Solid medical waste has been referred to as any discarded solid material generated from activities involving health protection, medical diagnosis, treatment, scientific research, dental and veterinary services (US Congress Office of Technology Assessment, 1988; Rao, 2008; Coker et al., 2009; Hossain et al., 2011). This type of waste has been considered potentially harmful to humans and requires special treatment. Non-hazardous waste from health-care facilities is comparable to domestic waste and often ends up in the municipal solid waste stream discarded in landfills (Pruss et al., 1999).

Solid medical waste has remained a source of concern because of the potential to transmit diseases, contaminate soil, surface and ground water with pathogenic microbes, toxic and heavy metals often present in it (Pruss et al., 1999). Diseases associated with poor medical waste management include nosocomial diseases, typhoid, skin disorders, intestinal parasitosis and hepatitis (Bassey et al., 2006).

In addition, there is a potential risk of HIV transmission to a susceptible human host from percutaneous injury by infected sharps (WHO, 2004). Therefore, inadequate handling and disposal of medical waste has consequences for patients, relatives or carers, healthcare workers, waste workers, scavengers, the public and the environment (Abor, 2007; Coker et al., 2009; Mesdaghinia et al., 2009).

Africa is estimated to have 67,740 health facilities and produce approximately 282,447 tons of medical waste every year (AGENDA, 2009, Udofia and Nriagu, 2013). However, the composition of the waste stream considered hazardous and requiring special treatment may be higher than the expected 10 to 25% because of poor waste handling practices reported in many studies (mixing hazardous with non-hazardous waste (Haylamicheal et al., 2011; Fadipe et al., 2011; Abah and Ohimain, 2011). Studies in Africa indicate the continent is not positioned to tackle the quantity of hazardous waste it produces. Much of the waste is dumped without treatment in open dumps and poorly functioning incinerators (Nkhuwa et al., 2008, Nemathaga et al., 2008, Sawalem et al., 2009, Coker et al., 2009, Saad, 2013). While increasing awareness has driven many individual country reports on general solid waste streams in Africa, the overall picture of solid medical waste management is unclear. Consequently information on solid medical wastes in Africa appears to remain on shelves and only scanty in scientific literature.

To the best of our knowledge, this review is the first on solid medical wastes in Africa and sought to compare medical waste management activities (segregation, collection, storage, transport, treatment and final disposal) reported in studies done in Africa with WHO recommendations (WHO, 2014). The general objective of the review was to determine how many of WHO standards were broadly met in each country in Africa and how specific waste management activities compared across the countries included in the review.

Search strategy

A review of literature was conducted using electronic databases wide distribution of studies on healthcare and solid medical waste management. The search strategy employed was as follows:

1. PubMed was searched applying the terms ‘medical waste OR biomedical waste OR clinical waste OR hospital waste OR hazardous waste OR healthcare waste AND Africa’. Additional databases searched using the same search terms included Web of Science, Embase, Scopus, Proquest and African Journals Online. 

2. The search was repeated with the same keywords but replacing Africa with names of individual countries. The list of African countries was adapted from World Bank websites: www.worldbank.org/en/region/mena (North African countries) and www.worldbank.org/en/region/afr (Sub-Saharan Africa) with the addition of Mauritius.

3. A more in-depth search on medical waste in Ghana and Madagascar using the search terms “medical waste in Ghana” and “medical waste in Madagascar” respectively, added 3 articles.  All searches covered the period from 1997 up to October, 2014.

Articles were selected for inclusion in the review if they: described SMW management activities such as waste segregation, collection, transport (on-site and/or off-site), temporary storage, treatment and final disposal; with the study location in an African country and were written in English; or if written in a different language, had an English abstract with the relevant information. Articles which did not meet the selection criteria and focused on liquid waste management and veterinary services were excluded. Duplicate publications were removed manually.

The papers included for review were categorized and evaluated according to the following items: segregation into at least 2 categories of waste (sharps and non-sharps waste); appropriate use of color coded bags, containers and symbols; waste collected at least once a day from generation points; on-site transport with dedicated vehicle; secured temporary storage area; stored waste is treated or discarded not later than the second day; off-site transport in enclosed vehicles with back loading; treatment option includes an advanced thermal method for infectious waste; final disposal at sanitary landfill or disposal site; and periodic training of healthcare staff. These items were based on recommendations by WHO (2014) as the standard set for acceptable waste management activities.

Literature search

Table 1 summarizes the number of hits identified by databases and shows the number of articles involved in the preliminary screening. The flowchart (Figure 1) depicts the literature search process. The search in PubMed produced a total of 299 articles of which 278 articles were excluded on preliminary screening (Figure 1) and 1 full text unavailable in the databases. The other databases yielded a total of 38 articles in full text, after excluding those which were not available (4 articles). Finally, 58 full text articles that met the selection criteria were reviewed.

The reviewed articles covered twenty (20) countries namely: Algeria, Botswana, Cameroun, Egypt, Ethiopia, Ghana, Kenya, Lesotho, Libya, Madagascar, Mauritius, Morocco, Nigeria, Senegal, Somaliland, South Africa, Sudan, Tanzania, Uganda and Zimbabwe (Table 2). Figure 2 shows the distribution of articles by these countries. Figure 3 shows the distribution of articles over the study period and indicates increasing interest and research in solid medical waste management in Africa.

Table 3 summarizes the characteristics of the identified articles. Twenty eight (28) studies (48%) covered a variety of healthcare facilities, such as public and private healthcare facilities or were a mix across the levels of the healthcare system– primary, secondary, tertiary level healthcare facilities. Most studies (55%) employed mixed methods. This often comprised of waste surveys (measuring the quantity and determining the composition of solid waste, that is, waste stream analysis) in healthcare facilities, questionnaire surveys of healthcare workers and housekeeping staff and direct observation of waste handling practices. In other studies, key informant interviews were conducted with management staff regarding the awareness of existing policies, availability of waste plans and teams, as well as protocols on medical waste management in the healthcare facility. Eight articles involved review of secondary data, relevant documents and analysis of existing data. One article was a desk review of existing studies in Tanzania.

Waste management activities

Table 4 summarizes information reported on activities conducted in compliance with WHO’s recommendations on solid medical waste management (WHO, 2014). In the table, the number of articles reporting compliance was inserted in parenthesis beside the countries. For instance, Nigeria, Tanzania (3) means that Nigeria and Tanzania each had three articles that reported compliance with the standard for the specific solid medical waste management activity.

The least reported activity was off-site transport which 19 articles reported and only three articles (in two countries) indicated compliance with the recommendations. Although all papers reporting daily waste collection indicated compliance with recommendations, this represented less than half of the reviewed articles and half of the countries represented. Overall, Nigeria and South Africa had articles reporting compliance with at least nine (9) of the ten (10) recommendations by WHO. However, South Africa demonstrated a higher overall compliance with fewer reviewed articles (3) as compared to Nigeria (23). The majority of countries fulfilled less than five recommendations.

To the best of the authors’ knowledge, this review is the first attempt to present an overview of the status of SMW management activities in sub-Sahara Africa. Available evidence from the 58 journal articles from across 20 countries in sub-Sahara Africa in the period 1997 to 2014 indicates that SMW management still face many challenges and that South Africa appears to meet best practice according to the WHO-2014 recommendations on solid medical waste management practices. The fact that most of the papers were from reputable and credible scientific databases including peer-reviewed articles underlie the scientific validity of the findings, the most valuable information was obtained from surveys which covered a variety of healthcare facilities and was the method used in 35 articles. Case studies also provided greater detail and tended to cover most of the waste management activities discussed.

More than half (53%) of the publications reported segregation of SMW but appropriate use of color coded receptacles was low (18%). Segregation was reported at least for sharps in most countries. Poorly separated waste increases the amount of waste sent for incineration or sent untreated to the landfill. Overloading incinerators eventually made them dysfunctional. Untreated waste in open dumps or unsecured landfills had the potential of transmitting infections to scavengers. Collection bags (including colour coded ones) were reported to be diverted to other uses such as storage of items by patients’ relatives making it difficult to appreciate that the materials contained in the bags were potentially harmful (Mbongwe et al., 2008). The inappropriate use of black plastic bags for infectious waste in a bid to save costs has also been reported (Majara and Leduka, 2009). In healthcare facilities where waste is segregated, it often gets mixed at the temporary storage site or during collection by transporting companies or waste collection service providers (Coker et al., 2009; Debere et al., 2013; Sawalem et al., 2009). Appropriate segregation and resource recycling has been found to achieve a 15% reduction in the quantity of medical wastes (Sabour et al., 2007). This has economic implications for the health sector. For instance, it was noted that £15 million could be potentially saved in the UK, through improved segregation and waste minimization of the 40-60% of the healthcare waste stream which is non-hazardous (Tudor et al., 2009).

It has also observed in the UK that segregation of medical waste has not been given high priority. Some of the barriers are no different from those in African countries, limited space for multiple receptacles at service areas, inadequate budgetary provision for waste management activities and limited continuous training opportunities for healthcare workers (Tudor et al., 2009).

Our review indicated that nearly a quarter of articles reported compliance by most facilities having a secured storage area. Storage areas were often unsecure permitting access to both unauthorized persons and stray animals (Bendjoudi et al., 2009; Ndiaye et al., 2012; Nemathaga et al., 2008, Sawalem et al., 2009). In some cases, no temporary storage area existed in the facilities surveyed (Muluken et al., 2013). Scavengers and workers often recover valuable items to recycle and re-sell to the public (Bassey et al., 2006; Taru and Kuvarega, 2005). Rodents may serve as vehicles for pathogens in untreated SMW. Both act in different ways as ‘bridge populations’ with potential to transmit infectious agents to the general population. Inadequate contain-ment of medical wastes, collection and storage has been reported in both advanced (Blenkharn, 2007) and developing countries (Manga et al., 2011; Mbongwe et al., 2008)

All papers that reported daily collection of waste showed that most facilities complied with this standard, but only 30% of the reviewed articles reported compliance by use of dedicated vehicles for on-site collection. Although conveyances used included wheeled carts, trolleys and wheelbarrows (Abor, 2013; Ndiaye et al., 2012), manual lifting of waste receptacles by hospital cleaners, waste handlers and auxiliary staff was also reported (Abah and Ohimain, 2011; Coker et al., 2009; Manga et al., 2011; Muluken et al., 2013). In Zimbabwe, a small vehicle with a carrying capacity of up to 14 waste bins at once (totaling 15kilograms in mass) was used to convey SMW from hospital corridors to the storage site. This vehicle was able to collect an estimated 124 bins daily (Taru and Kuvarega, 2005). In some of the studies reviewed, vehicles that were reportedly used to convey SMW to final disposal sites were not described in detail especially when municipal trucks (Manga et al., 2011) or waste companies were used (Abor, 2013).

In healthcare facilities where disposal was reported to be done on-site, open dumping in refuse pits, burning and burial have been described (Ajimotokan and Aremu, 2009; Manyele and Anicetus, 2006; Abah and Ohimain, 2011; Manga et al., 2011). Although incineration was available and compliance was reported by 73% of the articles, they were often rudimentary, dysfunctional and/or lacked regular maintenance (Abd El-Salam, 2010; Mbongwe et al., 2008; Nemathaga et al., 2008; Nkhuwa et al., 2008). Most incinerators described did not have modern technology such as air pollution control (APC) equipment and adequate air inlets. They often had a single chamber made from local bricks, which did not completely burn off the gases generated during combustion process.

Furthermore, coal or wood fuels were used for combustion which made it difficult to control the temperature. As a result, they became a source of air pollution themselves especially within the hospital premises and the surrounding communities (Jerie, 2006; Nemathaga et al., 2008). Incinerators were often loaded with plastics made of polyvinyl chloride (PVC) which released carcinogenic dioxins and furans on incineration (Nemathaga et al., 2008; Singh and Prakash, 2007).

Due to incomplete burning of the waste, a large quantity of ash has been reported to be generated with high concentration of heavy metals. Such ash may find application as manure for growing vegetables (Nkhuwa et al., 2008). Heavy metals find their way into the food chain and are ultimately consumed by humans with considerable implications for human health. In contrast, common methods used for medical waste treatment in advanced countries include steam sterilization, auto-claving and incineration (Patwary et al., 2011). Treatment technologies in the UK fall into two main categories: high temperature incineration/combustion and non-burn or low temperature alternative technologies (Tudor et al., 2009). In the first category, examples include incineration, pyrolysis, plasma technology and gasification whereas examples in the second category (non-burn technology), are: autoclaves, steam augur, dry heat, microwaves and macrowaves (Tudor et al., 2009). In Canada, there has been a shift from onsite incinerators towards centralized facilities, which handle medical waste generated over a wide geographic area (Walkinshaw, 2011). This approach helps to reduce air pollution resulting from on-site incineration.

An interesting dimension was the use of unlined placenta pits which are fed with acid digesters to prevent them from getting full (Nkhuwa et al., 2008). In areas where the ground water table is shallow and the soil porosity permits easy percolation, potential contamination of groundwater could be possible (Nkhuwa et al., 2008). Placentae were also taken home to bury in keeping with traditional (Manga et al., 2011) or religious practices (Abd El-Salam, 2010). Due to the natural decomposition of placental organic contents, it is considered less harmful in more stable soils.

In some of the articles that reported training of healthcare workers, training in solid medical waste management was found to be inadequate and was not undertaken periodically (Coker et al., 2009; Haylamicheal et al., 2011; Saad, 2013; Sawalem et al., 2009). Similarly, the present survey showed that only one of every six articles reported periodic training in the surveyed health-care facilities. It has been shown that there is a significant association between training in healthcare waste management and waste management practices (Muluken et al., 2013). However, Beghdadli and co-authors (2010) portend that while training and the provision of color coded receptacles are essential, these measures alone are not sufficient for segregation of solid medical waste. Accountability and remedial action for waste malpractices by health staff should be defined and upheld in relevant facilities (Beghdadli et al., 2010).

This review provides an overview of solid medical waste management practices in Africa as evident in published literature. Key weaknesses identified were the inappropriate use of color codes and symbol, lack of periodic training for health staff and off-site transport in appropriate vehicles. Although incineration was often used as an advanced thermal option, it was often dysfunctional or lacked air pollution control equipment. Traditional methods of open burning and burial were still common-place. Institutional challenges relating to appropriate use of colour codes and symbols, and periodic training can be addressed with adequate management commitment and technical support from health ministries. As off-site transport is often the responsibility of municipal authorities or privately contracted, it is essential that health and environment ministries, municipal authorities, private and public sector waste management firms collaborate to ensure that vehicles assigned for transport of solid medical waste are appropriately designed, labelled and dedicated for solid medical waste to minimize potential risk to the public. Selection of waste treatment technologies and final disposal options should be done in a manner that takes into account impacts on human health and the environment (healthcare facility and communities living in proximity to it), capital and maintenance costs, technical capability, local resource constraints and the prevalence of scavenging peculiar to SMW.

The review revealed that independent national efforts have made only slow progress in managing solid medical waste leaving the authors to question whether or not a unified approach across all countries would yield better results. A unified approach demands the assemblage of experts in solid medical waste management and related disciplines across the continent to identify and aggregate available technology, expertise, funding, and best practices to bear on SMW management. A conference which brings together waste management experts, toxicologists, public health (environmental and occupational health) experts, governments, and other stakeholders focused on SMW management in Africa would be a good starting point. Challenges faced in African countries which are not often articulated in published literature, can be shared at such gatherings. Sharing and documentation of country experiences should include a platform for improving visibility and accessibility of information from participating countries to strengthen research and evaluation. Funding mechanisms for SMW management and accessibility of funds is critical to every activity especially improving technology for waste treatment. However, priority should be given to internal funding which is self-sustaining rather than externally funded projects.

This review paper was written as part of the lead author’s doctoral research funded by the Building Stronger Universities in Developing Countries – Human Health Platform of Danish Government. Prof. J. Nriagu of the Faculty of Environmental Health Sciences, University of Michigan, United States of America is acknowledged for his guidance when this review was first conceived. The authors are indebted to the librarians: Ms. Carol Shannon, Taubman Library, University of Michigan, Ann Arbor, USA, Ms. Irene Rattenborg, University of Southern Denmark, Esbjerg campus and Mrs. Theodosia Adanu, University of Ghana, Legon campus for their invaluable support. 

The authors did not declare any conflict of interest.