MIT team finds that the ratio of component atoms is vital to performance.
Starting this spring, MIT Press will publish the new Journal of Industrial Ecology, a multidisciplinary publication on environmental policy and management, to be co-edited by Dr. John Ehrenfeld, a senior lecturer in chemical engineering.
Industrial ecology is a field that systematically examines local, regional and global materials and energy uses in products and processes. More than end-of-the-pipe mandates, it allows industry to remain productive and profitable by incorporating policy changes with technology developments.
"Industrial ecology is ecological in that it looks to the natural world for models of highly efficient uses of resources, energy and byproducts," said Dr. Ehrenfeld. "Also, it places human activity--industry on the very broadest sense--in that larger context of the biophysical environment." He is director of the Technology, Business and Environment Program at the Center for Technology, Policy and Industrial Development.
The journal, which will be edited at the Yale School of Forestry and Environmental Studies by Reid Lifset, will address such topics as life cycle analysis, design for the environment, extended producer responsibility, and eco-industrial parks.
In his own research, Dr. Ehrenfeld has focused on an eco-industrial park in Kalundborg, Denmark, one of the earliest and most successful industrial ecology systems. It is a town where heavy industry obeys the cyclical laws of a natural ecosystem, with the waste products of one factory used to heat homes or power other factories, forming a web of conservation and dependency.
According to Dr. Ehrenfeld, what made Kalundborg so fertile for growing an Industriel Symbiose, as the Danes call it, is the town's environmental awareness and an ability to work together. Industries cooperated in money-saving efforts to follow new pollution-control policies, cut back on virgin energy and material inputs and reduce escalating disposal costs.
Kalundborg has four main industries: Asnas Power Station, a coal-fired plant; Novo Nordisk, a maker of enzymes and pharmaceuticals; Gyproc, a plasterboard manufacturer; and Statoil, a refinery. Asnas produces steam and heat while generating electricity. The company now funnels some of that steam to Statoil and Novo Nordisk. Statoil, which meets 40 percent of its steam requirements this way, uses the steam to heat pipes and tanks.
Novo Nordisk gets all its steam from Asnas and uses it as a source of heat and pressure. Asnas also pipes its excess heat to local fish farms and many homes. In fact, the municipality plans to have every home heated this way by 2005. This process of heat and steam recycling has raised the efficiency of coal burning from 40 percent to more than 90 percent.
Gyproc benefits from Asnas' waste stream as well, by using the power company's gypsum to make plasterboard. Gypsum, a calcium sulfate, is produced by Asnas's scrubbers, which were set up to reduce sulfur emissions. Cement producers and local contractors also get Asnas's fly ash byproduct.
Statoil Refinery also contributes elements of its waste stream. Flue gas, a byproduct of oil refining, goes through a desulfurization process, and the hot, liquid sulfur which is captured is sold to the Kemira Acid Plant across the sea in Jutland. Statoil's sulfur-free flue gas then goes to Gyproc and Asnas instead of being burned off. Asnas saves 30,000 tons of coal a year by using this excess gas, while both companies are able to meet new SOx and CO2 regulations. And for Gyproc, Statoil meets nearly 95 percent of its gas needs.
Novo Nordisk gives its nitrogen-rich sludge to local farmers. A thousand or so farmers, who get this pasty sludge via pipeline or truck, each save about $50,000 a year in fertilizer costs. A 1976 Danish regulation placed serious restrictions on dumping organics into the sea, and landfill space was rapidly dwindling all over Europe, so it became cheaper for Novo Nordisk to install a piping and truck system, treat the sludge and give it to farmers. The company subsequently decided not to charge them, to forestall them from turning elsewhere for fertilizer in the future.
Another efficiently used resource in Kalundborg is water. Supplies had dwindled through the years, and citizens complained that the big industries were withdrawing too much ground water. Thermal pollution of Kalundborg Fjord also worried the locals.
Consequently, Statoil and Asnas now share water. Statoil dips into nearby Lake Tisso, then sends its cooling water not to the fjord or the lake, but to Asnas's boilers. Statoil also sends treated wastewater to Asnas, which the power company uses to clean and perform other "non-boiler" activities. Asnas does need to use Lake Tisso, but it can get 75 percent of its water from Statoil. Novo Nordisk, having completed its government-mandated wastewater treatment plant in 1992, is now considering sending water to Gyproc if the water is of high enough quality for making plasterboard.
No one was opposed to all of these symbiotic linkages, Dr. Ehrenfeld said, because the firms were saving money. Regardless of the environment, these were sound economic decisions in the face of new policies and promises of new technologies. As long as manufactures could keep the price of their "waste" below the market value of virgin materials, they could always find someone to buy it.
Other industrial complexes are trying to initiate an Industriel Symbiose--in north New Jersey, southeast Texas, and Northern Europe--but only with one or two industrial linkages.
Dr. Ehrenfeld's former graduate student, Nicholas Gertler, compiled a total assessment of Kalundborg's evolving industrial ecosystem, providing an in-depth look at how the symbiosis developed and critiquing its values and weaknesses in hopes of helping industries transplant such a system elsewhere. More information can be attained through the MIT Center for Technology, Policy and Industrial Development.
Also contributing to the Journal of Industrial Ecology is co-editor David Allen of the University of Texas in Austin, and Professor David Marks of MIT, who sits on the editorial board.
A version of this article appeared in MIT Tech Talk on February 12, 1997.