Since the advent of automated washing, water use inside tunnels and bays have become an issue of concern. As cities have grown and populations have become more concentrated, some states and municipalities have even fought court battles over water use and control. In the past, carwashes had limited hours or were shut down during times of intense drought. But these concerns have lessened as more and more washes adopted efficient and economical water reclaim and recycling systems.
A new option allows spent wash water to be reused, by means of a simple process incorporating chemicals, ozone, grit, filtration and reverse osmosis to create spot-free water, for reuse.
Reverse osmosis (RO) systems use a pump to increase the pressure on the feed side of the equipment and forces the water across and through a semipermeable membrane. This process, results in approximately 96 to 99 percent of total dissolved solids (TDS) coming out of the carwash process. When applied and functioning correctly, RO equipment can effectively reduce levels of salt, hardness and silica minerals that contribute to carwash-related spotting.
If an automatic tunnel wash station utilizes this system to process wash water, the plant backwash water it creates can be sent back to the head of works and recycled for re-use. The reverse osmosis reject water being approximately 3 – 4 % of the total water used cannot be reused as this will cycle up the dissolved salts to the point that would cause the plant to fail, unfortunately this water must be sacrificed and sent to drain.
A water recycling system must have a way to remove the suspended solids in used carwash water. Solids such as sand and clay particles in reused water can damage the paint on a vehicle and will most certainly be an ingredient creating overall poor carwash water quality.
Lastly, if the water from the processed recycling system were to be used for the wash processes, any used chemicals, detergents or oils and grease must be removed.
The benefit of utilizing this typical wash water recycle system, will ensure that the washing process is not interrupted by limited hours of operation due to water restrictions, which decreases revenue, but rather keep the operation functional on a continuous basis, also saving water usage derived from municipal supply. The process will result in a huge financial gain and aid water conservation. Ultimately the process will allow the user to be completely self-sustainable and not reliant on municipal water.