Kim Chang-Gyun, Seo Hyung-Joon, Lee Byung-Ryul
Department of Environmental Engineering, Inha University, Incheon Metropolitan City, Korea.
J Environ Sci Health A Tox Hazard Subst Environ Eng. 2006;41(4):599-611. doi: 10.1080/10934520600574807.
This study was undertaken to determine the optimal decomposition conditions when 1,4-dioxane was degraded using either the AOPs (Advanced Oxidation Processes) or the BAC-TERRA microbial complex. The advanced oxidation was operated with H2O2, in the range 4.7 to 51 mM, under 254 nm (25 W lamp) illumination, while varying the reaction parameters, such as the air flow rate and reaction time. The greatest oxidation rate (96%) of 1,4-dioxane was achieved with H2O2 concentration of 17 mM after a 2-hr reaction. As a result of this reaction, organic acid intermediates were formed, such as acetic, propionic and butyric acids. Furthermore, the study revealed that suspended particles, i.e., bio-flocs, kaolin and pozzolan, in the reaction were able to have an impact on the extent of 1,4-dioxane decomposition. The decomposition of 1,4-dioxane in the presence of bio-flocs was significantly declined due to hindered UV penetration through the solution as a result of the consistent dispersion of bio-particles. In contrast, dosing with pozzolan decomposed up to 98.8% of the 1,4-dioxane after 2 hr of reaction. Two actual wastewaters, from polyester manufacturing, containing 1,4-dioxane in the range 370 to 450 mg/L were able to be oxidized by as high as 100% within 15 min with the introduction of 100:200 (mg/L) Fe(II):H202 under UV illumination. Aerobic biological decomposition, employing BAC-TERRA, was able to remove up to 90% of 1,4-dioxane after 15 days of incubation. In the meantime, the by-products (i.e., acetic, propionic and valeric acid) generated were similar to those formed during the AOPs investigation. According to kinetic studies, both photo-decomposition and biodegradation of 1,4-dioxane followed pseudo first-order reaction kinetics, with k = 5 x 10(-4) s(-1) and 2.38 x 10(-6) s(-1), respectively. It was concluded that 1,4-dioxane could be readily degraded by both AOPs and BAC-TERRA, and that the actual polyester wastewater containing 1,4-dioxane could be successfully decomposed under the conditions of photo-Fenton oxidation.
本研究旨在确定使用高级氧化工艺（AOPs）或BAC-TERRA微生物复合体降解1,4-二氧六环时的最佳分解条件。高级氧化过程在4.7至51 mM的H2O2浓度下，于254 nm（25 W灯）光照下进行，同时改变反应参数，如空气流速和反应时间。在2小时反应后，H2O2浓度为17 mM时，1,4-二氧六环的氧化率最高（96%）。该反应产生了有机酸中间体，如乙酸、丙酸和丁酸。此外，研究表明反应中的悬浮颗粒，即生物絮凝物、高岭土和火山灰，能够对1,4-二氧六环的分解程度产生影响。由于生物颗粒持续分散导致紫外线穿透溶液受阻，在生物絮凝物存在的情况下，1,4-二氧六环的分解显著下降。相比之下，添加火山灰后，反应2小时后1,4-二氧六环的分解率高达98.8%。两种来自聚酯制造的实际废水，1,4-二氧六环含量在370至450 mg/L之间，在紫外线照射下引入100:200（mg/L）的Fe(II):H2O2后，15分钟内氧化率高达100%。采用BAC-TERRA进行需氧生物分解，培养15天后能够去除高达90%的1,4-二氧六环。与此同时，产生的副产物（即乙酸、丙酸和戊酸）与AOPs研究中形成的副产物相似。根据动力学研究，1,4-二氧六环的光分解和生物降解均遵循准一级反应动力学，k值分别为5×10(-4) s(-1)和2.38×10(-6) s(-1)。得出的结论是，1,4-二氧六环可通过AOPs和BAC-TERRA轻松降解，并且含1,4-二氧六环的实际聚酯废水在光芬顿氧化条件下能够成功分解。
