Bioclogging of biofilters and unsaturated porous media

生物滤池被用来处理各种受污染的废水和气流。它们在不饱和的条件下运行，以确保有足够的氧气可供有机化合物的有氧降解，以便从废流中去除。在废水过滤器的情况下，有机物质存在于溶解相或以悬浮固体的形式存在。气流的处理依赖于当空气通过过滤器时有机化合物在空气和水相之间的分配。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关注的污染物分解成危害较小的产品。废流为微生物提供了持续的食物来源，导致过滤器孔空间内的生物量增加。过多的生物质积聚会影响过滤器的运行和使用寿命，最终可能导致过滤器完全堵塞和失效。模拟生物滤池内发生的水力和过程的模型很少。过滤器通常被视为“黑匣子”，通过调整水力负荷和有机负荷来确定最佳的负荷条件。然而，每当考虑新的废流或新的过滤介质时，都必须进行类似的“黑匣子”实验。这项研究提案的总体目标是更好地了解生物滤池内发生的过程，以便可以开发概念和数字模型来评估生物滤池的潜在性能，从而减少为确定滤料的理想尺寸和运行条件而进行大量“黑匣子”实验的需要。所获得的知识和本文提出的模型将使生物滤池的制造商和设计者能够评估替代的生物滤池介质，有效地设计和调整新的生物滤池的大小，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.