In this article we will discuss about how to collect, transport and dispose biomedical waste.
Collection and Segregation:
Waste should be collected and segregated at the site of generation itself. Segregation of the waste denotes separation of waste into various specified categories as per its nature. It aims to keep the harmful and infected material separate from the harmless and noncontagious waste. It also helps in the appropriate disposal of a particular waste type. Briefly, segregation of the hospitals waste is the key to ensure that most of the hospital waste that is noninfectious in nature is treated easily at an economical cost. For this purpose, use of specifically colored waste containers and non-chlorinated plastic bags is mandatory.
ADVERTISEMENTS:
Color Coding and Types of Containers for Disposal of Biomedical Wastes:
Color coding of waste categories with multiple treatment options as defined in Table 4.1, shall be selected depending on treatment option chosen.
Waste collection bags of waste types needing incineration shall not be made of chlorinated plastics.
A brief description of the waste to be segregated into different colored bags is given below:
ADVERTISEMENTS:
i. Yellow Color Non-Chlorinated Plastic Bag:
Human tissues, organs and body parts; animal tissues and body parts, waste generated from the animal houses, microbiology cultures, waste generated from production of biologicals, solid contaminated waste like cotton, dressing, plaster casts, linens, beddings and other such material contaminated with blood or body fluids and discarded medicines and cytotoxic drugs.
ii. Red Colored Non-Chlorinated Plastic Bag:
Microbiology and biotechnology waste and other laboratory waste (waste from clinical samples, pathology, biochemistry, hematology, blood bank, laboratory cultures, stocks or specimens of microorganisms live or attainted vaccine. Human and animal cell cultures used in research, infectious agents from research and industrial laboratories, waste from production of biological toxins, dishes and devices used for transfer of culture, etc. Waste sharps (needles, glass syringes with fixed needles, scalpels, blades, etc. that may cause puncture and cuts. (This includes used or unused sharps).
ADVERTISEMENTS:
Infections solid waste (wastes generated from disposable items other than the waste sharps such as tubing, hand gloves, saline bottles with I/V tubes, catheters, glass, intravenous sets, etc.).
iii. Blue Colored Non-Chlorinated Plastic Bag:
Chemical waste (chemicals used in production of biologicals, chemicals used in disinfection, insecticides, etc.)
iv. Black Colored Non-Chlorinated Plastic Bag:
ADVERTISEMENTS:
Municipal hospital waste such as office waste (paper waste, etc.), kitchen waste, food waste and other noninfectious waste, shall be stored in black colored bags or containers and shall be disposed off in accordance with Municipal Solid Waste (Management and Handling) Rules, 2000.
Use of plastic bags makes the transportation easier, it prevents the spillage and the waste remains outside the view of others. This also keeps the original containers clean. The plastic bags are not to be reused.
When bag or container, as the case may be, is three fourth full, it should be sealed by tying it up. The disposable sharp container should be sealed by tape.
All bags or container must be labeled as given below at the site of generation of the waste:
Label for Biomedical Waste Containers/Bags:
Biomedical waste handlers should be trained in handling the waste and made aware of proper way of handling waste to avoid injury and accidents.
A certain procedure should be followed for collection of the waste:
i. Specifically colored plastic bag should be kept in its container. Bins as well as bangs should bear the biohazard symbol.
ii. The waste should be so put in this bag that it does not spill out-side.
iii. As soon as three-fourth of this bag is full, it should be removed from the container, tied with a plastic string and properly labeled. Excess waste in the bag increases the risk of spillage and tearing of the bags.
iv. Label shall be non-washable and prominently visible. Under no circumstances, an infectious waste should be mixed with the noninfectious waste.
v. Collection of disposable items (like syringes, IV bottles, catheters, rubber gloves, etc.) should be undertaken only when they have been mutilated (cut) and chemically disinfected (by dipping in 1% hypochlorite solution for 30 minutes). Syringe barrel should always be separated from the plunger before disinfection.
vi. Needles should be destroyed with a needle destroyer. Manual mutilation of sharps should never be tried as it may cause injury. All other sharps must be strongly disinfected (chemically) before they are shredded or finally disposed. Once this is done, they must be kept in a puncture proof container and properly labeled. This container can be finally put in the proper bin and bag.
vii. Noninfectious waste can be dealt with as a normal household waste and it does not require any special treatment (provided it has not been mixed with an infectious waste).
Minimize the Waste Generation:
Proper collection and segregation of biomedical waste are important. At the same time the quantity of the generated waste is equally important. A lesser amount of biomedical waste means a lesser burden on waste disposal work, cost saving and a more efficient system. Thus, all of us should always try to reduce waste generation in our day-to-day work in the hospital.
Some of the possibilities are given below:
i. Use a material only when it is absolutely must. Use it in the minimum possible quantity.
ii. Try to replace the disposable items with more conventional, reusable article (if an adequate sterilization can be ensured, whenever needed). For example, use cloth aprons, caps and masks instead of disposable paper ones. Similarly, beverages can be served in proper cups, glasses or earthen posts. Paper envelopes may be used instead of aluminum foil.
iii. Buy in bulk (e.g. antiseptic concentrate, dilute as and when needed). This would minimize the generation of packing materials waste. Find materials that are more environment friendly at all stages and even during disposal.
Transportation and Storage:
Transporting the waste from the site of generation to the central storage area and from the central storage to the site of final disposal/ common biomedical treatment facility. Storage (locally as well as at the site of final disposal). Ideally, as soon as the waste bag is three-fourth full, it should be tied, labeled and sent to the site of final disposal. However, it may not be practical to make frequent trips to the site of disposal just with a few bags-full of waste. In this situation, the waste may be temporarily stored at a central area in the hospital and from there it may be sent in bulk to the site of final disposal daily or twice a day.
Transport to the Central Storage Area:
I. Check that waste bags/containers are properly and effectively sealed.
II. Waste bag is properly labeled.
III. Bags should be picked up by the neck and placed, so that bags can be picked up by the neck again for further handling. Hand should not be put under the bag. At a time only one bag should be lifted.
IV. Manual handling of waste bags should be minimized to reduce the risk of needle prick injury and infection. Avoid close contact between body and bag/container.
V. Waste bag or container should not be thrown or dropped.
VI. While shifting the container with sharp waste, care should be taken to avoid prick/injury.
VII. Biomedical waste should be kept only in a specified storage area.
VIII. After removal of the bag, clean the container including the lid with an appropriate disinfectant.
IX. Waste bags and container should be removed daily from wards/ OPDs or even more frequently from the operation theaters, intensive care units (ICUs) and labor rooms. Bags and containers should not be removed unless they are properly tied, secured and labeled. Bags or containers containing the waste should be transported in covered wheeled containers or large bins in covered trolleys dedicated for this purpose. The bags and containers should be replaced by fresh bags/containers at appropriate intervals.
X. Biomedical waste storage areas must be separate from general waste storage sites and should have clear signs indicating “For Biomedical Waste Only”
XI. Waste route must be designated to avoid the passage of waste, through patient care areas. Dedicated wheeled containers, trolley or cart should be used to transport the waste bins to the main storage areas. They should be thoroughly cleaned and disinfected in the event of any spillage.
XII. In case, a lift is to be used during transportation of biomedical waste it should be designed and reserved for this purpose only.
Central Storage:
The central storage area in a hospital should be ideally situated on the ground floor and near the rear entrance. This will make the transportation of waste to the site of final disposal easier. The central storage area should be big enough to store the required number of waste bags at a time. There should be sufficient storage capacity to store at least two day’s waste. It should have a good flooring, light, ventilation and water supply. There should be special drain to discharge the washing, which should go to the sewer.
A full time storekeeper should be responsible to receive and dispatch the waste and maintain proper records. Unauthorized people should not be able to enter the storage area. An accidental spillage should be properly attended and reported in Form III as per rule the biomedical waste cannot be stored for more than 24-48 hours. Refrigerated storage room (cold rooms) can be considered where the waste has to be stored in bulk for over 48 hours.
Transport to the Final Disposal Site:
Transportation from the healthcare establishment to the final disposal (incinerator/common bio waste treatment facility site) should be done by authorized motor vehicle specific for this job. A closed transport with biohazard symbol on sides should be used and these vehicles are not used for any other purposes.
Temporary storage of biomedical waste may also be needed at the site of final disposal. It should have all characteristics similar to that described for the central storage area of the hospital.
Disposal of Biomedical Waste:
Disposal of biomedical waste is done in two steps:
1. Pretreatment – The infected waste that cannot be incinerated (e.g. plastic and rubber items, sharps, etc.) has to be disinfected first, before it is sent for the final disposal.
2. Final disposal – This involves incineration or secured land filling and deep burial (restricted).
1. Pretreatment:
Disinfection of non-incinerable items can be done in many ways as described below:
i. Chemical Disinfection:
Plastic, rubber and metallic items (like IV sets, blood bags, gloves, catheters, syringes and needles) must be chemically disinfected before they are sent for final disposal (landfill).
Chemical disinfection can be done in following steps:
a. Mutilate the syringes and needles with a needle destroyer. Cut all other plastic/rubber item with the help of scissors (so that they cannot be reused.
b. Make 1% hypochlorite solution (fresh everyday) by dissolving 10 g of this powder (approx. 2 spoonful) in 1 L of water in a plastic bucket.
c. Keep another, smaller bucket with perforations inside the main bucket (having the solution). Put all the items that are to be disinfected inside the perforated bucket and ensure that they are kept well-dipped in the solution for 30-60 minutes.
d. After 30-60 minutes, pull out the perforated bucket (while solution remains back in the main bucket), take out the disinfected items and put them in a proper waste bag. Sharps should be first kept in a tough cardboard box and then only put in the plastic bag so as to avoid damage to the bags.
e. Change the solution every 12 hours.
ii. Autoclave:
This is an effective technique for sterilization of microbiology, biotechnology waste and also for the infected disposable plastic and rubber waste (e.g. gloves, blood bags, IV sets, syringes, etc.). This technique works on the basis of heat and pressure applied for a period of time.
Certain rules should be followed while using autoclave:
a. There should be a separate autoclave for the sterilization of biomedical waste.
b. While an autoclave works, the indicator must show appropriate temperature, time and pressure. If not, the whole procedure should be repeated.
c. Medical waste shall be subjected to:
Operating a Gravity Flow Autoclave:
I. A temperature of not less than 121°C and pressure of 15 pounds per square inch (psi) for an autoclave residence time of not less than 60 minutes, or
II. A temperature of not less than 149°C and a pressure of 52 psi for an autoclave residence time of less than 30 minutes.
Operating a Vacuum Autoclave:
I. A temperature of not less than 121°C and pressure of 15 psi for an autoclave residence time of not less than 45 minutes; or
II. A temperature of not less than 135°C and a pressure of 131 psi for an autoclave residence time of not less than 30 minutes.
d. Each autoclave shall have graphic of computer regarding device throughout the autoclave cycle for proper record and efficiency.
e. Validation test, spore tests.
f. Routine test strip/temperature strips should be recorded.
g. After autoclave, plastic items can be shredded but rest of the items should be sent for final disposal in the landfill.
In this method, shredded infectious waste is exposed to high temperature, high-pressure steam like an autoclave. This also inactivates most of the microorganisms if temperature and contact time are sufficient.
This method has a relatively low investment and operating cost and its environmental impact is also less.
Certain rules to be followed are:
a. All waste must be shredded before subjecting to this method. Sharps must be milled or crushed.
b. Effectiveness should be routinely checked.
c. The equipment should be operated and maintained by adequately trained technicians.
Alternate to incinerator, plasma pyrolysis treatment technology can be installed for disposal of biomedical waste categories 1, 2, 5 and 6 wherein destruction of biomedical waste similar to incineration can be achieved. In this technique, waste is treated at high temperature under controlled conditions to form gases like methane, hydrogen and carbon monoxide which are subjected to combustion (oxidation) in secondary chamber.
In the plasma pyrolysis process, waste is converted into small clinker which can be disposed in the secured landfill.
v. Microwave Irradiation:
This technique is also effectively (like autoclave/hydroclave) in sterilizing the infected, disposable waste. Most microorganisms are destroyed by the action of microwaves. The water contained within the waste is rapidly heated and the infectious components are destroyed by the heat conduction. The waste is first shredded (in the unit itself) and then humidified and irradiated. Lastly, the waste is compacted inside a container and can go to the municipal waste system. This is an expensive system and it also requires a good operational and maintenance control. These disadvantages may make it unsuitable for use in a developing country.
Shredder for Plastic Material:
Shredder for plastic material (plastic bottles, IV sets, syringes, etc.) cuts the plastic waste into small pieces of 1 cm size chips. It ensures that syringes and other plastic material are rendered non-recyclable.
The following techniques can dispose of the biomedical waste on a final basis:
I. Incineration:
It is a high temperature, dry oxidation process that reduces organic and combustible waste to inorganic, incombustible mater. It also reduces the waste volume and weight. It is usually selected for the waste that cannot be reused, recycled or disposed of in a landfill site.
Incineration requires no pretreatment provided certain waste types are not included.
Following waste types may be easily submitted for incineration:
i. Human waste (tissues, body parts, blood and body fluids)
ii. Animal waste
iii. Dressing material.
Following waste should not be incinerated:
a. Pressurized gas containers
b. Large amount of reactive chemical waste
c. Photographic/radiographic waste
d. Halogenated plastic such as polyvinyl chloride (PVC)
e. Waste with high mercury or cadmium content (such as thermometers, used batteries)
f. Sealed ampoules or ampoules containing heavy metals.
Incinerators are of three types:
i. Single Chamber Furnaces:
These may be the cheapest units.
ii. Double Chamber Pyrolytic Incinerators:
These are most reliable and are commonly used for disposal of biomedical waste. They are also referred to as double-chamber incinerators. In the first (pyrolytic) chamber, waste is destroyed through an oxygen deficient, medium temperature combustion process (800°C). This produces solid ashes and gases. In the second (post-combustion) chamber, gases are burnt at a high temperature (900° to 1200°C) using an excess of air to minimize smoke and odor. This equipment may be somewhat expensive and requires trained personnel to handle it. Regular maintenance and operational care are also needed.
iii. Rotary Kilns:
It comprises of a rotating oven and a post-combustion chamber. It may be specifically used to burn chemical waste (chemicals, pharmaceuticals including cytotoxic drugs).
A number of recommendations are to be made while using incineration as a final disposal facility for the biomedical waste:
a. An incinerator should be situated at a safe distance from the residential areas.
b. Incinerator plant should have a strong fencing and unauthorized entry (including that of rag-pickers) should be prohibited.
c. The plant area should have proper electricity and water facility.
d. Waste should be loaded directly to the furnace preferably using an automatic loading device.
e. Biomedical waste should not be stored for more than 24 hours at the incineration plant.
f. Efficiency of the plant should be regularly checked.
g. Biomedical waste should be introduced into the furnace only when the normal conditions of combustion have been established (never during start-up or shut down of the process).
h. Suitable techniques must be adopted to keep the air pollution to the minimum.
i. Residual ashes should be sent to the landfill.
j. Facilities should be available at the incineration site for the cleaning and disinfection of transportation equipment including vehicles.
Besides other methods of disposal for sharp, burial in safe pit is an effective and economical method. Sharps (needles and blades) are being used in day-to-day practice in all healthcare units. Needle prick may be responsible for tetanus, HBV and HIV/AIDS diseases. To avoid recycling of needles and sharps, these should be buried in safe pits.
Design and Construction:
It can be constructed by 5 feet deep circular concrete ring of 3′ diameter or by using bricks (4′ x 3′ x 5′ deep) which can be made circular or rectangular. A slab is used on top in which GIC pipe with 5″ or 6″ diameter is used which is fitted with lock and key arrangements. Size will vary as per requirement, i.e. is quantum of sharp waste.
The pit is plastered inside at bottom and around. The size and shape of pit varies as per space available and requirement. When it is filled up, cement slurry can be used to close it and second pit is constructed.
i. Eco-friendly
ii. Cost-effective
iii. Easy to construct within 48 hours
iv. Most suitable for rural health center and hospitals when space is available.
Local bodies such as Gram Panchayats, Municipalities or corporations will provide or allocate suitable land for secured landfill/common biomedical waste treatment and disposal facility for safe treatment and disposal of biomedical waste in their respective jurisdictions.
It is another choice for final disposal of biomedical waste and it can be quite effective if practised appropriately. While open dumping of biomedical waste cannot be recommended for the reasons of acute pollution problems, fire, higher risk of disease transmission and open access to scavengers and animals, a sanitary landfill observing certain rules can be an acceptable choice particularly in developing countries.
Some essential elements for design and operation of a sanitary landfill are given below:
a. A specifically designated place should only be used for the landfill. Proper permission to use the place for the said purpose must be obtained from the relevant authority.
b. The site should preferably be away from the residential areas.
c. Location should be such that vehicles carrying waste can easily approach it in all weathers.
d. The area should be under constant supervision and security control. Unauthorized entry must be strictly prohibited.
e. It should not be in the vicinity of a drinking water source as pollution may result.
f. The site should be divided into various manageable phases and all of them should be adequately prepared before the actual landfill starts.
g. The site should be so organized that the waste can be spread, compacted and covered daily.
h. A final cover should be constructed to prevent the rain water infiltration when each phase of landfill is completed.
i. Waste should be buried as rapidly as possible so as to minimize the exposure to humans or animals.
Common biomedical waste treatment facility as an option has been legally introduced in India. It is set-up where biomedical waste generated from small and big healthcare units is collected, treated and disposed off at a comparatively less cost. It also reduces the monitoring pressure on regulatory agencies.
In order to set-up a Common Biomedical Waste Treatment Facility (CBWTF) to its maximum perfection, care shall be taken to in choosing the right technology, development of CBWTF area, proper designing of transportation system to achieve optimum results. On these key features, CBWTF’s guidelines for the establishment have been prepared to be followed throughout the country.
The guidelines have the following features:
i. Location
ii. Land requirement
iii. Coverage area of CBWTF
iv. Treatment equipment
v. Infrastructure setup
vi. Regular record keeping, regular for waste movements, log book for the equipment site records
vii. Collection and transportation of biomedical waste
viii. Disposal of treated biomedical waste
ix. Cost to be charged by CBWTF from healthcare units
x. Setting up and operation of CBWTF
xi. Checklist for development of common biomedical waste treatment facility.
Techniques for Management of Biomedical Waste:
Several other techniques have been developed for management of biomedical waste.
Using a plasma converter, the system forces gas through an electrical field to ionize the gas into plasma state that conducts electricity and achieves high temperatures. The converter is fired by electricity and uses a plasma torch to produce an intense field of radiant energy reaching very high temperature that causes waste material to break up into its elemental atomic components thereby completely destroying the waste. Useful recyclable such as elemental metals, silicates and pure hydrogen gas can also be produced. The plasma converter is very well-insulated and completely computer controlled.
The advantages are:
i. Can process any and all waste material.
ii. Recycles waste into valuable commodities.
iii. Provides safe and irreversible destruction of the most hazardous waste.
iv. Converts toxic substances into harmless material and does not require the waste to be sorted.
v. As there is almost no residue, it eliminates the need for landfills and can be used in the countries which lack landfill space.
2. Electro Thermal Deactivation (ETD) Technology:
It uses radioactive frequency (RF) waves from treatment of regulated waste. This is an alternative technology to incineration and similar to microwave.
The advantages over microwave is that RF waves have a longer wave length (9-12 feet) having deep penetration.
Compared to incineration, this technology has no toxic air or water emissions. The waste is reduced by 80% volume and rendered unrecognizable.
Accessory Processes:
Before treatment with RF, waste is shredded, usually under continuous negative pressure using filters to present aerosol contamination of the environment. After treatment with RF, a roll off compactor is applied to reduce the volume of the waste.
The validation of the process is done by Bacillus subtilis spores count with at least 1 x 104 spores per milliliters.
Under detoxification technology, waste is simultaneously shredded and heated to 480-700°C. Gases evolved raise temperature to 1540°C, by which the organic compound is destroyed.
4. Other Emergency Technologies:
Other emergency technologies include electrochemical oxidation, molten metal technology, solvated electron process and superficial water oxidation.