Water - Reuse, Reclaim, Restore

By Tom Gibney

03/01/15

Water is and always will be the lifeblood of the vehicle wash industry. The question is: What are we doing as an industry to protect our lifeblood?

Why should our industry focus on managing water and sewer costs? Some states have been in drought conditions. Water supply shortages will drive the cost of water higher, and we have seen this happening with double digit increases throughout the country. 

As tax revenues are down in most cities and states, the sewer department’s ability to maintain or expand sewer treatment facilities have been stretched. To cover their operating budget shortfalls the cities are going out to industries and demanding that wastewater be treated and cleaned before sending the water to the sewer treatment plants. If industry doesn’t pre-treat the water, heavy fines are assessed. It’s only a matter of time before they get to vehicle wash facilities.

In a vehicle wash there are generally four products discharged in the used wash water: chemicals, solids, oils, and water. When looking at a water reclamation system, it’s important that you first understand what components exist in the discharge water that needs to be removed or cleaned.

 

SYSTEM TYPES

In the vehicle wash industry there are three types of water treatment systems available: reuse, reclaim, and restoration.

Water reclaim system. 

Reuse

This system utilizes three or more settling tanks to settle out most of the solids via gravity. From the last stage of the settling tanks water is pumped back to the wash equipment for reuse. The water this system delivers contains suspended solids and all the chemicals used in previous washes. In warmer weather, when this water is reused, it will contain an odor, which is hydrogen sulfide gas (rotten egg smell), which is a gas given off by the natural anaerobic bacteria in the water.

Reclaim

In a reclaim system the waste-water is sent through a series of settling tanks like the reuse system to settle out the heavy solids using gravity. When the water is pumped out of the last settling tank the water is processed through some form of filtration or cyclonic separation to further reduce the solids to micron level. This water is then treated with ozone, UV, zinc, or copper oxide to kill the natural bacteria in hopes that the water won’t smell when reused. The water coming from a reclaim system still contains most of the chemicals used in previous washes. As used chemicals are not removed in a reclaim system, there are limitations where this water can be reused in the wash.

Restoration System

A water restoration system utilizes the same settling tanks as the reuse and reclaim systems and when the water is pumped from the last settling tank it’s sent through hydro cyclones which cyclonically separate any remaining solids down to 5 micron. The wastewater is aerated, which turns the natural growing anaerobic bacteria aerobic. In their aerobic state the bacteria are 90 percent more aggressive in consuming chemical waste in the water. When aerobic bacteria consume waste in the water they give off a CO2 gas, which has no smell so odor is never a problem when the water is reused. In the last step in a restoration system, the wastewater is sent through a biologic chamber where active aerobic bacteria are grown to consume the chemicals in the water. With the chemicals removed, the water has been restored and can be reused in all functions in the wash except the spot-free or freshwater final rinse.

 

Water restoration system w/touch screen control panel. Hydro cyclones for cyclonic separation of suspended solids down to 5 micron.

 

NATURAL RECLAMATION

Nature has always been best at resolving pollution control. Natural bacteria exist in every part of our environment. The EPA has been successful in cleaning up petroleum contamination by injecting bacteria into the soil to consume contamination. When the Exxon Valdez ran aground in Alaska and spilled oil into the sea, enzymes, bacteria, and a vitamin combination were sprayed on the sea to activate natural bacteria to consume the oil. Most recently, the Gulf oil spill poured millions of gallons of oil into the Gulf and was ultimately cleaned up by the natural bacteria in the sea.

Septic systems use anaerobic bacteria to break down human waste. At sewer treatment plants, aerobic bacteria are used along with high levels of oxygen to biodegrade clean wastewater.

 

BIOLOGICAL RESTORATION

In a natural biological reclamation system, how does this technology address the waste present in vehicle wastewater? A natural approach to treatment is achieved through use of aerobic bacteria and oxygen, both of which are found in our environment.

In the human body we have a bioreactor in our stomachs using bacteria to break down the food and drink we consume.

In a simple glass of drinking water, if you looked at it under a microscope, you would see natural bacteria moving around. These bacteria can be either anaerobic and/or aerobic depending on the level of oxygen in the water.

 

Anaerobic Bacteria

Anaerobic bacteria prefer to be in a dark environment that is devoid of oxygen in the water. If you think about the settling tanks in a car wash, they are dark and have little access to oxygen. Anaerobic bacteria thrive in used car wash water. Anaerobic bacteria give off a gas that smells like sulfur or more commonly referred to as a rotten egg smell. These are the same bacteria that are present in home septic systems.

Aerobic Bacteria

Aerobic bacteria become active in water that has high levels of oxygen concentrated in the water. Aerobic bacteria that consume waste in the water give off CO2 gas which has no smell.

Over the years different companies have tried to inject oxygen in the wastewater by using a small air pump or floating membrane. These types of systems simply cannot infuse enough oxygen in the water to maintain aerobic bacteria levels. In an all-natural water restoration system oxygen is supplied by an oxygen blower that delivers high volumes of oxygen under low pressure, which is dispensed through aeration membranes much like they use in sewer treatment plants.

Aerobic bacteria are the differentiating factor in an all-natural wastewater restoration system. These aerobic bacteria are used to consume the used car wash chemicals in the wastewater as long as the chemicals are biodegradable and compatible. I’ll address biodegradability of chemicals in the “Biodegradable Chemicals” section.

For the bacteria to consume the chemicals, the bacteria must come in contact with the chemicals in the water. If bacteria are activated in an open tank, the bacteria will attach to the walls of the tank. Only the water and chemicals that make contact with the walls of the tank will be cleaned. All the water in the center of the tank will not be effectively cleaned. To achieve complete cleaning, the bio chamber is filled with bio media where the bacteria can live. This dramatically increases the surface area and bacteria count in the bio tank to ensure that bacteria can consume the waste chemicals.

 

BIODEGRADABLE CHEMICALS

Wastewater coming from a wash contains chemicals that are made up of cationic, anionic, and nonionic chemicals. Most of the chemicals used are biodegradable. However, the time it takes to biodegrade varies. It’s very important that chemical manufacturers know and understand the biodegradability and compatibility of their chemicals when used in a natural biological water restoration or reclaim system. In the past, biodegradability wasn’t an issue as all the wastewater went to sewer. Biological restoration makes it essential that chemical suppliers formulate for biodegradability and compatibility.

Biodegradability of chemical components is classified at three levels. The first classification is Readily biodegradable. This means that the natural bacteria present in the water can easily biodegrade the chemicals and turn them into CO2 and water.

The second classification is Slow to biodegrade. This means it requires high levels of oxygen concentration in the water and time for the bacteria to biodegrade the chemical components. Slow to biodegrade components are difficult to use in a biologic treatment system as there isn’t enough time to biodegrade them before more of the same components are added to the waste water.  This means the concentration of these components continues to rise until the system is overwhelmed.

The last classification is Not biodegradable. These chemical components cannot ever be used in a biologic treatment system. These are chemicals that will kill the bacteria.

The last factor that impacts the ability of bacteria to break down and biodegrade chemical components is whether the chemicals are anionic, cationic, or nonionic. Nonionic and cationic chemicals will readily mix together and be biodegraded by bacteria. Anionic chemicals are not compatible with nonionic or cationic chemicals. When Anionic chemicals are used, the resulting mixture is very difficult for natural bacteria to biodegrade.

Chemical manufacturers need to be aware of what biodegradability means in a biologic treatment system when formulating their chemical lines to be used in a biological treatment system.

Nature has been cleaning our environment since the beginning of time. By utilizing this natural cleaning process and incorporating it into the vehicle wash market, reclamation of wastewater has become a real possibility. In doing so the supply of water and the costs associated with its use and discharge can be managed and controlled.

 

Tom Gibney is president of Aqua Bio Technologies. Formerly the vice president of the industrial division of Turtle Wax, he has over 25 years of experience in the vehicle wash industry. You can contact Tom at (877) 881-9141 or via e-mail at tgibney@aquabio.co. You can also visit the company on the web at www.aquabio.co.

 

 



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