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Environmental

environmental technology - air and water quality facility

Pilot Air Treatment SystemsThe Environmental Technology Group houses a 1,600 square foot Air and Water Quality Laboratory, designed to research air and water pollution control technologies and monitoring methodologies. The Laboratory is currently staffed to support bench-scale feasibility efforts through pilot-scale demonstrations and conceptual system design. The Air and Water Quality Laboratory contains a pilot-scale, 2,000 scfm air pollution control system (APCS), which is modeled after a commercially available "hybrid-advanced oxidation" technology.

This process uses a self-contained, self-regenerative multistage process that does not rely on incineration and produces no waste stream of its own. The design captures and oxidizes a broad range of volatile organic compounds (VOCs) and hazardous air pollutants (HAPs), including halogenated compounds.

A schematic diagram of the pilot system is shown. The pilot contains three independent unit operations, each based on a unique VOC/HAP removal concept:

  • Two gas-phase photolytic reactors that use UV radiation and ozone to initiate photolytic, photocatalytic, and free radical reactions that promote oxidative breakdown
  • Two aqua reactors, each consisting of a counter-current packed bed scrubber, a mist air dispersion unit (MAD), and an ozonated water phase treatment system promotes that oxidative breakdown
  • A granular activated charcoal (GAC) reaction unit that absorbs residual components and byproducts and, during regeneration with advanced oxidation technology, promotes oxidative breakdown

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The process gas stream passes through the three unit operations in series, but, in this research-configured system, provision is made for many alternative flow patterns and operating conditions.

A unique feature of this system is its capability of water and GAC regeneration using ozone and/or UV radiation leaving no secondary waste streams.

 

 

Some of the process and design variables that can be studied in the pilot unit include:

  • Molecular species in the incoming air
  • Wavelength and power of UV radiation
  • Geometric configuration of light sources
  • Use of catalytic surfaces
  • Oxidant type and concentrations, vapor and liquid phases
  • Liquid to gas flow ratios
  • Scrubber bed packing and configuration
  • pH and composition of liquid phase
  • Adsorption bed geometry
  • GAC types and efficiencies

The Air and Water Quality Laboratory also houses an array of state-of-the-art instrumentation for the analysis of VOC-HAP-laden air and water streams. These capabilities include gas chromatography with FID, ECD, NPD and TCD detection, gas chromatography with mass selective detection, VOST sampling systems, automatic sample concentrators with cryo concentration and cryo focusing (for EPA method sampling and analysis for TO-1, TO-2, TO-3, and TO-4 air analysis), thermogravimetric analysis, gas standards generation, etc., and other necessary support equipment and supplies.

An important thrust of the research in this laboratory is the elucidation of process chemistry, process optimization, and design improvement directed towards cost reduction for the effective treatment of contaminated air and water streams.