the reduction efficiency dropped to a level of 34 to 29% at the higher concentrations above 8 ppm. The reaction orders for phenanthrene and pyrene were found to be zero-th and ca. -0.4th order, respectively, thus implying that the reported assumption of pseudo 1st order reaction for some PAHs would be no longer valid. PAH degradation was roughly proportional to the intensity of UV (number of lamps), exhibiting maximum 92.5% of the degradation efficiency. The solution pH was lowered to 4.4 from 6.4 during the experiments partially because the carbons decomposed by the energy reacted with oxygen radicals to produce carbon dioxides. Ultrasonic irradiation on phenanthrene solutions gave relatively poor results which matched to 50 to 70% of degradation efficiency even at 2 ppm of initial concentration. Phenanthrene was found to be degraded more efficiently than pyrene for the two energy sources. Ultrasound also followed the same reaction kinetics as UV energy on PAH degradation.