In a push towards sustainability, innovative solutions to age-old problems are coming to the forefront. The garment cleaning industry is no different, with revolutionary wet and green cleaning methods that utilize water instead of the hazardous chemicals utilized in traditional dry cleaning. However, what are the environmental impacts of these two very different laundry processes? This article considers the environmental impact of wet cleaning, dry cleaning, and everyday laundering, as well as one company’s innovative solution to the problems dry cleaning provides.
RE:THRED is championing the green-cleaning movement by broadening cleaning options. The company employs high-tech, energy-efficient machinery, biodegradable detergents, and eco-friendly herbal pretreatments. Additionally, RE:THRED is the only professional cleaner in Massachusetts to use Biosoft, a groundbreaking Glycolipid product that augments energy use, trash output, and LCA’s (Life Cycle Assessment Employer) biodegradable rate efficacy.
The long-term effects of chemicals utilized in traditional dry cleaning are currently unknown, but studies have demonstrated how harmful the solvents can be. Trichloroethylene, a commonly used solvent, is also a probable human carcinogen. Additionally, dry cleaners frequently dump wastes in landfills or down sewers, which contaminate air and groundwater and impact nearby populations through hazardous vapor releases. Those working in the cleaning industry and individuals who work or live near those establishments are at the highest risk.
Gaining in popularity among the health-conscious and environmentally aware, machine wet cleaning uses computerized machines to clean garments just like home washing machines, but without the typical wear and tear. A new cleaning process, as gentle as or more gentle than dry cleaning, is on the horizon. Caring for woolens, silks, and other complex fabrics can safely be treated.
Historical Overview of Dry Cleaning
In the collection of early patents, Bradley 1869 is the first view of dry cleaning as an industrial wet process [1]. The action of liquid on fabric is the same in launder and dry clean (Bradley 1869, 1). It is observed that dry cleaning does not draw out the pigments of a dark cotton garment, while launder washed it out so that the fabric was no longer usable (Bradley 1869, 5). Because pigments are soluble in a solvent other than water, dry cleaning was assumed to be different from launder, which prompted research on other suitable liquids (Bradley 1869, 4). This path of examining suitability of different liquids was taken by at least four others: Barrett on turpentine, Brenner on a mix, etc. The terms of “dry” cleaning, “liquid” cleaning, and “wet” cleaning were never fully and explicitly explicated.
The other early dry cleaning patent is Goodman 1872. Goodman thought that “detergent” is the attribute of any liquid that can clean a garment. Evans 1872, Henle 1872, and Brenner 1875 expanded this research by examining what “detergent” really is; they described soap and the mechanism of forming an emulsion as this ability. Henle’s rinsing patent is about shaking the liquid through the fabric, making dry cleaning no longer a “dry” process. All these patents were written in 1869-1875, and they worried about the same problems: Soiling of garments was evidently accounted in all of them, more than “wearing through” (the aftermath of washing)” could happen.
Pseudo-globalization invented in the 1850s by Dry Cleaning Industry, Carpet Cleaner Industry, etc. In this period, the only feasible travel to globalize dry cleaning was to ship full pieces of carpets abroad. Many carpet cleaners sent carpets to Spain for more than one year to clean and dry it, without using chemicals, which completely transformed the carpet’s texture. Textile prices increased in London because the Industrial Revolution raised labor and transportation prices abroad. The salient period of Dry Cleaning Industry ended by the unification of the chemical process (1869). Postbellum Era and Age of Reconstruction of the 1860s – the 1870s: Mode of transportation was shifted from ocean ship to railway and European weather made high prices of wool and cotton.
The Process of Wet Cleaning
Wet cleaning is a professional textile care method that employs a highly controlled combination of water, biodegradable detergents, and non-toxic additives. During the process, environmental aspects are carefully monitored, including water consumption, energy usage, pH, and chemical concentration in the wash water. There are three main wet cleaning techniques and associated equipment: (1) standard washing with water; (2) the use of tensioning and drying equipment; and (3) the use of special detergents and additives.
Standard Washing
The typical method of laundering domestic textiles, such as towels, sheets, tablecloths, and shirts, is to wash them in hot water (60-95 °C) with non-bio laundry detergents. Many household and professional detergents contain surfactants that help to disperse dirt and stains from fabrics into wash water, allowing the dirt to be rinsed away. Although hot washing is effective in killing bacteria, it has a negative impact on fabric dimensions and is energy-consuming, so only a small fraction of domestic textiles is washed this way. Synthetic and delicate textiles are usually washed in cooler water (30-40 °C) with bio washes and detergents. In dry cleaning parlors, however, perspiration is regarded as a very difficult stain to wash off, and therefore garments that have been sweat on but not dry cleaned may be refused for cleaning.
Tensioning and Drying Equipment
To maintain the dimensions of professional textiles, such as uniforms and tablecloths, tensioning and drying machines specifically designed for the wet cleaning method have been introduced. Wet cleaning is a versatile process that can be used for diverse textile cleaning needs, ranging from professional laundry washing to delicate rug cleaning, allowing the treatment of many problems that “conventional” dry cleaning cannot solve. In the late 1970s, improved cleaning processes for domestic clothes were developed to replace solvent cleaning with water, and since then consumer demands and company policies have also changed. Innovations in textile materials and cleaning methods have led to the acceptance of new textile care methods.
Special Detergents and Additives
The wet cleaning method can be performed with standard home or laundromat washing machines, but the combination of special detergents and cleaning additives has been found to be essential in removing difficult stains and preventing felting of delicate textiles. Similar to the way bio washes actively remove stains by enzymatic hydrolysis, hemicellulosis stereospecific hygrophylic surfactants diffuse in damaged or greasy textile surfaces and help to wet the added water, but also remove any residual impurities by trapping and encapsulating them in small droplets that will not stick back to the fiber.
Techniques and Equipment
Wet cleaning is a professional garment care method that employs the precise use of water, biodegradable detergents, and mechanical action to remove a wide variety of soil and stains, even from the most delicate fabrics. With the right equipment, its techniques can be adjusted to whether the garment is luxuriously embroidered, heavily soiled, or on the verge of fibers felting. Commercial wet cleaning was introduced as an eco-friendly cleaning process for textiles and garments.
Wet cleaning uses as its main cleaning agent distilled water, with additives of biodegradable surfactants. Newer versions of cleaning agents utilize enzymes to augment the action of surfactants on protein-based soils, thus removing stains from milk, eggs, grease, blood, and grass more effectively. Solvents used in conventional dry cleaning are toxic to humans. A perceived advantage of these solvents is that they do not damage delicate fabrics. That said, when poorly formulated, these solvents can affect the overall quality of the garment. For example, synthetic wool garments may shrink if dry-cleaned in perchloroethylene, while borders of synthetic wool garments may not shrink if dry-cleaned in hydrocarbons, as fiber chemical compositions differ. In contrast, commercial wet cleaning has demonstrated that careful wet processing not only removes stains from delicate fabrics, even those that previously overcame cleaning attempts, but also improves the appearance of garments.
There is a great variety in the configurational design of wet-cleaning machines. There exist machines with stand-alone/univocal tambours (variously called washers, driers, and ironers). Each machine must use a separate water treatment unit and/or energy recovery system. The arrangement of the whole wet-cleaning shop is usually linear for this machine type.
In contrast, some other wet-cleaning systems consist of a combined machine. Such a machine type is typically an inwardly-directed tumble type that processes wet clothes in a washer-extractor mode with an active water recycling system. After washing, such a machine automatically continues treatment in a drier mode. Similar machines may handle a combination of wet and dry cleaning.
Environmental Impact of Dry Cleaning
The majority of people are unaware of the fact that dry cleaning is not as environmentally friendly as it may seem. In fact, dry cleaning poses a much greater risk to the environment over wet cleaning. Instead of water, which is utilized in wet cleaning, dry cleaning generally utilizes perchloroethylene (also known as perc) as a solvent. According to the National Center for Biotechnology Information, “Perc is a colorless, nonflammable liquid that has a sweet odor somewhat like that of ether.” Because perc is heavily used in dry cleaning, dry cleaning can have a severe adverse effect on the environment. In fact, perc is listed in the Clean Air Act as a hazardous chemical that must be monitored in specific quantities. Dry cleaning is widely regarded as environmentally hazardous because perc evaporates rapidly and can contaminate the air.
The most notable area where dry cleaning creates pollution is around the plants themselves. The process of dry cleaning fabrics involves rinsing them with perc, and after the rinse cycle is complete, the perc is distilled from the fabrics and recycled. However, some of the perc is never completely distilled out of the fabrics and is instead left in the water. After the rinse cycle is complete, a blow dryer-like device blows hot air through the fabric to dry it. The heat causes the residual perc to evaporate into the air, creating a very hazardous atmosphere around dry cleaning plants. Because perc is such a chemical hazard, many dry cleaners have lost their jobs due to closures of their plants in urban areas.
Although perc is heavily regarded by the EPA as a hazardous chemical, there is still an excessive number of companies using perc in their dry cleaning processes. The EPA published a list of dry cleaning companies known for using perc in a 1993 press release. This list has remained publicly available, and states that dry cleaning companies that do not switch to alternative solvents will be at high risk for government action.
Another hazard that is well known to the public is the groundwater contamination from dry cleaning facilities that use perc. Since perc is a highly water-soluble chemical, it can easily seep into the ground. Most dry cleaning facilities are built close to groundwater sources to facilitate the process of pumping water from the ground to make use of it in their machines. If perc contaminates the groundwater, it can pinpoint the exact location of the dry cleaner using it. Since perc is so hazardous, any facility with perc in the groundwater must have its ground watched 24/7 by the federal government. The facility is then forced to invest large amounts of money to dig holes in the ground and pump pure water into them, cleaning the contaminated water out of the ground. After the water is purified, the facility is often forced to close for good, since aquifers are such a vital part of the environment.
In conclusion, dry cleaning fabrics with perchloroethylene instead of pure water severely harms the environment, much more than wet cleaning ever could. Dry cleaning without recycling of solvents creates a highly contaminated atmosphere around dry cleaning plants. If left carelessly untouched, perc can contaminate the air and harm people nearby. Dry cleaning plants that use perc without recycling the solvents can be forced to close down by the federal government if they are found to be polluting areas too heavily. So in the end, it really does not matter how someone cleans their clothes, as dry cleaning screws the environment over a lot harder than wet cleaning.
Chemicals Used
Dry cleaning uses several chemicals, including volatile organic compounds (VOCs), to clean garments. These compounds contribute to ozone formation in the troposphere and affect ambient air quality. Among the VOCs used in dry cleaning, aliphatic hydrocarbons account for the greatest emissions. In Korea, the commonly used dry-cleaning solvents are either petroleum-based or F-Gs. The air pollution created by dry-cleaning facilities was first studied in 1971, and it has since been identified as a major source of ground-level ozone. Since the ban in the USA and the EU on the use of ozone-depleting chemicals, the focus has shifted to the environmental impact of petroleum-derived solvents compared with tetrachloroethylene (TCE), as well as patterns of substitutive technologies [2].
After fabric cleaning in dry-cleaning processes, indoor concentrations of petroleum-derived VOCs are attributed to emissions from fabric items and perceived as greatly affecting sick building syndrome. The effect of alkane-based organic solvents used in dry-cleaning processes became more apparent in recent years. To build a database of VOCs emitted from dry-cleaning facilities, a comprehensive analysis of most of the compounds was performed compared with those in several fields.
Waste Generation
The dry cleaning process generates several types of waste, of which the largest is wastewater containing trichloroethene (TCE), a suspected human carcinogen and a chemical that has been detected in drinking water wells near dry cleaners [1]. Various other toxic and hazardous chemicals can also be detected in this wastewater, including ethylene glycol, isopropyl alcohol, 1,1-dichloroethane, tetrachloroethene, and ethyl benzene. A common misconception is that because TCE is volatile, it simply evaporates into the air. In fact, about 90% of it dissolves in the water used in the process, and only about 10% evaporates. Concerns over trichloroethene began as early as 1980, and there were calls in 1984 for the Environmental Protection Agency (EPA) to list it as a hazardous air pollutant.
Waste sludge is generated as a by-product of the water during a dry cleaning process. There are two concentrations of sludge: filter cake waste (69% moisture) and machine drain water (95% moisture). The aromatics detected in the dry-cleaning sludge from the pond and the wastewater depots were toluene, ethylbenzene, xylene, naphthalene, and phenols. They were noted to leach significantly out of the sludge. The naphthalene concentration was detected in the parts of the sludge, indicating the presence of polycyclic aromatic hydrocarbons in the dry-cleaning sludge. Solid wastes are very harmful and dangerous to human health and are classified as hazardous type-A waste and light type-A waste.
Environmental Impact of Wet Cleaning
Shifting the focus to the environmental impact of wet cleaning, particularly the water usage and energy consumption associated with this alternative method, wet cleaning should conform to regulations in respect of water usage quarried from the environment. Energy should be reused, minimized, and treated carefully, as it is a requirement and contributive to the environmental global warming effect that occurs nowadays [3]. Although no studies or regulations specifically analyze the eligibility of wet cleaning in respect of its water usage and energy consumption, this alternative method should still be analyzed since it is available as an alternative to the conventional dry cleaning method. Indeed, a several decades-oft discussion on the environmental impact of dry cleaning has risen interest in the wet cleaning method. However, to fully understand the eco-friendliness of the wet cleaning method, the impact of the water usage and energy consumption concerning the hazardous garment cleaning operation should be analyzed. Most importantly, to make a fair comparison with the conventional method, the water usage and energy consumption of the wet cleaning method should be analyzed properly [1].
Water Usage
Wet cleaning is a process that utilizes water as the primary solvent and employs biodegradable detergents. Water consumption is one of the crucial aspects to evaluate when assessing the environmental impacts of the wet cleaning process. It brings forward the analysis of whether the water consumption in the wet cleaning process is justifiable, or, in other words, if the water consumption is excessive. According to the model, the overall water consumption in the wet cleaning process comprises two general types: machinery water consumption and other water consumption. Based on the water consumption data recorded during the field test at the selected commercial wet cleaning facility, it can be seen that the average water consumption in the wet cleaning process is about 134 liters per 10 kg of fabric articles processed [3].
Energy Consumption
Water is the most important resource to be consumed during the wet-cleaning process; it can be utilized after reconditioning for various purposes [4]. Water use varies between 16 and 62 L/kg, depending on the type of textile, the cleaning process (i.e., washing machine, drum type, wet cleaning machine or systems), and various water reuse patterns. Like water, the effluent treated on-site can also be reused in wet cleaning a number of times at different stages. Effluent reuse is a widely applied practice in many laundries in Europe, South America, the Middle East, and Turkey in particular. Reductions of water consumption from a few to 96% can be achieved via effluent recycling and reusing technologies. Nevertheless, despite the widespread implementation of effluent reuse among many laundries, this practice has additional energy consumption and hence environmental loads. In this regard, techno-economic analyses need to be completed regarding trade-offs between wastewater reuse and treatment needs.
In general, 0.2–7.19 kWh/kg energy was needed during the wet-cleaning process. Energy consumption depended on the type of laundering process. In addition to direct energy consumption, greenhouse gas emissions, air pollution, and other environmental loads can be estimated through energy use accordingly.
Comparative Analysis of Environmental Impact
Wet cleaning is often viewed as an environmentally friendly alternative to traditional dry cleaning processes. The latter, which utilizes volatile organic solvents (VOCs), can inadvertently introduce harmful chemicals and toxins into the air, water, and soil. However, it remains unclear exactly how much toxic and ozone-depleting emissions are prevented compared to the widespread use of perchloroethylene, the most common dry cleaning solvent [3]. Drycleaners that invest in and utilize a much rarer cleaning process – hydrocarbon cleaning – can greatly reduce or eliminate these emissions and associated hazardous waste disposal issues. Hydrocarbon cleaning would be a non-issue in industrialized areas within Clean Air Act non-atainment zones; yet, in non-attainment zones, hydrocarbon cleaning remains a practice possibly subject to even greater regulation. Furthermore, since it is unclear how dry cleaning solvent use would be prevented in general within industrialized areas, research is needed to explore the potential ramifications of dry cleaning mechanization in those areas. With adequately complex models and systems, stakeholders on all sides of the dry cleaning debate will find valuable insight regarding the damage done to communities that dryclean and are not aware of the costs associated with the vicious cycle between poverty and toxic industries.
Conclusion and Recommendations
The comparative analysis of wet cleaning and dry cleaning has highlighted some key findings, observations, and insights. The wet cleaning method needs improved air quality control due to the possibility of releasing excessive amounts of volatile organic compounds into the environment. Although the dry cleaning method could produce other kinds of pollutants during the process, it produced little air pollution compared to detergent and microbe shedding from the wet cleaning method [3]. Water pollution is the most problematic milestone for the wet cleaning method, providing a net increase in environmental impacts compared to the dry cleaning method. However, recycling ozone and wastewater treatment can significantly reduce environmental impacts, making the wet cleaning method preferable to the dry cleaning method.
The findings of this study could be further developed into green practices in the garment industry. Garment manufacturers are recommended to avoid washing products with excess additives and to use a washing machine that adheres to the water treatment method. To enhance the wet cleaning method’s sustainability in the garment cleaning process, it must be developed in terms of the setting-up method and air quality control. Large-scale adoption of the wet cleaning method must be accompanied by the improvement of wastewater treatment and the quality of discharged water [5]. Policymakers are recommended to promote and facilitate the development of the wet cleaning method with subsidies and other incentives.
References:
[1] A. Brooks, K. Fletcher, R. Francis, E. Dulcie Rigby et al., “Fashion, Sustainability, and the Anthropocene,” 2018. [PDF]
[2] D. M. Eun, Y. S. Han, S. H. Park, H. S. Yoo et al., “Analysis of VOCs Emitted from Small Laundry Facilities: Contributions to Ozone and Secondary Aerosol Formation and Human Risk Assessment,” 2022. ncbi.nlm.nih.gov
[3] E. Kosasih, A. Yuniawati, V. Suryaputra, and A. Limijaya, “Model for Calculating Cost of Laundry Services by Considering Environmental Impacts and Costs,” 2019. [PDF]
[4] A. Kır, E. Ozturk, U. Yetis, and M. Kitis, “Resource utilization in the sub-sectors of the textile industry: opportunities for sustainability,” 2024. ncbi.nlm.nih.gov
[5] H. Jin Gam, “Development and implementation of a sustainable apparel design and production model,” 2007. [PDF]