A Look at Drycleaning

Do you know what actually happens to your clothes when you take them to a dry cleaner? For a long time, I didn't, as I did not frequent the dry cleaner and really never looked into it. For me, the clothes went in, and a few days later you got them back, supposedly cleaned without ever getting wet. Magic? Well, not exactly.

Turns out "dry cleaning" is actually a very deceptive name for the process. In reality, your dry-cleaned clothes get very wet; they just don't get wet with water. The reason dry cleaning exists is because some textile fibers, like wool, are extremely sensitive to water and swell or are distorted if washed in a normal washing machine. Instead of water, dry cleaners use organic solvents such as perchloroethylene (perc) to remove grease, dirt, and other unwanted substances from your garments. So what does the dry-cleaning process look like?

When you drop off your suits or dresses at the dry cleaner, they are first tagged and sorted into a grouping based on weight, fabric type, and color. Next, they are pre-treated at a spotting station to remove any noticeable stains and put in a dry-cleaning machine. Once washed, they enter an industrial drier and upon removal are spot-cleaned again for any remaining stains. Although old dry-cleaning machines used to have separate washing and drying pieces, all new machines are dry-to-dry self-contained systems that handle both washing and drying. This reduces solvent losses resulting from the transfer of clothes from one machine to another. The clothes are then pressed as needed and assembled for return to the customer.

While customers may be unfamiliar with the basic dry-cleaning process, the complicated part for the dry cleaners themselves is handling and disposing of their cleaning chemicals. The problem is that dry-cleaning solvents are hazardous to the environment and human health; they cannot be flushed down the drain to a community wastewater system like dirty washing machine water can. Instead, dry cleaners must handle and dispose of solvent as hazardous waste. Retaining and reusing solvent is thus an important part of the business: dry-to-dry self-contained equipment was introduced largely for the purpose of reducing solvent losses to the air during the transition from washer to dryer. And almost all modern dry-cleaning facilities use filtration and distillation to reclaim as much used solvent as possible and reduce waste. However, the generation of some spent solvent and spent filter waste is inevitable.

Unfortunately, because of the complications of waste disposal (or because of historical ignorance of the solvent's toxicity), many dry cleaners have a history of disposing dirty solvent in unethical ways (e.g. literally dumping it out the back door). Poor solvent handling and cleaning practices were also typical, which often caused indoor air health issues and soil contamination underneath and around the buildings. This has created thousands of cleanup projects throughout the U.S. for environmental remediators.

There are alternatives to using traditional dry cleaning solvents, like for example this list of approved perc alternatives from the NYS Department of Environmental Conservation. Some facilities have also utilized professional wet-cleaning and liquid carbon dioxide methods. Professional wet cleaning actually uses water as the cleaning solution with the understanding that almost any "dry clean only" fabric can be water-washed with the right soaps, conditioners, and temperature controls. Pressurized liquid CO2 can also be used in combination with other cleaning agents as a replacement to perc, though the capital cost for machines that use these agents is quite high.

In looking at processes like dry cleaning, I often wonder how much longer traditional chemicals like perc will remain in use with so much pressure in our society to use "green" methods. But that is a discussion for another day. For now, I'm thankful for the ability to dry clean my clothes, and for the places that handle these duties and manage their facilities in a safe and responsible way.

Reference: Dry-Clean Coalition