Wash Quality is Dependent on the Condition of Your Water

We are in the vehicle washing business. When there was an unlimited supply of water, we washed without a care in the world. Now we are faced with the reality that there never was unlimited water, and some carwash operators are scrambling to stay in business. Cleaning and reusing some of your water to wash vehicles is a great idea. Now that it makes financial sense, everybody should do it.

Water is the primary means of rinsing the dirt, road grime, salt and snow off the surface of a vehicle during the wash process. All soaps use water as the delivery medium from the chemical station out to the vehicle to assist in breaking up those contaminants. The higher the quality of water you use, the higher the quality of wash you will deliver.

There are three types of water used in vehicle washing:

Tap water, either from a municipal water supply or private well, ranges in quality from great to terrible. Some of the symptoms of poor quality tap water include high TDS (total dissolved solids) counts and pH readings that are either too high or too low (7.0 to 7.4 is neutral and the ideal).

Other quality issues to consider: Is the water turbid or cloudy? Is iron present? What is the hardness of the water?

Simple tests conducted at the site by your carwash equipment representative can help determine the quality of your fresh water. The entity supplying your water also should have a report (often available online) with information that can help you determine how to improve the quality of your washes.

Water is an increasingly expensive commodity. Fresh water use in a vehicle wash application should be carefully considered and applied to maximize its value.

Spot-free water should have a TDS count below 20 parts per million. This may occur naturally or can be achieved through processing. The overwhelming majority of spot-free systems currently in use are reverse osmosis.

RO systems have an impact on water conservation because most equipment requires two gallons of fresh or tap water to make one gallon of product. There are ways to reuse this extra gallon of “reject” water. It can be captured in a tank and, using an appropriate pump, delivered anywhere you would use fresh water without a chemical application.

For example, in a high-pressure automatic, using the RO reject water blended with fresh water for the last rinse before the spot-free rinse would net a two-for-one use on that gallon of water. For systems without reclaim equipment, this process will result in significant savings to your water bill.

This is water that has been used in the wash process, then cleaned and reused. Many municipalities now require some form of reclamation or recycle system prior to permitting. Systems may also help you avoid expensive impact fees.

Can you recycle all of the water in a closed loop? For wash quality it is always best to have some fresh water in every cycle. The 90 percent shown in the accompanying cost analysis table (page 76) is about the highest usage recommended. As is evidenced by the chart, a water reclamation system can be the single most important piece of equipment to help with water conservation and cost savings.

Water reclamation systems are not new to vehicle washing, but there are several different technologies in use. All reclamation or recycling systems use a tank system to capture the water after it is used. These are often called clarifier tanks or oil water separator tanks. Usually these tanks are required by the municipality that provides the sewer service. It helps the sewer system if the suspended solids are allowed to settle in these tanks, thereby clarifying the water.

If the tank system is properly sized, not only will the solids settle to the bottom, the oils and lighter-than-water contaminants will rise to the top and become trapped out of the reuse stream. Periodically these tanks will need to be pumped out and the water hauled off to be processed.

Suspended and dissolved solids in water are measured in microns. How big is a micron? The smallest particle that can be seen by the human eye is approximately 40 microns. The diameter of a human hair is 50 to 75 microns. Suspended solids that are 150 microns and larger, with a specific gravity (sg) of 1.2 will settle in 70 degrees of still water at a rate of 0.8 inches per minute. Oil with a sg of .88 will rise at a slightly slower rate of .68 inches per minute.

Specific gravity is the measurement of weight of material relative to water, with water having a specific gravity of 1. Gold has a sg of 19.29, nearly 20 times heavier than water, and would settle very quickly. Colder water slows the settling and raising rates.

There is a wide range of reclaim system capabilities available as well as a wide array of pricing. Finding a reclaim system that is right for your operation is much like purchasing other carwash equipment. Ask yourself these questions: Is the equipment well made? Will the manufacturer and distributor stand behind it and be able to fix it if it breaks? How much space will it require in the equipment room?

Working with your equipment suppliers and their distributors to answer these questions will go a long way toward ensuring that you get the right system for your application.

There are many more questions and things to consider in your water usage. Your equipment supplier should have a good basic understanding of water use and can help guide you in your selections of equipment to make your wash a success.

For some, the notion of “green” may equal money because your water and sewer costs may not yet be a large percentage of your operating costs. That does not mean your turn isn’t coming. Right now operators in the Southeast are grappling with these issues. It behooves you to examine your capability to recycle water. Next year it could be you.

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