Everyone loves the concept of shredding treated medical waste and the perceived advantages. However, very few who have actually undertaken this option have been satisfied with the results. To better understand the realities of shredding, this report will outline some key areas that may not be covered by other suppliers of shredding systems. As the pioneer and world leader in the medical waste treatment technology industry, we have installed more on-site shredding systems than any other company. From our extensive experience and continued R & D efforts, we feel an obligation to dispel some of the myths associated with shredding.
Our responsibility is to fully educate all of our customers prior to selling them any type of equipment, including shredders. Unfortunately other shredder vendors or technologies that rely on shredding may not provide all of the facts. The following data and photos were gathered from various shredder and treatment technology manufacturers, including San-I-Pak, Inc. Below are the most common questions that people often ask regarding shredding.
Is shredded (unrecognizable) waste safer than recognizable waste?
Many people will be surprised to find out that shredding provides more opportunity for injury because all of the waste, including sharps, is not contained in bags. In addition, there are no visual indicators to verify the waste was in fact treated. People can shortcut the treatment process by simply shredding the raw medical waste and dispose of it without any treatment. This provides a great opportunity for exposure to the health care workers, waste professionals and the public. By keeping the treated waste recognizable, with proof of sterilization (thermal strip indicator), it is safely encapsulated in a polypropylene bag/liner. Be aware that shredded material is full of loose sharp items that are potentially hazardous because of being non-contained thereby increasing the risk of personal injury.
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| Treated Waste From A Two Shredder | Treated Waste From A Single Shredder |
Waste Prior to Treatment (left) & Waste After (right)Should the shredder be an integral component of the treatment system?If a facility is committed to shredding treated waste, it is imperative to investigate technologies that do not depend on shredding. More often than not, hospitals that utilize a shredding technology eventually abandon the use of the shredder(s). Reasons vary from exorbitant maintenance costs to landfill preference for recognizability in order to verify treatment. For the sake of safety, it is best to have the shredders designed so that the treated waste is automatically introduced to the system (i.e., conveyer, auger, etc.). With any treatment system, automation is paramount to reducing handling exposure, likewise, the system design should easily allow for shredding as an option, not an obligation.
Do disposal sites prefer shredded or recognizable treated waste?In accepting treated medical waste, two issues typically arise with disposal sites (landfills) regarding shredding. The first issue is verifying that the material is truly treated in a manner that is approved by the proper state and local regulatory bodies. Shredded material offers no visual verification of sterilization. The concern is that waste has bypassed the treatment process and may still be hazardous. The second concern is that shredded material can easily be carried and scattered by wind at the disposal site, thus being very messy. Note that treated recognizable waste is encapsulated in a polypropylene liner or bag. Each of these liners and bags has a special thermal strip that changes color after treatment. There are two means to visually verify treatment: the shrunken appearance of the waste from the treatment process and the thermal strip indicator. For many professionals in the waste industry, there is often a demand to be able to visually identify the waste as being treated.
Disposal site personnel are integral partners in the waste disposal process and are dependant upon hospitals to safeguard them from exposure. Since the shredded waste is often blown about by wind, it sometimes makes contact with the public. Needless to say, this can create a justified concern regarding facility liability.
Does shredding protect the security of the hospital and patient?There is a false sense of security associated with protecting hospital and patient data with shredding. Security is greatly compromised when pieces of shredded material containing confidential data are easily scattered at the hospital, en route to the disposal site and finally at the landfill. Contrary to popular belief, the waste will not resemble what is discharged from a paper shredder. Pieces can range from 2cm x 4cm to even larger with a single pass shredder. Additional equipment (hammermill) can be added to further reduce the size of the shredded waste, however, such equipment is extremely expensive and the high-speed operation of the teeth makes such equipment very vulnerable to damage when a non-shreddable item is introduced to the system.
What kind of maintenance can be expected from shredding treated medical waste?Aside from the high capital cost required to purchase a shredding system, shredders also require a significant financial obligation for maintenance. Many shredder suppliers and manufacturers will lay claim to having "trouble-free" or "maintenance-free" shredders. However, as a company that has manufactured more medical waste shredders than any other company, we at San-I-Pak know the liabilities posed by shredding. Medical waste is sometimes comprised of materials that are very damaging to shredders (i.e., titanium hip pins, bone reamers, etc.). In addition, other materials such as linen and bedding often will wrap around the shredder and cause the system to lockup requiring constant vigilance. Annual maintenance cost usually equals 18 to 25% of original purchase price.
Some treatment technologies also require or highly recommend a dedicated full time employee (FTE) to probe through the treated waste prior to shredding to retrieve non-shreddable objects. The purpose is to minimize maintenance and downtime. Although this may help avoid any unscheduled maintenance, it greatly increases the cost of processing on-site due to the (FTE).
FTE Searching For Non-shreddable objects
Even the world’s largest medical waste transporter, Stericycle, acknowledges the concerns of shredding treated medical waste. In a June 21, 2001 letter to the Department of Health and Hospitals in Louisiana, Stericycle writes:
"Stericycle (and BFI Medical prior to their acquisition by Stericycle) have years of experience shredding waste. Shredders were initially installed in BFI facilities in Washington DC, Sheridan, NY, Denver, CO, Toledo, OH, Vancouver, B.C., Lake City, GA, St. Paul, MN, Beaver Dam, KY, Carolina, Puerto Rico, Reserve, LA (MEDX site now closed) and Conroe, TX. All shredders were subsequently removed from service from all facilities with the exception of Conroe, TX.. The Conroe facility is currently applying for a permit modification for removal of that unit as well. BFI Medical and Stericycle have found that post-shredding of medical waste adds no value to our service. Medical waste is a very difficult waste stream to shred via size reduction equipment after autoclaving because of the melted mass containing a high quantity of glass and metal. Jams occur frequently in single stage low speed-high torque units, and damage occurs frequently in two-stage units, which include a high-speed granulator second stage. These jams with result down time effect customer service due to waste transfer requirements to back-up facilities.
The size reduction efficiency of these units is questionable as well due to the issue of what constitutes "unrecognizable". Due to the high throughput requirements, there exists a balance between throughput, maintenance cost and shred size, which is used to find the optimum shredder knife combination. The result is a knife size and spacing that can result in whole syringes passing through the shredder untouched. Only by adding a second stage granulator can adequate size reduction be assured with resultant high maintenance and downtime.
Unless segregation occurs with the utmost discipline at the point of generation, there will inevitably be problems. We have countered many of the issues associated with non-shreddable items with our advanced electronics, but this comes at a financial price for the technology. General shredder maintenance can range from $15,000 a year and up. A hospital in Sacramento, California using a non-San-I-Pak technology, which relies on shredding, has been tracking their annual cost of maintenance to be $80,000-$85,000 per year.
Since San-I-Pak designs and manufactures the electronics for shredding systems, it is important to note how quickly our systems are able to respond to non-shreddable objects, less than seven milliseconds, to stop the shredder when such destructive material enters the system. Other systems average a 100-200 millisecond response time. This can easily equate to significant damage and stress put on the teeth, motor, and shredder casing at 1740 RPM drive motor speed. Note: Granulators and pasticalizers are considered unusual for medical waste by San-I-Pak because of the frequent extensive damage and resulting cost caused by their high operational speeds.
What concerns are there regarding noise and odor while shredding?When shredding hot, 200oF (93oC)+, waste, odors are immediately released when the waste load is broken into. High torque, low speed shredders are generally quiet to operate, around 60 decibels. However, high speed hammermills and granulators are very loud, around 100 decibels, and can be piercing to the ears.
Do shredders help reduce volume?When trying to achieve volume reduction of the treated waste, shredding may be the least effective means of accomplishing this. Shredded material has a spongy effect when being compacted. After the compactor ram has retracted, the shredded material springs back. Please see the following photo of the shredded waste spilling out of the compactor.
Compacting loose shredded waste
The San-I-Pak sterilization process alone achieves 40% volume reduction of the waste. By utilizing San-I-Pak’s high-density compactor (6:1 compaction ratio), there is an 80% volume reduction of the treated compacted waste. Shredding serves no additional benefit since Department of Transportation regulations restrict the waste load to ten (10) tons. This can easily be achieved with a high-density compactor alone.
Compacting encapsulated waste.
