BIOAVAILABILITY, SOIL HETEROGENEITY, AND BIODEGRADATION OF ORGANIC CONTAMINANTS

描述：本项目的目标是提高我们的理解 土壤异质性和限速的影响 吸附/解吸对生物降解和原位生物修复的影响 地下系统中的有机污染物。具体目标， 将在本拟议研究中解决的问题将是：1）调查 物理不均匀性（“优先流”和微观 孔/大孔传质）对生物降解位置和速率的影响 2）研究接触时间（ 污染物和土壤）和限速解吸对生物有效性的影响; 3)建立数学模型，模拟生物降解，速率， 有限的吸附/解吸扩散传质和运输 非均质多孔介质提出了一种新的方法来表征 物理（孔隙大小分布、非均质性对流体的影响 运输）、化学（吸附程度的速率）和微生物 （细菌的位置、浓度和活性）土壤的性质 包含在用于测量污染物传输的柱中。这 方法结合了流动和运输表征技术（水- 保留功能，示踪剂运输，染料染色）与吸附 测量和先进的技术来表征性质和 细菌数量（放射性标记细胞、基因探针）。这 这种方法将使他们能够将土壤异质性的影响 对土壤异质性对水流和输移速率的影响 吸附/解吸和生物降解的位置和速度。

Description: The goal of this project is to enhance our understanding of the effects of soil heterogeneity and rate-limited sorption/desorption on biodegradation and in-situ bioremediation of organic contaminants in subsurface systems. The specific objectives that will be addressed in this proposed research will be to: 1) investigate the influence of physical heterogeneity ("preferential flow" and micro- pore/macro-pore mass transfer) on location and rate of biodegradation during transport; 2) investigate the effect of contact time (between contaminant and soil) and rate-limited desorption on bioavailability; 3) develop mathematical models for simulating biodegradation, rate- limited sorption/desorption diffusive mass transfer and transport in the heterogenous porous media. A novel approach is proposed to characterize the physical (pore-sized distribution, impact of heterogeneity on fluid transport), chemical (rate in extent of sorption), and microbiological (location, concentration, and activity of bacteria) properties of soil contained in the columns used to measure contaminant transport. This approach combines flow and transport characterization techniques (water- retention function, tracer transport, dye staining) with sorption measurements and advanced techniques for characterizing the nature and quantity of bacteria population (radio-label cells, gene probe). This approach will allow them to correlate the impact of soil heterogeneity on flow and transport to the impact of soil heterogeneity on the rate of sorption/desorption and on the location and rate of biodegradation.