Professional Carwashing & Detailing

Smell hath no fury

March 8, 2011

There is a lot of science and strategy associated with water reclamation systems used in the carwash industry and, some strife as well — especially when it comes to odor problems and odor control. In fact, odor is the number one concern for operators, according to Dean Taylor, system application specialist for CATEC Water Recovery and Ozone System, a supplier of technologies to treat and reclaim water.

“Using a good process to combat these odors can be very effective and financially rewarding,” Taylor expanded. “With a good reclaim system installed, the customer shouldn’t be able to tell reclaim water is being used.”

Professional Carwashing & Detailing spoke to the experts to help you sniff out the cause of odor problems and find the right solution for your carwash, because according to them, there is often more to an odor than just a bad smell.

What causes that smell?
According to Jim Keller, president of Con-Serv Manufacturing, a manufacturer of water reclaim and treatment systems, the primary source of odor in reclaim systems is a buildup of dead bacteria, which he describes as the universe’s little housekeeper. “A high concentration of dead bacteria creates Hydrogen Sulfide (H2S) gas,” Keller said, “Otherwise known as that rotten egg smell.”

“All carwash soaps and foam cleaners, etc. are made, by law, to be bio-degradable and start the degrading process the minute they are introduced with water,” he continued. “The primary design of bacteria is to degrade various types of organic matter in a multiplicity of environments.”

According to Keller, it is estimated that less than five percent of all forms of bacteria are pathogens (disease-causing), and 95 percent are beneficial organisms happy to degrade whatever they degrade best.

Charles Borchard, vice president of operations for the PurClean and PurWater divisions of New Wave Industries, a manufacturer of water reclaim systems, said bacteria thrives in the absence of oxygen and is mostly found in the muck of the settled solids either in the trench or holding tanks of the reclaim system.

Taylor said to think of it as if food were rotting. “Odor associated with some reclaim systems is bacteria and a natural biodegrading process. Contaminants (including biodegradable wash chemicals) in the water are decaying in a process similar to that of rotting food,” he said. “These bacteria multiply exponentially and can manifest very quickly. These odors are often offensive.”

It’s not just the smell that’s bothersome
According to Taylor, the bacterial odor can enter car vents, door jams, and other nooks and crannies and continue to make the vehicle smell bad long after it is washed. “This problem,” he said, “can be — and usually is — very detrimental to a carwash business, as customers who have encountered this will seek out a wash that does not stink, resulting in loss of business.”

Joel Wollin, director of sales and marketing at Autowash Systems, Inc., also a manufacturer of water reclaim and treatment systems, said that a tremendous amount of organic matter is washed off of vehicles on a daily basis — from bird droppings to leaves to pine needles to dirt and mud.

“Dirt,” said Wollin, “has a tremendous amount of organic material in it. Even motor oil and other petroleum products are considered organic matter, because by definition, compounds that contain organic carbon are considered organic.”

Wollin said in order to remove the organic material, water has to be used. “Now,” he said, “we’ve mixed all of that organic material with water, which gives us our second condition for anaerobic bacteria: Moisture. On top of this, we’ve decided that we want to use this water more than once, so we install some underground storage tanks so that we can store this water and let the contaminants settle out. We’ve just eliminated oxygen. But, in doing so, we’ve basically created a stagnant, underground swamp.” Which he added, is quite nasty and unpleasant.

And, anytime you have organically contaminated, stagnant water sitting around, it becomes a breeding ground for anaerobic bacteria. “The anaerobic bacteria are feeding on the decaying contaminants in the water, and they are multiplying at a dizzying rate,” Wollin said.

“In fact,” he added, “the growth curve of bacteria is measured by how fast the bacteria colony doubles in size. Under ideal conditions, many bacteria colonies can double in size every 15-20 minutes.”

The exponential growth of these undesirable anaerobic bacteria and the anaerobic digestion process quickly leads to huge quantities of Hydrogen Sulfide being produced…and unfortunately, the eutrophication of the water you’ve saved.

Combating the smell
Now that we know what the odor is and how it got there, what can be done about it? Lots, according to the experts we spoke to.

According to Wollin, the first step in controlling odor is to focus on preventing the conditions that lead to the anaerobic digestion and the Hydrogen Sulfide in the first place. In other words, you need to kill the anaerobic bacteria.

“Obviously, the better we perform on preventing anaerobic bacterial growth, the less we’ll need to be concerned about killing them,” he explained. He said the key is to eliminate the organic matter and oxygenate the water. Below are a few of the methods used.

1. TURNOVER: This is the least discussed method, according to Wollin. “Any freshwater applications in your carwash that add freshly used water to your reclaim system will improve the quality of your reclamation. The more freshly used water that is added to your system, the better your water quality will be,” he said.

“In addition, freshly used carwash waste water is heavily oxygenated,” Wollin added. “In most cases it was aerosolized in the carwash bay by spraying it through nozzles, and in many cases this water had air added to it from your air compressor during the wash process.”

2. CIRCULATING and AERATING: In addition to turnover, and probably more important, is circulation, said Wollin.

“The circulation of your reclaim tanks is important for many reasons … the most important of which is that it keeps the water moving,” Wollin said. “Moving water is always more oxygenated than stagnant water, as the water has some opportunity to mix with and absorb some air at the surface.”

In addition, he added, this circulation process gives the opportunity to inject even more oxygen at the circulation pump.

This is where the addition of ozone, hydrogen peroxide, and/or other disinfectants would occur. “In this instance, we’re actually forcing concentrated oxygen into your reclaim water to control anaerobic growth,” Wollin said.

According to Borchard, aerating the water by keeping it recirculating with an air injector or sparging air is are other methods. “Water can be aerated by having air delivered to the water from an air compressor via an air stone or pipe in the holding tanks,” he said. But, a better method, he added is called “sparging.”

“Sparging,” said Borchard, “is the forcing of a gas and liquid together (in this case atmospheric air is drawn into the water stream by a venturi effect as the water is recirculated) which creates a mass of air bubbles in the stream and these air bubbles keep the oxygen level higher in the water and helps keep the anaerobic bacteria down.

3. OZONE: Ozone is one of the most popular methods, according to Taylor and the best method, according to Borchard. “Sometimes called ‘activated oxygen,’ ozone contains three atoms of oxygen rather than the two atoms we normally breathe,” said Taylor.

“Ozone is the second most powerful sterilant in the world and can be used to destroy bacteria, viruses and odors. Ozone will also remove color such as triple-foam from the water.”

4. OZONE + BACTERIA: According to Keller, the latest technology in incorporates the use of both ozone and bacteria. “Ozone,” he said, “will remove color and separate emulsified oils, wax, and surfactants. The bacteria will co-exist to provide round-the-clock cleaning and removal of all organics that cause odor. More and more carwashes, existing and future ones, are turning to this combination to address the issues of using water reclaim systems.”

5. BIODIGESTERS: These (often referred to as bugs), according to Taylor, are a combination of bacteria and enzymes which are targeted to the food sources available in a waste water treatment system.

“By out competing the natural occurring bacteria for the food sources, odor-causing bacteria dies off and thus, the objectionable smell is eliminated.”

This can be an effective method however, there are some drawbacks, warned Taylor. First, there is an ongoing cost of having to purchase the bugs. Secondly, the bugs are pH and temperature dependent. And, thirdly, if you are bringing in city water for rinse and make-up water, the chlorinated water will have an adverse effect, killing off the colonies.

“If these colonies die off,” he cautioned, “it can take weeks to reestablish them. In the interim, you can expect dirty, stinky water.

6. AEROBIC BACTERIA: Wollin said this has been employed to further combat the growth of anaerobic bacteria. “Aerobic bacteria needs oxygen to survive and thrive, and the cultivation of aerobic bacteria colonies in water reclamation systems is proving to be useful in that the aerobic digestion process produces clean carbon dioxide gas instead of dirty, nasty smelling hydrogen sulfide,” he said.

Carbon dioxide is completely safe and pretty much inert, he added, and, it’s even used as a welding gas. “This method of water reclamation provides for both the addition of oxygen to the water as well as a means to dispose of the organic matter that the undesirable anaerobic bacteria love so much.”

Advancements and the future of water reclaim
According to Taylor, reclaim systems have come a long way in the last 10 years and are nearing the top of the learning curve, meaning the advances are starting to taper off.

“Almost all reclaim systems provide water that is suitable for washing a vehicle,” Taylor explained. “This is because there are still some soaps and surfactants in the reclaim water which will leave a film if not rinsed off. Fresh water is typically introduced for rinsing as well as providing make-up water to the system as some water is lost in carry-off, evaporation and atomization during the wash processes.”

Taylor added that any advances in reclaim technology at this stage are mainly directed toward producing a “rinse quality” water, which would be equivalent to incoming domestic water.

“Removing soaps and surfactants from water is possible but can become cost prohibitive because of the complexities involved,” he said. “Producing rinse quality water from reclaim water will allow a carwash to wash and rinse a vehicle with no excess water meaning no discharge. One can feasibly build a carwash with no sewer or septic system, which can be a huge advantage when selecting property. This equipment is available but again, can be very expensive.”

Utilizing rain water for final rinse, spot-free feed and make-up water is gaining interest because the water is “free,” Taylor said. “However, stored rain water must be treated to keep it fresh and usable for rinsing,” he added. “Systems for this application are available and can be very affordable. This could be enough water to use full time in a self-serve wash where water use is relatively low, however, for larger washes such as express exterior tunnels, this may not be as attractive due to the high ratio of rainwater verses the domestic water required.”

According to Borchard, we are going to see more reclamation systems required, either by mandate from municipalities or due to the economy, because of the increases in water and sewer costs.

“Fifteen years ago, you could reuse carwash water on your undercarriage and maybe a soaker arch at the front of the wash and do that with a simple pump and maybe a dog bone separator and be recycling 30 to 40 percent of your water and be ‘green,’” Borchard explained – and that is no longer the case today.