This article appears in the March 19, 2007
Issue of Printing News, published by
Cygnus Business Media
By Fred Shapiro
Enzymes to the Rescue for Clean Air
As the United States Environmental Protection Agency (USEPA) proposes tighter standards for emissions from print shops, it behooves you to look beyond the traditional methods of destroying vapors for technology that can do the job and be more cost effective. The basic method employed by medium- and large-sized printers has been the addition of control systems, such as thermal oxidizers and solvent recovery systems. For small printers, as well as many of the medium size, the cost of the system and the energy required to operate the system are major negative factors. Innovative approaches to reducing the impact of chemicals in the workplace and on the environment have been investigated with mixed results. Sometimes the problem with an alternative has been the novelty of the approach. Biological remediation technology falls into this category. Early efforts required tremendous amounts of space and sophisticated controls for water bath temperatures. Later attempts concentrated on indoor air quality instead of the
treatment of fumes that were being exhausted to the outside.
Good Bacteria
Bioremediation or biotreatment is a method of utilizing bacteria and the enzymes they produce to convert hazardous compounds into safer non-hazardous chemicals. Solvent emissions can be converted to carbon dioxide and water. The key to success has been the identification of specific bacteria or microorganisms that can either digest or produce enzymes that will react with process chemicals and bring about the desired reduction of the hazardous components. Once identified, the question becomes how you can bring the organisms to the process and maintain them under normal production conditions. One essential ingredient in this formula is the presence of water to maintain the biomass. In practice, the bugs have proven capable of reducing pollutants in the air (VOCs, particulates, odors) to meet regulatory destruction efficiencies and have reduced indoor air pollution to acceptable OSHA limits. The opportunity that now exists for printers in the development of a system that is effective in reducing emissions, affordable, and can be housed in a limited, more reasonable space than previously.
Air and Water Solutions Inc., Nutley, N.J., has been a prime contributor to the development ofportable advanced bio-treatment systems that operate equally well for indoor air quality.
Environmental picture:
As described by the company, CAPs work by means of immobilized cell technology. The units contain a proprietary design in which naturally occurring, non-toxic microbes and their enzymes are immobilized on a spiral-wound plastic sheet. Ambient air is drawn into the CAP and forced around the cartridge by re-circulating water. As contaminants come into contact with the enzymes, they are naturally broken down to CO2 and water. Clean air is released. The spiral configuration allows a large surface area for biodegradation to take place in a small space. CAP units can treat emissions from presses and coating equipment. Single units or combinations of the cartridges can handle larger exhaust airflows and bring an end to burning natural gas to destroy the hydrocarbons. With ducts carrying the vapors directly from the drying systems on the press to the CAP, volatile organic compounds and particulates can be destroyed and eliminated, safeguarding both workers and neighbors. Re-circulated heated air from the reactions in the CAP can supplement or replace hot air used to foster drying of the inks and residual solvents during printing. A recent installation at a coating line for plastic sheets reduced emissions from 10 lbs. per hour to two lbs. per hour, qualifying the plant for a New York state permit. While thermal and catalytic oxidizers are cost effective for larger facilities, the small plant with one or two small-to medium-width presses can find relief from regulations with bio-treatment. The CAP can eliminate the air pollutants at a nominal capital cost with virtually minimal operating costs. You do not need a rocket scientist to understand how to operate the control units. With the elimination of a high percentage of air pollutants in the facility emissions, the category of air permit that may be required by the state environmental agency might be moved to a lower classification and possibly eliminate many of the constraints placed on printers to ensure compliance with the regulations. The technology would also provide larger printers with a strategy that could reduce emissions to a point where the facility could qualify for a less stringent and restrictive permit, a change in policy that is not being considered by the USEPA for major facilities. This innovative approach to a cleaner and healthier environment with less costly technology can safeguard you, your employees, and the people who work or live near your plant.
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Fred Shapiro is president of P-F Technical Services Inc., Silver Spring, Md., a technical and environmental management consulting firm to the graphics arts industry. He is also a member of Printing Industries of America/Graphic Arts Technical Foundation’s “Solutions on Site” consulting network.
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