Image courtesy AC Fox

Because gas prices are so high right now, and because the President and Congress have put a lot of emphasis on ethanol, and because GM is running their huge Go Yellow ethanol ad campaign, you should be sitting pretty. Unfortunately, you have a small problem.

The problem is the river of wastewater that corn ethanol creates. To understand this waste stream, think about the manufacturing process:

Image courtesy U.S. Department of Energy An ethanol plant

So far so good. Now you distill the alcohol out of the water and create a gallon of ethanol that you can sell. That's great too.

The problem is that for every gallon of ethanol you sell, you also create 10 gallons of polluted water. The water that is left over after distillation is full of proteins, sugars, enzymes, bits of dead yeast cells and a little remaining alcohol. What do you do with this polluted water? And keep in mind that there are 10 gallons of polluted water for every gallon of alcohol that you create. So if you are making 25 million gallons of ethanol each year, you have to deal with 250 million gallons of polluted water. Since industrial ethanol plants typically range in size between 25 million and 100 million gallons of ethanol a year, and there are a number of these plants in the United States, you can see that ethanol wastewater becomes a big problem.

Image courtesy Falke Bruinsma A clarifying tank at a sewage treatment plant

But the corn ethanol production process isn't the only manufacturing process that results in wastes and by-products. If you make biodiesel fuel, you get a by-product called crude glycerol that you have to deal with. If you have a food factory you may have a similar problem. Say you make pancake syrup or frozen pizzas, and you use water to clean parts of the assembly line. This water is now polluted, and the local sewage treatment plant may not want it. What are you going to do with it?

Now there's a completely new process available to handle water that is polluted with organic material like proteins, sugars, glycerol or even pizza debris. That process is called Activated Carbon Facilitated Oxidation, or AC FOX. AC FOX has huge advantages over the traditional ways of dealing with "organically contaminated waste streams."

In this article, you will learn all about AC FOX and how it can help manufacturers of a wide variety of products save money, help the environment and speed up their production lines. Let's take a look.

The Advantages of AC FOX
So let's go back to our ethanol factory. The factory creates 10 gallons of wastewater for every gallon of ethanol that it produces. The wastewater contains proteins, sugars, enzymes, DNA fragments and a little left-over alcohol.

How do you get rid of this wastewater? Ethanol plants today usually handle it by evaporating the water and making animal feed from the solids that are left behind. The sale of the animal feed does not cover the cost of evaporating the water, but it does solve the wastewater problem.

Another way to handle the wastewater is to treat it like sewage. Let's look at the sewage approach, since that can be applied to all waste streams that we are talking about. With sewage, you let the water stand in large tanks or holding ponds and you let bacteria eat all the organic material in the water. That works, but there are three problems:

1. The process often takes a lot of space
2. The bacteria are slow
3. The process completely ignores the fuel value of the wastewater

The third problem is key. Any stream of wastewater contaminated with lots of organic material like sugars and proteins can be thought of as a waste fuel. If you could somehow burn this fuel, you could use the resulting heat to do all sorts of things. You might use the heat in part of your manufacturing process, or use it to generate steam and make electricity. One great thing about this heat is that it would be free. Currently you are letting the bacteria eat that fuel, and it is all going to waste.

It turns out that, up until this point, burning wastewater has been impossible. Imagine trying to burn pancake syrup. Pancake syrup contains a huge amount of energy because of all of the sugar, but up until now there has been no way to "burn" it because the water in the syrup makes burning impossible. Even if you dehydrate the syrup and try to burn the dry sugar, it doesn't burn very well.

AC FOX completely changes the equation. The goal of AC FOX is to quickly and efficiently "burn" all of the fuel in any stream of organic wastewater. With AC FOX you can, in fact, "burn" pancake syrup and capture all the heat. You can also "burn" the effluent from your ethanol factory, or glycerol, or water with lots of pizza crumbs dissolved in it. Any organic wastewater stream turns from "sewage" (which is a problem) into "fuel" (which is cool) if you have an AC FOX reactor in your factory.

By "burning" your wastewater, you now have an asset instead of a liability. You can use the free heat created by the AC FOX reactor anywhere in your factory. You can also immediately reuse the water, because it is clean. And you also speed up the whole process. Instead of letting the wastewater stand for days in a settling pond or bacterial digestion tank, you can "burn" the wastewater quickly, as soon as you create it.

The core idea behind AC FOX is both ingenious and remarkably simple. You start with a big, rotating tube. The size of the tube depends on the size of the waste stream you have. If the waste stream is small, the tube might be the size of an office desk. If your waste stream is huge, the tube could be as big as a tractor trailer.

You then fill the tube with activated carbon. Activated carbon is nothing but charcoal that has been "activated" to give it more surface area. It's the black granules that you find in aquariums and gas masks, and it's a completely safe, organic product.

The tube is motorized so that it rotates and stirs the carbon granules. This rotating tube full of activated carbon is the AC FOX reactor.

Now you take your wastewater stream and inject it and a source of oxygen (typically air) into the reactor. What happens next is the key to AC FOX. Here are the steps:

• The activated carbon has a huge surface area (5 million square feet per pound), and that surface area grabs hold of all of the organic molecules in the wastewater that you injected.
• Because the reactor is hot, the oxygen that you injected wants to react with something.
• All those organic molecules trapped on the surface of the carbon granules are an easy target for the oxygen atoms inside the reactor.
• The oxygen reacts with the organic molecules.

The reaction is very fast, and it produces three things:

1. Carbon dioxide and water vapor from the reaction of oxygen with the organics
2. Lots of heat, which boils off the water in the wastewater and keeps things hot
3. A little ash containing mostly nitrogen and other inorganics in the waste

The ash is a great fertilizer, and the excess heat can be used anywhere that you need it in your factory. Or, you could use the heat to generate steam and drive an electric generator.

With an AC Fox reactor, we have taken what used to be sewage and we have turned it into fuel.

The AC FOX reactor can do even more. It turns out that there are lots of places in factories that use activated carbon for filtering. Refineries, for example, use lots of activated carbon in their filters. The carbon granules do their filtering by adsorbing and holding onto molecules (see How Gas Masks Work for details). Once the carbon granules in a filter get "full," you have to either throw them away or "reactivate" them.

With AC FOX, you have a reactor that is perfectly suited to reactivating carbon. You load the reactor up with spent activated carbon, let the AC FOX reactor do its normal thing, and then take the carbon back out a day later. The newly reactivated carbon is ready to go back into the filter. This ability to reactivate carbon can also save factories a huge amount of money.

If you have a factory or process that currently produces a stream of organic wastewater, you are probably dealing with the wastewater as "sewage". If you use an AC FOX reactor instead, the wastewater turns into "fuel":

• You "burn" all the organics in the wastewater in a bed of activated carbon and capture the heat from the reaction.
• The heat comes out in the form of steam, which you can use anywhere in your factory.
• After using the heat, you can condense the steam and reuse the water in your manurfacturing process.
• In addition, you can use your AC FOX reactor to reactivate carbon for filtration.

AC FOX is a great way to turn lemons into lemonade.

AC FOX has an estimated payback period of less than two years. If you can use the AC FOX reactor to reactivate carbon as well, the payback period is even shorter.

AC FOX is the invention of Hugh McLaughlin, Ph.D. The AC FOX reactor is currently being used several factory environments and licensing rights are available. You can learn more by visiting ACFOX.com.

Remember the scene in “Back to the Future” where Doc Brown throws garbage into Mr. Fusion, powering his time machine? While household fusion is still in the realm of science fiction, we might be closer than you think to generating electricity for our homes using trash, and plasma waste converters will do the job.

Photo courtesy PyroGenesis © 2006 Plasma torches. See more plasma converter pictures.

At the most basic level, a plasma waste converter is a plasma torch applied to garbage. A plasma torch uses a gas and powerful electrodes to create plasma, sometimes called the fourth state of matter. Plasma is an ionized gas; in other words, it’s a gas with free-roaming electrons that carries a current and generates a magnetic field. On Earth, we can see natural displays of plasma fields in lightning. The temperatures generated by a plasma torch can be hotter than the surface of the sun (more than 6,000 degrees Celsius).

Photo courtesy of PyroGenesis ©2006 PyroGenesis Plasma Arc waste disposal system

At these temperatures, garbage doesn'’t stand a chance. Molecules break down in a process called molecular dissociation. When molecules are exposed to intense energy (like the heat generated by a plasma torch), the molecular bonds holding them together become excited and break apart. What's left are the elemental components of the molecules. With cyanide, for example, you’ll end up with atoms of carbon and nitrogen.

Organic molecules (those that are carbon-based) become volatilized, or turn into gases. This synthetic gas (syngas) can be used as a fuel source if properly cleaned. Inorganic compounds melt down and become vitrified, or converted into a hard, glassy substance similar in appearance and weight to obsidian. Metals melt down as well, combining with the rest of the inorganic matter (called slag).

Unlike incinerators, which use combustion to break down garbage, there is no burning, or oxidation, in this process. The heat from plasma converters causes pyrolysis, a process in which organic matter breaks down and decomposes. Plasma torches can operate in airtight vessels. Combustion requires oxidization; pyrolysis does not.

Plasma waste converters can treat almost any kind of waste, including some traditionally difficult waste materials. It can treat medical waste or chemically-contaminated waste and leave nothing but gases and slag. Because it breaks down these dangerous wastes into their basic elements, they can be disposed of safely. The only waste that a plasma converter can’t break down is heavy radioactive material, such as the rods used in a nuclear reactor. If you put such material in a plasma furnace, it would probably catch on fire or even explode.

In the upcoming sections, we will look at what makes up a typical plasma waste converter, examine the byproducts produced from the gasification process, and discuss the benefits and concerns about plasma converters.

Currently, plasma plants aren't standardized. Many different companies are designing plasma facilities, and for the moment each facility is essentially custom-built. Still, most converters have the following components in common:

Conveyor system
In order to feed garbage into the converter, almost all plasma facilities have a conveyor system. Garbage is loaded on the conveyor and is pushed into the furnace (or pre-treatment system if the plasma facility uses one) by a plunger.

Pre-treatment mechanism
Although a plasma torch can break down waste without any special pre-treatment, most plasma facilities employ some sort of pre-treatment process to make the entire system more efficient. Some designs use grinders or crushers to reduce the size of the individual pieces of garbage before moving in to the furnace. The plasma torch can break down the smaller pieces faster.

Furnace
Here's where the magic happens. Furnaces have an airlock system to allow garbage to come in while preventing the hot gases in the furnace from escaping into the atmosphere. The furnace houses at least one plasma torch; many furnaces have multiple torches to break down all the matter. These torches are usually placed a little lower than halfway down the furnace. The furnace also features a drainage system to tap off the slag as it accumulates and a vent system to vent out the gases. In order to withstand the intense heat, furnaces are lined with refractory material and often have a water-cooling system as well.

Plasma torch
The plasma torches used in these facilities are custom-built. The amount of energy they consume, the lifespan of the electrodes it uses, the gas used for ionization (most torches just use ordinary air), the downtime it takes to replace an offline torch and the size of the plasma field it generates all depend on the specific manufacturer. Plasma torches are water-cooled.

Slag drainage
Molten slag pools at the bottom of the furnace and helps maintain the high temperature inside the gasification chamber. Occasionally slag must be drained from the furnace. Some furnaces have drains positioned at a certain height, others use a tap system. Either way, slag drains away from the furnace and cools in a separate chamber.

Gas ventilation
The furnace also has a vent system to allow gasified components to pass into another part of the system (either an afterburner or a gas cleaning chamber).

Afterburner
Gases can pass through a secondary chamber where natural gas flames combust any remaining organic material in the gases. These extremely hot gases then pass through a Heat Recovery Steam Generator (HRSG) system, where they heat water to form steam. This steam then turns a steam turbine to create electricity.

Syngas cleaning
Alternatively, the gases from the furnace enter a chamber where they are cooled and scrubbed, usually by water. The gases pass through a spray of water, which scrubs the gases of pollutants and particulates. A filter system containing a base filter neutralizes acid gases. The acids in the gases and the bases in the filter combine to form inert salts. The cooled and clean gases continue through the system, which in most cases involves a gas turbine connected to an electricity generator. Some systems also harness the heat from these gases to generate steam, similar to the afterburner method mentioned above.

If the plant uses an afterburner, the remaining gases must be cleaned thoroughly to get rid of any hazardous material. Many designs include a dry scrubber system. In this system, powdered carbon is injected into the gases to strip away mercury, a poisonous element. Gases also pass through a fabric or bag filter to remove any other dangerous particulates, like lead. Once the gases have been cleaned they move to the stack, where they are released into the atmosphere.

Molten slag pools at the bottom of the furnace and helps maintain the high temperature inside the gasification chamber. Occasionally slag must be drained from the furnace. Some furnaces have drains positioned at a certain height, others use a tap system. Either way, slag drains away from the furnace and cools in a separate chamber.

Gas ventilation
The furnace also has a vent system to allow gasified components to pass into another part of the system (either an afterburner or a gas cleaning chamber).

If the plant uses an afterburner, the remaining gases must be cleaned thoroughly to get rid of any hazardous material. Many designs include a dry scrubber system. In this system, powdered carbon is injected into the gases to strip away mercury, a poisonous element. Gases also pass through a fabric or bag filter to remove any other dangerous particulates, like lead. Once the gases have been cleaned they move to the stack, where they are released into the atmosphere.

There are three main byproducts that are a result of the plasma gasification process: synthetic gas (syngas), slag and heat. Let''s look at each of these byproducts in more detail.

Syngas is a mixture of several gases but mainly comprises hydrogen and carbon monoxide. It can be used as a fuel source, and some plants use it to both provide power for the plant and sell excess electricity to the power grid. Garbage contains a great deal of potential energy; the gasification process enables engineers to convert the potential energy into electrical energy.

How much gas is generated by a plasma converter? That depends on what you put into the furnace. If the garbage contains a lot of carbon-based material (in other words, organic waste), then you'll get more gas. Waste with a lot of inorganic material won''t yield as much gas. Because of this, some plasma facilities sort through garbage before feeding it into the system.

Photo courtesy PyroGenesis © 2006 Molten slag draining from a plasma furnace

The solid byproduct from the gasification process is called slag. The weight and volume of the original waste material is dramatically reduced. According to Dr. Circeo of Georgia Tech's Plasma Department:

The slag can take different forms depending on how you cool it.

Metal nodules can be separated from the sand

Water-cooled slag forms sand

If slag is air-cooled, it forms black, glassy rocks that look and feel like obsidian, which can be used in concrete or asphalt. Molten slag can be funneled into brick or paving stone molds and then air cool into ready-to-use construction material.

Air-cooled slag forms rocks like this

Photo courtesy Georgia Tech Research Institute Rock wool

If you were to blow compressed air through a stream of this molten material, you'd end up with rock wool. Rock wool has the appearance of gray cotton candy. It''s light and wispy, and according to Dr. Circeo, it has the potential to revolutionize the plasma waste treatment industry. Rock wool is a very efficient insulation material, twice as effective as fiberglass. It's also lighter than water, but very absorbent. Because of this, it could potentially be used to help contain and clean oil spills in the ocean. Cleanup crews could spread rock wool over and around an oil spill. The rock wool would float on the water while soaking up the oil, making collection a relatively easy process. Hydroponic growing systems can also use rock wool -- farmers can plant seeds in slabs or blocks of it.

Currently rock wool is produced by mining rocks, melting them down and then streaming the molten material onto spinning machines. The spinning machines fling strands of molten material in the air. Today, the price of rock wool is over a dollar a pound. Since rock wool would be a byproduct of the plasma gasification process, it could be sold for as little as 10 cents a pound. The price of insulation would decrease, efficiencies in energy-saving techniques would increase and plasma gasification plants would have another substantial source of income apart from selling electricity back to the grid.

Plasma technology experts, including Dr. Circeo, assert that the slag is virtually unleachable, meaning that any hazardous materials are inert and will not dissolve out of the slag.

The heat created by plasma facilities is considerable, measured in thousands of degrees Centigrade. Heat from the molten slag helps maintain the temperature within the furnace. Some of the heat from gases can be used to convert water into steam, which in turn can turn steam turbines to generate electricity.­

Waste treatment through gasification is unique in that it not only gets rid of garbage and generates electricity, it also produces byproducts that are valuable commodities themselves. In the next section, we'll talk about existing and future plasma plants and pioneering companies in this technology.

Currently, there are only two commercial plasma plants that process MSW, and they are both in Japan. In 1999, Hitachi Metals commissioned a pilot plant in Yoshii, Japan. This plant was modest, processing less than 30 tons per day of MSW. The successful operation of the plant spurred the development of two other plants within Japan. The pilot program ended in 2004, and Hitachi Metals decommissioned the plant.

Photo courtesy Georgia Tech Research Institute The Mihama-Mikata plasma facility

The plant at Mihama-Mikata industrial park began operations in 2002. This plant can process up to 24 tons per day of MSW and four tons per day of wastewater treatment plant sludge. Because the plant is relatively small, it doesn't produce syngas for fuel. It does produce steam and hot water, however, which is used both for power and heat generation in the industrial park. The plant uses a water cooling system for the molten slag and separates the metal nodules to sell as scrap. The sand is mixed with concrete and used in paving stones.

Photo courtesy Westinghouse Plasma Corporation Eco Valley Utashinai Plasma Facility

The plasma gasification plant in Utashinai, Japan also began processing MSW in 2002. The original design of the plant factored in a capacity of around 170 tons per day of MSW and automobile shredder residue (ASR). Today the plant processes approximately 300 tons per day. The plant generates up to 7.9 megawatt-hours (MWh) of electricity, selling about 4.3 MWh back to the power grid.

Plasma gasification is also used for specialized waste handling projects. In Bordeaux, France, plants designed by Europlasma are used to melt asbestos or vitrify fly ash, particulates that are a result of using incinerators to destroy waste. Fly ash can contain hazardous materials and traditionally have been stored in specialized landfills. Using a plasma torch facility, Europlasma can convert the ash into slag, where the heavy metals and other hazardous materials are rendered inert.

Future Facilities
A demonstration facility Israel built by Environmental Energy Resources, Ltd. is scheduled to be converted into a commercial waste treatment facility. Russia has also expressed an interest in plasma gasification facilities, and currently uses plasma plants to treat low level nuclear waste in a plant outside of Moscow.

In the United States, Atlanta-based firm GeoPlasma is working with St. Lucie County in Florida to build and operate a plasma gasification plant. This plant would process all of the incoming waste for the county and begin to mine the existing landfill for waste. Once it is built, the facility will be able to process up to 1,000 tons of garbage per day and generate 67 MWh a day, with a net output of 33 MWh.

GeoPlasma has created a modular design for the plant, with two large plasma gasification chambers that will handle 500 tons per day. The modular design allows further expansion in the future – the proposed plan is to increase capacity to 3,000 tons of waste per day within a few years of operation. Engineers project that within 18 years, the existing landfill will be completely mined and treated. The electricity generated by the plant will be more than enough to power the 98,000 homes in the county.

Many areas across the nation are beginning to look into plasma gasification as a way to approach waste management. Several companies such as GeoPlasma, StarTech, Recovered Energy, Inc. and Plasco Energy Group are pioneers in bringing this technology into commercial use. Assuming the St. Lucie County project is a success, we may see more of these facilities commissioned across the nation soon.

Plasma arc technology has been used in various fields for decades. Experiments using plasma for waste management began in the 1980s. With all the benefits of plasma converters, why are we just now seeing these facilities being built? In the next section, we'll look at why it has taken decades for this technology to go from experimentation to implementation.

Plasma waste facilities have had several obstacles to overcome. First, they are a new technology. As Dr. Circeo points out, it can take many years for a new technology to go from discovery to commercial use. Sometimes this gap seems to coincide rather conveniently with the expiration of the initial patent on the idea. New technologies are also expensive; almost every plasma application requires a custom built facility. Until facility production can be standardized, costs will be high for plasma plants.

A typical landfill

Aside from the cost of custom building the plant, other costs are a major factor. Until very recently, land costs were so low that it was cheaper to use landfills than it would be to design, build and maintain a plasma waste facility. Environmental concerns often take a back seat to economic realities, and it wasn't until tipping fees (the fee you have to pay to have garbage hauled to landfills) increased and landfill space decreased that plasma plants became economically feasible. Even in an ecologically-concerned culture, some companies don't focus on the environmental aspect for their business model. GeoPlasma, for example, positions itself as a power facility that uses a renewable resource for fuel. Dr. Hillestad of GeoPlasma asserts that by focusing on GeoPlasma's ability to produce electricity for low costs makes it a viable operation.

Waste management is big business. Any major revolution in waste management faces critics and opposition from those that benefit from the status quo. As environmental pressures increase (both from the perspective of waste management and that of renewable sources for fuel), city and county governments are more willing to explore alternate strategies to handle waste.

Making Plasma Plants Profitable
Plasma waste treatment facilities are becoming more cost effective, however. Because a plasma plant can generate revenue beyond tipping fees, they can competitively price tipping fees to make it cheaper to ship garbage to the facility than a landfill. As plasma facilities are standardized, tipping fees will continue to decrease.

With the right capacity, a plasma plant can generate enough syngas to run an engine or gas turbine and generate electricity. A 1,000 ton per day plant can generate enough electricity to power the plant itself and still have plenty of power to sell back to the grid.

The hot gases can be used to generate steam, which can turn steam turbines for electricity or be used to generate heat for the plant and other facilities.

Slag can be sold in any of its forms. The rock form can be used as gravel or molded into bricks. Sand can be mixed with concrete and used in various paving and construction projects. Rock wool can be used for insulation or to contain dangerous oil spills. The St. Lucie County plant will produce 12 tons per day of vitrified slag (from 1,000 tons of waste). If the molten slag is cooled by water, metal nodules can be separated from the slag and sold for scrap. The St. Lucie facility is expected to produce about 4 tons per day.

Dr. Hillestad of GeoPlasma calls the present the "perfect storm" for plasma gasification technology. With focus increasing daily on mankind's environmental impact and the growing concern to look to renewable energy resources, plasma plants are well positioned to become an important part of how we generate power and deal with waste.

Potential uses for this technology (apart from new plasma waste treatment plants) include:

In-situ facilities
Dr. Circeo proposes the creation of a portable plasma gasification system to treat existing landfills without building an entire plant. Instead of a stationary furnace and gas treatment facility, he suggests boring holes into existing landfills, sticking a plasma torch into the hole, and capping the hole with a gas capture system. The landfill itself would act as the furnace vessel. Since plasma gasification is not a combustion process, the landfill contents would either gasify or vitrify, with no danger of fire.

Co-location with existing power plants
Another option that would significantly reduce the price of a plasma plant is the co-location of the plasma gasification chamber with a pre-existing power facility. Because the amount of gases produced by plasma plants is relatively small when compared to coal or oil-fired power plants, the power generators in plasma plants are smaller and less efficient (larger generators require much more gas). Coal and oil power plants use the same processes as plasma plants to treat gases and generate power. By connecting a line from a plasma gasification furnace to a coal or oil furnace, you eliminate the need for a plasma plant's gas treatment equipment, which make up approximately 50 percent of the overall cost of building a plasma waste treatment facility. The gases from the plasma furnace would combine with the gases in the coal or oil furnace. The relatively clean gases from the plasma furnace would help boost efficiency and reduce the amount of coal or oil needed to generate power.

Decontamination
The intense heat from plasma torches can completely neutralize the hazardous components found in diseased livestock or contaminated soil. Engineers could transport modular, portable plasma facilities to dispose of animal carcasses or treat soil on site. Incineration of such hazardous material doesn't always destroy all the contaminates, or produces ash that is also hazardous waste. Plasma gasification would destroy or render inert any harmful material.

Let's face it. Most of us have a car or truck and we enjoy driving it, especially when it's shiny and clean. For this reason, car washes have remained popular ever since two Detroit men opened the first one, the Automated Laundry, in 1914. A lot of people wash their own cars at home, but the convenience of an automated car wash and relatively low cost can be hard to beat.

A look inside a typical automated car wash. See more car wash pictures.

Car washes fall into five categories:

• Self service - An open bay (the area that the car sits inside) is typically used in these systems. Self-service systems have a pressure sprayer, and sometimes a foaming brush, that is connected to a large central pump. The sprayer has a coin-operated dial system to select the option you want, such as "soap," "rinse" and "wax." A timer shuts the water off after a certain period of time, at which point you must put in more coins if you want more water.

   

• Exterior rollover - A system that is growing in popularity, exterior rollover car washes are automated systems where you drive your car inside the bay. Once your car is in the correct position, a signal informs you to stop. At that point, the car-wash equipment moves over your car on a track, performing a specific function, such as applying soap or rinsing, with each pass. Exterior rollover systems are very common at gas stations, where the price is often discounted in conjunction with buying a tank of gas.

   

• Exterior only - This automated system is popular in the northeastern part of the United States, but can be found all over the world. You drive your car into the entrance of a long, tunnel-like bay. The front tire, usually on the driver's side, is positioned on a special conveyor belt, and you put the car in neutral. The conveyor belt guides the car through the bay, where the car goes past several pieces of equipment, each with a specific purpose.

   

• Full service - A modification of the exterior-only system, full service uses the same conveyor-belt-based automated system. The difference is that the interior is manually cleaned by attendants, and some exterior services, such as hand-drying and wheel-cleaning, are available.

   

• Detail shop - A detail shop may hand wash or use an automated system to wash the car. Then, attendants completely clean and polish the car, normally applying wax and using a tool called a buffer to remove the wax and polish the car. Detail shops are often able to remove dull paint and small scratches, steam clean carpets and seats, brighten chrome, remove tar and perform a variety of other services.

In this article, we will focus on the conveyor-driven systems used in exterior-only and full-service systems. You will learn about each step of the process and see the machinery that makes it happen. So sit back, make sure that your windows are closed and that your antenna is down. Let's enter the tunnel.

Drive In

Car washes are normally either touchless or cloth friction wash. A touchless car wash relies on high-powered jets of water and strong detergents to clean the car. Only the water and cleaning solutions actually come in physical contact with the car.

Cloth friction wash systems use soft cloth that is moved around against the surface of the car. The system that we will discuss uses cloth friction wash technology, but quite a few of the same components are used in touchless car washes.

First, the car is placed on the conveyor track. At the beginning of the conveyor is a device called a correlator. This is simply a series of wheels or rollers that allow the wheel of the car to slide sideways until it is aligned with the conveyor.

The correlator in this system is a set of long rollers.

The car is turned off and placed in neutral. Most conveyor systems have small rollers that pop up behind the wheel once it is on the conveyor. The roller pushes the wheel forward, causing the car to roll along through the tunnel, which is the term used to describe the long bay used for exterior-only and full-service systems. There are two standard types of conveyor systems:

• Front-wheel pull (FWP) - Engages the front left wheel
• Rear-wheel push (RWP) - Engages the rear left wheel

This car wash uses RWP to pull the car along the conveyor system.

Once the car enters the tunnel, it passes through an infrared beam between two sensors, called eyes.

The eye on one side emits infrared light that is picked up by the eye on the other side.

As soon as the beam is interrupted, the eyes send a signal to the digital control system (DCS), the computer that runs the automated portion of the car wash. By measuring the amount of time that the signal is interrupted, the DCS determines the length of the vehicle and adjusts the system accordingly

Soap Up

Immediately after the eyes, most car washes have a pre-soak. This is an arch that contains several small nozzles that spray a special solution all over the car. This solution does a couple of things:

• Wets the car down before the application of any detergents
• Contains chemicals that begin loosening the dirt on the car

A lot of car washes also have a set of nozzles arranged near the ground that are called tire applicators. These nozzles spray the tires with a solution designed specifically for removing brake dust and brightening the black rubber of the tire.

In this photo, you can see the tire applicators, the mitter curtain and part of the pre-soak arch.

In this car wash, the car then passes through a mitter curtain. This is a series of long, soft strips of cloth that hang from a frame near the top of the tunnel. The frame is connected to a motorized shaft that moves the frame up and down in a circular pattern. This makes the cloth strips rub back and forth across the horizontal surfaces of the car.

The mitter curtain cleans the hood, roof and trunk of the car by swishing back and forth over the surface.

The next item in our car wash is the foam applicator. The foam applicator applies a detergent to the car that becomes a deep-cleaning foam on contact. The nozzles on the foam applicator, as well as most other spray systems in a car wash, can be adjusted to change the angle of the spray and the size of the opening. The foam is created by mixing a chemical cleaner, which varies between car washes, with water and air. There are usually separate adjustment controls for determining the exact mix of the three components. The chemical typically contains some coloring agent to make the foam more eye-pleasing and obvious.

You can see the foam created by detergent from the foam applicator.

Scrub

Scrubbers are large vertical cylinders with hundreds of small cloth strips attached to them. The scrubbers rotate rapidly, anywhere from 100 to 500 rpm, spinning the cloth strips until they are perpendicular to the cylinder. Although the cloth strips are quite soft, it would feel like a whip if you got hit by them. Scrubbers normally have hydraulic motors that spin them. There is at least one scrubber on each side, and there may be two or more. As the car moves past the scrubbers, the cloth strips brush along the vertical surfaces of the car.

Most car washes have multiple pairs of scrubbers.

Some car washes also have wrap-around washers. These are scrubbers on short booms that can move around to the front and rear of the vehicle, scrubbing those vertical surfaces as well. Like most of the mechanical equipment in the car wash, the washers are run by a combination of electric motors and hydraulics. Normally, a single, large hydraulic power unit is connected to all of the various hydraulic pumps throughout the car wash.

Wrap-around washers clean the front and back of the car.

The cloth used in the scrubbers is very soft and regularly cleaned to ensure that there is nothing caught up in them that could scratch the cars. They are replaced once they become worn or too soiled to clean effectively.

The scrubbers remove the dirt that the foam and pre-soak has loosened up.

Blast

The high-pressure washer is a system of rotating water jets that spray concentrated streams of water onto the car. The nozzles of each water jet are typically arranged like a pinwheel, with each nozzle angled slightly away from the center.

The nozzles of the water jet are reminiscent of a pinwheel.

The force of the water shooting from the nozzles causes the water jet to spin rapidly. This means that the stream of water moves in a circular pattern as it hits the car. The strength of the stream and the circular motion combine to provide a powerful scrubbing action on the surface of the car. The force of the water is incredible, with some systems rated at 1,000 pounds per square inch (psi), enough to easily knock a person off his or her feet!

The powerful water jets remove most of the detergent and grime from the car.

High-pressure systems use a lot of water -- perhaps 300 to 400 gallons (1,100 to 1,500 liters) per car. In order to provide so much water in a rapid manner, a car wash usually has a special pressure tank nearby that holds the water for this specific system. In most systems, almost all of the water is recaptured and recycled back to the pressure tank after each use.

The pressure tank for a high-pressure washer

A lot of car washes, particularly those in areas where winter means lots of snow, have a device called an undercarriage wash applicator. This system is located at ground level and has several nozzles pointed upward to wash dirt, mud and salt from the bottom of the car.

Rinse

Next, the car goes through a rinse arch. This is a series of nozzles arranged on an arch that use clean water to remove whatever residue is left after the high-pressure washer, scrubbers and mitter curtain have done their respective jobs.

The rinse arch removes almost all of the residue left from the cleaning systems.

In an average car wash, there are multiple rinse arches, usually after each major cleaning station. A typical car wash may have the following stations:

1. Pre-soak
2. Mitter curtain
3. Rinse arch
4. Foam applicator
5. Scrubbers
6. High-pressure washer
7. Undercarriage wash applicator
8. Rinse arch
9. Wax applicator
10. Mitter curtain
11. Scrubbers
12. Rinse arch
13. Dryer

As you can see, the example above has three rinse arches. It also has two mitter curtains and two sets of scrubbers, which is also common in most installations. In fact, some car washes have even more of each type of station!

Most car washes have two or more mitter curtains along the tunnel.

The last rinse arch in the tunnel, aptly called the final rinse, should always use clean, non-recycled water to ensure that all residue is removed from the surface of the car.

Going through the final rinse

The majority of car washes also provide some type of protectant that can be applied to the car.

Wax

A standard feature of the car wash is the wax arch. The wax that is used in a car wash, which forms a water-resistant coating, is quite different from the wax you would apply by hand. One of the key differences is that car-wash wax is formulated to work on glass, chrome and rubber, as well as the painted plastic and metal surfaces of the car. Also, it leaves a clear, thin film that does not have to be polished first. However, car-wash wax does not provide the same level of protection, nor help to remove or cover up tiny scratches, as standard wax does.

This wax arch has a triple-foam applicator. Each wax protectant is a different color of foam.

The wax arch uses one of two methods to apply wax. The first type of wax arch uses a system of foam applicators, the most common being a triple-foam applicator, to apply a foam wax.

The wax foam is applied to the car in a heavy coating.

The second type uses nozzles, similar to those of the rinse arch, to apply a liquid wax. In this case, the next step is usually to go through a rinse arch. But when wax foam has been applied, the car usually goes through another set of scrubbers and another mitter curtain before going through a rinse arch.

Touch Up

As the car comes out of the tunnel, it is pushed off of the conveyor track.

The end of the line

In an exterior-only system, you most likely remain in the car. When it comes out of the tunnel, you put it in park, start the engine and leave. In a full-service car wash, an attendant drives the car over to the finishing station. Here, attendants clean the interior of the car, removing trash and vacuuming. They usually clean the windows, wipe down the dashboard and doors, add some air freshener and hand-dry the exterior. They may also clean and polish the wheels and polish any chrome, depending on the service options available.

Attendants at Bunkey's Car Wash hand-dry a car.

The vacuum system at a car wash is a lot different from your typical home vacuum. It normally has a large central vacuum with multiple hoses connected to it. The hoses are usually either stretched overhead to each vacuuming station or buried underground.

This vacuum is about 6 feet (1.8 m) tall and over 2 feet (0.6 m) in diameter.

The air pump on this vacuum is very powerful, which is necessary to support all the hoses and handle the distance that each hose must cover.

The Controls

All of the equipment in an automated car wash requires a heavy-duty power source. Each station has its own fuse-protected circuit. Most car washes are designed so that the car wash can continue to operate even if one of the stations completely fails.

These boxes contain the fuses for each station in this car wash.

The digital control system (DCS) is the brains of the car wash.

The digital control system

From the moment that the eye tells the DCS that a car has entered the system, the DCS controls every aspect of the car wash. It knows exactly where the car is at all times and turns on the appropriate stations as they are needed.

The Operation

A typical car wash uses less than half the amount of water you would use to wash your car at home.

An interesting fact is that most car washes use substantially less water to wash your car than you would use if you were washing it yourself at home. For example, one report says that washing your car at home typically uses between 80 and 140 gallons (304 and 532 L) of water, while a car-wash facility (without a high-pressure wash) averages less than 45 gallons (171 L) per car. In addition, all of the chemicals and detergents are washed into the sewer when you wash your car at home, but a car-wash facility must dispose of the waste in accordance with local regulations. This means that washing your car at a car-wash facility is usually better for the environment.

This pit captures the water that runs off the cars and recycles it.

To cut down on the amount of water used, a lot of car washes recycle water. The recycled water is normally used in the early rinses and to mix with the detergents. It may also be used in the high-pressure washer. It should never be used in the final rinse.

There you have it! Next time you pull up to the car wash, you will know just what each machine is doing. Be sure to check out the links on the next page for additional information.