Cold water wash and ozone require specific chemistries that differ from traditional wash cycles Ozone is a very difficult for some people to accept when they have done something for 20+ years a certain way. Change is difficult. Why do we care so much about having the same amount of detergent, builder, bleach, and sour each and every time? We will cover this in depth. Ozone Cycle Guidelines
Heat kills ozone –for every 5 ⁰ F you raise the temperature of 70 ⁰ F, you destroy 20% of the ozone level. pH levels must be correct! Regulating pH will effect wash quality if done incorrectly. Ozone is used to as a catalyst to activate the soap/detergent and relax the fibers and to oxidize soils and microorganisms. It does NOT replace good wash chemistry. The system is set to generate the maximum amount of ozone without creating unpleasant levels of ozone in the room. Ozone Chemistry
Flush – cold high level (flush or break) – 2 to 4 min. This is designed to allow the ozone levels to build and, in turn, break up solids, and rinse out bloods. In extremely heavy soiled loads a small amount of builder and detergent can be used to aid in flushing. A very important step for heavy soiled loads. Flush Step
Suds – cold low level wash – 6 to 9 min. pH levels must be correct. Wash water pH should measure 8.5 to 10.5. When using a non- built detergent we can “ adjust the pH ” otherwise in a built detergent we only can adjust the amount of product. In correctional and healthcare facilities the stains are mostly bleachable. We use a slightly lower pH in this instance. Non bleachable stains, such as grease, will require a high pH. We adjust the amount of product according to load. Too much detergent. Suds Step
If we have used a step that requires a higher pH we may have to introduce what we call a “ cheater rinse ” – a rinse between the suds step and the bleach step. You would raise the existing water level from low to high to dilute the product. We might need it as well if the soap doesn ’ t rinse well in cold water such as L2000 product. Solarbrite works great. The purpose is to bring the pH levels back down so we can bleach properly. If the cheater rinse doesn’t work you might have use a immediate extract. In cases of a double wash it is almost mandatory. We only use it as a last resort and rarely. Cheater Step
This is the most important step! The bleach step maybe included with the Suds step with lightly soiled linen. We like to bleach at 105 ⁰ for 6-9 minutes, low to medium fill level. We put enough bleach into the washer to achieve 100 to 120 ppm of bleach. The pH is critical for successful bleaching. We need a pH of 8 to 9. Bleach should be under 50 PPM measured at the drain at the end of the step. If you have left over bleach when a sour is injected, there will be a reaction that makes a toxic gas. It will also degrade linen fibers in as little as one load. Bleach Step
Tools for pH burn adjustment: A higher pH will slow bleach burn A lower pH will quicken bleach burn AND Low Temperature will cause a slow burn Higher Temperature will cause a quicker burn 9.5 pH needs roughly 110 ⁰F to burn up 120 PPM 9.0 pH needs roughly 100⁰F to burn up 120 PPM 8.5 pH needs roughly 90⁰F to burn up 120 PPM Bleach Step - cont.
Cold High level Rinse – 2 minutes Rinses are designed to bring the active alkali down, and to remove soil and suds. Cold water is always used in a rinse step. The number of rinses typically needed in a ozone formula is two, because of the reduce amount of chemicals needed during the wash step. Sometimes only one rinse is needed if the active alkalinity is below 30 PPM. Rinses
Cold low level sour -2 to 4 minutes, to be used as required Sour is used in normal wash cycle to drop the pH to just below the neutral at the end of the wash cycle. When using ozone, pH changes are much less severe than a traditional hot water wash. When large pH changes do occur, the chemical reaction leaves behind a crystal-like residue. This residue makes the linen feel rough and wears out the linen faster. Normally this is covered with the use of a softener, which is used to lubricate the linen and make it feel softer. Sour / Softener
High Speed Extract Time will vary with linen type and washer speed Extract is used to remove water from linen Extract
Washer loading and water quality will effect wash quality Overloading prevents the linen from moving in the washer. This lessens the wash action in the washer. It also prevents proper flushing and rinsing. Proper sorting of linen into proper classifications is important in delivering the highest quality linen without using excessive amounts energy, water, time, and chemicals Wash Room Basics
Bleach Bleaching agents are used to whiten stains that can ’ t be washed out. The most popular is chlorine bleach, which is used in most laundries in the U.S. There are other bleaching agents such as oxygen bleach (hydrogen-peroxide). I know of at least three different types of oxygen bleach currently in the market. The bleach should go from 100 to 150 PPM at the beginning of the step to less than 50 PPM at the end of the bleach step as the washer drains. This is a controlled burn. If the bleach does not burn off during these 6 or 9 minutes you will get very little bleaching effect. If the bleach burns off too fast you will burn up the linen fibers, this will be linen that just tears when pulled. Wash Room Chemistry
Machine malfunctions that effect wash quality: Drain Valves leaking by letting out water and then the machine refills. It dilutes the crafted wash chemistry and then the formula won ’ t work Water valves leaking by causing excess amounts of water and again diluting the wash “ liquor ”. Chemical pump squeeze tubes will need to be replaced every three to six months. As the tubes where out they will pump less chemical thereby causing issues. Already discussed under/over loading issues. Not running the correct formulas and/or times. Stains
Bleachable Stains Bleachable stains usually arise from a lack of proper bleach burn. Test these stains by soaking in 50% bleach and water solution for 5 minutes. If the stains disappear in this solution, then the cycle is not bleaching properly. Remember – a properly designed wash formula WILL get 3% to 5% rewash. This is normal and anticipated. Stains - cont.
Iron Stains Iron comes from incoming (raw) water or medications in use within the facility. If you think you have iron in the linen, put some hot water in a cup mixed with a iron remover (oxalic acid). Soak the linen in this solution for a few minutes (1o to 15 minutes) and then rinse. The iron should rinse out Iron stains can be reduced by using LESS bleach and more rust-removing sour. Oxidizers detach the iron from water; making the linen a filter, resulting in stains. If lowering the bleach does not solve the iron issue, then the facility needs a water softener. If the problem only shows up occasionally, having some iron reclaim packets is a good idea. Stains - cont.
Re-deposition Stains are lack of surfactants If you have lack of detergent in the wash, the dirt will be removed and will re-deposit back on the linen. This will gray linen significantly. It will be similar to bleachable stains, but covers large portions of the linen. The solution will be to increase the amount of soap being injected during the wash step – provided it is not in excess of a normal amount. Stains - cont.
Bright yellow blotches are unrinsed chemicals (alkalinity) burnt into the linen when drying. It is caused by inadequate rinsing, too much soap, faulty equipment, employees advancing the cycles and the like Bleach and iron remover cannot remove these stains. Usually, if you get the cycle corrected, then these blotches will come out over the course of several washes. In severe cases a reclaim cycle will become necessary. Soap Stains
Using ozone in the wash process is NOT a magic bullet. It requires the same discipline as a hot water wash. Ozone typically requires 25% to 30% less chemicals. If your pumps are setup for ozone and you use a hot water wash you will experience wash quality problems. If you change chemicals, the amount required most likely will change as well. If the viscosity of the product changes the amount of product being pumped will be effected. If the pH of the chemicals change – again it could severely impact wash quality.. Equipment malfunctions can impact wash quality. In Review