Testing PIMW Treatment Units

Testing Requirements

Title XV of the Illinois Environmental Protection Act (Act) establishes statutory requirements to ensure that Potentially Infectious Medical Waste (PIMW) will be handled in a safe and responsible manner. On June 17, 1993, the Illinois Pollution Control Board (Board), in accordance with Title VII of the Act, adopted regulations prescribing the standards and criteria for the handling of PIMW. These regulations became effective June 21, 1993. The requirements found in the Act and the Board’s regulations are intended to reduce the occupational and environmental health risks that occur during the storage, treatment, transport, transfer, and disposal of PIMW.

The information presented in this fact sheet does not eliminate any person’s responsibility to fulfill any legal obligation under the Act or regulations promulgated thereunder.

The purpose of this fact sheet is to provide some of the PIMW requirements, found in both the Act and the Board’s regulations. For the complete requirements, please see Title XV of the Act and 35 Illinois Administrative Code (Ill. Adm. Code): Subtitle M.

For additional information on PIMW regulations in Illinois, contact the PIMW Coordinator at the Illinois Environmental Protection Agency; Bureau of Land #33; 1021 North Grand Avenue East; P.O. Box 19276; Springfield, Illinois 62794-9276, or call (217) 524-3289.

Who needs to follow testing requirements?

Anyone who is going to treat Potentially Infectious Medical Waste (PIMW), whether on-site or off-site and no matter how small the amount, must follow these testing requirements as found in the regulations.

Basic Overview

When a treatment unit is manufactured or installed, an Initial Efficacy Test (IET) must be performed. This test is done to prove that the unit is effective in reducing the number of microorganisms present in PIMW. Once a unit has passed this initial test, the infectious potential of the waste is then considered to be eliminated.

After the IET has been performed and the treatment unit has passed the required standards, a Periodic Verification Test (PVT) must be performed once a month (or more often if the permit or manufacturer requires it). This is usually a simpler test than the IET. It is done to show that the treatment unit is still operating as demonstrated in the IET (i.e., eliminating the infectious potential of the waste).

Initial efficacy test

The Initial Efficacy Test (IET) may be performed by the owner/operator once a treatment unit has been installed at a specific site, or it may be performed by the manufacturer on a particular model. If the manufacturer performed the IET, the testing procedures used and the results obtained must be provided to the owner/operator. The owner/operator must keep this information at the treatment facility site and make it available to the Illinois Environmental Protection Agency (Illinois EPA) upon request.

The IET is broken into 3 options, depending upon the type of treatment unit which is being tested:

Option 1: Treatment units that do not maintain the integrity of the container of microorganisms (e.g., grinding followed by chemical disinfection)
Option 2: Treatment units that maintain the integrity of the container of microorganisms (e.g., autoclave)
Option 3: Treatment units that maintain the integrity of the container of microorganisms and are thermal (e.g., incinerator)

Option 1 uses all 6 test microorganisms
Option 2 uses all 6 test microorganisms
Option 3 uses only 1 indicator microorganism

Test Microorganisms

  1. Staphylococcus aureus (ATCC 6538)
  2. Pseudomonas aeruginosa (ATCC 15442)
  3. Candida albicans (ATCC 18804)
  4. Tricophyton mentagrophytes (ATCC 9533)
  5. MS-2 Bacteriophage (ATCC 15597-B1)
  6. Mycobacterium smegmatis (ATCC 14468)

Indicator Microorganisms

  1. Bacillus subtilis (ATCC 19659)
  2. Bacillus stearothermophilus (ATCC 7953)
  3. Bacillus pumilus (ATCC 27142)
Challenge Loads

In order to perform the IET, waste loads with a particular makeup are required; these loads are called "challenge loads." The three types of challenge loads are High Moisture, Low Moisture, and High Organic. Each load begins with a base of 5% of each of the following:

  • blood/broth cultures
  • fibers
  • metals
  • sharps
  • bottles of liquids
  • plastics
  • pathological waste
  • glass
  • non-woven fibers

In addition, the challenge loads must meet these requirements:

  • High Moisture >50% moisture (Challenge Load 1)
  • Low Moisture <5% moisture (Challenge Load 2)
  • High Organic >70% organics (Challenge Load 3)

If a treatment unit is designed to treat only select categories of PIMW (e.g., a sharps treatment unit), written approval may be obtained from the Illinois EPA to alter the composition of the challenge loads.

Each type of microorganism to be used must be run through the treatment unit with each type of challenge load for the IET. Each container of microorganisms must be placed in the load to simulate the worst-case scenario, or the part of the load that is most difficult to treat. For example, in an autoclave, the worst-case scenario would be to place the microorganisms into a container of sharps, which is then placed in a plastic biohazard bag, which would then be placed in the center of the challenge load.

This initial test must be conducted under the same operating conditions as those to be used on a day-to-day basis. If operating parameters or mechanical operations change, a new IET must be performed.

Document of Initial Efficacy Demonstration

A Document of Initial Efficacy Demonstration must be retained at the facility; this Document must be made available to the Illinois EPA upon request and must include such items as a detailed description of test procedures, operating parameters, and test data. Please refer to Section 1422.124(f) of 35 Ill. Adm. Code: Subtitle M for exact details of what is to be included in this Document.

Option 1

Option 1 is used for Treatment Units that do not maintain the integrity of the container of microorganisms (e.g., grinding followed by chemical disinfection). It consists of two phases. All 6 test microorganisms must be used in both phases with all 3 types of challenge loads.

Phase I determines the dilution factor from the treatment unit.

  1. Prepare two low-moisture challenge loads, sterilize by autoclaving, and reserve one load for Phase 2.
  2. Determine the number of viable organisms in the container to be used; only one type of organism may be used at a time.
  3. Introduce the container of microorganisms into the treatment unit. Processing must begin within 30 minutes. The test microorganisms and challenge load must be processed together without the physical and/or chemical agents designed to kill the microorganisms. (For example, an equal volume of water must be substituted for a chemical disinfectant.)
  4. A minimum of 5 grab samples must be taken from the processed residue.
  5. Calculate the effect of dilution for the treatment unit:
    D = Log Nintro - Log Nremain Log Nremain must be > 6
    D is the effect of dilution of the treatment unit; it is the log of the number of viable test microorganisms that were not recovered after processing
    Nintro is the number of viable test microorganisms introduced into the treatment unit
    Nremain is the number of viable test microorganisms remaining in the processed residue
  6. If Log Nremain is < 6, the number of test microorganisms introduced (Nintro) must be increased and this entire Phase I repeated until Log Nremain is > 6.

Repeat these steps for a High Moisture challenge load and for a High Organic challenge load. Then proceed to Phase 2.

Phase 2 is to determine the log reduction of each test microorganism in the treatment unit.

  1. Using the Nintro value determined in Phase I, repeat the steps in Phase I under the same operating parameters, except that the physical and/or chemical agents designed to kill the microorganisms must now be used.
  2. The effectiveness of the treatment unit may be calculated as follows:
    L = Log Nintro - D - Log Nremain2 L must be > 6
    L is the log kill of the test microorganisms after treatment
    Nintro is the number of viable test microorganisms introduced into the treatment unit
    D is the dilution factor as determined in Phase I
    Nremain2 is the number of viable test microorganisms remaining in the treated residue for Phase 2

Repeat these steps for a High Moisture challenge load and for a High Organic challenge load.

Option 2

Option 2 is for a treatment unit that maintains the integrity of the container of test microorganisms (e.g., autoclave). All 6 test microorganisms must be used with all 3 types of challenge loads; all 6 types of organisms may be introduced into the system at the same time, in separate vials.

  1. Place the container(s) of test microorganisms in a Low Moisture challenge load and process the load and container at the same time.
  2. Calculate the effectiveness of the treatment unit as follows:
    L = Log Nintro - Log Nremain L must be > 6
    L is the log kill of the test microorganisms after treatment
    Nintro is the number of viable test microorganisms introduced into the treatment unit
    Nremain is the number of viable test microorganisms remaining in the treated residue

Repeat these steps for a High Moisture challenge load and for a High Organic challenge load.

Option 3

Option 3 is for a treatment unit that uses thermal treatment and also maintains the integrity of the container of microorganism spores (e.g., autoclaves and incinerators). Only 1 indicator microorganism must be used with all 3 types of challenge loads.

  1. Place a container of indicator microorganism spores (at least 1,000,000) in a Low Moisture challenge load and process the load and container at the same time.
  2. Calculate the effectiveness of the treatment unit as follows:
    L = Log Nintro - Log Nremain L must be > 6
    L is the log kill of the indicator microorganism spores after treatment
    Nintro is the number of viable spores introduced into the treatment unit
    Nremain is the number of viable spores remaining in the treated residue

Repeat these steps for a High Moisture challenge load and for a High Organic challenge load.

Periodic verification tests

The continued effectiveness of a treatment unit is verified by the Periodic Verification Test(s) (PVTs), which must be conducted in accordance with 35 Ill. Adm. Code 1422.125. PVTs are performed monthly, or more often if required by an Illinois EPA permit or manufacturer's instructions. A PVT must satisfy at least one of the following:

  1. Pass the Initial Efficacy Test by using Option 1, 2, or 3. All three challenge loads do not need to be used in the monthly testing.
  2. Correlate the log reduction (L) of the test microorganisms in the IET to an equivalent log reduction (T) of the indicator microorganism spores by using a Correlating Periodic Verification Test. Details of this test are given elsewhere in this Fact Sheet, or can be obtained from Sections 1422.125(b) and 1422.Appendix B of Subtitle M.
  3. Obtain written approval by the Illinois EPA for a procedure that is equivalent to a Correlating PVT. Approval of an alternative procedure may require more frequent testing and/or monitoring of the treatment unit. An example of this would be visually inspecting the ash from each load of treated PIMW (for incinerators only) to insure that all PIMW within each load is completely combusted.

Correlating periodic verification tests

The Correlating Periodic Verification Test (Correlating PVT) may be used as one method of passing the Periodic Verification Test (PVT). It is designed to allow the owner/operator to use indicator microorganism spores in place of test microorganisms for the PVT, even for treatment units which do not use Option 3 of the IET. The procedure for the Correlating PVT is as follows:

  1. A container of test microorganisms and at least 1,000,000 indicator microorganism spores is introduced into each of the three challenge loads (for the Initial Correlating PVT). The container of organisms must remain intact during treatment, and must be placed in the challenge load to simulate the worst-case scenario.
  2. Calculate the log reduction of the test microorganisms (L) and the log reduction of the indicator microorganism spores (T) as follows:
    L = Log Nintro - Nremain L must be > 6
    T = Log Sintro - Sremain T must be > 3
    L is the log kill of the viable test microorganisms after treatment
    Nintro is the number of viable test microorganisms introduced into the treatment unit
    Nremain is the number of viable test microorganisms remaining
    T is the log kill of the viable indicator microorganism spores after treatment
    Sintro is the number of viable indicator microorganism spores introduced into the treatment unit,br> Sremain is the number of viable indicator microorganism spores remaining
  3. The log reduction of test microorganisms must be at least 6; the log reduction of indicator microorganism spores must be at least 3. The log reduction of spores must be used in future PVTs. For example, if L (log reduction of test microorganisms) was 6 and T (log reduction of spores) was 4 for this test, a population of 10,000 (104) indicator microorganism spores must be used in all future PVTs, and there must be zero growth of spores at the end of the test run.
  4. The Initial Efficacy Test and Correlating Periodic Verification Test may be run concurrently to verify the correlation.

What if a PVT fails?

If a load of PIMW fails a PVT, the PVT must be repeated. This second PVT must be performed immediately after discovery that the first PVT failed. Loads of PIMW that were processed prior to receiving results showing a failure of the PVT are considered treated and may be disposed of accordingly. The operator must implement the quality assurance program [Section 1422.122(a)(4)] to identify and correct the problem(s) until the unit can eliminate the infectious potential of the PIMW. If the operating parameters are altered, another Initial Efficacy Test must be performed to demonstrate the effectiveness of the unit and, if applicable, another Correlating PVT. If the second PVT shows a failure, the processed waste is considered PIMW and must be managed as such in accordance with Subtitle M.

What records must be kept?

In addition to the Document of Initial Efficacy Demonstration, as previously discussed, records of Periodic Verification Tests and Correlating Periodic Verification Tests must be kept at the treatment facility and made available to the Illinois EPA upon request. Details of the information these records must contain may be found in Section 1422.125 of Subtitle M.