Keeping costs down while operating efficiently is typically a launderer’s top priority, but managing that task has grown more challenging as water sources figuratively dry up and utility rates skyrocket.
To make the most of the precious water their plants use daily, industry experts say laundry managers should consider filtering and recycling waste water for reuse and/or recouping some of its thermal energy through a heat-recovery system. A variety of systems for both purposes are available today.
FILTER, RINSE, REPEAT
In a typical laundry, water is fed into the plant from the local source and split into two sources. The cold-water source feeds directly into the washers. The hot-water source is heated in the hot-water tank and then fed into the machines. Water is used only once and discharged into the sewer. A laundry that utilizes water reuse mechanically filters its waste water and pumps it back into the system.
Kemco Systems’ Air Backwashing Filtration System, for example, filters the rinses to 100 microns, making them suitable for flush, suds and bleach cycles.
“Because you’re able to filter the rinses to an acceptable level of filtration to allow it to be reheated with a water system, that’s the key to getting a high volume of water reuse,” says Al Jenneman, vice president of sales for the Clearwater, Fla., company.
“Essentially, you can reuse 40% to 50% of the water by reintroducing it into the flush, suds and bleach cycles, which are on the front of the formula. It allows you to run a washer/extractor on 1 to 1.2 gallons per pound, which have been levels achievable only with tunnel washers in the past.”
Jim Gross, president of 3E Technologies, frequently combines the Aquamore water-reuse system, built by partner Bosen Industries of Temecula, Calif., with an ozone-based washing system to further slash water usage because ozone washing doesn’t require heat.
“If we can go in and save 35% with ozone, we can save 70% with ozone and water reuse,” he says.
The 3E Tech-RFG concept precharges fresh or recycled wash water with dissolved ozone to appropriate levels for whitening, soil removal and disinfection; feeds additional ozone into the washers as needed; and recirculates rinse water in much the same way other reuse systems do. When both hot and cold rinses are saved, an optional heater can provide hot wash water.
Thermal Engineering of Arizona (TEA), a Tucson-based company, offers a simple rinse water-reuse system featuring a compact storage tank with an immersion steam heating coil, a top-mounted shaker screen for 100-micron solids removal, and a premounted water delivery pump for supplying the washers.
TEA takes care to not overstate the potential for water savings, according to Jeff Kosek, technical sales.
“Between 20% and 35% of the water can be reused very easily and economically, and this depends on the product mix and what kind of processing they’re doing,” Kosek says.
While some systems make claims for up to 80% reuse collection capabilities, it’s important to distinguish where in the wash formula this water can be used. Above levels of 35%, reuse water must be used for bleaching and rinsing, TEA says.
Water reuse contributes in part to other savings, including associated chemical costs and water softening.
As production costs rise and equipment paybacks shrink to two or three years, water-reuse systems gain popularity.
“Twenty years ago, when a facility designed a new laundry, oftentimes they would design water reuse into a facility and they may or may not have implemented it at that time depending on the cost of water and whether the equipment itself had a payback,” Jenneman says. “Today, laundries are paying so much for water. Water costs have gone from $2 per 1,000 gallons to as high as $10 per 1,000, and even as high as $20 in some of the resort areas. ... A lot of what drives water-reuse applications is the cost of water and whether the return on investment is there.”
The Central Coast Water District Board in California voted last month to allow a small hotel – equipped with just one washer – to add another 24 rooms based on the projected water savings from his ozone and water-reuse system, Gross says.
“Water’s not just critical because it costs (money), it’s critical because it’s not available,” he says.
Smaller laundries haven’t been good candidates for water-reuse systems because of the long-term payback, but now TEA is introducing a product specifically suited for that market segment.
The Mighty Midget can handle up to three washers, depending on size, and contains all the components necessary to efficiently run a water-reuse system and produce a savings of 20% to 30%. Its 40-square-inch footprint allows it to be installed in even those laundries with the least available space.
And the price is “small,” too. The Mighty Midget will cost 75% less than typical water-reuse systems, Kosek says.
Some equipment manufacturers are integrating water-reuse systems right into their washer/extractors. Examples are UniMac’s Water Saving System™ available on its UW hardmount and UF softmount series, and EDRO’s new self-contained system on its 200-pound model, the DW200-WRS.
A heat-recovery system captures the heat from waste water and uses it to preheat incoming cold water.
Kemco’s Wastewater Heat Recovery System, which uses counterflow shell-and-tube heat reclaimers, can effectively preheat the water to within 5 to 10 degrees of the average 115 F wastewater stream, Jenneman says.
“If you’re using water at 160 and you’re starting at 50, then you’ve got a significant amount of heat to put in that water,” he says. “If you start out at 105 and you’re going to 160, you’re halfway home with wastewater heat recovery.”
TEA’s heat-recovery System 2000 uses a plate-and-frame heat exchanger to preheat two streams of water – one for a plant’s hot-water supply and the other to produce tempered water. Its Smart-Therm controls automatically modulate the water flows to recover the maximum energy from the hot waste water before discharge.
“We’re able to get higher preheat temperatures, extract more heat out of the waste water, and therefore save more energy,” Kosek says.
TEA pledges to heat the incoming fresh water to within about 10 F of the waste water.
Eighty percent or more of today’s commercial laundries use wastewater heat-recovery systems because they realize their cost-effectiveness, Jenneman says, but most on-premise laundries have not implemented such systems.
Because many institutional laundries start as projects let for bid, he says, one of the first things to be cut if a project exceeds available funding is ancillary equipment such as water-reuse or heat-recovery.
Jenneman, Gross and Kosek all say their business related to energy conservation, particularly water reuse, has been brisk.
“I think conservation awareness in the country and the fact that we do have limited water resources will continue to drive the reuse market,” Kosek says.