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UNDP GEF Project on Global Healthcare Waste

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MODULE 15: NON-INCINERATION TREATMENT AND DISPOSAL OF HEALTHCARE WASTE

Estimated Time Lecture: 1 hour and 30 minutesModule Overview Present the principles and basic approaches for healthcare waste treatment

Describe the basic processes used for healthcare waste treatment Lay out factors for consideration when selecting waste treatment methods Describe the different types of non-incineration treatment processes for healthcare

waste Describe some of the advantages and disadvantages of the treatment methods Describe disposal options

Learning Objectives Understand the factors to consider when selecting a treatment method Understand the different non-incineration treatment processes and technologies Understand ways to dispose of HCW Discuss current and future options for healthcare waste treatment

Target Audience HCWM coordinators Administrators Healthcare professionals and other staff interested in participating in HCWM

planning On-site treatment managers and operators Central treatment plant managers and operators National staff and advisors in the Ministry of Health, Ministry of Environment and

other relevant government ministries, country level staff of international organizations or agencies, country level staff of national organizations and NGOs, and others involved in national or regional HCWM planning

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Instructor Preparation Make notes pages of PowerPoint slides to hand out to class Make copies of class exercise for distribution after PowerPoint presentation Read Chapter 8 in Blue Book, and other materials included in the References Global and country specific laws and guidelines for treatment and disposal of

healthcare wastes Make copies of any additional documents/readings that may be handed out to class,

such as those included in the References Prepare any additional notes to be discussed during the presentation Prepare any additional discussion points or review questions

Materials Needed Projector Student handouts: slides, exercise, homework Flip chart and marker pens and/or board and chalk

Student Preparation Blue Book Chapter 8 Global and country specific laws and guidelines regarding incineration of wastes Think about waste treatment and disposal methods utilized in your facility.

Review Questions What regulations or policies exist in your country or region regarding treatment and disposal methods for healthcare waste?

What are some factors that your facility considers when deciding on a waste treatment method? What do think is important when evaluating which method would be most appropriate?

What are some non-incineration treatment technologies that are used in your facility? Which do you think work best or should be used?

What disposal methods are used at your healthcare facility? What are the barriers to using new treatment technologies? How can we overcome

these barriers?

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PRESENTATION

Slide Number/Title Teacher’s NotesSlide 1: Title Slide This module can be used to provide a general overview of non-incineration treatment

technologies to inform participants of current or future options. The module can be modified to focus on those technologies that exist in the participants’ healthcare establishments. If there are no participants working under low-resource conditions, the slides dealing with options for low-resource settings can be eliminated.

Throughout this module, some of the slides have a good deal of information included in the Teacher’s Notes. You may choose what points to include in your presentation based upon what is important or applicable to your own country/region/facility and the time constraints of your presentation.

Slide 2: Module Overview Introduce the outline and major points of the presentation

Slide 3: Learning Objectives Describe what participants will learn at the end of this module.Slide 4: Steps in Healthcare Waste Management

This module focuses on waste treatment and disposal using non-incineration technologies.

Slide 5: Principles of Waste Treatment

Introduce some principles of waste treatment

Slide 6: Treatment Approaches Different treatment approaches:-on-site-cluster treatment-central treatment

There is a fourth treatment approach: mobile treatment. In mobile treatment, the treatment technology is mounted on a vehicle which then goes from hospital to hospital to treat the waste. This is used in some countries mainly with autoclave-type treatment.

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Slide 7: Processes Used in the Treatment of Healthcare Waste

The Blue Book discusses five main processes for the treatment of hazardous components in HCW:-thermal-chemical-irradiation-biological-mechanical

Slide 8: Thermal Treatment Processes

Rely on heat to kill pathogenic organisms; divided into low-heat and high-heat designs.

Pyrolysis: thermal degradation of a substance through the application of heat in the absence of oxygen

Slide 9: Low-Heat Thermal Process

Microwave treatment is an example of a moist (or wet) process.

In general, dry heat processes use higher temperatures and require longer exposure times than steam-based processes; they are not commonly used in large facilities since they can only handle small volumes of wastes.

Slide 10: Chemical Treatment Process

Chemical treatment processes make use of a wide range of disinfectants. Aside from disinfectants, encapsulating compounds may also be used that are capable of solidifying sharps, blood or other body fluids within a solid matrix before disposal.

Chemical disinfection is usually carried out on hospital premises, but recent developments of commercial, self-sustained, and fully automatic systems have been developed for HCW treatment that are operated away from medical centers.

Slide 11: Irradiation Process Irradiation: process by which an object is exposed to radiation

Slide 12: Biological Treatment Process

Biological treatment processes are those found in natural living organisms, specifically those that help to break-down organic matter when applied to healthcare wastes.

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Vermiculture: digestion of organic wastes through the actions of worms

Burial may also be considered a natural process, whereby pathological waste is decomposed.

Slide 13: Mechanical Process Processes that are able to reduce the volume of waste, but that cannot destroy any pathogens present. Thus, they usually supplement other treatment methods.

Slide 14: Factors in the Selection of Treatment Methods

Go through the listed points in this and the following slide to show that there are many factors to consider when deciding upon a treatment method.

Slide 15: Factors in the Selection of Treatment Methods, cont’dSlide 16: Environmental ConsiderationsSlide 17: Environmental ConsiderationsSlide 18: Examples of Treatment Technologies That Do Not Generate Dioxins/Furans

Under the Stockholm Convention, these technologies should be given priority consideration.

Slide 19: Autoclaves Low-heat thermal processes such as autoclaves produce substantially less air pollution than high-heat thermal process.Autoclaves are not generally used for large anatomical remains (body parts).

Slide 20: Autoclave SchematicSlide 21: Types of Waste Treatment Autoclaves

Waste is introduced at the top of a vertical autoclave. Waste is placed in horizontally in a horizontal autoclave.

A gravity-displacement autoclave takes advantage of the fact that steam is lighter than air. Hence, steam is introduced under pressure into the chamber, forcing the air downward into an outlet port at the bottom of the chamber.

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A more effective, but costlier, method is the use of a vacuum pump and/or a steam ejector to evacuate air before introducing steam, as is done in pre-vacuum (also called high vacuum) autoclaves. Pre-vacuum autoclaves need less time for disinfection due to their greater efficiency in removing air and disinfecting waste.

Other autoclaves use pressure pulsing to evacuate air. The three basic types of pressure pulsing systems are: pressure gravity, vacuum pulsing and pressure-vacuum. Pressure gravity (or steam flushing) entails repeatedly releasing steam and reducing the pressure to near atmospheric after the pressure has reached a pre-determined level and then allowing the pressure to build up again with the addition of steam. Vacuum pulsing is similar to a high vacuum operation except that two or more vacuum cycles are used at the start of the treatment process. Pressure-vacuum systems operate by building pressure then pulling a vacuum and repeating this process several times during treatment. Alternating pressure cycles are used to achieve rapid penetration of steam. In general, the pressure-vacuum systems have the shortest time for achieving high disinfection levels.

Slide 22: Testing Pathogen Destruction in Autoclaves and Other Steam-based Systems

There is a lot of information associated with this slide; you may choose to go over/summarize the major points.

When evaluating waste treatment technologies for healthcare waste, the ability to destroy pathogens (disease-causing microorganisms) is a key factor. Microbial inactivation efficacy refers to the capability of a treatment technology for eliminating or substantially decreasing the potential of infectious waste to transmit disease. The terms disinfection and sterilization are often used when discussing treatment efficacy. Disinfection can be defined as the reduction or removal of disease-causing microorganisms in order to minimize the potential for disease transmission. Sterilization is defined as the destruction of all microbial life. Since the complete destruction of all microorganisms is difficult to establish, sterilization of medical and surgical instruments is generally expressed as a 6 Log10 reduction (i.e., a 99.9999% reduction) or greater of a specified microorganism that is highly resistant to the treatment process. This corresponds to a one millionth (0.000001) survival probability of the microbial population. A 6 log10 reduction is also called a Log10 6 kill, Log10 6 reduction, or simply a Log 6 reduction. A 4 Log10 reduction is a 99.99% reduction of a ten-thousandth

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(0.0001) survival probability.

The State and Territorial Association on Alternate Treatment Technologies (STAATT) classification system (www.istaatt.org), in lieu of the terms disinfection or sterilization, denotes levels of "microbial inactivation" specifically for healthcare waste treatment. It was established in order to define measures of performance of healthcare waste treatment technologies. The international microbial inactivation standard for healthcare waste treatment based on the STAATT criteria is Level III, that is: inactivation of vegetative bacteria, fungi, lipophilic/hydrophilic viruses, parasites, and mycobacteria at a 6 Log10 reduction or greater; and inactivation of G. stearothermophilus spores and B. atrophaeus spores at a 4 Log10 reduction or greater.

The representative microbiological indicators generally used to test compliance with this standard are: Mycobacterium phlei or Mycobacterium bovis (BCG) at a 6 Log10 reduction or greater; and heat-resistant spores Geobacillus stearothermophilus or Bacillus atrophaeus at a 4 Log10 reduction or greater.

Spores of Geobacillus stearothermophilus, formerly called Bacillus stearothermophilus, are dormant nonpathogenic endospores that are able to withstand the high temperatures of steam treatment as well as dry heat. Spores of Bacillus atrophaeus, formerly Bacillus subtillis var. niger, are also resistant to moist and dry heat as well as chemical inactivation. These bacterial spores more resistant to heat and chemical disinfectants than viruses, vegetative bacteria, fungi, parasites, and mycobacteria. Due to the high resistance of the bacterial spores, validation testing with the spores of Geobacillus stearothermophilus or Bacillus atrophaeus is generally all that is required for waste treatment autoclaves.

Slide 23: Autoclaves The operation of autoclaves requires the proper combination of pressure/temperature and exposure time to achieve disinfection.

Slide 24: Why Preventive Maintenance is Essential

Describe why preventive maintenance of healthcare waste technologies is essential

Slide 25: Preventive Maintenance

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Slide 26: Autoclave Operation Note: You may choose how much of the following information to share with participants during the presentation.

The operation of autoclaves requires the proper combination of pressure/temperature and exposure time to achieve disinfection. A minimum recommended temperature-exposure time criterion of 121°C for 30 minutes is often used. However, waste loads that are outside the norm, such as bags stacked in a huge pile, waste containing many drapes and blankets, waste with large quantities of liquids such as blood bags, very big loads, etc. may require higher temperatures or longer exposure times. Microbiological tests should be conducted using waste samples that are representative of actual waste produced in the healthcare facility in order to determine or validate the minimum temperature, pressure and exposure time or pulsing cycle required to achieve the microbial inactivation standard.

After the initial tests, regular validation tests using biological indicators should be performed at periodic intervals and color-changing indicators could be used with each waste load to document the treatment process in addition to time-temperature-pressure logs provided by the equipment.

A typical operation for an autoclave involves the following:

Waste collection: Infectious waste bags are placed in an autoclavable cart or bin usually made of stainless steel or aluminum. The cart or bin can be lined with a plastic liner to prevent soft waste from sticking to the sides of the container

Pre-heating (for autoclaves with steam jackets): Steam is introduced into the outside jacket of the autoclave

Waste loading: The cart or bin is loaded into the autoclave chamber. With every load, a color-changing indicator is attached to the outer surface of the waste bag in the middle of the waste load to monitor treatment. The charging door is then closed, sealing the chamber

Air evacuation: Air is removed through gravity displacement, pre-vacuuming or pulse

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vacuuming

Steam treatment: Steam is introduced into the chamber until the required pressure or temperature is reached. Additional steam is automatically fed into the chamber to maintain the temperature and pressure for a set time period. Pressure pulsing autoclaves vary the pressure according to a set process cycle

Steam discharge: After the treatment cycle is complete, steam is vented from the chamber, usually through a condenser, to reduce the pressure and temperature. In some systems, a post-vacuum cycle is used to remove residual steam and to dry the waste.

Unloading: Usually, additional time is provided to allow the waste to cool down further, after which the treated waste is removed and the indicator strip is checked. The process is repeated if the color change on the indicator shows that the treatment cycle was insufficient

Documentation: A written log is maintained to record the date, time and operator name; type and approximate amount of waste treated; and post-treatment confirmation results from any automated equipment recording or temperature-pressure monitoring indicator, such as the indicator strip

Mechanical treatment: If desired, the treated waste may be fed into a mechanical process such as a shredder or compactor prior to disposal in a landfill. Treated waste from an autoclave retains its physical appearance. A shredder or grinder is used after treatment to make the waste unrecognizable, if desired. Shredding reduces the volume of the treated waste by 60 to 80 percent, but is prone to break downs. Compactors with high compaction ratios can reduce the volume by as much as 75%.

Slide 27: Autoclave Maintenance

Note: This slide is intended primarily for technology operation managers, operators and facility engineers.

Maintenance requirements for autoclaves differ according to manufacturers. A detailed maintenance schedule should be provided by the manufacturer during commissioning and as part of operator training. The list below is intended to provide a general idea of the

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maintenance schedule of a typical waste treatment autoclave.

Sample daily maintenance schedule (conducted by the operator)(a) Visual checks for steam and water leaks(b) Checks for cleanliness of the internal chamber, filter screen for the condensate drain, and door seal; cleaning where necessary(c) Inspection of chart recordings for unusual traces and reporting of any abnormalities.

Sample weekly maintenance schedule (conducted by the operator)(a) Checks of operation of the indicator lamps(b) Comparison of temperature and pressure gauges with recordings and correlation of temperature and pressure during a cycle(c) Inspection of chart recordings for abnormalities.

Sample monthly maintenance schedule (conducted by the facility engineer and operator)(a) Check of door gasket or O-ring and replacement where necessary, following manufacturer’s instructions(b) Validation test using microbiological indicators to determine microbial inactivation efficacy and adjustment of parameters when necessary (microbiological tests should be conducted more frequently if any test samples fail). Sample quarterly maintenance schedule (conducted by the facility engineer)(a) Check of control parameters that may require recalibration or replacement(b) Check of valves to determine if they need cleaning or replacement(c) Check of piping joints (d) Check for corrosion and wear in the chamber(e) Inspection of all electrical heat terminal points(f) Check for cleanliness of water and steam line main strainers (g) Check of piping and drains to ensure they are clear and operating(h) Check for correct functioning of door interlocks(i) Test of air removal efficiency with the chamber empty.

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Sample annual maintenance schedule and inspection (conducted by the facility engineer)(a) Check of service history for recurring faults and corrective action(b) Inspection and removal of any scales from the chamber following manufacturer’s instructions(c) Check of the water-level control and indicator systems(d) Check of condition and operation of temperature indicator and pressure gauges(e) Test of the operation of safety valves, door interlocks and other safety and emergency devices under operating conditions(f) Check of all control functions including correlation of pressure and temperature against known references, during a cycle with the chamber empty(g) Test of all functions under working conditions to the satisfaction of the responsible person

Slide 28: Examples of Small to Medium Autoclaves

Waste treatment autoclaves range in size from 20 liters to over 20,000 liters and must be able to withstand repeated build up and release of steam pressures. Manufacturers’ rated capacities range from 1 kg/hour to 2,700 kg/hour including the time needed for putting in the waste, steam exposure, and waste removal.

Slide 29: Example of a Medium-Size Autoclave in Tanzania

Top photos: Autoclave (left) and shredder (right) from IndiaBottom: Treatment of sharps boxes, right photos show the sharps waste after sterilization and shredding

Slide 30: Examples of Large-Scale Autoclaves for Central Treatment Plants

Top left: Large autoclave in the PhilippinesTop right: GK Moss autoclave Bottom left: large Bondtech autoclaveBottom right: Bondtech autoclave in South Africa

Slide 31: Post-Treatment Shredders Designed for Healthcare Waste

Left photo is a Mercodor medical waste shredder from Germany.Middle top photo shows the cutter disks of the Mercodor, and middle bottom photo shows results of shredding of sterilized hospital waste.Right top photo: Vecoplan medical waste shredder (Germany).Bottom right photo: Aduromed AVR 50 shredder with auger

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Slide 32: Example of a Modular Autoclave System

This particular system uses a tilting autoclave integrated with an automatic dumper and compactor. The autoclave tilts at an angle to allow waste to be loaded, then rotates horizontally during steam treatment, and then tilts downward to eject the treated waste into a compactor.

Slide 33: Autoclaves and Re-melting of Materials

Advantages and disadvantages of autoclaves

Slide 34: Example of Autoclaves and Re-melting

Sharps waste from the hospital and HIHT’s health outreach is collected in autoclavable metal containers and brought back to the hospital where the waste is autoclaved. The sterilized sharps waste is then crushed in a locally built shredder. A bin full of water is used to separate the plastics (which float) and the metals (which sink). The plastics are re-melted to produce other plastic products. (It is possible for sterilized glass to be re-melted into new glass products and metals to be re-melted in a foundry.)

Slide 35: Example of Autoclaves and Re-melting

The Swiss Red Cross piloted a project at a hospital in Kyrgyzstan. Hub cutters were used to separate the needles from the plastic barrel immediately after giving an injection. The needles were autoclaved and buried. The plastic portions of the syringes were autoclaved, crushed in a locally-made hammermill shredder, and then sold to a plastic manufacturing plant that re-melted the plastics and made them into coathangers, flower pots and covers for electrical wiring.

Slide 36: Hybrid Steam-based Systems

Essentially work as autoclaves, but with advanced and improved features.

Able to achieve higher levels of disinfection over a shorter period of time due to improved rates of heat transfer.

Requires little operator attention since they are computer controlled.

Slide 37: Example of a Hybrid Steam System: Autoclave with Internal Fragmentation and Mixing

These are autoclaves that have mixing arms or paddles inside the pressure vessel. The rotating arms or paddles break open the bags and containers allowing the contents to be exposed to steam. The Hydroclave has a loading lid at the top or front, a rotating mixing arm inside the pressure vessel, and steam injected in the outside jacket of the vessel. The inset

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shows what the waste looks like after treatment. Hydroclave is a Canadian company.

Slide 38: Example of a Hybrid Steam System:Rotating Autoclave with Internal Mixing-Fragmenting, Drying and Post-treatment Shredding

The Rotoclave is a rotating autoclave system which combines steam treatment with mixing-fragmenting and drying. The first rotating autoclave was developed by Tempico Manufacturing, a US company. The rotating autoclave is designed as a pressure vessel with a rotating internal drum having fixed vanes. As the drum slowly rotates, steam is introduced. The rotation causes waste to tumble against the vanes thereby breaking open bags and containers and allowing the contents of the bags to be exposed to the steam. An optional post-treatment grinder further reduces waste volume down to about 20% of the original volume.

Top left to right: Rotoclave during operation, Rotoclave with the door open, waste fed into the autoclave by an automatic waste dumperBottom left to right: photo of waste bags inside the Rotoclave before the door is shut, photo of the waste after shredding

The Rotoclave has been shown to be able to treat anatomical waste or body parts.

Slide 39: Example of a Hybrid Steam System: Vertical Autoclave With Internal Shredding and Drying

The French-built Ecodas is a vertical autoclave with an internal shredder. It is a pressure vessel containing a two-shaft shredder inside the vessel. After the waste is placed in the vessel at the top and sealed, the waste is first shredded and then steam is injected into the vessel. Since the inside of the whole vessel is heated to 138°C and a pressure of 3.8 bars, only about 10 minutes of exposure is needed to reach high levels of disinfection, after which cooling water is sprayed along the outside walls of the inner chamber to cool the waste to 80 °C. A vacuum cycle is used to condense steam from the waste after which the bottom lid is opened to unload the treated waste at the bottom onto a bin.

Hybrid steam treatment systems with internal shredding can be used for anatomical waste or body parts.

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Slide 40: Example of Continuous Steam Treatment with Internal Shredding, Mixing and Drying

In the ChemClav system, waste is loaded into the hopper where a negative pressure is maintained by drawing air through a high efficiency particulate air (HEPA) filter. The hopper is then sealed shut. The waste in the hopper drops into a heavy-duty shredding unit where downward pressure is applied using a ram. The feed mechanism is controlled by an integral process controller. Shredded material enters an inclined rotating auger (screw) where steam is introduced through multiple ports raising the temperature in the conveyor from 96 to 118°C. The steam is discharged through a vent at the very end of the conveyor and through a condenser causing the waste to dry off. The decontaminated waste exits the conveyor into a self-contained compactor or roll-off container for transport to final disposal. The heavy-duty shredder reduces waste volume down to about 10% of the original. The photos show examples of large and small Chem-Clav systems. The drawing is a schematic of the inside of the system. Chem-Clav is made in the US.

Slide 41: Internal Shredding of Waste

Internal shredding should be in a closed (hermetically sealed) system to prevent pathogens (disease-causing microorganisms) to be released into the work space.

The image is of a typical cassette-type shredder used as internal shredders. Whenever the shredder has to be replaced or cleaned, the shredder is easily removed much like a cassette.

Slide 42: Microwave TreatmentTechnologies

Microwave treatment is essentially a steam-based process since treatment occurs through the action of moist heat and steam generated by microwave energy. Water contained in the waste is rapidly heated by microwave energy at a frequency of about 2450 MHz and a wavelength of 12.24 cm. In general, microwave treatment systems consist of a treatment area or chamber into which microwave energy is directed from a microwave generator (magnetron).

Wastes commonly treated in microwave systems are the same as those treated in autoclaves, such as materials contaminated with blood and body fluids, sharps, and laboratory wastes.

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Slide 43: Example of Small to Medium Microwave Systems

A typical batch microwave system, as shown in Figure 11.7, is designed to handle between 30 to 100 liters of waste. Some units require reusable, fully enclosed, microwavable containers. The systems may have multiple programmable cycles corresponding to different treatment temperatures or levels of disinfection. A cycle may range from 30 minutes to one hour.

Photos from top going clockwise: Meteka Medister 10 (8 liter capacity), Meteka Medister 60 and 360 (30 and 60 liter capacities, respectively), Sintion (103 liter capacity), and Sterifant which uses 10-liter containers. Metaka and Sintion are Austrian manufacturers. Sterifant is from Luxembourg.

Slide 44: Examples of Large-scale Continuous Microwave Systems

Top left: Sanitec (US)Top right: Micro-Waste (US)Bottom right: AMB Ecosteryl (Belgium)

Typical operation based on the Sanitec:Waste loading: Red bags are loaded into carts that attach to the feed assembly. High temperature steam is then injected into the feed hopper. While air is extracted through a HEPA filter, the top flap of the hopper is opened and the container with medical waste is lifted and tipped into the hopper. Internal shredding: After the hopper flap is closed, the waste is first broken down in the hopper by a rotating feed arm and ground into smaller pieces by a shredder. Microwave treatment: The shredded particles are conveyed through a rotating conveyor screw where they are exposed to steam and then heated to between 95° and 100°C by four or six microwave generators. Holding time: A holding section ensures that the waste is treated for a minimum total of 30 minutes. Optional secondary shredder: The treated waste may be passed through a second shredder that breaks it into even smaller pieces. This is used when sharps waste is treated in the microwave unit. The optional secondary shredder can be attached in about 20 minutes prior to operation. It is located at the end of a second conveyor screw.Discharge: The treated waste is conveyed using a second conveyor screw or auger, taking waste from the holding section and discharging it directly into a bin or roll-off container. The

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bin can be sent to a compactor or taken directly to a sanitary landfill.Documentation: The operating parameters can be printed for documentation.

The Sanitec has been shown to be able to treat anatomical waste or body parts.

Slide 45: Examples of Frictional Heat Treatment Systems

Newster (left) and Ompeco (right) are both made in Italy.

The Newster technology utilizes frictional heating supplemented by resistance heaters to heat the waste up to about 150°C while shredding it into a dry powder. The sterilization process is also aided by the addition of sodium hypochlorite. A high-speed rotor operating at two speeds—1300 to 2800 rpm—is used. The first part of the treatment employs moist heating by steam generated by the rotor causing the waste to reach a temperature of 100°C. The steam and other vapors generated pass through heat exchangers and filters to condense steam and filter the air before being released to the environment. When all the fluids have evaporated, the waste continues to be heated to dry superheated conditions. The waste is kept above 135°C up to 150°C for several minutes to achieve sterilization. The whole process takes place at atmospheric pressure. The residue is an odorless, dry product resulting in an average 70-75% volume reduction and 20-25% mass reduction. The system uses a programmable logic controller. Two Newster models handle 100 and 130 liters per 30-minute cycle.

The OMPeco technology combines frictional heating and internal shredding to produce a dry, odor-free waste with a 70% volume reduction and 30% mass reduction. The process takes place in about 30 minutes. The larger units consist of an automatic waste bin loader, sterilization chamber or cell containing rotor blades at the bottom, valves for water injection and waste discharge, pumps for vapor extraction, filter and condenser, and a heat exchanger. Vapors and condensate are filtered. The system is fully enclosed and controlled by a programmable logic controller. Six Ompeco models can handle from 100 liters to 11,000 liters per cycle or 10 to 1500 kg per hour.

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Slide 46: Examples of Small Dry Heat Systems

Photo sources: Demolizer, Sterigerms

Left photos: Demolizer (US) is a table-top unit that heats to 177oC and uses its own disposal container with a capacity of 3.8 liters. Processing time is 2.5 hours per container.

Right photos: Sterigerms (France) heats the waste to 150oC for 20 minutes and compacts the waste using a piston. The output is a flat compact disk that can be discarded as regular waste. The two models of the Sterigerms have capacities of 12 and 60 liters per cycle with a process cycle of 55 minutes.

In dry heat processes, heat is applied without adding steam or water. Instead, the waste is heated by conduction, natural or forced convection or thermal radiation. In forced convection heating, air heated by resistance heaters is circulated around the waste in the chamber.

As a general rule, dry heat processes require higher temperatures and longer exposure times than steam-based processes. They are commonly used to treat small volumes. Bacillus atrophaeus spores, which are resistant to dry heat, are used as a microbiological indicator for dry heat technologies.

Slide 47: Chemical Treatment Technologies

Go through the elements regarding the chemical disinfection of solid infectious wastes.

Shredding or milling is likely necessary before disinfection, which will require powerful disinfectants.

Slide 48: Chemical Treatment Technologies

Used to inactivate microbes on medical equipment, or reduce their numbers to acceptable levels.

It is important to follow manufacturers’ instructions when handling disinfectants and to store them properly, keeping an eye on stability and expiration dates.

Chemicals popularly used for HCW disinfection include chlorine compounds, aldehydes,

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lime-based powders or solutions, ozone gas, ammonium salts and phenolic compounds.Sodium hypochlorite (NaOCl) is a common chemical disinfectant, and may be found in such products as household bleach.

Slide 49: Examples of Chemical Treatment System

Trinova Medical Waste Solutions (left photo) is a provider of an automated healthcare waste treatment system utilizing chlorine dioxide (ClO2) as a disinfectant and an internal granulator that pulverizes the waste. The shredded waste is submerged for a short period in an aqueous solution of chlorine dioxide disinfectant and then dewatered. The resulting confetti-like material is then discarded as regular waste. Periodically during the operation of the machine, depleted chlorine dioxide solution is discharged into a neutralization tank where it is then mixed with the neutralization chemicals and monitored for safe disposal into any sanitary sewer. Three Trinova models handle from 270 to 680 kg per hour of waste.

The SteriMed (right photo) simultaneously shreds, grinds, mixes and treats infectious waste in a proprietary mixture containing glutaraldehyde and quarternary ammonium compounds, both of which are toxic and have to be handled carefully. After treatment, the material is discarded as conventional solid waste. The shredding, grinding and mixing of the waste is initiated to expose all surfaces of the medical waste to the chemical solution during the 15-minute processing cycle. At the end of each cycle, a valve in the treatment chamber automatically opens, allowing the entire contents to be released into the Separator, which separates the solid from the liquid components. Once the processed waste is transferred to the Separator additional waste can be loaded and new cycle begun. SteriMed can process up to 70 liters per 15-minute cycle.

Slide 50: Alkaline Hydrolysis TechnologiesSlide 51: Examples of Alkaline Hydrolysis Systems

Sources: WR2 (top left), BioSafe Engineering (bottom left and top middle), PRI (middle bottom), Bio-Response Solutions (top right), Peerless (bottom right)

Alkaline hydrolysis or alkaline digestion is a process that converts animal carcasses, human body parts and tissues into a decontaminated aqueous solution. The alkali also destroys fixatives in tissues and various hazardous chemicals including formaldehyde, glutaraldehyde and chemotherapeutic agents. The technology uses a steam-jacketed, stainless steel tank

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and a basket. After the waste is loaded in the basket and into the hermetically sealed tank, alkali (sodium or potassium hydroxide) in amounts proportional to the quantity of tissue in the tank is added along with water. The contents are heated to between 110° to 127°C or higher while being stirred. Depending on the amount of alkali and temperature used, digestion times range from six to eight hours. Low-pressure alkaline digestion units are also available. They generally have longer operating times.

The technology is designed for tissue wastes including anatomical parts, organs, placenta, blood, body fluids, specimens, human cadavers and animal carcasses. The process has been shown to destroy prion waste. The byproducts of the alkaline digestion process are biodegradable mineral constituents of bones and teeth (which can be crushed and recovered as sterile bone meal) and an aqueous solution of peptide chains, amino acids, sugars, soaps, and salts. An excess of hydroxide could lead to a high pH of the liquid waste. Alkaline hydrolysis units have been designed to treat from 10 kg to 4500 kg per batch. The technology has been approved for the destruction of prion waste when treated for at least six hours.

Slide 52: Non-Incineration Technology ResourcesSlide 53: Disposal Methods Introduce disposal methods

Slide 54: Disposal in a Landfill Go through the elements of a sanitary landfill

Slide 55: Uncontrolled Dumping in Low-Resource Settings

Uncontrolled dumping is likely to result in adverse public health and environmental problems.

Photo: Scavengers at a dumpsite (Patwary, Masum A., An Illicit Economy: Scavenging and Recycling of Medical Waste. Journal of Environmental Management, 2011, vol. 92, 2900-2906)

Slide 56: Upgrading Land Disposal in Low-Resource Settings

A well-engineered landfill is designed to minimize the contamination of soil, surface water, and groundwater, limit atmospheric releases and odors, keep pests and vectors from wastes, and block public access to the site.

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Slide 57: Encapsulation of Healthcare Waste in Low-Resource Settings

It is not recommended to dispose of untreated HCW in municipal landfills, but if no other option exists for the facility, encapsulation may be an option.

It is important to follow the proper procedures if this method is to be safely and effectively used.

Primary advantage of this process is that it reduces the risk of scavengers gaining access to the wastes.

Slide 58: Encapsulation Schematic

Picture showing an example of encapsulation

Source: Diaz, L.F., et. al. Alternatives for the treatment and disposal of healthcare wastes in developing countries. Waste Management, 2005, vol. 25, 626-637

Slide 59: Inertization of Healthcare Waste in Low-Resource Settings

Inertization is another disposal method.

For the inertization of pharmaceuticals, the packaging should be removed, the pharmaceuticals ground up, and a mixture of lime, water, and cement added.

The proportions of the mixture by weight are typically as follows:65% pharmaceutical waste15% lime15% cement5% water

Slide 60: Disposal of Untreated Healthcare Waste in Low-Resource Settings

In some cases, the healthcare facility may lack the means to treat waste before disposing of it to a landfill.

Mature = waste that is at least 3 months old

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Slide 61: Disposal of Untreated Healthcare Waste in Low-Resource Settings

In other cases, the facility may have no option except to bury the waste on its own premises.

Go through the list of safety measures if this minimal approach is to be exercised.

Slide 62: Schematic of a Burial Pit on Hospital Premises

Schematic giving an example layout of a special burial pit

Source: Diaz, L.F., et. al. Alternatives for the treatment and disposal of healthcare wastes in developing countries. Waste Management, 2005, vol. 25, 626-637

Slide 63: Other Resources

Slide 64: Discussion Generate a discussion with the class using the review questions.

References (in order as they appear in slides)

Blue Book, Chapter 8

Compilation of Vendors of Waste Treatment Autoclave, Microwave, and Hybrid Steam-Based Technologies (UNDP GEF, 2012)

Compendium of Technologies for the Destruction of Healthcare Waste (UNEP, 2012)

Non-Incineration Medical Waste Treatment Technologies (HCWH, 2001) and Non-Incineration Medical Waste Treatment Technologies in Europe (HCWH, 2004), available from Health Care Without Harm in www.noharm.org

Patwary, Masum A., An Illicit Economy: Scavenging and Recycling of Medical Waste. Journal of Environmental Management, 2011, vol. 92, 2900-2906

Global Inventory of Alternative Treatment TechnologiesEmmanuel, Jorge and Stringer, Ruth (2007). FOR PROPER DISPOSAL: A Global Inventory of Alternative Medical Waste Treatment Technologies.http://www.gefmedwaste.org/downloads/For%20Proper%20Disposal.pdf

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http://www.gefmedwaste.org/downloads/For%20Proper%20Disposal.pdf

http://www.noharm.org/


“Non-Incineration Medical Waste Treatment Technologies” (2001) and “Non-Incineration Medical Waste Treatment Technologies in Europe”(2004), HCWH, available in www.noharm.org

“Safe Management of Bio-medical Sharps Waste in India: A Report on Alternative Treatment and Non-Burn Disposal Practices,” SEA-EH-548, WHO South-East Asia, New Delhi (2005)

“Waste Management and Disposal During the Philippine Follow-Up Measles Campaign 2004,” joint report, HCWH and Philippine Department of Health (2004)

List of vendors of autoclaves and other non-incineration technologies are available from the GEF Medical Waste Project: www.gefmedwaste.org

Diaz, L.F., et. al. Alternatives for the treatment and disposal of healthcare wastes in developing countries. Waste Management, 2005, vol. 25, 626-637

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http://www.gefmedwaste.org/

http://www.noharm.org/

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