The decision to reclaim water in a car wash is usually based on economics, environmental or regulatory issues. The Clean Water Act legislates that car washes capture their wastewater and governs the disposal of this waste.
Also, the US Environmental Protection Agency has banned the construction of new drains connected to motor vehicle disposal wells. Once this ban is enacted, more car washes will be forced to look into reclaim systems.
Some chemicals found in the waste stream of carwashes include: benzene, which is used in gasoline and detergents, and trichloroethylene, which is used in some grease removers and other compounds.
Most reclaim systems provide some combination of the following methods: settling tanks, oxidation, filtration, flocculation and ozone.
Car wash reclaim systems usually will provide wash quality water within a range of 30 to 125 gallons per minute (gpm) with a particulate rating of 5 microns.
Gallon flow requirements in a typical facility can be accommodated using a combination of equipment. For example, odor control and color removal of reclaimed water can be accomplished by high-concentration ozone treatment of water held in holding tanks or pits.
When designing, installing and operating reclaim systems for your customers’ car washes, first determine two things: whether to use an open or closed-loop system and whether there is access to a sewer.
Typical applications can be operated in a closed-loop environment by following a general rule: The amount of fresh water added to the wash system does not exceed water loss seen through evaporation or other methods of carry-off.
The amount of water lost will vary with different types of car wash applications. The addition of fresh water to compensate for carry-off and evaporation loss will always be accomplished as the final rinse pass of the wash application. The final rinse adds back the lost water. The final rinse pass should always be high pressure and low volume for the purpose of rinsing off any residual reclaimed water used in the wash process.
In the event sewer access is available at a particular car wash site, water treatment equipment can offer car wash operators greater flexibility when selecting which functions in the wash process will use reclaim vs. fresh water. The decision probably will be based on the cost of sewer utilization fees and associated tap or wastewater capacity fees.
Post time: Apr-29-2021