After toilets and showerheads, washing machines make up the next largest percentage of water use in the residential sector. For small businesses that may use a residential-scale washing machine, consider purchasing a washing machine certified by the U.S. Environmental Protection Agency's ENERGY STAR program. Most full-sized ENERGY STAR qualified washers use 18 to 25 gallons of water per load, compared to the 40 gallons used by a standard machine. The water efficiency of various models are evaluated using a "Water Factor," which measures the gallons of water used per cycle per cubic foot (for example, a 3.0 cubic foot washer using 27 gallons per cycle has a water factor of 9.0). The lower the water factor, the less water the machine uses.
Continuous Batch Washers
Many larger commercial, institutional, and industrial facilities operate large laundry operations for table and bed linens, uniforms, and other washable fabrics. For such operations, consider using continuous batch washers or "tunnel" washers, which have one or more modules for each process step and pass laundry items automatically from one module to the next. Counter-current flows in these washers achieve significant conservation, typically 60 to 70 percent of the water needed by washer-extractors. Heat recovery from the laundry itself is also possible during the rinse cycles.
Systems have also been developed to partially or fully reclaim wastewater from commercial laundries and can be cost effective due to savings in soap, water, energy for heating, and sewage fees. Reclamation systems use such elements as mixed media filters, activated carbon, ion exchange, and ultrafiltration, and they can provide reuse rates of 75 percent (City of Phoenix, undated).The final rinse water from clothes washers can be reused, often times in future laundry pre-wash or wash cycles. Some manufacturers offer retrofit options for existing washers. However, when facility managers invest in replacement machines for existing units, the purchase of rinse water recycling options are encouraged.
Ozone washing is an alternative laundry source that reduces the need for hot water. When used in laundry wash water, ozone works best in cold water washing and allows for shorter wash cycles resulting in significant energy and water/sewer surcharge savings. Enhanced soil removal, powerful disinfection and reduced garment wear-and-tear are some of the added benefits. For this reason ozone laundry systems are gaining rapid international acceptance over conventional methods which require substantial amounts of hot water (AWWA, Water Wiser). Industrial laundries using ozone washing systems are estimated to be able to save up to one third of the total water consumed. Because of the high volume of hard-to-clean items that commercial laundries must clean, up to75 percent of the water saved would be hot water. The average estimated payback time on ozone washing systems is a relatively short 1.6 years.
City of Phoenix. Undated. Water Conservation Guide for Hotels and Motels. Water Conservation and Resources Division, Phoenix, AZ.