Waste treatment appropriate measures

These are the appropriate measures for waste treatment at regulated facilities with an environmental permit for treating healthcare waste.

General waste treatment

1. Waste treatment must have a clear and defined benefit. You must fully understand, monitor and optimise the waste treatment process to make sure that you treat waste effectively and efficiently. The treated output material must meet your expectations and be suitable for its intended disposal or recovery route. You must identify and characterise emissions from the process, and take appropriate measures to control them at source.

2. You must have up-to-date written details of your treatment activities, and the abatement and control equipment you are using. This should include information about the characteristics of the waste you will treat and the waste treatment processes, including:

• simplified process flowsheets that show the origin of any emissions
• details of emission control and abatement techniques for emissions to air and water, including details of their performance
• diagrams of the main plant items where they have environmental relevance – for example, storage, tanks, treatment and abatement plant design
• details of physical treatment processes, for example shredding, separation, compaction, filtration, heating, cooling or washing
• details of any chemical treatment processes
• details of any biological treatment processes
• details of any effluent treatment, including a description of any flocculants or coagulants used
• an equipment inventory, detailing plant type and design parameters – for example, time, temperature, pressure
• waste types to be subjected to the process
• the control system philosophy and how the control system incorporates environmental monitoring information
• process flow diagrams (schematics)
• venting and emergency relief provisions
• a summary of operating and maintenance procedures
• process instrumentation diagrams

3. You must have up to date written details of the measures you will take during abnormal operating conditions to make sure you continue to comply with permit conditions. Abnormal operating conditions include:

• unexpected releases
• start-up
• momentary stoppages
• shutdown

4. You must demonstrate that your treatment process will make sure that clinical waste is ‘rendered safe’, as defined in Health Technical Memorandum 07-01 – Safe Management of Healthcare Waste.

5. For a relevant waste to be considered rendered safe, your treatment process must:

• reduce the number of infectious organisms present in any infectious waste to a level that no additional precautions are needed to protect workers or the public against infection by the waste
• destroy any anatomical waste (human or animal tissue) so that it is no longer recognisable
• make any clinical waste (including any medical equipment and items) unusable and unrecognisable
• destroy the component substances of any chemical, or medicinal and medicinally-contaminated waste
• make any patient information within the waste unrecognisable

6. You must have tested and validated each treatment device you use as part of a site commissioning validation programme. This must meet the requirements in the section Plant commissioning and validating treatment efficacy.

7. You must carry out appropriate efficacy testing to measure and demonstrate that your process can effectively treat clinical waste on an ongoing basis. This testing must meet the requirements in the section Routine plant efficacy testing.

8. Your treatment process must, as a minimum, meet the level 3 criteria provided by the International Society on Analytical Assessment of Treatment Technologies (IStAATT) if you treat infectious waste. It must meet the level 4 criteria if you treat certain bio-hazardous waste (for example, laboratory waste). You must only receive bio-hazardous waste under exceptional circumstances and must not pre-macerate or shred these wastes.

Here are descriptions of the IStAATT level 3 and 4 treatment criteria:

Level 3

Inactivation of the following organisms at a 6 log₁₀ reduction or greater:

• vegetative bacteria
• fungi
• lipophilic or hydrophilic viruses
• parasites
• mycobacteria

Inactivation of the following organisms at a 4 log₁₀ reduction or greater:

• Geobacillus stearothermophilus spores
• Bacillus atrophaeus spores

Level 4

Inactivation of the following organisms at a 6 log₁₀ reduction or greater:

• vegetative bacteria
• fungi
• lipophilic or hydrophilic viruses
• parasites
• mycobacteria
• Geobacillus stearothermophilus spores
• Bacillus atrophaeus spores

9. Your treatment process must not shred or macerate untreated infectious wastes before the disinfection step. The exception is if the plant used is specifically designed and built to provide full bioaerosol containment.

This would be provided by operating the plant under negative pressure, with air extracted from the feed hopper and passed through high efficiency particulate air (HEPA) filters. Feed hoppers must have doors on the opening to contain bioaerosols and other potential emissions. The doors must be closed whilst the shredder or macerator plant is operating, with process interlocks or equivalent measures to prevent the plant operating when the doors are open.

10. You must have appropriate containment measures to prevent microbial emissions from pre-shredded or pre-macerated waste before its disinfection. You must assess and demonstrate the effectiveness of these measures through your microbial emissions monitoring.

11. You must exclude the following wastes from alternative treatment activities – unless you have provided us with additional written justification for their treatment and we have specifically permitted and approved your plant for the treatment of these wastes:

• waste medicines and chemicals
• wastes contaminated with or containing residual medicines or other chemicals, including syringes that are fully discharged, partially discharged or undischarged (for example 18 01 03* infectious waste contaminated with 18 01 09 medicines)
• non-infectious wastes (for example 18 01 04 offensive hygiene wastes)
• anatomical waste
• dental amalgam

Justification for the alternative treatment of these wastes must assess any impact on emissions to air and water from the facility and demonstrate that the treatment:

• is effective (including validation of worst-case scenario wastes and conditions)
• is an efficient use of energy and raw materials
• enhances the recovery or recycling of the waste where possible
• does not impede the treatment of any other wastes

12. You must exclude biohazard waste from alternative treatment activities. This is:

• any waste known or likely to contain Advisory Committee on Dangerous Pathogens hazard group (HG) 4 biological agents
• any waste from a containment level 3 laboratory
• all microbiological cultures from any source
• any potentially infected waste from pathology departments and other clinical or research laboratories (unless autoclaved before leaving the site of production)

13. The following wastes should be treated (inactivated) at the site of production:

• class 2, 3 and 4 genetically modified microorganism cultures or contaminated material
• HG 2, 3 and 4 pathogen cultures or positive specimens

However, there may be very exceptional (emergency) circumstances when you can receive these wastes for treatment at a permitted waste facility. For example, when the treatment process at the site of production has broken down. If you receive any of this waste at your permitted facility under these circumstances, then you must meet the following appropriate measures:

• you must not shred or macerate untreated wastes before the disinfection step
• the treatment process must demonstrate a higher level of treatment (IStAATT level 4 criteria)
• you must have waste pre-acceptance and acceptance procedures that make sure you only accept this waste in exceptional circumstances, for example as a ‘one off’ because on site treatment has malfunctioned
• you must submit a written justification in advance to the Environment Agency to demonstrate that you have addressed all of these requirements and have the appropriate procedures in place

14. You must correctly describe, classify and code waste from alternative treatment using the appropriate LoW codes to make sure that it reflects the residual characteristics and properties.

Here are some examples of different treatment scenarios, and the LoW codes to use for the wastes produced.

Waste hazardous by ‘infectious’ property only

If you are treating (rendering safe) waste that is hazardous by ‘infectious’ property only (orange stream waste – 18 01 03, 18 02 02 and 20 01 99) use these waste codes:

• 19 02 10 (if combustible)
• 19 02 06 or 19 02 99 depending upon nature of output material

Waste contaminated with or containing hazardous chemicals or medicines

If you are treating infectious waste containing or contaminated with hazardous chemicals or medicines, which are not specifically treated (removed or destroyed) by the treatment process, use the waste code 19 02 04*.

You can only use waste codes 19 02 06, 19 02 10, or 19 02 99 if the treatment plant validation demonstrates that the process renders the waste safe and treats all chemical and medicines (including pharmaceutically active substances).

Process failures

If there has been a process failure where waste has not been fully treated or rendered safe, use the waste code 19 02 04*. This applies if the wastes have been mixed and not fully treated or rendered safe. Wastes must keep their original waste code and classification if they have not had any form of treatment.

Sterilisation of waste at producer premises

For infectious healthcare waste (18 01 03*) sterilised at a producer site, for example, in a laboratory autoclave, use the waste code 18 01 04. The waste must be rendered unusable and unrecognisable unless it is subsequently incinerated.

Treatment of offensive waste to produce a waste derived fuel

If you are treating non-hazardous offensive waste (18 01 04) to produce a waste derived fuel, and it has only had mechanical treatment such as shredding, use waste code 19 12 10. For waste that has been subject to physico-chemical treatment (such as heating or drying), use waste code 19 02 10.

Plant commissioning and validating the efficacy of treatment

1. As part of the plant commissioning process, you must carry out performance validation tests to demonstrate that the treatment plant will render safe each of the waste types that your facility is permitted to treat. You must submit written proposals detailing the plant commissioning process and validation tests that you will carry out to the Environment Agency for prior approval.

2. Validation tests must be supervised by a suitably qualified, experienced and independent person. An appropriately accredited laboratory must do the analysis. For the treatment of infectious wastes, tests must be supervised by an appropriately qualified microbiologist. Analysis must be carried out at an accredited microbiological laboratory.

3. To comply with the pre-operational conditions in your facility’s environmental permit, you must submit the results of plant validation tests in a written report to the Environment Agency for approval. We must approve this before you can start the commercial operation of the treatment plant at your facility.

4. The validation report must detail the operating conditions and parameters of the plant at which you carried out the validation tests. You must include the type and composition of waste stream(s) treated, and batch quantity or throughput rate.

We will base our approval of the validation report on these validated plant operating conditions and parameters. The subsequent operation of the plant will be limited to these operating conditions and parameters.

5. For mobile plant, you must carry out site commissioning and validation tests before you start operations on the first deployment.

6. Waste produced by an alternative treatment plant that has not passed a validation test, or received approval from the Environment Agency, must be considered untreated until rendered safe by a validated and approved plant.

7. You must repeat plant validation and send a written validation report to the Environment Agency for approval periodically throughout the operational life of the plant and at intervals of 4 years or less.

You must also do this if:

• any process parameters or conditions (for example, treatment duration, temperature, pressure, mass or type of waste) change from those assessed and approved during plant commissioning or validation
• you make any changes to the design or engineering of the treatment plant
• changes to the waste types accepted for treatment mean that the challenge load considered during plant commissioning or validation is no longer the worst-case scenario
• the plant fails routine treatment efficacy testing

8. If the results of periodic plant validation do not demonstrate that treated waste will be rendered safe (for example, they do not demonstrate the required microbial disinfection efficacy for the treatment of infectious waste) then you must stop plant operations until you can identify the cause and recommission the plant. Before restarting operation, plant validation must be approved in writing by the Environment Agency.

Validation tests for treating infectious wastes

1. You must use an appropriate certified test organism for the tests.

2. You can use spore strips to validate thermal treatment plant if you can guarantee their integrity. That is, if you can insert them into the waste after the pre-shredding or maceration process and before the disinfection step. Or, if there is no pre-shredding or maceration, you can insert them into the waste before the disinfection step.

You should use spore suspensions to validate chemical treatment plant or thermal treatment plant if you cannot guarantee the integrity of spore strips.

3. You must use Bacillus atrophaeus (BA) or Geobacillus stearothermophilus (GS) for IStAATT tests. You should use BA to test chemical treatment processes and those involving dry heat technologies, and GS for wet heat (steam) treatment.

4. When using spore strips or suspensions:

• you must use spore strips or suspensions from the same batch number in the tests
• if you use spore strips, they must be certified as containing ≥1 x 10⁶ spores
• if you use spore suspensions, you must add sufficient suspension to each load to make sure that ≥1 x 10⁶ spores are present per gram mass of the total load

5. For thermal treatment plant, the spores used must have a minimum certified D-value ≥1.8 minutes at either:

• 121°C wet heat for GS
• 160°C dry heat for BA

The D-value is the time at the temperature required to achieve a log (or 90%) reduction in relevant micro-organisms. For chemical treatment plant, where the D-value for the chemical disinfectant is not available, you must determine the D-value and demonstrate it is comparable to the values reported in the literature.

6. For thermal processes, the spores must be supported by the parallel use of either:

• thermal indicator strips which indicate time and temperature of exposure
• multi-point thermal data loggers co-located in the waste load

7. The time and temperature combination of the indicator strips must be indicative of the plant operating parameters needed to achieve microbial inactivation.

8. You must base the validation of plant performance for disinfection on:

• the treatment of a worst-case challenge load – in terms of spore strip containment or insulation and presence of interfering or inhibiting substances or items
• the maximum quantity of waste that will be treated – that is the maximum batch size or throughput of the plant

9. The worst-case challenge load used must reflect the type and design of the treatment plant, specifically whether the:

• treatment process provides thermal or chemical disinfection
• waste is pre-shredded or macerated prior to disinfection, or not

10. You must detail and justify the worst-case challenge load used in the validation report.

Here are example challenge loads for 3 test scenarios.

Spore strips – thermal treatment with pre-shredding or maceration

Each spore strip is placed in a separate carrier designed to mimic normal conditions in the waste being treated. Examples used include net bags, tennis balls, socks, punctured plastic or alloy containers.

If metal containers are used, the spore strips must be insulated, for example using cotton wool or equivalent, to prevent direct heat conduction. Each spore carrier containing a spore strip must be inserted loose into the bulk of the pre-shredded or macerated waste and distributed throughout the waste load.

You can only use fixed carriers or test ports for routine monitoring if you have demonstrated through additional parallel testing that there is no significant difference between the results from these and loose carriers.

Spore strips – thermal treatment without pre-shredding or maceration

Spore strips are fixed in the centre of filled, sealed items of varying size. These are representative of the toughest and most resistant items commonly found in healthcare waste, such as suction canisters and chest drains.

Items should be filled with fluid and thermally stable gel. You should also consider using other items that could inhibit heat penetration and include them in the load.

The items should be placed in worst-case packaging, for example, sealed rigid bins or containers and bags, and distributed throughout the waste load.

Spore suspensions – assumes pre-shredding or maceration before or during treatment

At least 6 small glass vials or bottles containing spore suspension are securely attached to the outside of suction canisters containing fluids (for example blood) and placed inside worst-case packaging (for example, sealed rigid bins).

The waste load should contain other substances present in the waste stream that could inhibit the disinfection process, for example, organic matter, chemicals, blood and items that could inhibit heat or chemical penetration.

For a typical waste load we recommend that a minimum of 5% heavy organic load (for example, blood) is added by weight.

If a process is permitted to treat waste with a significantly higher organic load (for example, blood bags) then a higher organic content should be considered.

Validation test format for infectious wastes

11. You must use an appropriate validation test format, which will depend on whether you are using spore strips or suspensions, as follows.

Spore strips

12. You must test each plant over 3 separate treatment cycles, retrieving the treated test packages before starting the next cycle. In total, you must hold a minimum of 6 untreated spore strips outside of the device to use as controls that you will compare with the treated strips.

The minimum number of spore strips recovered is set out in this table.

Minimum number of spore strips

Plant load (kg) or throughput (kg/hour) capacity	Recovered per cycle or collection	Total recovered (assuming 3 runs)	Retained as controls
0 to 10kg	3	9	6
11 to 50kg	4	12	6
1 to 250kg	6	18	6
251 to 500kg	8	24	6
501 to 750kg	10	30	6
Over 750kg	12	36	6

13. You must analyse the entire test sample except for the control samples which will require serial dilution. You must preserve samples appropriately and send to an accredited laboratory for analysis in a timely manner.

14. Analysis must be quantitative and based upon the number of spores per spore strip. You must achieve the required log reduction (the number of spores recovered from control strips compared with those recovered from the test strips) with 95% confidence. All thermal indicator strips must also show that the required time and temperature parameters were achieved.

Spore suspensions

15. You must test each plant over 3 separate treatment cycles, taking representative samples from the treated material before starting the next cycle. The test must include a control run, where waste (treated clinical waste or a suitable surrogate waste material) is passed through the plant without activating the treatment process. You should add the same total quantity of spore suspension to each control and test run.

If the mass of the waste differs between each control and test run, you will need to correct the test data for each run (spores present per kg of sample) to account for this difference.

The minimum number of samples taken from the treated material is set out in this table.

Minimum number of samples

Plant load (kg) or throughput (kg/hr) capacity	Recovered per test run	Total recovered (assuming 3 runs)	Recovered per control run
0 to 10kg	3	9	3
11 to 50kg	3	9	3
51 to 250kg	4	12	4
251 to 500kg	4	12	4
501 to 750kg	5	15	5
Over 750kg	5	15	5

16. Each sample should be at least 0.1% of the waste load, with a minimum sample of 50g for smaller units. You must preserve samples appropriately and send them to an accredited laboratory for analysis in a timely manner.

The entire test sample must be analysed, except the control samples. You must achieve the required log reduction (the number of spores recovered from control samples compared with those recovered from the test samples) with 95% confidence. Samples must be preserved appropriately until received by the laboratory for testing.

Assessment methodology for infectious wastes

17. You must follow an appropriate assessment methodology, which will depend on whether you are using spore strips or suspensions.

Microbial disinfection efficacy – spore strips

For the control data, you must calculate and record the following:

• number of spores (colony-forming units (cfu)) recovered from each individual control spore strip
• mean number (X_C) of spores recovered from the control strips
• log₁₀ of (X_C)

You must then subtract 4 from the log₁₀ of (X_C) to generate the pass criteria.

Subtracting 4 provides the 4 log₁₀ reduction for IStAATT Level 3 criteria. For the treatment of certain biohazard wastes a 6 log₁₀ reduction is needed, in which case 6 must be subtracted from the log₁₀ of (X_C) to generate the pass criteria.

Using the combined test data from each test run you must calculate the following:

• number of spores recovered from each individual test strip
• mean (X_T) number of spores recovered
• standard deviation (σ) of spores recovered
• upper 95% (Lu) confidence interval of (X_T) (this will be approximated by X_T+ 1.96 σ)
• log₁₀ of the upper 95% (Lu) confidence interval of X_T (log₁₀Lu)

Note: if Lu = 0, then use ‘0’ for log₁₀Lu.

The test data used must include all the recovered test strips. If you suspect contamination, you should either retest the sample or, if that is not possible, include the results in the data analysis.

The following criteria represent the minimum standards that must be achieved:

• the log₁₀Lu for each run must be less than or equal to the pass criteria
• log₁₀ (X_C) must be equal to or greater than 5
• for thermal processes all thermal indicator strips should indicate that the required temperature time parameters have been achieved

Where these criteria are passed then it is more than 97.5% probable that the worst-case items present in any clinical waste will be treated to the minimum standard.

Here is a worked example.

Control data

Step 1. 6 control strips are analysed and give results of:

81, 93, 107, 121, 79, 119 cfu from analysis of the 1 in 10,000 dilution.

This equates to:

0.81, 0.93, 1.07, 1.21, 0.79 and 1.19 x 10⁶ cfu respectively (X)

Step 2. The mean (X_C) of spores recovered from each control strip = 1.0 x 10⁶

Step 3. The log₁₀ of (X_C) = 6

Step 4. The pass criteria = log₁₀ of (X_C) – 4 = 2 (Level III criteria)

Test data

Three test runs were done, each with 3 test strips. All were recovered and analysed.

Step 5. The following results were obtained from each run and spore strip:

• run 1 – 0, 0 and 9 cfu
• run 2 – 0, 5 and 22 cfu
• run 3 – 0, 0 and 39 cfu

Step 6. The mean (X_T) of colonies recovered from each spore strip = 8.33 cfu

Step 7. The standard deviation (σ) of the results = 13.63 cfu

Step 8. The upper 95% (Lu) = 8.33 + (1.96 x 13.63) = 35.04 cfu

Step 9. The log₁₀ of Lu (log₁₀Lu) = 1.54

Interpretation

We have determined in step 4 that the pass criteria = 2

We have determined in step 9 that the log₁₀ of the upper 95% confidence interval (log₁₀ Lu) of the spores recovered from the test runs = 1.54

In this case:

• the results from the test runs show that the log of the upper 95% confidence interval for recovered spores (1.54) is less than the pass criteria (2)
• log₁₀ (X_C) is greater than 5 so sufficient spores have been recovered for the results to be valid
• for the purposes of this example we will assume that all 9 data log points recorded that a temperature of 121°C had been achieved for 15 minutes

The IStAATT level 3 criteria have therefore been successfully demonstrated.

Microbial disinfection efficacy – spore suspensions

If you have used spore suspensions you must correct the data to allow for any differences in the total mass of waste used in each control and test run.

You must determine the results from the control samples using the procedures given for spore strips.

Instead of determining how many spores are present in each control spore strip you determine how many are present per kg of control sample.

You must record the mass of waste used in the control run (MC) in kg.

You must determine the results from the test samples using the procedures and example given for spore strips with the following exception.

You must record the mass of waste used to load each test run in kg (for example, mass of test 1 (MT 1, MT 2, MT 3)).

You must determine the individual results (as cfu per kg) for each test sample taken (equivalent to step 5 of the worked example provided for spore strips).

You must then multiply each of the test results by the mass of the corresponding test (for example, MT 1, MT 2, MT 3) divided by the MC. This is to correct any differences in mass between the tests and control run. You must do this before proceeding to the next steps of the calculation (equivalent to steps 6 to 9 of the worked example provided for spore strips).

Validation tests for treating wastes contaminated with or containing medicines

1. Validation tests must demonstrate that the plant is capable of destroying the range of pharmaceuticals and active ingredients that may be present in the waste stream.

You must base your identification of potential substances (including potential breakdown products), and assessment of their thermal stability and decomposition, on an initial review of available literature. This must be supported by laboratory scale trials, where appropriate, to define a worst-case challenge load.

Dilution of pharmaceuticals is not considered a valid form of treatment. If you are proposing a chemical treatment process, you must consider and assess the potential for reactions occurring between the chemical agents used and the pharmaceutical chemicals that may be present in the waste.

2. Validation tests must assess and demonstrate the efficacy of each plant. These must involve:

• a control run
• a minimum of 3 test runs
• considering at least 3 worst-case substances

The 3 worst-case substances are those that literature reviews and trials have identified as being the most thermally resistant. You must dose the waste with the substances so the concentration is significantly higher than the limit of detection and the background level of any potentially interfering pharmaceuticals or other chemicals.

3. You should introduce chemical tracer dyes resistant to the treatment process with the pharmaceuticals to demonstrate the treated waste is homogenous and material sampling is appropriate.

4. You must consider and assess any effect on plant emissions that may result from the treatment of the pharmaceuticals.

Validation tests for treating wastes contaminated with or containing chemicals

1. Validation tests must demonstrate that the plant is capable of fully treating the range of chemical contaminants that may be present in the waste stream. You must clearly define the objectives of the treatment process, along with any reaction chemistry.

2. You must provide an assessment of the efficacy of the treatment, demonstrating the fate of the substances in question. Simple physical dilution or absorption, without any concurrent chemical change, is not an acceptable treatment process in itself.

3. Validation tests must assess and demonstrate the efficacy of each plant. These must involve a control run and a minimum of 3 test runs. You must take representative samples from the treated material resulting from each test run.

4. You must consider and assess any effect on plant emissions that may result from the treatment of the chemical contaminants.

Validation tests for treating anatomical wastes

1. Anatomical waste must be made unrecognisable – this generally means that it is incinerated. It is not appropriate or acceptable to shred and treat anatomical waste by alternative treatments involving chemical or heat-based disinfection. Novel technologies like alkaline hydrolysis that dissolve and totally destroy the tissue could be used for such wastes.

2. Validation tests must demonstrate that the treatment process achieves the equivalent level of tissue destruction as incineration. The tests must also consider any chemicals present in or with the anatomical waste (for example preservatives). The tests must demonstrate that the plant is capable of effectively treating the range of chemicals that may be present. See Validation tests for treating wastes contaminated with or containing chemicals.

Routine plant efficacy testing

1. You must test and assess the treatment efficacy of each waste treatment plant regularly throughout its operational life to make sure that its performance is maintained and all waste is rendered safe. You must follow an appropriate testing methodology, which for infectious wastes will depend on whether you use spore strips or suspensions.

2. The methods you use for routine efficacy tests must be the same as those used for site commissioning validation. You can only use alternative methods if parallel tests carried out during commissioning validation demonstrated that an alternative method met both of these criteria:

• it was appropriate (accurate, reliable and repeatable)
• it produced the same results as those produced following the methods described in this guidance

3. For thermal processes, you must always use thermal indicator strips or multipoint data loggers in parallel where possible.

Spore strip tests

4. The minimum frequency of efficacy tests and number of control strips used is specified in the table Routine monitoring of microbial inactivation using spore strips. You must schedule the efficacy tests and evenly space them throughout the calendar year.

5. You can test spore strips quantitatively (population of >1 x 10⁶) or qualitatively (population of >1 x 10⁴). Controls and certificates from the test batch must also accompany each set of samples.

6. The criteria for success are as follows:

• you must investigate each individual ‘fail’ result as soon as possible
• 95% of the individual spore strips in the first 6 months of operation, and each subsequent calendar year, must demonstrate 4 log₁₀ inactivation or higher (quantitative), or no growth (qualitative)
• thermal indicator strips must accompany each spore strip and indicate that you achieved the minimum time and temperatures for 99% of spore strips
• for each calendar year you must prepare a summary report that indicates the results obtained and any failures
• the data in your summary report must be referenced to the validation report to demonstrate that you are meeting the treatment efficacy achieved during plant commissioning, rather than minimum standards
• if more than 5% (or 1, whichever is greater) of qualitative spore strips exhibit growth in any calendar year, you must use quantitative testing for the next calendar year

These criteria must include all scheduled monitoring results. You should not include additional investigative results. The percentage success criteria allow for both potential contamination and the uncertainty of microbial data.

7. If at any point during the calendar year the number of failures exceeds the annual 5%, you must stop operations at the plant until you can identify the cause and recommission the plant.

In any circumstances, if you become aware that one or more batches of waste may not have been treated to the required standard, you must take appropriate action and manage the waste as untreated.

Routine monitoring of microbial inactivation using spore strips

Continuous hourly throughput or batch cycle load (kg)	Test frequency (first 6 months of operation)	Test frequency (operational, after the first 6 months)	Minimum number of spore strips or sub-samples	Minimum number of control strips
0 to 50kg	Monthly	Quarterly	3	1
51 to 500 kg	Fortnightly	Every 2 months	3	1
501 to 1,000kg	Weekly	Monthly	3	1

Spore suspension tests

8. The minimum frequency of monitoring, number of test runs and sub-samples per test run is specified in this table.

Routine monitoring of microbial inactivation using spore suspensions

Continuous hourly throughput or batch cycle load (kg)	Test frequency (first 6 months of operation)	Test frequency (operational, after the first 6 months)	Minimum number of sub-samples per test run	Minimum number of test runs
0 to 250kg	6 monthly	Annually	3	1
251 to 750 kg	6 monthly	Annually	3	2
Over 751kg	Quarterly	6 monthly	3	3

9. You must carry out quantitative enumeration of spore suspensions with a certified population.

10. You must carry out a single control run.

11. In other respects, the procedures and quantitative criteria for success in the section on spore strips will apply, including the actions you must take if a plant fails the test requirements, or waste is not treated to the required standard.