ANN ARBOR—Although dry cleaning is an effective and inexpensive way to clean clothes, a relatively new approach to water-based cleaning may work just as well, while posing less of an environmental burden and producing less harm to human health, according to a University of Michigan study.
" Most people don't think about how their clothes are going to be cleaned when they drop them off at a neighborhood dry cleaner," say graduate student researchers at the U-M School of Natural Resources and Environment. "They are only interested in receiving professionally cleaned and pressed clothing at a reasonable price within a short amount of time.
" But the cleaning method a professional cleaner chooses affects the environment, human health, the profitability of the business, the number of regulations with which the business must comply, and the cleanliness and appearance of clothes. "
In a comparative study of professional clothes-cleaning methods, graduate students Catie Blackler, Richard Denbow, William Levine, Kathy Nemsick and Ruth Polk found that wet cleaning, which uses water and biodegradable detergents, can be an environmentally and economically viable alternative to dry cleaning, which involves the use of perchloroethylene (perc), a chlorinated solvent used by most dry cleaners today.
Prior research has shown that perc is toxic to humans, can contaminate ground water, and must be disposed of through incineration and landfill disposal, the researchers say. Further, perc has been linked to leukemia and cancers of the bladder, intestines, pancreas and esophagus, and the National Institute for Occupational Safety and Health cautions that perc should be handled as a human carcinogen.
According to the U-M report, more than 80 percent of commercial dry cleaners in the United States use perc. In 1991, dry cleaners released about 180 million pounds of perc into the atmosphere and another 90 million pounds of perc- laden waste were removed by authorized hazardous-waste disposal facilities, the researchers say.
On the other hand, wet cleaning, which uses water and non-toxic detergents, greatly reduces health and environmental risks associated with perc use, they say. Wet cleaning uses a combination of water-based machines with sophisticated timing, agitation and temperature controls to clean the majority of clothes, while steaming, tumbling, spotting and hand washing account for the remaining amount.
The researchers add, however, that a concern exists over the amount of waste water and water-usage expenses associated with wet cleaning.
" The environmental impacts of using and treating water are much higher for wet cleaning than they are for dry cleaning," they say. " The process uses significantly more water, but this could be partially mitigated through the use of water recycling. "
While the cost of perc and charging detergents used in dry cleaning is cheaper than the cost of wet-cleaning detergents and sizing agents, dry cleaning incurs additional costs related to the disposal of hazardous perc-contaminated wastes, the study shows.
" When these disposal costs are included in the cost of perc usage, the cleaning agents for wet cleaning are less expensive than those for dry cleaning," the researchers say.
In addition, wet cleaning involves fewer initial capital expenditures and lower electricity costs than dry cleaning, in large part because dry cleaning uses energy- intensive pollution-control equipment, they say.
Citing a 1994 demonstration project that found a 97 percent customer-approval rate, the researchers say that wet cleaning appears to wash clothes as well as dry cleaning. While water does not dissolve stains such as oils, greases, fats and waxes as well as perc, non-chlorinated spotting agents used in wet cleaning are quite effective in removing them.
Another potential problem of wet cleaning—garment shrinkage—can be controlled through the use of specially designed programmable drying machines for most garments or by drip drying, they add.
In all, their study calls for more research on the long-term performance effects of wet cleaning, an analysis of the amount of labor it requires and development of waste- water recycling technologies. To encourage commercial dry cleaners to use wet cleaning systems, the researchers recommend government-subsidized worker-training programs, tax breaks and low-interest loans to buy equipment.
Moreover, cleaners who are expanding capacity should consider buying a wet cleaning machine, which would " provide the cleaner and their customers with greater flexibility in choosing how to clean garments," they say.
Despite financial incentives, the researchers concede that persuading dry cleaners to convert to wet cleaning may be an arduous task.
" Most wet cleaners have been operating for less than one year and their business is being compared to an industry with over 40 years of experience," they say. " Until wet cleaning has been operating long enough to collect empirical data on both cost and performance, dry cleaners will continue to maintain a level of skepticism about its practicality. "
The report was published by the U-M's National Pollution Prevention Center (NPPC). Greg Keoleian, assistant research scientist and NPPC manager, was the faculty adviser for the study.