Choosing the right reclaim system for your self-serve carwash can be a difficult task considering the increased probability of waste material. Because self-serve washes are largely unattended, it is not uncommon for customers to rinse out horse trailers or put motor oil down the drain in a self-serve bay, contributing to issues in tanking systems.
In order to reclaim self-serve washwater properly, it is important to not only understand the challenges ahead, but also the water type and the reclaim process itself.
It is important to distinguish between the three types of water used in vehicle washing process.
1. Fresh water is considered tap water, either from a municipal water supply or private well. It can range in quality from great to terrible. The entity supplying your water will have a report, often available online. This report can be of value in helping to decide how and with what equipment will improve the ability to deliver a quality wash.
Water is an increasingly expensive commodity. Fresh water use in a vehicle wash application should be carefully considered, and applied as to maximize its value.
2. Spot-free water is water that either naturally, or by processing, has a total dissolved solids (TDS) count below 20 parts per million (PPM). The overwhelming majority of spot-free systems in current use are reverse osmosis. RO systems have an impact on water conservation as most equipment will require 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, deliver it anywhere fresh water without a chemical application would be used.
- In a self-serve wash, the RO reject can be blended with fresh water in the high pressure wash tank. This nets two uses for one gallon of water. In systems without a reclaim, this alone will result in a significant savings on your water bill with the investment of a tank and pump.
3. Reclaim water is water that has been used in the wash process, then cleaned and reused. Many municipalities now require some form of reclamation or recycling system prior to permitting. Having one may assist in avoiding expensive impact fees. Some water districts have evaluated their ability to deliver water and treat the sewer effluent; they then set their rates based on this capability.
It is not unusual to find water service providers to charge three times as much for sewer as for water. In self-serve wash systems where 15-18 gallons used per vehicle is a lot of water, reclamation systems are not such an obvious choice as a hybrid express tunnel where you could use 80-100 gallons per vehicle.
The processes necessary to clean the water are the same for a small or large amount of water, so a reclaim system to process 10 gallons a minute is not 10 times cheaper than one that does 100 GPM.
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. 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.
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 150 microns and larger, with a specific gravity (SG) of 1.2 will settle in 70 degrees Fahrenheit still water at a rate of 0.8 inches per minute. Oil with a SG of 0.88 will rise at a slightly slower rate of 0.68 inches per minute.
Overall, it is important to do your homework when choosing a reclaim system. Work with a representative that understands the needs of you and your carwash. Making sure you have local support is also vital. If you can, try contacting other owners and operators in your area to learn from their experiences, trials and errors. In the end, your level of comfort with the provider and with the chemicals will ensure your success at the wash.
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. He is in his 18th year in the water treatment business.