Bioclogging of biofilters and unsaturated porous media

生物过滤器用于处理各种受污染的废水和气流。它们在不饱和条件下运行，以确保有足够的氧气可用于从废物流中去除的有机化合物的好氧降解。在废水过滤器的情况下，有机物质存在于溶解相或作为悬浮固体。气流的处理依赖于空气通过过滤器时空气和水相之间有机化合物的分配。在这两种情况下，居住在水相和/或附着在固相上的微生物种群将所关注的污染物分解成危害较小的产物。废物流为微生物提供了连续的食物来源，导致过滤器孔隙空间内的生物量增加。生物质的过度积累将影响过滤器的运行和使用寿命，并可能最终导致过滤器完全堵塞和失效。目前很少有模型能够模拟生物过滤器内部的水力学和过程。过滤器通常被视为一个“黑匣子”，并调整水力和有机加载以建立最佳加载条件。然而，每当考虑新的废物流或新的过滤介质时，必须进行类似的“黑匣子”实验。本研究计划的总体目标是更好地了解生物过滤器内发生的过程，以便可以开发概念和数值模型来评估生物过滤器的潜在性能，减少进行大量“黑匣子”实验以确定理想尺寸和过滤介质的操作条件的需要。本文所获得的知识和提出的模型将允许生物过滤器的制造商和设计师评估替代生物过滤介质，有效地设计和尺寸新的生物过滤器，并评估和优化操作条件，以增加这些过滤器的使用寿命。

Biofilters are used to treat a wide variety of contaminated wastewater and air streams. They are operated under unsaturated conditions to ensure that there is sufficient oxygen available for the aerobic degradation of the organic compounds to be removed from the waste streams. In the case of wastewater filters the organic materials are present in the dissolved phase or as suspended solids. The treatment of air streams relies on the partitioning of the organic compounds between the air and aqueous phases as the air moves through the filter. In both cases, the microbial population, which resides in the aqueous phase and/or attached to the solid phase, breaks down the contaminants of concern into less harmful products. The waste stream provides a continuous food source for the microorganisms causing the biomass within the pore spaces of the filter to increase. Excessive build up of biomass will impact the operation and service life of the filter and may eventually lead to complete clogging and failure of the filter. Very few models exist that simulate the hydraulics and processes occurring within biofilters. The filter is often treated as a "black box" and the hydraulic and organic loading adjusted to establish the optimal loading conditions. However, any time a new waste stream or a new filter media is considered, similar "black box" experiments must be conducted. The overall goal of this research proposal is to better understand the processes occurring within the biofilters such that conceptual and numerical models can be developed to assess the potential performance of a biofilter, reducing the need to conduct numerous "black box" experiments to determine the ideal size and operating conditions of that filter medium. The knowledge gained and the models proposed herein will allow manufacturers and designers of biofilters to evaluate alternate biofilter media, to effectively design and size new biofilters, and to evaluate and optimize operating conditions to increase the service life of these filters.