Professional Carwashing & Detailing

Get a spot-free in-bay today

October 11, 2010

In-bay automatic vehicle wash systems are not just found behind the service station anymore. One of the faster growing segments in vehicle washing is the stand alone in-bay automatic in a strip mall, self storage lot, or added to a self-serve wash.

As the vehicle wash equipment has gotten more sophisticated so has the water treatment. In earlier days, a water softener was considered high-tech, but today, sometimes that is now considered obsolete.

Spot-free standards

Spot-free rinse systems for in-bay automatics are rapidly approaching standard equipment. A final spot-free rinse effectively displaces all residual chemical and mineral-laden water, including reclaim water.

This allows the entire vehicle, including glass, chrome and painted surfaces, to dry completely spot-free. The overwhelming choice for making spot-free water in the in-bay automatic is the reverse osmosis (RO) system.

Most carwash manufacturers have made provisions for RO to be incorporated into their wash process and either offer or recommend one when building or updating a wash facility.

A reverse osmosis system is a simple addition to any vehicle wash location and will increase customer satisfaction, generate additional profit and create customer loyalty.

RO logistics

On the technical side, all RO systems work in much the same way. Tap water is introduced into a pump, which increases the pressure to 180-250 pounds -per- square inch gauge (psig) and forces water through the membrane. Some water conditions will require additional pre-treatment, so be sure to consult with the equipment supplier.

Because most municipal water systems use chlorine as an anti-bacteria treatment and membranes do not tolerate chlorine, it is necessary to remove the chlorine before the RO process.

A simple, activated charcoal filter tank works for this purpose and most RO manufacturers include this as part of the system.

All systems will have some form of a pre-filter — usually a 5-micron pre-filter — that is provided to separate the larger solid material from the water.

Plugging or damage to the RO membrane or pump will result if the large solid particles are not removed by the disposable filter first.

A pre-filter needs to be changed at least once per month; some water conditions may require more frequent changes. When pre-filters are not changed regularly, RO systems will produce poor product water quality and/or a significantly lower production rate.

RO re-circulation

The most common size membrane used in carwash applications is 4x40 inch, which requires five gallons across the surface of the membrane for every gallon of product or permeate water produced.

In years past, most operators would just send the four gallons of bad or concentrate water down the drain.

Today, water costs are expensive and some locations are limited to how much water they can send to the sewer.

Most, but not all, RO manufacturers re-circulate a portion of that concentrate water back into the inlet stream.

Out of the five gallons you start with, one gallon of product water goes into the RO storage tank, one gallon of concentrate water goes to the drain and three gallons are re-circulated.

RO systems are typically sold by the amount of water they produce in a 24-hour period. This is usually at an optimum performance with 77 degree Fahrenheit feed water.

The wash manufacturer will be able to tell an owner how much spot-free water will be needed per wash. With some educated guessing the owner should be able to determine the size unit he or she will require.

If the estimated calculations are close, upsize the storage tank or select the next unit size up for safe measure.

Dealing with delivery

Years ago, most RO manufacturers didn't provide delivery — that was up to the wash manufacturers, and the one that did provide a pump usually sent a plastic pressure-activated pump that was inadequate.

Today, the options for pumps are much better. The pumps usually are output activated by the wash and there are choices for pressure and volume.

The 150 pounds-per-square-inch (psi) range from a V-nozzle arch provides an excellent pressure for getting the bad water out of the body lines and crevices and at approximately five to seven gallons-per-vehicle.

It is a good conservative choice to allow a reasonably small 3000 gallons-per-day to provide enough spot-free water for even the busiest site.

Some wash manufacturers are using a "rain bar" with V-nozzles on the sides, this is also a good choice. It would require a different pump, will probably use a little more water, and may require a larger storage tank or RO system.

With the widespread use of Variable Frequency Drives, a number of the touch-free wash manufacturers are using the main pump for spot-free delivery. This is an excellent choice, but will use a little more water.

Widespread use of spot-free water for chemicals has in some cases eliminated the water softener from the in-bay automatic equipment list. Check with your wash manufacturer to see if spot-free water use for chemicals is an option for your wash.

In-bay advancement

Remember a good local distributor is an excellent resource for information and support when installing an in-bay automatic.

With the new technology and water reclaim advancements, in-bay automatic washing is an attractive add-on for various businesses.

Charles Borchard is the vice president of operations for New Wave Industries, the manufacturer of Pur-Clean Spot-free Rinse Systems and Pur-Water Water Recovery Systems, and is in his sixteenth year in the water treatment business. Charles can be reached at