Healthcare sector is growing at a very rapid pace, which in turn has led to tremendous increase in the quantity of medical waste generation in developing countries, especially by hospitals, clinics and other healthcare establishments. The quantity of healthcare waste produced in a typical developing country depends on a wide range of factors and may range from 0.5 to 2.5 kg per bed per day.
For example, India generates as much as 500 tons of biomedical wastes every day while Saudi Arabia produces more than 80 tons of healthcare waste daily. The growing amount of medical wastes is posing significant public health and environmental challenges across the world. The situation is worsened by improper disposal methods, insufficient physical resources, and lack of research on medical waste management. The urgent need of the hour is to healthcare sustainable in the real sense of the word.
Hazards of Healthcare Wastes
The greatest risk to public health and environment is posed by infectious waste (or hazardous medical waste) which constitutes around 15 – 25 percent of total healthcare waste. Infectious wastes may include items that are contaminated with body fluids such as blood and blood products, used catheters and gloves, cultures and stocks of infectious agents, wound dressings, nappies, discarded diagnostic samples, swabs, bandages, disposal medical devices, contaminated laboratory animals etc.
Improper management of healthcare wastes from hospitals, clinics and other facilities in developing nations pose occupational and public health risks to patients, health workers, waste handlers, haulers and general public. It may also lead to contamination of air, water and soil which may affect all forms of life. In addition, if waste is not disposed of properly, ragpickers may collect disposable medical equipment (particularly syringes) and to resell these materials which may cause dangerous diseases.
Inadequate healthcare waste management can cause environmental pollution, growth and multiplication of vectors like insects, rodents and worms and may lead to the transmission of dangerous diseases like typhoid, cholera, hepatitis and AIDS through injuries from syringes and needles contaminated with human.
In addition to public health risks associated with poor management of biomedical waste, healthcare wastes can have deleterious impacts on water bodies, air, soil as well as biodiversity. The situation is further complicated by harsh climatic conditions in many developing nations which makes disposal of medical waste more challenging.
The predominant medical waste management method in the developing world is either small-scale incineration or landfilling. However, the WHO policy paper of 2004 and the Stockholm Convention, has stressed the need to consider the risks associated with the incineration of healthcare waste in the form of particulate matter, heavy metals, acid gases, carbon monoxide, organic compounds, pathogens etc.
In addition, leachable organic compounds, like dioxins and heavy metals, are usually present in bottom ash residues. Due to these factors, many industrialized countries are phasing out healthcare incinerators and exploring technologies that do not produce any dioxins. Countries like United States, Ireland, Portugal, Canada and Germany have completely shut down or put a moratorium on medical waste incinerators.
Alternative Treatment Technologies
The alternative technologies for healthcare waste disposal are steam sterilization, advanced steam sterilization, microwave treatment, dry heat sterilization, alkaline hydrolysis, biological treatment and plasma gasification.
Nowadays, steam sterilization (or autoclaving) is the most common alternative treatment method. Steam sterilization is done in closed chambers where both heat and pressure are applied over a period of time to destroy all microorganisms that may be present in healthcare waste before landfill disposal. Among alternative systems, autoclaving has the lowest capital costs and can be used to process up to 90% of medical waste, and are easily scaled to meet the needs of any medical organization.
Advanced autoclaves or advanced steam treatment technologies combine steam treatment with vacuuming, internal mixing or fragmentation, internal shredding, drying, and compaction thus leading to as much as 90% volume reduction. Advanced steam systems have higher capital costs than standard autoclaves of the same size. However, rigorous waste segregation is important in steam sterilization in order to exclude hazardous materials and chemicals from the waste stream.
Microwave treatment is a promising technology in which treatment occurs through the introduction of moist heat and steam generated by microwave energy. A typical microwave treatment system consists of a treatment chamber into which microwave energy is directed from a microwave generator. Microwave units generally have higher capital costs than autoclaves, and can be batch or semi-continuous.
Chemical processes use disinfectants, such as lime or peracetic acid, to treat waste. Alkaline digestion is a unique type of chemical process that uses heated alkali to digest tissues, pathological waste, anatomical parts, or animal carcasses in heated stainless steel tanks. Biological processes, like composting and vermicomposting, can also be used to degrade organic matter in healthcare waste such as kitchen waste and placenta.
Plasma gasification is an emerging solution for sustainable management of healthcare waste. A plasma gasifier is an oxygen-starved reactor that is operated at the very high temperatures which results in the breakdown of wastes into hydrogen, carbon monoxide, water etc. The main product of a plasma gasification plant is energy-rich syngas which can be converted into heat, electricity and liquids fuels. Inorganic components in medical wastes, like metals and glass, get converted into a glassy aggregate.
