Green Cleaning Whitepaper

Ozone is rapidly becoming the ‘oxidant of choice’ in commercial laundry facilities. Many benefits await organizations that adopt this new ‘green’ approach to the age-old chore of washing linens.

Make the switch today! There are many reasons to go from toxic chemicals and hot water to Super-Clean, Super-Green ozone and cold water. These include the following:

A drastic reduction in energy cost by the elimination of hot water(ozone cleansing only works in cold water)

A substantial reduction in the amount of water used
(due to the elimination of fill/drain steps from the wash formulas used to add chemicals and then to rinse them out)

A necessary improvement in the sanitation of your linen

A significant increase in the life of your valuable linen and a sizable decrease in your linen replacement costs

A welcome and valuable improvement in the Guest Experience for everyone using the cleaner linen

These are but a few of the compelling reasons that commercial laundry facilities for hotels, resorts, hospitals and nursing homes are moving to this new technology.

Improving Ozone Wash Effectiveness

Our exhausting research on the process has proven that consistent and reliable delivery of dissolved ozone concentrations of 1.0ppm and higher to the wash wheel produces the most consistently superior finished product. Several factors must be addressed to maintain a consistent amount of dissolved ozone, including:

Contact time between the ozone gas and the water

Pressure exerted upon the ozone gas as it comes in contact with the water

Thorough mixing of the ozone and the water

Water temperature

Bubble size and concentration of ozone inside the gas bubbles

pH of the wash liquor

Containment of the ozone gas entirely within the system

Because water conditions tend to vary with location, an understanding of each factor’s interaction with the others is imperative in formulating an approach that maximizes the efficiency of the system / location relationship. Therefore we use a proprietary formula in calculating the ratio of variables to apply for each installation to assure quality and reliability.

Choose the Right Ozone Technology

Once you have made the decision to investigate the use of ozone in your laundry, you should become familiar with the technology used to generate the gas and get it dissolved into the water. Several different processes for generating ozone are available on the market today — each system approaches the process differently.

The key thing to remember when specifying a system is that for the ozone to work, it must be dissolved in the water. Only ozone thoroughly dissolved in water is capable of oxidizing contaminates (dirt, oils, odors, bacteria, viruses, etc.) found on the submerged fabrics. The higher the concentration of dissolved ozone in the water, the better it is able to clean the fabrics thoroughly and completely.

Contact Tank and Superior Mass Transfer Technology: Recommended

To consistently and reliably deliver a superior finished product with an ozone laundry system, all of the factors outlined above and others we prefer not to reveal here must be carefully addressed in the construction and installation of each system. Successful ozone laundry systems are completely ‘non-invasive’ to your washing equipment. You want creation, mixing, storage and delivery of dissolved ozone to occur independently of your washers. Our patented Contact Tank system described here has many advantages including keeping the ozone mixing process independent of existing equipment.

Variables such as age and condition or variations of makes and models of your existing washing equipment (and their various components, such as water pumps) do not affect the delivery of proper ozone concentrations to the wash wheel. It is imperative to use a mass transfer (ozone dissolving) technology that has been designed to address each factor of proper and efficient transfer of gaseous ozone to a liquid phase. Our proprietary method employs patented contact tanks that insure all factors are addressed: bubble size, ozone concentration, proper mixing, contact time, temperature, pressure, pH and total gas containment within the system. Ozone lasts for only a short while after it has been created in an ozone generator so you must do something with it immediately after it is created if you want it to work for you.

Bubbling/Sparging Technology: Not Recommended

Bubbling technology is the simplest method for adding ozone to water. Ozone gas is simply injected directly into the wash wheel. However, with this method there is no precise way to control the amount of dissolved ozone in the wash mix. There is also no way to measure the concentration of dissolved ozone. Several factors work against this approach. In the bubbling method, the wash drum is first filled with water, then ozone gas is pumped directly into the wash drum during the cleaning cycle. This approach does not provide enough contact time for the ozone to dissolve — the contact time is limited to the time it takes the bubbles of ozone to travel from the bottom of the sump, or wherever the fizzy-stone is located, to the top of the water column. Another problem is that since the wash drum is not pressurized, your mass transfer is severely limited. You just don’t get the gas into solution. Some minute quantities of gas will be dissolved in the water where contact is made through agitation of the washer, however most of the ozone gas will be wasted without cleaning the laundry and will be released into the washer where it will greatly increase the possibility of worker exposure to ozone gas. Therefore, we recommend customers avoid using a bubbling technology.

Side-Arm Injection: Not Recommended

Side-arm injection systems use a pump and a filter located on the floor behind each washer. Water is pumped from the washer, through this contraption where more ozone is bubbled into the water stream and sent back into the washer. This is a continuous process for the duration of the wash cycle. Even though this is a step up from bubbling ozone into the washer, it presents other problems.

First, the contact time of the water and the ozone gas is inadequate because of the short amount of time the water travels in the loop. If enough time is not given for the ozone to dissolve into the water, it will simply off-gas into the surrounding environment. Second, it is difficult to estimate how much pressure will be present to aid in dissolving the ozone into the water while the water is traveling through the loop, as this varies widely depending upon the size of the water recirculation pump. Also in this scenario there is no process at work to properly mix the two elements after they are introduced to each other to make sure that the water and gas are not traveling through the loop in two separate streams. Another drawback is that you have an additional pump and filter and pipes associated with each washer that adds daily maintenance headaches and a shock hazard because of the electrical equipment sitting on the wet floor behind every washer. Because of the limited contact time, mixing inefficiency, and the possible absence of sufficient pressure, the dissolved ozone levels are not consistent. Therefore, we do not recommend the side-arm injection approach for our customers.

Direct Injection: Not Recommended

Direct injection is similar to the closed-loop side-arm injection system in that it simply injects ozone gas through a venturi into the water right before it is dumped into the washing machine. Where these two methods differ is that direct injection places the injection point of the ozone gas on the supply line of the washer. This means that a venturi is installed on the city water supply line to the washer. The venturi feeds ozone gas through the supply line which in turn goes into to the washer drum. This approach suffers from the same performance shortfalls as Side-Arm Injection. Even though this system can utilize the pressure provided from the city water source, the actual levels of ozone dissolved into the water are extremely low due to the lack of adequate contact time. Any chemicals present in the city water, such as residual chlorine, will also act to deplete the ozone levels further. These factors, in conjunction with the absence of a mechanism to promote mixing of the water and ozone after passing the venturi, add up to lower concentration levels and less cleaning efficiency. Therefore we do not recommend the Direct Injection approach for our customers.

About Water Energy

Water Energy was established in 1996 to promote the conservation of scarce natural resources. We deliver practical solutions to solve today’s problems, utilizing the latest high technology solutions in the fields of physics, chemistry, bio and nano-technology. We offer products and services, as well as education designed to help industry improve the environment while saving money in the process. Our ozone water treatment systems can help businesses, such as restaurants, hotels, and hospitals save tremendous amounts of money by eliminating the need for hot water when washing laundry and linens. We invite you to join us and be part of the Water Energy revolution. Welcome aboard.