Modern Car Care 09/2002: Coming Clean at the Carwash

Coming Clean at the Carwash
Customers value a spot-free wash

By Dave Sayers

Let's face it. Car owners love their cars and take pride in making them look as good as new. This often requires many visits to the local carwash. In order to keep customers coming back, operators now offer additional features to enhance their services.

One feature that continues to be in high demand is a spotless car. Customers will pay extra to have a spot-free car, whether it is sold as an option at a full-service wash or turned on at the final rinse of a self-serve wash. Either way, the driver expects to pull away without a single spot on his car.

But the benefit of a spotless wash doesn't come easily. Washing with soap and water removes debris from a car, but using untreated water for the final rinse leaves residue that forms spots. As ordinary rinse water evaporates, anything that is not water (such as dissolved materials) will remain on the car as unwanted spots.

Evaluating the options

When it comes to a spot-free carwash, the name of the game is reducing dissolved materials in water. Two main technologies can accomplish this--de-ionization (DI) and reverse osmosis (RO). However, the means to the spot-free end are quite different for each of these processes.

Before the advent of RO, DI exchange was the technology of choice. Because DI uses a two-stage process that removes nearly all ionic material in water that does not create wastewater, carwash owners are able to produce high-quality water that is suitable for all carwash applications. While the quality is as good or even better with DI, the technology has a significant capacity limitation. The DI tank can remove materials to a certain extent, after which time it no longer provides the quality that a carwash needs. This leaves carwash owners with two choices: regenerate on site, which is a meticulous process involving hazardous chemicals; or set up a tank exchange where a fresh tank is delivered when needed. Although the initial capital investment may be small with the exchange option, over the course of a year, the cost of replacement tanks quickly adds up.

Since DI uses hazardous chemicals such as acid, regenerating on site poses potential hazards for the typical carwash owner. Because most carwash operators do not typically deal with hazardous chemicals, they have neither the expertise nor desire to handle them. Without the right mechanical skills and knowledge to properly apply these chemicals, DI can be unsafe.

Unlike DI, RO technology does not require the use of chemicals. Instead, RO uses pressure and semi-permeable membranes (filter-like material) to produce pure water. In addition, the technology has become more accepted over the past 15 years as people have become more familiar with RO and its associated benefits. This has resulted in an increased comfort level in the use of the technology.

Unfortunately, RO systems have an Achilles heel--water usage. As pure water is generated with RO technology, a concentrate stream is also generated. On one side there is the spot-free rinse water and on the other is the concentrate stream, which is two to four times the volume of its counterpart. The end result of RO is that the carwash is always generating a concentrate stream. Fortunately, in the carwash environment, this concentrate water is generally captured and reused in the carwash process.

Getting started

A lot has changed since RO was first brought to the carwash industry in the 1970s. When first introduced, RO machines were expensive and complicated. Today, carwash owners are looking for inexpensive solutions to remove spots, and because of its widespread use, RO is delivering the results.

Because of the simplicity of an RO machine, it can be easily added to a spot-free carwash operation. Maintenance is also relatively simple. For example, a typical RO machine can last 10 to 15 years since the only item needing attention and occasional replacement is the membrane element that removes material from the water. It is important to remember that the technology is only as good as the person maintaining it. When maintained correctly, membrane elements can last two to three years.

Once the equipment is in place, the RO system uses the carwash's standard water source (typically city water) as well as two common pretreatments--water softening and activated carbon--depending on the condition of the feedwater. Most carwashes already have softening installed, since it requires less soap during the process. Activated carbon is used to remove chlorine and protect the membrane. By adding this step, the RO membranes achieve a significantly longer life, saving the owner time and money.

Examining the results

Using an RO system to provide a spot-free rinse provides the carwash owner with many benefits. For starters, the system typically pays for itself in about a year, providing a fast return on the initial investment. In addition, the technology is safe and easy to use and maintain. The simple technology means that once an RO system is installed, aside from some minimal routine maintenance, it is capable of operating virtually trouble-free.

Additionally, the quality of water produced with RO is consistent. Reclaim water has many variables that impact quality. A carwash owner needs only to turn the dial on the RO system to see the spot-free water produced. Finally, full-service carwashes benefit since the car does not have to be wiped off, which eliminates the need for towels and additional personnel to dry cars at the end of the line.

RO systems' ease of maintenance and use, and adaptability to numerous applications, provide carwash operators with a simple, cost-effective solution to a spot-free rinse. For those who wish to offer a superior service, applying an RO system to their operation offers cost-effective benefits that will keep customers coming back to maintain their cars' sparkling finish.

Dave Sayers is standard equipment product manager for Osmonics. He can be e-mailed at dsayers@osmonics.com.