Reusing vs. Recycling Water
The Difference Is Night and Day

By Robert Harvey

If you mention the subject of early reclaim systems to a carwash operator with 20 years experience and ask what thoughts come to mind, you’ll probably get a description of a piece of equipment that doesn’t do a very good job treating water, needs a lot of maintenance, has filter bags to change and replace, and produces water that offends customers with its odor. Although most reclaim manufacturers have made great gains in making their systems more user friendly, they are still missing the goal of sufficiently cleaning the water.

In general, the reason that many reclaim systems blacken equipment, destroy pumps and damage nozzles is that they simply do not remove suspended soils to low enough levels. The “filtered” water these systems produce contains high concentrations of total suspended solids (TSS) less than 20 microns in size. As the water is continuously reused, the concentration of these unfiltered particles increases exponentially. To combat their inability to remove solids effectively, some systems use a fresh water makeup line with a solenoid valve to dilute the poorly filtered water with a higher-quality city water. If these systems were capable of filtering the solids sufficiently, dilution with city water wouldn’t be needed. Remember, a reclaim system is supposed to save you from using city water.

Overall, the surface area and the particle-retention capabilities of the filtering or separating mechanism establish the flow rate for a given system. Some filters feature microscopic projections that allow very fine particulate matter to penetrate deeply into the filter bed. These filters can effectively remove solids down to 5 microns or less.

Due to the tight filtration and the high solids removal capacity, these types of depth filters are larger in size than typical canister or cyclone systems. Consequently, if a reclaim unit has a filtration system of small canisters or cyclones, the only way for this system to meet the water demands of the wash is for the system to only take out the very largest particles and send the water on its way. That’s the reason why water from these types of systems is black in color and wreaks havoc on nozzles -- it’s simply not filtered tightly enough.

In small canisters, it would take far too many vessels for the system to produce the 100 to 150 gallons per minute or more that many of today’s high-volume washes demand. Consequently, filtration is sacrificed. The biggest problem with this is pump warranties can be voided if the solids in the water are not filtered to within published tolerances. Also, the visible signs of poor filtration are all over the walls, which is not impressive to customers.

Comparing treated, recycled water with reused, dirty water is like comparing night and day. In most cases, treated, recycled water will satisfy the requirements of publicly owned treatment works. In more and more municipalities, water departments are monitoring businesses to evaluate various impurities sent to the sewer, and carwashes are moving to the head of the list. We, as operators, must be conscious of increased regulation which can and will impact our ability to function — and our reputations in the communities we serve.

Imagine my dismay at my washes when county officials showed up six years ago and placed sampling devices in the carwash discharge stream. They collected composite samples and sent them to a laboratory. A few weeks later, we received a violation notice stating that our water discharge was out of compliance with our discharge permit. The county gave us 30 days to resolve our discharge issues or start facing fines!

We had entirely new, much more complex issues to suddenly resolve. We were no longer talking about just clogged nozzles and dirty equipment. We were now faced with removing or significantly reducing the chemical oxygen demand, biochemical oxygen demand, total suspended solids, and oil and grease levels in our discharge. We reviewed the chemistry we were using in our wash tunnel and made some changes, but still could not meet the discharge criteria imposed by our permit. But once we installed the appropriate water treatment and recycling system, we resolved this issue entirely. Since we upgraded, we’ve been tested three or four times per year for the past six years, with no discharge compliance issues whatsoever.

Obviously, the cost of a recycling system that effectively treats carwash water will be greater than that of a system that partially filters the water on the way to the tunnel. But justifying the cost is easy. The proper water-recycling system can easily save 50 percent to 60 percent or more of the water and sewer discharge bills that a wash with no reclaim system pays. With increasing usage fees being assessed for water in most municipalities today, a wash with reasonably decent volume will be able to save thousands of dollars per year in water costs by employing a water-recycling program. If the payback in terms of savings on water bills can be accomplished in five years — and it is usually less — the decision to purchase a water-recycling system was the right one. That said, the more water you can recapture, the less fresh water that has to be used and the lower your bills.

But it’s not just about the money — though there’s nothing wrong with that. Have you seen signs in your competitors’ washes announcing they are environmentally conscious? Do you have such a sign? At the four carwashes our company built, the customers were very appreciative of the fact that we used recycled water, especially during periods of drought when conservation was foremost on everyone’s mind. There is nothing wrong with being a good corporate citizen — or getting credit for it from your customers. Actually, there is everything right with it! People want to do business with caring people. If you conserve this precious commodity, your customers will reward you with more business.

There is one more contributing part to ROI. It’s less tangible, but still very real. To present your facility in the most positive light, you spend time cleaning and maintaining it, and you pay the hourly labor for it. Equipment repairs due to aggressive wear and tear, too, cost capital dollars. If the reclaim system you install does a better job of keeping the facility clean with less damage to your washing equipment, you will spend less on labor and equipment maintenance. It may be an ancillary benefit, but the savings in dollars is, nevertheless, very real.

What about the odor? Odor is caused by bacteria, which multiply at an incredible rate. When they die, which is also quickly because they have a very short life cycle, they decompose and begin to smell. If you can smell them at a wash that has a water-recycling system, you know that the system does not have an effective way to control the decomposing bacteria.

There are a number of ways to control bacteria. We have found that ozone is the most effective way to control this odor, so we use it in our systems. Not all ozone systems are created equally. There are two ways of creating it —UV light and corona discharge. Systems we have seen which utilize UV light to produce ozone don’t seem to produce enough of it to effectively kill 100 percent of bacteria. In addition, production of ozone diminishes as the bulb ages, so its effectiveness gets even worse. When considering a reclaim system that controls odor in this way, make sure you get a satisfactory answer about how it will control odor in the long run.

In our experience, the most effective way to manufacture ozone (03) is through corona discharge. Simply put, corona discharge sends a high-energy electric charge across compressed concentrated oxygen to split the oxygen (O2) molecules. These molecules combine with other oxygen molecules to form ozone.

Not all corona discharge ozone systems are created equally, either. Many that we have seen are also insufficient to effectively treat 100 percent of the bacteria present in reclaim holding tanks. Why is that, you may ask? Heat is a by-product of ozone generation. As the heat in the ozone generator and the equipment room in the summer increases, the amount of ozone produced decreases. The end result is a quantity of ozone that is not going to control all the odor-producing bacteria. There is a solution, however. There are systems available that can, and do, cool the generators sufficiently — even in the summer — to maintain their output at a high enough level to contain odor and to treat other impurities in the water over the long haul. The result is water that does not smell and that can be discharged to the sewer without riling governing authorities.

As previously discussed, most carwashes discharge water to the sewer based on the stipulations in a discharge permit secured by the operator when the carwash is built. This permit lays out what you are and are not allowed to discharge to the sewer. Beware that noncompliance with this permit can be very expensive. As we said previously, more and more water departments are placing magnifying glasses on businesses such as carwashes to insure the protection of the water supply. If your reclaim system is not properly treating your water to meet these increasingly stringent regulations, you are asking for trouble.

In the final analysis, carwashing is still the great business today that it has always been. Technological improvements to equipment have made their impact in all phases of the business, including water-recycling technology. The key to which equipment you purchase and put online lies in what you want to accomplish for your business. In our experience as operators, there was no debate. Hands down, recycled water was far more beneficial to our business than poorly filtered water. Our cars were cleaner, our washes stayed cleaner, our equipment maintenance was substantially less and, most of all, our customers were happier. After all, isn’t that the name of the game?