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Biological reclaim systems have actually been around for a long time. In the European carwash market, they have been in use for over 15 years.
European standards for the required use of reclaim are much more stringent than those in the U.S., so they were required to develop technology that worked.
Although we have become familiar with the mechanical type of reclaim that has been available to our industry, the cleaning of water by bacteria is quite common among city and municipal sewer treatment plants.
This type of sewage treatment is much more technically involved and requires the attendance of certified personnel. After all, a city sewer plant treats millions of gallons of water that contain anything and everything discharged from homes, factories, businesses and storm sewers.
In carwash biological reclaim, the process is much simpler and much more focused on the contaminants to be dealt with — primarily soap, wax, oil and grease — and does not require certified personnel to operate.
Starting from the beginning, the water enters the system from the carwash pits. Its first stop is the “sludge pit” (see diagram). All pits in this discussion are sized to the hourly capacity of the reclaim system.
For our purposes, we will use a 2,000 gal/hr system. The sludge pit would have a 2,500-gallon holding capacity. In this pit, the heavier particles, such as gravel and heavy mud, are allowed to settle to the bottom, thereby separating from the water to be eventually treated.
This tank, along with the bay or tunnel pits, will still need to be pumped periodically to remove these heavier items, the same as without reclaim. The water from this pit overflows into the aeration pit.
For our example, the aeration tank has a 2,000-gallon holding capacity. These tanks are usually septic-type tanks made of concrete, although they can be plastic and round.
In this pit, there is a floating aerator which continuously bubbles air from the control panel of the system.
This aeration process keeps dissolved oxygen levels in the water in the entire system above 40 percent. This allows bacteria in the water to exist in the aerobic state, and the waste products of the contaminants they consume, like soap, wax and oil, will become water and carbon dioxide.
This is the great thing about biological reclaim — odor removal!
Odor comes from bacteria in the wash water that evolve into the anaerobic state because of lack of dissolved oxygen. When they consume contaminants, the waste product is water and hydrogen sulfide, the reason carwashes tend to stink in the summertime.
Also in the aeration tank is the grinder pump, which pushes water from the aeration pit to the next step of the process, the bioreactors. The grinder pump is suspended in the tank by a chain and is easily replaceable through the cover on the aeration pit.
As the water is brought to the bioreactors, it goes through a cyclone separator which spins out all suspended material over 5 micron in size. Those suspended solids are immediately returned to the carwash pits or sludge pit, where they will be removed during the pumping-out process.
All heavy material and suspended solids are removed without any mechanical filtration such as multi- media tanks, sediment filters or carbon filtration, all of which could create maintenance problems by becoming filled with grease, oil and soaps.
The water now enters the bioreactors. Inside these bioreactors, which in our example are four units plumbed together, are thousands of rings. These rings are the actual surface area where the bacteria colonize, reproduce and grow.
As the water passes through the bioreactors, it flows in, around and through these rings where the bacteria actually eat the contaminants they have been programmed to consume.
This process takes place billions of times everyday in nature, is perfectly natural and extremely effective. Again, we see removal of the contaminants without any physical barriers or filtration.
The water will gravity overflow from the bioreactor to the clean water tank where it will be pressurized and sent back to the wash pumping equipment and the whole process starts over.
Not all biological systems are created equal. Some cannot use the items discussed here because of patents held worldwide. Education and investigation will lead you to the best performing systems.
The bacteria used in a system is planted, or placed, in the bioreactors prior to startup. There are hundreds of different bacteria strains used for a myriad of processes. Some are broad spectrum which means they attack an array of contaminants such as a city sewer plant would require.
A small number pinpoint specific contaminants they will consume. The carwash biological system is one of the pinpointed ones.
These bacteria, which are completely harmless, act the same as they do in nature. They are born; they eat contaminants; and they die. The bacterial colony is in a state of constant regeneration.
How fast they reproduce, and at what specificity they look for and consume contaminants, is the key to a successful biological reclaim unit.
The great thing about this technology is it allows a carwash to recover 100 percent of the water captured in the wash process. The only water not recovered and reused is water lost to drive-off, evaporation, and overspray.
This means an 80-85 percent reduction in fresh water usage. Understand that reclaims don’t make water, and drive-off, evaporation and overspray must be replaced.
It becomes easy to understand that by reclaiming the same water over and over, the system works extremely well without a sewer.
Many washes which have been in service for several years are operating with no sewer. Hundreds of thousands of dollars have been saved on environmental impact fee waivers and sewer connection fees.
Thousands of dollars more have been saved by an 80-85 percent water reduction and zero discharge costs.
Many municipalities are beginning to offer incentives to carwashes which reclaim their water. Rebates of up to 50 percent of the total cost of the reclaim system are offered in some cities.
Avoid drought scares and ever increasing water and sewer rates. The technology is here to reclaim 100 percent with results you will be happy with.
Cary L. Wise is the general manager for North American Operations of Rowafil USA, LLC in Lakehills, TX. For more information, e-mail Cary at firstname.lastname@example.org.