The volume of medical wastes generated world-wide has seen a significant rise since the pandemic. There has been an increase in the usage of masks, gloves and single-use personal protection equipment. Most of these single-use products are made from fossil-based sources like polyethylene, polypropylene, polyurethane etc. Apart from the environmental concerns, littering of these can harm ecosystems, and microplastics can find their way into the food chain. The growth in population has also contributed to the increase in medical waste. More than 150 tonnes of medical waste are generated in the GCC countries every day. 

Medical wastes can be classified as laboratory waste (from pathology units), biological wastes (human blood, bodily fluids, waste from contagious diseases, body parts such as excised tumors and organs), sharps (used syringes, needles, surgical tools, scalpels or broken glass), radioactive wastes (Liquids used from radiotherapy or laboratory research), cytotoxic wastes (drugs used in cancer treatment) and pharmaceutical wastes (expired or unused drugs and vaccines). Waste must be segregated to comply with environmental and health safety standards and minimise risk of exposure to hazardous substances.

Medical wastes need to be handled with care and disposed of appropriately to ensure that there is no risk of contamination. Improper disposal methods pose risks to patients, health workers and the general public as it can cause transmission of diseases like typhoid, Hepatitis B and AIDS. Dental clinics discharge harmful amalgams into the environment that can be converted by certain bacteria to methyl mercury which enters the food web and gets accumulated in higher organisms. Segregation of waste is crucial in waste management and in many cases, this is not implemented.

The common disposal methods used in the MENA region are incineration and landfilling. Incineration is the most common technique and involves the burning of both infectious and non-infectious waste. The process can emit significant amounts of particulate matter, carbon monoxide, oxides of nitrogen and sulphur, and organics. Incineration also releases dioxins and furans, which are carcinogenic, and can cause developmental and hormonal issues. The residual ash, which contains heavy metals and other hazardous substances is discarded in landfills where there is a risk of them leaching into groundwater. 

Disposal methods and challenges

Some of the issues with landfill disposal include emission of harmful gases like methane, the proliferation of rodents and insects and soil degradation. Leachate from these landfills can contaminate ground and surface water. Pharmaceutical wastes promote the growth of antibiotic-resistant bacteria. Potent and expensive antibiotics are required to treat these strains and prolonged hospitalisation is needed in some cases. Disposing of needles and syringes in open landfills poses the risk of re-use and infections. Plastic waste or masks and PPEs can choke animals that scavenge on openly dumped waste in landfill sites.  

In contrast, autoclaves provide a safe method for sterilising medical waste, including highly infectious sharps waste. Steam at high temperature and pressure is used to kill pathogens. However, this process is unable to reduce the volume of medical wastes and use of autoclave technology is expensive for developing countries. Water and energy requirements are quite high. The advantage of this method is that it does not produce strong carcinogenic dioxins. Microwave technology works on a similar principle wherein electromagnetic waves are used to generate steam from the moisture in the medical waste, which then destroys the microorganisms. This method, too, is expensive and there is a risk of the residual leachate contaminating the groundwater.

Pyrolysis is a promising technique, which involves thermal degradation of matter in an anaerobic environment. Energy can be recovered and products like biochar, biogas and bio–oil can be obtained. The process is environmentally friendly as it reduces the emission of toxic gases.

It is imperative to make the waste management processes sustainable. In this context, non-incineration methods cause minimal pollution and are the preferred techniques for waste management. Autoclaves powered by solar energy are a promising alternative in the Middle East region, where there is good sunlight all year round. This technology can be used with power backup if required and considerably reduces the carbon footprint. The fly ash generated from incineration can be treated and used in concrete mixtures and as building blocks. Plastic, which constitutes about 35% of medical waste, can be recycled and re-used. Using RFID tags facilitate segregation of medical wastes and monitors their transportation to designated locations for further treatment. This has been implemented in many hospitals in UAE, Oman and Saudi Arabia.  Workers in the health industry should mandatorily undertake waste management training sessions to renew their professional licences. Social awareness could motivate individuals to adopt more sustainable practices. 

A comprehensive strategy involving a variety of stakeholders, such as legislators, governmental and non-governmental organisations, and the community, is needed to develop and implement sustainable healthcare waste management. 

Dr. Manjula Nair is an Assistant Professor in Chemical Engineering, School of Engineering and Physical Sciences (EPS), Heriot-Watt University Dubai.