Coexisting Chemical-Biological Modifications of Chlorinated Solvents as a Basis for Waste Reduction in Pollution Prevention

9613258美国瓦茨的物理化学工艺可以提高工艺用水中生物难降解有机化合物的生物降解性，可以作为减少废物、降低毒性和通过再循环节约用水的基础。 本研究探讨复合式高级氧化工艺（AOP）-生物系统中化学氧化与生物氧化共存的现象. AOP是一种铁羟基氧化物催化的类Fenton反应，其中羟基自由基是通过矿物表面的多相催化产生的。 含有低微生物数量的非生物-生物系统可能由类芬顿氧化作用主导。 相反，具有高生物量的系统可能以较少的芬顿样氧化为特征，因为过氧化氢将被过氧化氢酶分解。 然而，在非生物和生物机制的最佳比例下，在矿物表面的微环境中产生的羟基自由基将修改生物难降解化合物，随后的氧化产物的转化将由共存的好氧菌群促进。 四氯乙烯将被用作羟基自由基探针。 13 C标记的丙酮酸将用于测定微生物代谢。 一系列的实验将研究生物质，过氧化氢浓度，铁羟基氧化物矿物浓度，和磷酸盐稳定的过氧化氢在促进平行的非生物-生物氧化的相互作用。 转化反应将通过监测14 C标记的四氯乙烯进行确认;降解产物将通过13 C标记的四氯乙烯的气相色谱/质谱和液相色谱/质谱进行跟踪，以区分其产物与天然有机化合物的质谱。 研究结果将提供基础数据，可应用于现场混合非生物-生物系统。 ***

9613258 Watts Physicochemical processes that can enhance the biodegradability of biorefractory organic compounds in process water can serve as a basis for waste reduction, toxicity reduction, and water conservation through the recycling. The proposed research investigates coexisting chemical and biological oxidations in hybrid advanced oxidation process (AOP)-biological systems. The AOP is an iron oxyhydroxide-catalyzed Fentonlike reaction in which hydroxyl radicals are generated by heterogeneous catalysis at the mineral surface. Abiotic-biotic systems containing low microbial numbers may be dominated by Fenton-like oxidations. Conversely, systems with high biomass would likely be characterized by fewer Fenton-like oxidations because the hydrogen peroxide would be decomposed by catalase. However, under optimal proportions of abiotic and biotic mechanisms, hydroxyl radicals generated in a microenvironment at the mineral surface would modify biorefractory compounds and subsequent transformation of the oxidation products would then be promoted by a coexisting consortium of aerobic bacteria. Perchloroethylene will be used as a hydroxyl radical probe. 13C- labeled pyruvate will be used to assay microbial metabolism. A series of experiments will investigate interactions of biomass, hydrogen peroxide concentration, iron oxyhydroxide mineral concentration, and phosphate stabilization of hydrogen peroxide in promoting parallel abiotic-biotic oxidations. Transformation reactions will be confirmed by monitoring 14C-labeled perchloroethylene; degradation products will be tracked by gas chromatography/mass spectrometry and liquid chromatography/mass spectrometry of 13C- labeled perchloroethylene to differentiate its products from the mass spectra of natural organic compounds. The results will provide fundamental data that can be applied to on site hybrid abiotic-biotic systems. ***