One of the most interesting audits I ever conducted took place at a fragrance factory. Every couple of steps, the odor of the air would change markedly, from roses to raspberries, from lavender to lemons, as small quantities of each scent escaped from the processing units.
Chemists call the property that gives fragrances their rich perfume "volatility". Volatility means a substance evaporates easily, filling the air with molecules that trigger our sense of smell. In some cases, such as fragrances, the escaped chemicals may be harmless, or even pleasant -- although even fragrance factories must take caution with their air pollution equipment to ensure neighbors are not overwhelmed by a jungle of odors.
Controlling Volatile Air Pollutants
To an air pollution control engineer, volatility means work: methods must be found to control these chemicals in the interest of keeping the air clean. The pollutants known as "volatile organic carbons (VOCs)" have long posed a challenge for air pollution engineers. They tend to escape at every possible point, and how can you capture and treat molecules that have such a strong tendency to fly away?
The best methods that exist today rely upon energy intensive processes, primarily thermal oxidation and adsorption. Thermal oxidation is fancy engineering language for burning the VOCs. The equipment can be made more efficient with heat recovery and catalytic options, but the underlying energy costs remain high.
Adsorption refers to the use of materials like activated carbon -- the same stuff in your Britta water filter -- that attract and hold the volatile organics. But manufacture of activated carbon itself requires several steps in high temperature furnaces. Activated carbon recycling helps minimize the lifecycle energy costs, but even reactivation requires another pass through the furnace to burn off the organics that are adsorbed on the carbon surfaces.
Other options, like bio-reactors, have limited applications; these can be used only when the air pollutants don't overwhelm and kill the organisms that are trying to eat them.
Nature Offers a Better SolutionEnter inventor Matthew Johnson from the Department of Chemistry at the University of Copenhagen. "Biomimicry" may not be the perfect term to describe what Johnson did, which mimics how Mother Nature cleans Earth's atmosphere rather than how any particular life-form works, but the concept of copying natural processes seems to fit in the category. Johnson describes his inspiration:
I have investigated the self-cleaning mechanism of the atmosphere for years. Suddenly I realized, that the mechanism is so simple, that we could wrap it in a box and use it to clean indoor air. This makes for a better indoor climate, and in this particular case it also removes smells from this industrial process allowing the company to stay and making the neighbours happy.
Earth's atmosphere cleans itself when polluting gasses plus sunlight plus naturally occurring ozone cause the pollutants to clump together as particles, which can then be washed out in the next rain.
Low Energy, Natural Air TreatmentJohnson has been working in deepest secrecy to turn nature's secret into a viable air pollution control technology. Now Johnson and his investment partner, INFUSER, have announced that their tests prove the technology works. The tests solved real-world air pollution problems at the Danish company Jysk Miljoerens, where oils are separated from ship bilge waters.
The newly patented process, referred to as an "atmospheric photochemical accelerator," sits in five aluminum boxes near the source of air pollution. The process has no filters that require expensive maintenance and consumes little energy.
Environmental agencies have increasingly clamped down on emissions of volatile organic carbons. Many VOCs do not have acute health effects, but they have long been of concern as precursors to smog. The high costs and technical infeasibility of air pollution controls allow regulators to tolerate more emissions than they otherwise might, as the costs of economic harm or climate effects from currently available pollution controls must be weighed against the costs of treatment. But as our understanding of the long term health effects of VOCs in our air improves, the pressure to ensure factories clean the air of any and all pollutants increases.
The atmospheric photochemical accelerator offers a promising solution to this age-old industrial problem.