Reduce Rewash Through Proper Sorting, Formulas, Stain Treatment (Part 1 of 5)

What measures can a laundry manager take to reduce the percentage of stain rewash found in their operation? How can they differentiate stains from soils? What do you consider an acceptable reject/rewash rate to be?TEXTILE/UNIFORM RENTAL: Roger Bourdeau is chief engineer for the Angelica Textile Services plant in Pawtucket, R.I. He's worked 22 years in the plant, having started as a production associate in 1983. He's completed many training programs and has a Rhode Island Stationary Operating Engineer license.
You can start by tightening up your plant!
Often the equipment is a bigger factor in many plants than it should be. Dare I say, a preventive-maintenance program is only good if you actually do the stuff. Leaking seals, poor water flows and poor incoming water quality all take a serious toll on your rewash percentage.
If you have a much easier time keeping water on your floor than in your washers, consider replacing them with something newer, or at least better. This will not only have an immediate effect on your rewash, the return on investment on more efficient equipment is frequently shorter than you think.
Those issues not withstanding, the first thing you should do is conduct a stain audit, if your chemist has not already done so. Start by making up a 1% bleach solution (or similar-strength peroxide if that is your sanitizer/brightener) and soak a few stained items in it for 30 minutes or so.
If the stained area lightens or disappears, the stain is oxidizable and can be removed in a rewash. Otherwise, it’s probably a legitimate stain.
Now you know where to focus your attention. What caused this stain? Was it linen abuse (the guy who mopped up an ink spill with your nice white towel), a high iron or rust content in your water (an oxalic acid wash may remove it), rub-off (linen hanging out of carts) or something else?
Different personnel within your organization will address different types of stains. Someone in customer service should speak to the ink guy, engineering should check on the rusty water and perhaps a route man can look into the rub-off issue. All this will help establish your real rewash percentage.
Everyone knows how to take their rewash pounds and divide them by their total pounds processed (clean, dry weight) to get their rewash, right? But what’s a good percentage? Most industry folks would probably say 3-6% is good. Healthcare and hospitality may be at the lower end; uniform and restaurant perhaps on the higher side.
Work together with your chemist toward the goal of removing all oxidizable stains in the first wash. This may seemingly cost more at the outset but will save energy, utilities, overtime, equipment wear and tear, etc.CHEMICALS SUPPLY: Tom Storm is vice president of technical development for WSI, Cincinnati, a national company specializing in providing washroom and wastewater chemicals plus accompanying service to commercial laundries. A chemical engineer, Tom has 38 years of laundry industry experience.
There can be numerous causes of a higher-than-acceptable stain-rewash percentage, including overloading, mechanical room problems (e.g., hot-water and steam deficiencies), washer malfunctions and customer abuse. However, the three areas where effort will most often lead to the lowering of rewash percentages are soil sorting, wash formulas and an appropriate stain-treatment procedure.
The combining of regular-soiled items with heavy-soiled items and washing on a regular-soil wash formula will produce a higher-than-acceptable percentage. To reduce this, the entire load must be washed on a heavy-soil formula or, preferably, the items should be sorted by soil level and washed on the appropriate wash formula.
Two areas of a wash formula that can cause higher stain-rewash percentages are the soil-removal steps (e.g., break, carryover, second suds) and the bleach step.
For the soil-removal steps, check the temperatures, times, water levels and product concentrations. For the bleach step, check the soil carryover, temperature, pH, bleach concentration, time and the water level.
A common problem that causes high stain-rewash percentages is the recycling of stains, also known as the “merry-go-round” effect. This occurs when stains that are not removed in the stain-treatment process are allowed to remain in inventory and build up over time.
The way to eliminate this buildup is to first ensure that an adequate stain-treatment procedure is being followed, and then remove all items from inventory that still contain stains after treatment.
A good stain-treatment procedure begins with proper stain sorting. Misfolds, tears and ironer rejects should be separated from stained items and simply reprocessed using the normal wash formula.
Stains should be sorted into iron stains, mildew and others. Each of these three categories should be treated with the appropriate procedure (discuss them with your chemical supplier). Items that are still stained should then be processed on a reclaim formula. Any items not reclaimed should be removed from inventory. Never recycle stained items back into a normal washload.
In the commercial laundry industry, soil is typically defined as materials that can be removed in the flush, break, carryover and additional suds operations, and stains are any foreign material left.
This definition has some pitfalls. There may be some soils that can be removed in the soil-removal operations if excess product, temperature and time is applied, but it may not be economically effective to do so.
I would suggest classifying everything left over after the last suds operation of a properly designed wash formula as stains. If these “stains” are too numerous at the end of the wash process, the procedures recommended above to reduce the stain-rewash level will address the problem.
An acceptable stain-reject level is dependent on many things. First of all, the items rejected will depend on the classification. For example, visible stains on bar mops and shop towels are acceptable, while any stains on white napkins are not.
Over the last 10 years, as labor and utility costs have increased, and newer wash chemistries have evolved, the stain-reject level considered acceptable has dropped.
I used to say that a 0% stain-reject rate is too low, and above 10% is too high. In today’s environment, stain-reject rates can be kept below 8%.
I like to divide stain-reject rates into two additional levels: 0-4% and 4-8%. Light to medium soil should be in the 0-4% range, while it’s satisfactory for heavier soil classifications to be in the higher range.
For example, tablecloths, sheets and bath towels should be in the lower range, while it would be acceptable for napkins, pillowcases and washcloths to be in the higher range.


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