Showing papers by "Joseph R.V. Flora published in 2003"

Modeling Sorbent Injection for Mercury Control in Baghouse Filters: I—Model Development and Sensitivity Analysis

Abstract: A two-stage mathematical model for Hg removal using powdered activated carbon injection upstream of a baghouse filter was developed, with the first stage accounting for removal in the ductwork and the second stage accounting for additional removal caused by the retention of carbon particles on the filter. The model shows that removal in the ductwork is minimal, and the additional carbon detention time from the entrapment of the carbon particles in the fabric filter enhances the Hg removal from the gas phase. A sensitivity analysis on the model shows that Hg removal is dependent on the isotherm parameters, the carbon pore radius and tortuosity, the C/Hg ratio, and the carbon particle radius.

Modeling Sorbent Injection for Mercury Control in Baghouse Filters: II—Pilot-Scale Studies and Model Evaluation

Abstract: Activated carbon injection for Hg control in a 500-lb/hr pilot-scale coal-fired furnace equipped with a fabric filter for particulate control was evaluated at different operating conditions. The pilot-scale tests showed that Hg removal was improved at lower temperatures and higher C/Hg ratios. The two-stage mathematical model developed to describe Hg removal using powdered activated carbon injection upstream of a baghouse filter was used to obtain Langmuir isotherm parameters as a function of temperature by fitting the model to a subset of experimental data. The predictive capability of the model was then tested by comparing model calculations with additional experimental data from this system obtained using different operating temperatures and sorbent to Hg ratios. Model predictions were in good agreement with experimentally measured Hg removal efficiency. Based on the model predictions, Hg removal in the duct appears to be limited and higher C/Hg ratio, lower operating temperature, and longer cleaning cycle of the baghouse filter should be utilized to achieve higher Hg removal in this system.

Sodium azide interference in chemical and biological testing

Abstract: This paper discusses the results of sodium azide interference encountered during lab-scale studies in which sodium azide was used as a microbial growth inhibitor. In separate tests to evaluate the ...

Modeling and Comparison of Electrolytic Aeration and ORC® Aeration of Anoxic Groundwater in a Simulated Laboratory Aquifer

Abstract: This study investigated the electrolytic method of aerating anoxic groundwater, where the goal for aeration is to enhance in situ bioremediation by indigenous microbes. Experiments in a simulated a...

Theoretical analysis of the influence of process parameters on the use of an encapsulated phosphate buffer to control pH in a soil column

Abstract: A one-dimensional mathematical model was developed to analyze the influence of different physical and chemical parameters on the performance of an encapsulated phosphate buffer for controlling pH and enhancing a pH-dependent process in a soil column. Three scenarios were investigated where base equivalents are produced through the degradation of the target compound (scenario I), through reactions in the matrix (scenario II), and a combination of both mechanisms (scenario III). In all three scenarios, the production of base equivalents is countered by the release of the acidic core of the encapsulated phosphate, resulting in an enhanced removal of the target compound. A sensitivity analysis on the model shows that under the conditions investigated, the removal of the target compound is dependent on the flowrate, porosity, dispersion coefficient, reaction rate constants, mass of added capsules, and the point of addition of the capsules. The approach can be used to analyze scenarios where encapsulated buffers can control pH and optimize pH-dependent processes in a soil column.

Why is Environmental Engineering an Important Aspect of Environmental Education

Abstract: Environmental education has become the focus of national attention. The vision statement for a recent national environmental conference included exploring ‘‘the role of education regarding one of the central issues of the 21st century—how to achieve a more sustainable relationship between people and the environment. The security of people and nations, economic opportunity and quality of human life depend upon the continued availability of a life-sustaining environment’’ ~‘‘Vision’’ 2002!. Some of the university level topics explored at this conference included curricular needs for environmental sciences and environmental studies degree programs, integrating human health and environmental education, and transforming education at business schools. There appeared to be very little emphasis placed on the role of environmental engineering in the collegiate environmental education curriculum. As environmental engineers, we need to make sure that we are included in this national agenda. Why is it important to include engineering in this vast interdisciplinary grouping of knowledge? It is important because one of the goals of environmental education is ensuring that people continue to have a life-sustaining environment available to them. Engineering is part of the process in effecting this. In 1949, Merriam-Webster, Inc. ~then known as G & C Merriam Co.! defined ‘‘environment’’ and ‘‘engineering’’ in Webster’s New Collegiate Dictionary ~1949! as en•vi’ron•ment...n...2. That which environs; surroundings; specific, the aggregate of all the external conditions and influences affecting the life and development of an organism, etc., human behavior, society, etc.-en•vi’ron•men’tal,adj.... en’gi•neer’ing...n... 1. Originally the art of managing engines. 2. Applied science concerned with utilizing inorganic products of earth, properties of matter, sources of power in nature, and physical forces for supplying human needs in the form of structures, machines, manufactured products, precision instruments, industrial organization, the means of lighting, heating, refrigeration, communication, transportation, sanitation, and public safety, and other productive work... Almost a half century later, these definitions have become slightly more concise in the 1996 edition of Webster’s II New Riverside Dictionary ~1996! en•vi•ron•ment...n. 1. Surroundings. 2. The combination of external physical conditions affecting the growth and development of organisms.--en•vi’ron•men’tal adj.... en•gi•neer•ing...n. 1. The application of scientific principles to practical ends. 2. The design and construction of large-scale or complex structures such as bridges, roads, and tunnels.