Hospital and laboratory waste management is becoming a significant problem in most countries of the world. Due to its infectious and toxic nature, the waste bears numerous health and safety hazards. Health care activities, like diagnosing, treating, and immunizing humans or animals or while conducting research produce hospital waste. Likewise, the waste generated from industry laboratories, educational institutes, hospitals, and laboratories is laboratory waste.
K. Park gave a statement, “Let the waste of the “sick” not contaminate the lives of “the healthy”, clarifies that the proper waste management of hospitals and laboratories plays a crucial role in improving public health as well as the quality of the environment. Therefore, such waste must be handled and treated more carefully than general municipal waste.
Table of Contents
Sources of waste
The following things generates hospital and laboratory waste:
- Government and private hospitals
- Nursing homes and clinics
- Laboratories of different educational institutes and industries
- Primary health care centers
- Blood bank and collection center
- Mortuaries
- Medical research and training center, etc.
Category of waste
Hospital and laboratory wastes can be broadly classified into three groups:
- Non-hazardous waste covers 80% or more of total waste and includes general office/ kitchen waste.
- Infectious waste covers 10-15% of total waste, including sharp objects and anything contaminated with blood, bodily fluids, or body parts.
- Non- infectious but hazardous waste covers 5% of total waste, including X-ray film developer, chemical dyes, pharmaceutical, toxic, and nuclear waste, batteries, used oils, spent solvents, or mercury items.
The municipality or public authority manages the non-hazardous waste, whereas hospitals and laboratories manage infectious and hazardous waste.
WHO has classified hospital waste in to nine types, based on which waste is segregated into either recycling or incineration.
- General waste: no risk to human health. E.g. Office paper, wrappers, general sweeping wastes, etc.
- Pathological waste: human tissue or fluid. E.g. Body fluid, body tissue, body parts.
- Sharps: sharp waste items. E.g. needles, scalpels, knives, etc.
- Infectious waste: can transfer bacterial, viral, or parasitic diseases. E.g. laboratory waste, used cotton or gauze, tissue swabs, bandages, suture materials, etc.
- Chemical waste: chemicals used in treatment or diagnosis, e.g. laboratory reagents, disinfectants, X-ray film developer, etc.
- Radioactive waste: unused liquid from radiotherapy or lab research, contaminated glassware, etc.
- Pharmaceutical: expired or outdated drugs
- Pressurized container: gas cylinder, aerosol cans, etc.
- Genotoxic waste: waste containing cytotoxic drugs used in cancer therapy
As per CDC, Atlanta under US classification, Pathological and Sharp waste also belong to ‘INFECTIOUS WASTE’.
The types and nature of hospital waste depend upon the service available in the hospital and the nature of the hospital.
Hospital and Laboratory Waste Management (Tips and Steps)
A waste management system is a systematic collection, sorting, storing, transporting, and disposal of waste produced by an organization. A significant idea to the success of the system is waste minimization. Hospital and laboratory personnel should be encouraged to generate less waste.
Some tips on How to Manage Waste
- Implement the principle of 3R; Reduce, Reuse and Recycle.
- Keep devices up to date.
- Try to avoid purchasing chemicals in bulk quantities
- Recycle and reuse as many materials as possible. Chemical agents like xylene, formalin, and ethyl alcohol can be distilled, filtered, or recycled.
- Reduce the size and number of containers if not used.
- Store all hazardous waste in the appropriate storage container with proper labeling.
- Regularly train employees in safety procedures because only verbal briefing is not sufficient. Give training for adding waste to and removing from storage containers and types of hazardous and infectious wastes.
Steps of Waste Management
Waste Segregation
The nature of hospital and laboratory waste determines how it will be managed. Therefore, the first step of waste management is the segregation of waste.
Waste segregation is implemented at the point of generation of waste. Different types of waste are kept in separate color-coded and well-labeled bags or containers. Color codes for different types of waste are different country-wise. However, the use of red, yellow, white, blue, and back bins is common. Labeling each bin with symbols, like, as the symbol of biohazard and cytotoxicity is necessary. Regular cleaning and disinfection of the garbage bin are very important.
The nature of waste in different bins is shown in the figure.
Storage and Transportation of Waste
Waste should not be stored for a more extended period in the generation area. It should be transported in a sealed container for treatment and disposal.
Waste Treatment
Chemical Treatment
Chemical treatment applies to all types of waste except body parts and body fluids. Users should wear protective clothes, gloves and goggles while working with chemicals. Chemicals used in disinfection can vary according to the type of waste; some examples are bleach, sodium hypochlorite, chlorine, etc.
Microwave irradiation
It is effective for all except large metals and body parts. A frequency of 2450 MHz with a wavelength of 12.24 cm destroys most microbes. The water of the waste heats, which eliminates the infectious component.
Autoclaving
It is applied to sterilize dressings, gloves, syringes, specific instruments, discarded culture plates, and culture media. Plastics and sharp instruments should not be included in autoclaves. A temperature of 121°C under 15 lb/square inch pressure is effective enough for sterilization.
Encapsulation
It is recommended for the safe disposal of sharp objects. The waste is collected in a puncture-proof container. After it becomes a three-quarter full mortar, material like cement, plastic foam, or clay is poured. After it gets dry, it is disposed of.
Incineration
Incineration is applied only for most hazardous waste that cannot be reused or recycled or can’t be disposed of at the landfill site. An incinerator’s high temperature and dry oxidation process reduce organic, combustible waste to inorganic waste in reduced volume and weight. Finally, ash is generated and disposed of in the sanitary landfill.
Waste that can’t be incinerated is:
- Pressurized containers
- Halogenated plastics
- Waste with high content of heavy metals
- Radioactive waste
Types of Incinerator
- Single-chambered incinerator
Here, the waste is burnt at 300-400°C. This type of incinerator may not achieve proper sterilization due to low temperature.
- Double-chambered incinerator
In this type of incinerator, the waste is burnt in the primary chamber at 800°C, whereas volatile gas is in the second chamber at 1000°C +/- 50°C.
- Pyrolytic Incinerator
The anaerobic combination is conducted in doubled chambered pyrolytic incinerator at 900-1200°C. Waste transforms into combustible liquid and gases, which can be used as fuel for pyrolysis. It reduces operating costs. Compared to the common incinerators, pyrolytic incineration has a high energy recovery rate, less pollution, and is cost-effective.
Figure source: https://www.researchgate.net/figure/Scheme-of-the-laboratory-rotary-kiln-system_fig2_267992380
Incineration has certain disadvantages, like, emitting toxic gases, carcinogens, and toxins like dioxins, furans, and mercury. Fabric filters are fitted in the chimneys of the incinerator chamber to minimize such emissions.
Plasma technology
It is a new technique that uses a gas cloud generated by ionizing an inert gas. As a result, a high temperature, up to 3000°C, is produced, destroying pathogens in the waste. The final product is then disposed of in the landfill.
Though plasma technology is expensive to run, it has certain advantages such as:
- No harmful products are released
- The final volume is reduced
- Heat energy produced can be recycled to lower the operation cost.
However, hospital and laboratory waste is often incinerated or autoclaved.
Waste Disposal
After proper treatment of waste, it is now safe for its disposal.
Landfilling
Landfilling is the oldest technology, but still, several low-income countries rely on it. The main idea is decomposing waste into harmless substances through long-term storage. Unfortunately, the problem of infiltration arises; as a result, toxic, pathogenic, or radioactive materials have access to soil and water resources.
Open dumps should be avoided due to public health risks.
Sanitary landfill: Sanitary landfill with an anti-seepage system has been developed to overcome the harmful effects of a general landfill. It is covered with clay, high-density polyethene, a gas collection system and output pipelines. But, disinfection and reduction of waste are necessary before landfilling.
Figure source: https://www.researchgate.net/figure/A-modern-sanitary-landfill-designed-to-replace-Avu-and-Ihie-open-dumpsites_fig1_270762454
Liquid waste is disposed of in sewage drains.
Proper waste management depends on good planning, funding, administration, and commitment at the policy level. If waste management is implemented correctly, it will benefit both individuals and the environment. Conversion technologies may apply to plastic or lignocellulose fraction, cotton, paper, etc., to convert them into fuel/material production, combining with the municipal waste.
It is wise for hospitals and laboratories to collaborate with local municipalities for waste management. Apart from state and local agencies, waste can also be governed by various international agencies.
References
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- Environmental, M. (2021). Laboratory Waste Management 101 | MLi Environmental. MLi Environmental. Retrieved 23 June 2022, from https://mlienvironmental.com/blog/laboratory-waste-management-ways-improve-output/.
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