Water — Who Uses How Much?
Vehicle washes use a fair amount of water. Some friction in-bay automatic systems use approximately 35 gallons per vehicle, and a high-volume in-bay site could average 100 cars a day — that’s 3,500 gallons a day, 105,000 gallons per month, or 1.26 million gallons per year. Other in-bay automatics, employing the high-pressure touchless method, use 70 gallons per vehicle. At the same 100-cars-per-day average, that’s 7,000 gallons a day, 210,000 a month, or 2.52 million gallons of water a year.
A tunnel car wash with a moderate amount of high-pressure applications could use 120 gallons of water per vehicle. Assuming an average of 400 cars washed, daily usage would total 48,000 gallons. This site is therefore using 1.44 million gallons of water a month or more than 17 million gallons a year. If you own this wash and your sewer and water cost are low, say $4 per 1,000 gallons, your annual water and sewer cost is nearly $70,000. There are water reclamation systems to help limit that cost. With a $25,000 system and $10,000 worth of underground plumbing, you could easily save 75 percent of your water and sewer cost. It would take just over eight months for the system to pay for itself. I don’t know much else legal and/or moral that would provide a better return on your investment.
Surprisingly, this article isn’t about water reclamation systems for the car wash. It is about how much water other businesses use.
Did you know it takes three gallons of water to clean a pound of laundry generated by a hotel? Figure three and a half pounds of linens per room, about the same weight in towels per guest, a hundred rooms, half of them double occupancy and you arrive at 3,000 gallons per day — before pool towels and serving linens. A small mid-range hotel is using as much water as our first in-bay automatic example.
In that reasonably efficient in-bay automatic, you could easily reduce water usage per car by half with a fairly priced reclamation system. In the cleaning of vehicles, the majority of water used is for washing, and that water — with a minimum of equipment and effort — can be recycled and reused to provide the bulk of the water needed for the cleaning. You then would only require a small amount of fresh water for a rinse.
In laundering, the three gallons of water used to clean that pound of linen or towels go the other way: one gallon to wash, two gallons to rinse. In the newer high-end washers the used wash water is sent down the drain at the end of the wash cycle. At the end of the rinse cycle, the rinse water is diverted to a holding tank, repressurized, and used in part as the wash water for the next load. In car washing, we can — and do — recycle and reuse up to 75 percent of water on a routine basis; in laundering 30 percent to 35 percent is about as good as it gets.
The hospitality industry, just like the car wash industry, has been hit hard with increasing water and sewer costs. Clean, crisp, white sheets and soft towels are expected when you stay at a hotel. Because there are also health concerns — germs and vermin, for instance — washing hotel towels and linens requires most if not all of the wash and rinse water to be very hot. In addition, to get those snowy white towels both snowy white and germ-free a large amount of chlorine bleach is used. The cost of the water and sewer, the energy required to heat the water, and the chemicals — all familiar themes for vehicle washers — is even higher for the hotel owner.
The hospitality industry does not have as many options to reuse their wash and rinse water as we do. They have to try to save water and dollars in other ways. I travel fairly extensively; 100 nights a year in small, mid-range hotels has been my average for the last 10 years. I appreciate clean sheets and towels when I am staying at a hotel. Most hotels have a card they put on the bath counter or nightstand explaining the high cost of laundry service. These cards also tell you if you are staying more than one night to hang your bath towel on the shower curtain rod so you can reuse your towel the next day. Some have another card asking that you place it on your bed if you don’t need your linens changed daily.
This spring I found myself in Dubai, one of the seven Emirates that make up the United Arab Emirates. This is a city-state of almost two million people, in a country of nearly seven million. Seawater reclaimed through reverse osmosis makes up 95 percent of the fresh water in the UAE. The card at the hotel where I stayed explained that they would change the linens on a weekly basis if my stay exceeded a week, or on my checking out. The towels I had were all I was going to get for my stay unless I asked. Seven million people live in an area that has enough natural fresh water to support 350,000; the rest of their water is generated through a very expensive process. Don’t waste water in the UAE.
Back home in the United States, a large resort hotel of 1,000 rooms with a restaurant, pool, and maybe a small convention center will generate 30,000 pounds of towels and linen a day requiring 90,000 gallons of water — almost double our large tunnel wash example — just to do the laundry.
An average sit-down knife-and-fork restaurant uses 5,800 gallons of water a day, which puts them about midway between our two in-bay automatic examples. In the Southeast, where they have had several drought years lately, you do not automatically get a glass of ice water with your menu. You have to ask. You are thinking: Wow, that eight-ounce glass of water isn’t going to save much. Let’s see: There is the eight ounces itself. Assume it is half filled with ice, which means another four ounces. That is now 12 ounces, total. Would it surprise you to learn that it takes twice that much water to clean that glass each time it is used?
A fast-food restaurant will use a third to half as much water as our sit-down restaurant. In both cases a large amount of that water could go to make ice. Flake-style ice machines make exactly as much ice as it takes water, so 100 pounds of ice takes 12 gallons of water to make. With a flake ice machine you get all the impurities in the water in the ice, and you don’t get the satisfying crunch chewing an ice cube. Cube-type machines run water over a tray and some of the water loops back around, to run over that tray again; some water is evaporated in the condenser; and some carries impurities down the drain in a purge cycle. Some cube style ice machines may require as much as 300 gallons of water to make 100 pounds of ice. So in our ice-water example, if those four ounces of ice is cubed it could have taken as much as 100 ounces of water to make. To be fair: Cube machines make ice much faster than flake, so less energy is consumed. Also, the 300-gallon to 100-pound ratio is the high end of inefficient cube machines; there are much more efficient new icemakers out there.
Just like in the vehicle washing business, new equipment costs money, and until it is belching smoke and broken more often than it runs, the restaurateur, like the vehicle washer, is apt to keep it running with bailing wire and hope. Just like cleaning linens and towels for hotels — and for many of the same health concerns — water used for cleaning dishes in a restaurant will need to be very hot to kill germs. Heating water is always expensive. Restaurants are even more limited in their water-recycle options than our hospitality examples. Other than reusing the dishwasher water and drain-bound water from the icemaker as landscaping water, there is not much else available. You certainly don’t want to eat in a restaurant that keeps cleaning glasses and plates with the same wash water do you?
When you are building your next wash and the municipality you are dealing with starts busting your chops about water usage, you can ask/tell them about other businesses that use as much or more water than your dream wash. Please remember you have good options and a certain amount of responsibility to recycle and reuse your wash water. You can easily — and for not a too sizable investment — recycle and reclaim 75 percent of your vehicle wash water. Talk to your wash equipment supplier about water recycling and reclamation equipment, and remember to integrate it into your total wash equipment package.
Huh, I guess this article was about water reclamation systems for car washes after all.
Charles Borchard is the vice president of operations and also the vice president of technical sales for New Wave Industries, the parent company of both the PurClean brand of reverse osmosis final rinse equipment, and PurWater brand of water reclamation equipment. He has nearly 22 years of experience in the water treatment business. He can be reached via e-mail at firstname.lastname@example.org.