In the Lab

Fluid CO2

Researchers from France's oceanographic community are collaborating under the Programme Ocean Multidisciplinaire Meso Echelle (POMME) or the Multidisciplinary Meso Scale Ocean Program to study the effects oceans have on climate, or the weather conditions in an area, experimentally of an average size up to 10 miles. The aim of the project is to improve understanding of how the ocean influences climate due to the amount of carbon, heat and transformed living matter inhabiting the salty waters.

Four measurement campaigns are taking place between September 15, 2000 and October 2001 halfway between the Azores and the Iberian Peninsula in the North Atlantic Ocean.

The ocean is a huge thermal mass in contact with the atmosphere, carrying heat and energy from one end of the planet to the other through warm water currents. These water masses travel from ocean to ocean carrying gases, particularly a greenhouse gas -- carbon dioxide (CO2). Since the level of CO2 concentration in the atmosphere is an important factor in the warming of the climate, it is crucial to monitor the levels and find out how oceans absorb and carry the gas. The Atlantic Ocean is believed to be a major reservoir of atmospheric CO2.

The research program was developed to determine how ocean circulation acts to "bury" a 1,600 foot thick water mass that is relatively homogenous in terms of temperature and salinity. In the winter, this layer of water is often in active contact with the atmosphere, but in the spring it is separated from the atmosphere due to the warming of surface water. The dissolved surface gases are then trapped in the water mass, and since this phenomenon occurs in the spring, additional CO2 is trapped by flowering algae. Researchers will study the processes that trigger spring flowering and transform the biological matter pulled down into the water mass (particle fall, bacterial degradation, dissolving, etc.).

Through a multidisciplinary sampling strategy based on a number of actions and pieces of equipment, physicists, chemists and biologists will try to understand how whirlpools and underwater currents carry energy and matter. The size of the areas studied will correspond to the size of the whirlpools. This will include a meteorological buoy as well as other observation systems for ocean/air interface flows, 100 floats and anchorages with monitoring instruments, current meters, tomography (a technique of X-ray photography by which a single plane is photographed, with the outline of structures in other planes eliminated) and particle traps. Information recovered from regional digital simulations will be combined with satellite data on ocean water levels, ocean water coloring and wind data.

POMME will also be supported by real time actions on land, linked to the MERCATOR project for operational oceanic forecasting and by the data processing carried out in the framework of CORIOLIS, the French program from in situ operational oceanography on the Atlantic Ocean.

For more information, contact the French Technology Press Office at 312.222.1235.

Following the Scent of Odor Control Solutions

Developed in part by researchers at the Georgia Institute of Technology, Georgia state's rules for controlling and assessing malodors from food waste rendering plants could become a model for other states facing the same problem. Georgia Tech and University of Georgia researchers are working to improve treatment of odors so they don't drift into communities surrounding rendering plants.

"The problem of malodors from rendering plants is a longstanding issue. In fact, the industry dates back to Roman times. Today, it is a nationwide issue," says Jim Walsh, a researcher at Georgia Tech's Economic Development Institute.

Every year in the United States, 43 billion pounds of food processing waste materials are sent to rendering plants, where they are converted into pet and animal feeds. Of that waste, 23 billion pounds is from poultry.

"The bottom line is if we didn't render this material, it would be in landfills," Walsh says. "Instead, it's turned into usable byproducts."

Dealing with malodors is the difficult part of the equation. Though the problem is being addressed by the rendering industry, there is not a solution in sight, Walsh says. "It's just what we expected," he adds. "Odor is a complicated issue."

Currently, there are no state or federal limitations on malodorous chemical compounds emitted unless these compounds are classified as volatile organic compounds (VOCs) or hazardous air pollutants (HAPs).

The Georgia state-funded Traditional Industries Program for Food Processing (FoodPAC) and the Agricultural Technology Research Program are supporting Walsh's efforts as a liaison between industry, researchers and regulators. Walsh is tracking the latest technologies and research, including projects ongoing at Georgia Tech and the University of Georgia.

Recently, the two institutions began a collaborative project to enhance wet scrubber odor treatment technology and improve monitoring for odors and VOCs in the food processing industry.

Wet scrubbers transfer odorous chemicals and VOCs in the air to the water and neutralize them using oxidizing chemicals. But wet scrubber operations are often process-specific, and there is limited data available to effectively improve their performance. University of Georgia Professors K.C. Das and Jim Kastner hope their ongoing work in developing methods for chemical characterization of air emissions from rendering operations will eventually advance wet scrubber design. Characterizing malodorous chemicals is difficult because they tend to vary and occur in trace amounts, Walsh explains.

In the current project, University of Georgia's Agricultural Department researchers are focusing on the mass transfer of specific odorous compounds into water.

Specifically, researchers are continuing their chemical characterization studies and also evaluating the efficiency and appropriateness of water-based treatment technologies. Georgia Tech Research Institute engineer John Pierson is examining potential improvements to the gas-phase pre-treatment of total VOCs. Specifically, he is working with the developers of two different novel chemistries to improve wet scrubber efficiency, and Pierson is developing a predictive monitoring system to better manage rendering plant emissions.

Researchers elsewhere are working on improvements to biofilters, which take airborne emissions from the plant and push them through a box filled with packing material, such as wood shavings or ceramic balls. Bacteria grow on the packing material, and then they eat and remove most of the odorous chemicals. In Georgia, rendering plants in Cumming and Cuthbert have installed customized biofilters.

Progress in controlling malodors seems slow sometimes, but Walsh says, "I am constantly hearing of people developing new chemical treatments. A lot of research and development is going on, not only new chemical treatments, but new ways of controlling processing operations to eliminate odors."

For more information, go to www.gatech.edu.

A Clean Start

A team of University of Texas engineers and Ford Motor Co. have patented and tested a system that would cut hydrocarbon pollutants by 50 percent and tailpipe toxins by 80 percent. If the researchers can trim the costs, the invention could mean markedly cleaner air due to a new start-up system in vehicles.

Ronald Matthews, a University of Texas mechanical engineering professional and head of the school's engine research team, and Rudy Stanglmaier, working at a San Antonio research institute after getting his mechanical engineering doctorate, along with Ford engineers George Davis and Wen Dai, have been awarded a 17 year patent on the device.

Gasoline is a conglomeration of different hydrocarbon molecules, some heavier and some lighter. The lighter portion burns while the engine is cold, and the remaining 80 percent is expelled as pollutants and toxins. After the engine warms up, combustion is more efficient.

Matthews and Stanglmaier were working on a different problem that led them to the cold-starting emissions question. Stanglmaier wanted to find a way to help ethanol-powered vehicles start better. A common variety of ethanol, E-85 has only 15 percent gasoline, and it was difficult to get enough fuel vapor to a cold engine.

In effect, the system the engineers devised creates a second fuel for startup. By using the engine's heat, the system separates vapor from the heavier gasoline, cools it back into liquid, and then depends on the car's computer and valves to send the proper gasoline to the engine at the proper time. The system solved the ethanol start up problem, and then the researchers realized the possibilities for cutting emissions.

Ford's contribution to the effort, aside from the engineers' time, has been $20,000 to $30,000 for the patent process and $54,000 for a 2001 Lincoln Navigator.

For more information, contact Ronald Matthews at rdmatt@mail.utexas.edu.

Detective DNA

An inexpensive, real-time sensor technology that harnesses living deoxyribo nucleic acid (DNA) to detect metals such as lead, mercury and cadmium has been developed by researchers at the University of Illinois.

Genetic algorithms reportedly were used to discover the specific required DNA strands required to detect specific metals from within a population of trillions of random DNA sequences.

The university said that the DNA sensors react in real time to the presence of specific metals by emitting light into an inexpensive fiber-optic lens. Traditional methods require lengthy batch testing or expensive instrumentation.

"We have created a new class of ?catalytic DNA-based biosensor with highly sensitive fluorescence detection for metals," said professor Yi Lu.

Lu was assisted by graduate student Jing Li, coauthor of their recent paper in the Journal of the American Chemical Society.

Lu's innovation is based on a 1994 pharmaceutical discovery that DNA is not just a genetic information repository, but that DNA could also act in a manner similar to living enzymes that catalyze a specific chemical reaction right at the site where it is needed. These enzymes, called catalytic DNA, constitute a new class of metalloenzymes derived from metallo-nucleic acids.

Li first generated a population of one-quadrillion random DNA strands -- individual strands that can fold like proteins, rather than the familiar intertwined double-helix. A natural selection process then filtered out those strands that could only fold around lead. Li was able to obtain DNA strands that could detect lead over a concentration range of three orders of magnitude.

Then Lu engineered a way to attach a fluorophore to one end of the DNA strand and a fluorescence quencher on the other end.

In steady state when exposed to 560-nm light for excitation of the flourophore, the quencher's proximity keeps the fluorophore from glowing. When the desired metal is present, it cleaves the quenching end, resulting in an easily detectable 400 percent increase in fluorescence.

To deliver a working sensor technology, something yet to be done, would require attaching the fluorophore end to a chip substrate designed to have an optical fiber permanently attached. These chips could be reset by washing.

The National Institutes of Health (NIH), which provided the funding for Lu's experiments, has targeted the technology for health applications, including environmental monitoring, wastewater and treatment, industrial process monitoring and clinical toxicology.

For more information, contact Yi Lu at the University of Illinois at yi-lu@staff.uiuc.edu.




This article originally appeared in the May 2001 issue of Environmental Protection, Vol. 12, No. 5, p. 14.

This article originally appeared in the 05/01/2001 issue of Environmental Protection.

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