Mr. Angel Aguiar
2400 North Highway 27
Somerset, Ky 43503
Subject: Medical Waste Sterilization Efficacy Testing
of Two Bondtech Autoclave Systems
Dear Mr. Aguiar:
In accordance with your request, I have summarized the results of the medical waste
sterilization efficacy tests conducted by Koogler & Associates Environmental Services on
two Bondtech high vacuum/high pressure medical waste autoclave systems on January 26,
1994. The results of the testing were originally published in our report prepared and
certified by me as a registered Professional Engineer on February 15, 1994. The results
summarized in the following abridged report accurately summarize the results reported in
our original report. Our abridged report has been re-certified by me on this date.
The efficacy testing was conducted to demonstrate compliance with permitting
requirements established by the Florida Department of Environmental Protection. The
standards promulgated by FDEP exceed the guidelines established by the U.S.
Environmental Protection Agency.
The results of the medical wate sterilization testing demonstrated that both Bondtech
autoclave systems achieved 100 percent sterilization effectiveness using Bacillus
stearothermophilus as the biological indicator. This kill rate is in excess of log6 (in excess
of 99.9999%) and meets or exceeds all regulations and standards extablished by the U.S.
Environmental Protection Agency and U.S. state environmental agencies.
If there are any questions regarding the results of these tests, please do not hesitate to
contact me at 352-377-5822.
Very truly yours,
On January 26, 1994, Koogler & Associates Environmental Services of Gainesville,
Florida, performed biological sterilization efficacy testing on two Bondtech
high-vacuum/high-pressure medical waste autoclave systems. The efficacy test program
was required by the Florida Department of Environmental Protection prior to the
Company receiving an environmental operation permit for the two Bondtech
The purpose of the testing was to demonstrate the medical waste treatment efficacy
of both the Bondtech autoclave systems whose construction was permitted by the Florida
Department of Environmental Protection. The Florida Department of Environmental
Protection has promulgated medical waste regulations that exceed the guidelines
established by the United States Environmental Protection Agency.
The permitted medical waste treatment facility consisted of two Bondtech
high-vacuum/high-pressure autoclave systems each capable of processing over 1,500
pounds of waste per hour. The process cycles for this Bondtech installation are
controlled by programmable controllers that continously monitor and record the
temperature and pressure within each sterilizer while controlling the complete
2.0 PROCESS CYCLE
Prevacuum. The sterilization cycle in initiated by reducing the pressure to
0.06-0.16 bars (a vacuum of 25-28 inches of mercury). The prevacuum removes residual
air from the autoclave vessel and ensures thorough permeation of steam throughout
the entire medical waste load.
Pressurization. After completing prevacum, the Bondtech autoclave is
pressurized with saturated steam to 4.34 bars (50 pounds per square inch gauge).
At this pressure, the minimum operation temperature is 148Â°C (298Â°F).
Blowdown. Following the pressurization, the steam in the Bondtech autoclave is
vented through a steam condenser and the condensate safely drained to the sewer.
The generation of odors is effectively controlled by the Bondtech steam condenser
along with the post-vacuum process.
Post-Vacuum. A post-vacuum is applied to the vessel prior to the end of the cycle.
The post-vacuum ensures that no steam remains in the autoclave vessel and
therefore minimizes the occupational exposure of operating personell. Removing
the steam during the post-vacuum (drying) process also prevents the waste from
being wetted by condensed residual steam thus eliminating the additional weight
of moisture to the waste.
The total cycle time during the efficacy test program averaged 30.6 minutes. The
total load-to-load process cycle time averaged about 40 minutes. The waste loads
to each Bondtech autoclave ranged in weight from 379-665 kilograms per cycle
(835-1465 pounds per cycle). The average hourly waste processing rate of each
Bondtech autoclave was about 820 kilograms per hour (1800 pounds per hour).
The test program was designed to provide a comprehensive challenge to validate
the sterilization efficacy of the Bondtech high-vacuum/high-pressure autoclave
system. The validation efficacy test program is described in the following section.
3.0 STERILIZATION TEST
Biological Test Indicator. The biological indicator chosen for the validation testing
was Bacillus stearothermophilus spores. The spore vials used each had a mean
population of 1.6 million colony forming units (cfu). This organism is commonly
used by health industry professionals due to a resistance to heat that is
considerably greater than pathogenic organisms. A log 6 kill of Bacillus
stearothermophilus(99.9999% kill) is referred to as the "sterility assurance level or
sterilization level." This is the standard used by the medical device industry for the
sterilization of large quantities of medical devices in steam autoclaves.
Most state environmental agencies require a log 4 kill of Bacillus stearothermophilus (99.99% kill). A log 6 kill represents a kill rate 100 times higher than the log 4 kill.
Medical waste treatment to a log 6 kill meets or exceeds all regulations and
standards established by the United States Environmental Protection Agency and
state environmental agencies.
Validation Efficacy Test Program.
Feedstock Test 1: Bags. Two Bacillus stearothermophilus test vials were placed
in a rigid plastic shaprs container that was lined with absorbent underpads. The
rigid sparps container was then sealed and placed in a red bag and sealed. Two
test bags were placed in each waste load; one in the geometric center of the front
Bondtech autoclave waste bin and the other in the geometric center of the back
waste bin. Two waste bins are introduced to a Bondtech autoclave during each
Feedstock Test 2: Boxes. Two Bacillus stearothermophilus test vials were placed
in a rigid plastic sharps container that was lined with absorbent underpads. The
rigid sharps container was then sealed and placed in a red bag and sealed. The
sealed test bag was placed inside an approved medical waste cardboard box. Two
cardboard boxes were placed in each waste load as described above.
4.0 TEST RESULTS
Sterilized tests were conducted by placing three waste loads of boxed medical
waste and three waste loads of bagged medical waste in each one of the two Bondtech
autoclaves. The results of the 12 tests demonstrated that both Bondtech
autoclaves were 100 percent effective for sterilizing the bagged and boxed waste
loads based on a 100 percent kill rate of the biological indicator. The results of the
testing are summarized in the following table.
The results of the medical waste sterilization efficacy testing conducted on two
Bondtech high-temperature/high-vacuum autoclave systems on January 26, 1994,
demonstrated both autoclave systems achieved 100 percent sterilization
effectiveness using Bacillus stearothermophilus as the biological indicator. This is
a biological indicator kill rate in excess of log 6 (in excess of 99.9999%); the
standard commonly used by health care industry professions for the sterilization of
A log 6 kill of Bacillus stearothermophilus (99.9999% kill) is referred to as the
"sterility assurance level or sterilization level." Both Bondtech autoclaves achieved
this sterilization treatment level which meets or exceeds all medical waste treatment
standards established by the United States Environmental Protection Agency and
all U.S. State Environmental Agencies. The tests were conducted on both bagged
and boxed medical wastes at sterilization rates in excess of 820 kilograms per hour
(1800 pounds per hour) for each of the two Bondtech autoclaves.
6.0 CERTIFICATION OF RESULTS
To the best of my knowledge, all applicable field and analytical procedures comply
with the Florida Department of Environmental Protection requirements and all test
data and plant operating data are true and correct.
STERILIZATION CYCLE TIME, WASTE LOAD WEIGHTS
AND STERILIZATION TEST RESULTS
JANUARY 26, 1994