MEDICAL WASTE MANAGEMENT IN TANZANIA: CURRENT SITUATION AND THE WAY FORWARD

Transcription

1 MEDICAL WASTE MANAGEMENT IN TANZANIA: CURRENT SITUATION AND THE WAY FORWARD Abstract SAMWEL V. MANYELE Department of Chemical and Process Engineering, University of Dar es Salaam, P.O. Box Dar es Salaam, Tanzania. Medical waste has been defined in this paper, properties of which were identified, including hazardous nature and infection transmission properties. The types and quantities of contaminated wastes generated in selected hospitals, districts and regions, were quantified. A comparison between medical waste and municipal solid waste in terms of composition is also presented in this paper. The current efforts for attaining proper medical waste management (MWM) in Tanzania have been outlined including training for the hospital staff and construction of small-scale incinerators in all regional and district hospitals. Proper means of estimating the quantities of medical waste generated have been clarified from which sample data has been presented for hospitals, sections within hospitals, districts and regions. The analysis presented will assist the hospital management in distributing medical waste management manpower, facilities and funds in critical areas. This paper provides information on different classification systems for medical waste, average waste composition from immunization campaigns is presented based on weight and volume percent. The MWM efforts in Tanzania (comprising of segregation of the waste at the source followed by proper handling and incineration) have been outlined in this paper. A clarification on the challenges of plastics and glass in the medical waste on the performance of the incineration process is also provided. A survey of the legislation shows that there are currently no clear laws and proper policies related to medical waste management, compared to other countries. Necessary steps required to attain good environmental laws and compliance have been recommended. It was concluded that there is a need for further research in order to establish correct data and information on medical waste generation in Tanzania. 1.0 INTRODUCTION For many years, healthcare workers, hospital administrators, sanitarians, and other health-related professionals have understood the necessity to protect themselves and the public from exposure to wastes that might be reservoirs of disease-transmitting organisms. However, efforts to manage such wastes have differed between countries, the worse scenario being in developing countries like Tanzania. The efforts by the US Environmental Protection Agency (US-EPA), for example, are well documented to date, including registries of hazardous, toxic and biomedical wastes, appropriate (federal and state) legislation for managing different kinds of wastes; development and assessment of medical waste (MW) treatment technologies, medical waste testing protocols, etc. Tanzania is currently undertaking strong measures to combat the problems posed by medical waste, with financial assistance from the World Health Organization (WHO). Medical waste is the second most hazardous waste after radioactive waste. The term hazardous waste means a solid waste or a combination of solid wastes, which because of its quantity, concentration, or physical, chemical or infectious characteristics may (1) cause, or significantly contribute to, an increase in mortality or an increase in serious irreversible, or incapacitating reversible, illness or (2) pose a potential hazard to human health or the environment when improperly treated, stored, transported, disposed of, or otherwise managed (US-EPA, 1986). Applying more comprehensive waste management approach will help to ensure environmentally sound and economically feasible waste practices in Tanzania. At a minimum, it should be noted

2 that (as with most waste problems), there is no single management scenario that can solve all medical waste problems; rather, each MWM problem must be assessed independently to develop a viable and sound solution. Medical waste is defined as any solid waste generated in the diagnosis, treatment, or immunization of human beings or animals, in related research, production or testing of biologicals, (Blackman, 1996). Medical wastes include all infectious waste, hazardous waste (including low level radioactive wastes) that are generated from all types of healthcare institutions, including hospitals, clinics, doctor (dental and veterinary) offices, and medical laboratories. Infectious waste is the one capable of producing an infectious disease. This definition, however, requires a consideration of certain factors necessary for the induction of a disease, for example, presence of pathogens of sufficient virulence, dose, portal of entry and resistance of the host. Examples of miscellaneous contaminated MWs are given in Table 1. Table 1: Miscellaneous contaminated wastes from hospitals Contaminated waste Wastes from surgery and autopsy Miscellaneous laboratory wastes Dialysis unit wastes Contaminated equipment Examples Soiled dressings, sponges, drapes, lavage tubes, drainage sets, underpads, and surgical gloves. Specimen containers, slides and cover slips, disposable gloves, lab coats and aprons. Tubing, filters, disposable sheets, towels, gloves, aprons, and lab coats. Equipment used in patient care, medical laboratories, research, and certain pharmaceuticals. Generators of MW are defined as those producing more than 23 kg of regulated MW per month. For generators who manage their waste by shipping to offsite disposal facilities, they are supposed to separate, package, label, mark, and track the waste according to regulations (Blackman, 1996; van Veen, 1988). In Tanzania, all generators have, for long time, assumed treatment methods based on techniques suitable for treatment of municipal solid waste (MSW). Medical waste is infectious and it acts as an agent in the infections transmission. This is because it contains microorganisms (bacteria, viruses, fungi etc), which can be communicated by invasion followed by multiplication in body tissues. The so transmitted pathogens can cause disease or diverse health impacts to human (US-EPA, 1989). The medical waste management (MWM) efforts in Tanzania have emerged as a result of strong awareness on effects from the MW in terms of human health and the need to protect our environment. The Ministry of Health (MOH) and WHO conducted a survey in the year 2000 to study the management of the syringes and needles used during immunization programs in Tanzania. This was followed by a similar survey on the management of all MW types in From the two studies, it was established that hospitals did not have proper means of managing MW. Following these studies, about 13 pilot small-scale incinerators (SSIs) were built in the following areas: Muhimbili National Hospital (MNH), Kibaha, Tanga, Dodoma, Morogoro, and Kondoa. Other areas that received pilot incinerators include Korogwe, Ifakara, Ngerengere and Bagomoyo. In Zanzibar, three (3) such units were also built in The performance of the pilot incinerators was analyzed in Given the good results of the project, it was recommended to expand the program by building the small-scale incinerators in all referral hospitals, regional and district hospitals accompanied by training sessions for the hospital staff. 2

3 From August to November 2003, the training program was conducted in all four zones with the following number of districts: South-East (11), Lake (19), West (12) and Southern Highlands (18). Two representatives attended the training from each district. One member of staff and a contractor represented each regional hospital, with contractors responsibility of building incinerators in all district hospitals after the training. The training team comprised of members from MOH, WHO, University of Dar es Salaam (UDSM), and MNH. 2.0 MEDICAL WASTE GENERATION IN TANZANIA Medical waste is generated in a wide variety of sources, starting from the hospital (a primary target), human and animal clinics, health centers, intermediate facilities, physician offices, research institute (animal and human health), and homes (especially diabetic homes). This paper focuses on hospital waste management. Medical waste contains different items making it a special type of mixed waste. If not properly sorted, its handling becomes even more difficult. It can contain soiled or blood soaked bandages, culture dishes and other glassware, discarded surgical gloves and surgical instruments (like scalpels). Needles (used to give shots or draw blood), cultures, stocks and swabs used to inoculate cultures are the most common items in MW and well known to the health-care staff. Waste from operation theaters will also contain removed body organs (like tonsils, appendices, limbs etc.), which renders the medical waste scary, and nuisance. Medical waste will also contain lancets (the little blades the doctor pricks your finger with to get a drop of blood). However, during immunization campaign, medical waste will contain safety boxes and leftovers of empty boxes, cotton wool and bandages (Lloyd, 2003). Thus, if the waste is not segregated properly at the point of generation it will be a mixture of all these items plus kitchen waste, office waste and floor wastes which do not arise as a result of patients being attended. Starting with Dar es Salaam city, four sample hospitals were used to study the rate of MW generation: the Muhimbili National Hospital (MNH), which represents other referral hospitals; Mwananyamala hospital, which represents district hospitals; Agha Khan hospital, representing private hospitals and the UDSM Health Center representing other health centers. Figure 1 shows the waste generation in those areas estimated during the year Amount of waste (kg/day) Aga Khan Mwananyamala Muhimbili UDSM Hospitals Figure 1: Infectious medical waste generation in Dar es Salaam (Manyele et al., 2003) 3

4 The generation rate at MNH is the highest where more emphasis has been placed for the last few years. The generation rate reported in Figure 1 was based on the overall waste generation per day different from kg per bed per day, as shown later. Moreover, the data presented is only for the infectious waste despite the fact that hospitals generate both infectious and non-infectious wastes. There is also a marked difference between UDSM health center and the Agha Khan hospital in terms of the amounts of waste generated which necessitates further research. Currently, a new parameter for medical waste generation has been developed, putting into consideration the number of hospital beds in a given hospital as indicated by Ahmed (1997) and in the National Health-Care Waste Management Plan (NHCWMP, 2003). The rate of waste generation at a given hospital increases with the number of beds available and the occupancy rate. Using such analysis, data has been established for all regions in Tanzania. Another zoomed example is from Mtwara Region with four hospitals distributed as follows: 2 in Masasi, 1 each for Newala and Mtwara Urban and none in Mtwara Rural and Tandahimba districts. Figure 2 shows the number of hospitals on a histogram and the percentage of hospital beds for each district on a pie chart. The quantities of medical waste generated follow the same trend similar to that of number of beds. Mtwara Urban 29% Tandahimba 0% Mtwara Rural 0% Masasi 49% 3 Number of hospitals Masasi Newala Newala 22% Mtwara Urban Districts Mtwara Rural Tandahimba Figure 2: Number of hospitals and the percentage of hospital-beds in Mtwara region (Southern-Eastern Tanzania) 4

5 The occupancy rate is defined as the percentage of occupied beds to the available beds in hospitals. A survey of 9 hospitals (both district and regional hospitals) shows higher values of occupancy rates with a corresponding wide variation in this parameter, ranging from 44% to 200%. With an average value of 101%, it shows that all hospital beds are occupied at all times of the day. Figure 3 summarizes the values of occupancy rates and the estimated medical waste generation per bed per day, a survey conducted by a consultant in 2001 (NHCWMP, 2003). Occupancy rate, % Waste generated, kg/bed.day Amana Mbeya Regional hospitals District hospitals Referral hospital Iringa Mafinga Mtwara Dodoma Korogwe Bagamoyo Mwananyamala Figure 3: The variation of occupancy rate and the daily waste generation per bed for sampled hospitals in Tanzania. This data is not comparable to the report from Karachi, in Pakistan, for which the occupancy rate is low and ranges form 38 to 131% with an average value of 76% only (Ahmed, 1997). With such a wide variation in the occupancy rate, accurate data need to be established for Tanzanian hospitals in order to assist in budgeting and planning. However, for future research needs, this data can be used as a starting point. As a result of such an observed weakness in using occupancy rate, the training team insisted on establishment of medical waste registers in each hospital, whereby, the amounts are actually measured and recorded in special books for a specific period. This is a better means of establishing correct data on waste quantities to enable proper planning and budgeting. Based on data presented in Figure 3, it was possible to estimate the waste generation rates for different hospitals, and sum of the wastes for each region (NHCMP, 2003). Figure 4 shows the 5

6 clinical waste generation in some regions of Tanzania for the non-priority areas (which produce less than 800 kg of waste/bed/day) and for the priority areas (which produces more than 800 kg of waste/bed/day). 800 NON-PRIORITY AREAS Waste production in kg/bed/day Mtwara Lindi Ruvuma Mbeya Rukwa Tanga PRIORITY AREAS 800 DSM Kagera Kilimanjaro Pwani Iringa Mwanza Selected regions in Tanzania Figure 4: Clinical waste production in some parts of Tanzania (in 2003) Mwanza region is the leading area, basically due to high population (high occupancy rate), large number of hospitals (and hence many hospital beds). While comparing different regions, the reader is advised to follow the zoomed view of Mtwara region (presented in Figure 2) as a guide for understanding the differences in waste generation. However, by dividing the total waste generated to the number of beds, the data can still be misleading when the number of beds is small. Thus, actual measurements of waste generated is required disregarding the number of beds. Another way of expressing the medical waste generation in the hospital is the sectional overview, that is, waste generation per section of the hospital. In most hospitals, the dominant trend (in descending order) is large amounts of waste in the surgical, gynecology, orthopedic and medical sections produces smallest amounts, as shown in Figure 5. The psychology and pediatric sections give the least amounts of waste similar to the data reported by Ahmed (1997). 6

7 Psychology 13% Medical 15% Pediatric 13% Surgical 25% Orthopedic 16% Gynecology 18% Figure 5: Typical medical waste generation per hospital section. Such an overview will assist the hospital management to direct their waste management resources in the critical areas (Manyele et al., 2003). However, each hospital needs to generate its own data. This analysis will help the management to know exactly where to place more emphasis like waste collection frequency, number of containers required, and the number of waste handling staff. This will also lead to preparation of effective weekly rosters, and estimation of annual costs for medical waste management to improve the budgetary system. 3.0 MEDICAL WASTE MANAGEMENT IN TANZANIA The medical waste management in Tanzania comprises of different efforts such as classification of the waste, proper handling techniques different from municipal solid waste, focus on immunization campaigns, solving challenges of plastics and glass in the medical waste and medical waste treatment (in particular incineration). These efforts were strongly emphasized during training sessions conducted nationwide. 3.1 Classification of Medical Wastes For the waste to be infectious, it must contain pathogens with sufficient virulence and quantity so that exposure to the waste by a susceptible host could result in an infectious disease (US-EPA, 1986; Ahmed, 1997; Blackman, 1996). However, the terminology problem is complicated, because different terms are used to describe infectious waste, e.g. infectious, pathological, biomedical, biohazardous, toxic, and medically hazardous, with a possibility of difference in the meaning. The categories of waste to be designated as infectious waste are summarized in Table 2 (based on US- EPA, 1986). 7

8 Table 2: Categories of infectious wastes Waste category Isolation wastes Cultures and stocks of infectious agents and associated biologicals Human blood and blood products Pathological waste Contaminated sharps Contaminated animal carcasses, body parts, and bedding Examples Wastes generated by hospitalized patients who are isolated to protect others from communicable diseases Specimens from medical and pathological laboratories. Cultures and stocks of infectious agents from clinical, research, and industrial laboratories; disposable culture dishes and devices used to transfer, inoculate and mix cultures Waste from production of biologicals Waste blood, serum, plasma, and blood products Tissues, organs, body parts, blood, and body fluids removed during surgery, autopsy, and biopsy Contaminated by hypodermic needles, syringes, scalpel blades, Pasteur pipettes, and broken glass Contaminated animal carcasses, body parts, or blending of animals that were intentionally exposed to pathogens In this paper, the data on medical waste classification is based on type of waste (sharps, organics, domestic or general waste) or based on infections (pathological, sharps and infectious waste). Figure 6 shows such a classification for MNH and Mwananyamala hospital (both in Dar es Salaam). Domestic 82% Waste composition at Muhimbili Sharps 5% Organics 7% General 6% Waste composition at Mwananyamala Infectious waste 79% Pathological waste 14% Sharps 7% Figure 6: Classification of medical waste based on type of waste at Muhimbili National Hospital and infections at Mwananyamala hospital in Dar es Salaam (Manyele et al., 2003) 8

9 Based on the type of waste, domestic waste takes a large proportion of the waste volume, so that if such waste is not mixed with patient derived waste, it can be easily handled. However based on infections, it is important for healthcare staff to take precaution on handling sharps and pathological wastes, which comprises only about 21% of the total infectious wastes. Different classifications will give different results. For example, Blackman (1996) reported that 60% of the medical waste is infectious while 40% is non-infectious, depending on the classification used. 3.2 Infectious Waste Management The sound management of hazardous/infectious waste is the first step in health risk reduction. When the infectious waste cannot be minimized or eliminated at the source, it must be treated.the objectives of effective infectious waste management program were identified during the training sessions, that is, to produce protection to human health and the environment from hazards posed by the infectious waste. Proper management must ensure that the waste is handled in accordance to well established procedures from the time of generation through treatment of the waste (to render it noninfectious) and its ultimate disposal. The primary burden of infectious waste management falls upon the generators and handlers. Hospitals and other infectious waste generators must have ongoing management strategies. A proactive strategy of management would have two goals: first, to handle the hazardous/infectious waste, and second, to minimize costs due to improper management. The elements of a well documented infectious waste management plan were also outlined during training sessions, such as designation and identification, segregation, packaging, storage, transport and handling, treatment techniques, disposal of treated waste, contingency planning and continued staff training (Blackman, 1996; Griffin, 1989). 3.3 Medical Waste Management versus Municipal Solid Waste (MSW) Can medical waste be managed like municipal solid waste? The answer is obviously no. The old technologies for MSW management comprise of landfilling, composting, recycle and waste-toenergy technologies (WTE). Such methods are not totally applicable to medical waste except recycle and waste energy under well-planned management systems. Medical waste cannot be introduced into a waste-to-energy system or any other MSW combustion system because treatment of these two waste types needs different levels of care (Rx). Moreover, staff trained to burn MSW cannot perform medical waste incineration (MWI) until they receive special training. In developing countries, and Tanzania in particular, hospitals adopted management methods pertaining to MSW like open pit burning and pit burying. We went wrong at this juncture and correction was necessary. Currently, proper waste management techniques for MW are being promoted in Tanzania, especially during the training sessions. The first principal of MWM is waste reduction, which means reducing the quantity and toxicity of waste at the source. This comprises of eliminating or substituting substances that pose risk in the medical waste management with those that do not. Minimizing the amount of waste (by good housekeeping) and waste auditing (characterization, planning and education) are the best techniques for MWM. The key players for effective medical waste reduction are manufacturers and consumers of medical facilities (pharmaceuticals, equipment, packaging, etc.). Another principle of proper MWM combines waste segregation and recycling of useful materials. It should be noted that pathological and/or infectious waste is a small fraction of the 9

10 total hospital waste volume (see Figure 6), while the waste paper, cardboard and food remains comprise of the large portion. The latter is indirectly related to the patient care and can be easily handled. However, wet food materials should not enter the SSI incinerator at the initial or startup phase. Through waste segregation, useful materials can be recovered out of the uncontaminated portion, e.g., cardboard, paper, glass, plastics, cans, bottles, etc. However, as mentioned earlier, recovery of useful material requires well-planned waste management programs. Such efforts have been recently reported in Pakistan (Ahmed, 1997) and India (Iyer, 2001). The recovered portion of MW can easily be put into the WTE stream. For effective waste segregation and recycling, the hospital management needs to focus on the non-patient waste portion. Moreover, the actors in this technique are the decision-makers when it comes to procurement of containers, waste movers, and sorting. It should be noted that the non-combustibles must be prevented from entering the incineration and WTE streams. Noncombustible materials from hospitals comprise of used batteries, glass and metal, which are likely to cause continuous smoke in the flue gas by hindering complete combustion of the target materials. For proper MWM, several challenging issues must be overcome. Each hospital, for example, must establish the correct amounts and composition of the wastes they generate. Currently, there is strong inhibition towards hospital recyclables in the society. This is a selfdefense of the society, an advantageous nature of the human kind. Knowing that our medical staff is not well trained in the recycling of useful material, the society is not likely to indulge in this business. This is why the recyclables from hospitals are highly discriminated. To make the society accept recycled items from MW and get involved in the recycling business, one must clearly show them that the materials are harmless and show clearly the advantages of the business. For the time being, however, the knowledge and practice is still low, so that, recycling of MW should not be entertained. It should be borne in mind that sharps are not candidates for recycle. During immunization campaigns, for instance, the medical waste management staff needs to take an extra care. The wastes generated during such campaigns have different classes depending on mode of classification. The classification of sharps and softs on weight and volume basis shows that sharps are still a small portion of the waste, but which requires special care compared to the softs (Lloyd, 2003; Manyele et al., 2003). As a guide, Figure 7 shows the typical waste composition from such campaigns 10

11 Needles/syringes 14% Safety box 10% Cotton wool 5% Glass vials 5% vol.% Bandages 36% Softs bag 4% Packaging 26% Sharps 10% Sharps 29% wt.% Softs 71% Softs 90% vol.% Figure 7: Typical waste composition from immunization programs The medical waste is not very different from the municipal solid waste, except in some details as shown in Figures 6 and 7. There are items found in both MSW and medical waste like plastics, glass and food waste. Such items are very challenging in waste management. In case of medical waste, food remains and glass adversely affect the incinerator performance, while plastics pose a threat to the environmental health and safety of the personnel, through emissions in the flue gas. Items not commonly found in medical waste are tires, construction and demolition (C&D) wastes and pathological wastes. In many cases, there is a high percentage of recyclables in the MSW than in the MW for reasons of infectious nature and contents of medical waste. The chart below (Figure 8) shows the typical composition of MSW. The major difference is that there is less chance of infections in the MSW than in the medical waste except in chances of cholera outbreak. 11

12 Miscellaneous Plastics 5% Food waste 5% Glass 3% Textiles 2% 5% Tires 1% Metals 13% Construction & Demolition Yard 27% trash Other 15% paper 24% Figure 8: Typical composition of municipal solid waste (MSW) 3.4 Plastics and Glass in Medical Waste Plastics in Medical Waste A major concern in waste reduction efforts is the plastics content in the medical waste, especially the polyvinyl chloride (PVC). The plastics constitute about 40 percent of the total waste by volume 1. In terms of large volumes and concerns on environmental pollution during incineration, plastics are threatening the management systems for both MW and MSW. Large quantities of plastics are entering waste streams through packaging, bags, containers, etc. As a management tool, a general knowledge on plastics is given below. Plastics are complex organic compounds produced by polymerization, capable of being molded, extruded, casted into various shapes and films, or drawn into filaments used as textile fibers. This definition is based on Webster s dictionary. Plastics are not interchangeable. Each one has its own individual properties and characteristics that make it useful for certain applications. Figure 9 shows the composition of plastic wastes by type of resin used and by type of use based on data from MSW. 1 The data is based on the Characterization of MSW in the US: 1996 Update, US-EPA, Washington, DC. 12

13 PTFE 29% LDPE 33% PS 11% PPE 10% PET 9% PVC 5% Other 3% Coatings 7% Films and Bags 37% Closures 6% Containers 50% BY TYPE OF RESIN BY TYPE OF USE Figure 9: Typical composition of plastics in the municipal solid waste by type of resin and type of use (Source: Modern Plastics, 1992). The data presented gives a picture of what to expect for the plastics in MW. In the US, for instance, about 4% of the CFCs released into the atmosphere come from medical or healthcare waste 1. Beside CFCs and hydrogen chloride (HCl), when most plastics are burned at a slow rate and under starved oxygen supply and in the wrong temperature range, the probability of producing furans and dioxins increases, which threatens human health and the environment. The dioxins and furans have a property of accumulating in the environment, an issue that is being addressed globally by scientists and engineers. The control parameter for reduced dioxins and furans is the incineration temperature. However, under startup conditions, dioxins and furans can be stopped from entering the atmosphere by use of wet scrubbers. The actors in eliminating PVC plastics in the medical waste streams are the decision-makers. Plastics contain additives mixed during manufacture for different purposes like antioxidants, colorants, foaming agents and plasticizers. In the hospital waste, there are containers and closures made of plastics, together with bags and packaging films. Currently, the plastic bags used to cover food and fruits, clothing, etc., are entering the hospitals in large amounts, making it difficult to control. We have different types of plastics, that is, polyethylene, (PE), polypropylene (PPE), PVC, etc. These plastics have high heating value especially important in the startup of incinerators. However, chlorinated plastics cause high concentration of the HCl gas and CFCs in the flue gas. For further details on the elimination of PVC in medical waste, readers can visit the websites listed in Table 3. 1 The data is based on the Characterization of MSW in the US: 1996 Update, US-EPA, Washington, DC. 13

14 Table 3: Source reduction measures for dioxins and furans from biomedical waste incinerators Website d/dioxins/strategy.pdf pagree.htm legis/bills/billtext/ld asp com/gpr/2000/com2000_046 9en01.pdf Description of the contents Dioxins reduction strategy: virtual elimination of all PVC products from the medical waste stream. - Continuously reducing the use and disposal of PVC plastics in hospitals. - Continuously reducing the use of other chlorinated compounds such as chlorinated solvents (by replacing with non-chlorinated ones), e.g. sodium hypochlorite bleaches vs. non-chlorinated bleaches; bleached paper vs. chlorine-free/unbleached paper. - An Act to reduce the release of dioxins from consumer products into the environment. - Measures to avoid incineration of PVC products. - Purchase products alternatives to PVC products. - European Commission Green Paper on PVC. - Called for a strategy to substitute alternatives non-pvc products especially products directly linked to human health Glass in Medical Waste Glass containers are 50% clean (flint glass), 33% brown and 9% green. About 37 billion glass containers were produced in the USA only in The containers were 90% of the glass in the municipal solid waste stream in 1996 while 36% of all glass produced was recycled, up from 22% in By improving the recycled glass volumes, the US has improved and extended the life of the landfills. In Tanzania, however, there is no clear data on the life cycle of the glass. With no proper landfill, such materials are thrown everywhere so that, we might not even notice the actual threat of waste glass. This section will highlight the knowledge of glass recycle, which can help in reducing the amount of glass waste in the environment. The crushed recycled glass (whether based on hospital or municipal waste) is called cullet. Glass container manufactures recycle cullet combined with soda ash, limestone, sand and minor ingredients to create new glass. It is thus important to know what kind of glass such industries need. The cullet should meet the following criteria: separated by color (clear, amber or green), contaminant free, market specifications, and must come from container glass. Glass recycle contaminants include ceramic cups, plates and pottery, clay garden pots, laboratory glass, and crystal or opaque drinking glass. Other contaminants include mirrors, window glass, heat resistant glass (pyrex) and light bulbs. Other things which must not be included are ceramic and wire caps for beer bottle, lead collars from wine and champagne bottles, stones and dirt, metal caps, lids, and neck rings, drinking glass and hazardous glass containers. The knowledge about glass recycle is still rare in Tanzania, and very few individuals are involved in glass recycle business. The only possibility is scavenging of glass bottles for use in distribution of medicines. 1 The data is based on the Characterization of MSW in the US: 1996 Update, US-EPA, Washington, DC. 14

15 3.5 Medical Waste Treatment and Medical Waste Incineration Treatment of toxic and infectious waste is defined as any method, technique or process designed to change the biological character or composition of waste to render it non-toxic or noninfectious. Since landfill operations may cause loss of containment integrity and dispersal of infectious waste, it is recommended that all infectious waste be treated prior to disposal. There are several factors to consider when selecting among the medical waste treatment methods. One must know the waste type and the corresponding treatment method. Most types of medical wastes can be treated by incineration, which changes volume and weight of waste above 90%, as shown in Figure 10. Capital (equip. and install. onsite) Operating cost, cents/lb/hr Volume reduction, % STEAM AUTOCLV HYDRO CLV MECHAN. CHEMICAL MICROWAV. SHREDDER NA 15 UV & GRINDER INCINERTN. Figure 10: Comparisons of treatment technologies in terms of waste volume reduction operating charges and capital costs. 15

16 However, the capital cost for incineration is the highest. Moreover, the operating costs are also high due to the running cost of pollution control and waste preparation equipment. Other cost factors include operating charges, sterilization efficacy, maintenance and higher operator skills. Air emissions, water emissions and the characteristics of treated waste are other factors that must also be considered. However, incineration is still the best technology to date due to several advantages, despite the fact that it cannot remove radioactivity in the wastes generated from X-ray laboratory. When non-incineration methods are used for treatment of MW, further disposal problems must be solved because the volume is slightly reduced or almost constant. The nonincineration technologies also achieve a less significant volume reduction of less than 90% of the medical waste treated compared to incineration which reduce above 90% of the medical wastes, as shown in Figure 10. The hydroclave, mechanical/chemical treatment, microwaving of shredded waste and irradiation of ground waste by ultraviolet rays, gives intermediate values for volume reduction, operating charges and capital cost. The medical waste treatment covers a broad range of technologies, incineration being one of them. The MW management can be done by treatment, recovery of useful materials, modification of properties of the waste, making exposure less dangerous and enhanced environmental protection. In most cases, the treatment method used is incineration because it can be applied to many types of wastes. Incineration technologies can be grouped into small-scale and large-scale systems as shown in Figure 11. Among the large-scale systems a newer technology utilizing a fluidized bed combustor (Lee and Hoffman, 1996) is currently under development in Tanzania. At the moment, small-scale incinerators are being promoted by WHO and Mministry of Health, and are being built in l district and regional hospitals in Tanzania. The exact type of incinerator is the dual chamber type De Montfort incinerator of Mark III size. MEDICAL WASTE MANAGEMENT Recovery of useful materials Modification of properties Treatment technologies Making exposure less dangerous Environmental protection Incineration technologies Non-incineration technologies Small scale Inc. Large Scale Inc. Steam Autoclave Microwaving U.V. + Grinder Starved and excess air inc. Rotary kilns Fluidzed bed combustors Dual chamber De Montfort Single chamber Figure 11: Medical waste treatment technologies It is important, thus, to establish and document the standard operating procedures for each process used for treatment of infectious waste. For example, the overall procedure for operating a Mark III medical waste incinerator have been documented by the training team and distributed to 16

17 all hospitals operating these units. Monitoring of all treatment processes to ensure efficient and effective treatment is also recommended (US-EPA, 1986). The use of biological indicators to monitor the efficacy of a treatment method is important. For the case of MWIs, some microorganisms have been recommended to act as biological indicators of microbial inactivation as shown in Table 4. Table 4: Recommended biological indicators and the specific criteria for the selection of these microorganisms Type of organisms Vegetative Bacteria Fungi Viruses Parasites Mycobacteria Bacteria Recommended biological indicators Staphylococcus aureus (ATCC 6538), Pseudomonas aeruginosa (ATCC 15442) Candida albicans (ATCC 18804), Penicillium chrysogenum (ATCC 24791) Polio 2, Polio 3, MS-2 Bacteriophage (ATCC B1) Cryptosporidium spp. cocysts, Giardia spp. oocysts Mycobacterium, Mycobacterium, Mycobacterium, (BCG) (ATCC 35743) Spores stearothermophilus (ATCC 7953), subtilis (ATCC 19659) Criteria for the selection Staphylococcus aureus and Pseudomonas aeruginosa, selected to represent both grampositive and gram-negative bacteria respectively The selection of Candida albicans and Penicillium chrysogenum, representing yeast and molds, respectively, and are the most resistant to germicides Polio 2 (attenuated vaccine strain) and Polio 3 virus, selected based on their relative higher chemical and thermal resistance Both Cryptosporidium spp. oocysts and Giardia spp cysts are used as a test fore organisms to demonstrate germicidal effectiveness. Cryptosporidium have a higher chemical resistance and cryptosporidium spp. cocysts are more readily available than Giardia spp. cysts Mycobacterium has a demonstrated measure of disinfectant resistance, is a rapid grower and is pigmented for easy identification. Both B. stearothermophilus and subtilis spores are commonly used as biological indicators for both thermal and chemical resistance. R. stearothermophilus spores exhibit more thermal and chemical resistance than spores from R. subtilis Biological indicators selected to provide documentation of relative resistance to an inactivating agent should be chosen after evaluation of the treatment process as it relates to the conditions used during comparative resistance research studies. The degree of relative resistance of a microorganism to an inactivating agent can depend on various factors in particular temperature. Conditions used in literature studies that demonstrate a relatively high degree of resistance of a particular microorganism may be significantly different from the conditions found within a given treatment process. A comparison of the conditions used in the literature to those used in the treatment process will be made to determine if relative microbial resistance can be reduced as a result of a treatment process. Microorganism strains obtained from the American Type Culture Collection (ATCC) and methods prescribed by the Association of Official Analytical Chemists (AOAC) can assist in fulfilling these 17

18 recommendations by (1) providing traceable and pure cultures of known characteristics and concentrations and (2) providing recognized culturing protocols and detailed sampling and testing protocols. The recommended spores available for vegetative bacteria, viruses, parasites, mycobacterium and bacteria indicators are shown in Table 4 whereby the last column shows the criteria used for the selection. 3.6 Why Promote Medical Waste Incineration? Incineration is currently one of the best available technologies for disposing of various medical waste streams. It is the best because of highest volume and weight reduction, assured destruction, and it has an ability to treat or manage different types of wastes. Moreover, the incineration requires little processing of waste before treatment and renders the waste unrecognizable. With a high BTU value of the medical waste, incineration can be used as a source of energy, e.g. supplying hot water to the patients. Other treatment methods do not destroy the waste but can destroy the pathogens. Such methods are useful for treatment of medical waste that is not combustible, for instance ampoules and glass bottles. Such methods comprise of steam autoclaving, microwave irradiation, chemical treatment, and radio frequency irradiation (Blackman, 1996). The promotion of medical waste incineration as a sole treatment technique in Tanzania is based on several grounds. Most of non-incineration technologies are expensive, complex and are not locally available in Tanzania. Although initial costs of incinerators are high compared to drum and open pit burning, and can be polluting, the control of such shortcomings is easy for SSI if the operators are well trained. Moreover, drum, open pit burning and burial do not adequately destroy the wastes, is not safe and is even highly polluting. In most cases, the environmental problems caused by SSI can be solved. Open pit burning or burial of medical waste was strongly discouraged during training sessions. Considering the best of evils then incinerators rate high. To control and minimize the levels of environmental pollution and occupation health injuries from incineration processes, the hospital must control the waste stream, for example, avoiding certain materials in the waste stream and sorting the wastes at the point and time of generation. However, few disadvantages on incineration exist. Pollution risks, increased cost associated with controlling emissions, especially when many small sources are installed within one area; running and maintenance costs, and the necessity of highly skilled operators are the factor currently being addressed in Tanzania. Some areas still uses open pit burning even when incinerators are available (Lloyd, 2003). This is caused by low capacity of incinerator (especially those built long time ago); complaints from local communities about the smoke; and lack of fuel for the start-up of combustion. Another reason could be building of incinerator without the consent or participation of intended users. In terms of cost of SSI, there are several factors, which contribute to the overall cost of an incinerator. Depending on local area, transport, labour cost, cost of firebricks, metal work, etc., can vary. For example, the transport of firebricks from Dar es Salaam to different locations like Morogoro, Iringa, Mbeya and Sumbawanga, will differ widely, making a big difference in the overall cost of building incinerators of the same size in those locations. Decision-makers preparing the budget for such projects must view this analysis positively. Figure 12 summarizes the major cost items of SSI (Westlake, 2001), based on the total costs for a small-scale incinerator constructed in Mbeya, while the small pie chart shows the same analysis, including shade and base cost. 18

19 Transport 19% Fire Metal works bricks 21% 21% Labor cost 5% Sand/Cement 2% Standard bricks 2% Metal work 23% Shade 12% Fire proof materials 46% Roof covering 12% Concrete base 8% Fire cement 6% Bolts, screws 2% Base 21% Figure 12: Cost items for a low cost small-scale medical waste incinerator The problems of poor utilization of SSI have been reported from different areas (Lloyd, 2003). In Malawi for example 90 % and 36 % of centers with installed incinerators in the North and South, respectively, still use open pit burning. In South Africa, all SSI tested were outside regulatory norms. The solution to such utilization problems can be obtained if the experts provide the users of SSI with adequate pollution prevention techniques. In Tanzania, the MOH and WHO are promoting the use of wet scrubbers in SSIs built in urban areas. The utilization problems exist everywhere (Lloyd, 2003), and this is mainly due to inadequate understanding, and due to the fact that policy makers are not technologically oriented, and they are rather politically focused on environmental problems. During the training sessions, measures were provided for improving the utilization of SSIs. It was important to show clearly to the respective owners of SSI facilities the risks and advantages of incineration as the best option (the so called evidence based assessment). Another measure taken was a participative rural assessment (PRA). This helped to create awareness, attained by training for all strata (decision makers, operators, healthcare providers and the community). Training modules were formulated for SSIs to incorporate the management, community development programs, healthcare workers and the operators. The modules addressed issues like segregation, recycle and final disposal. Promotion and modification of existing designs for SSI should be promoted, as long as teamwork is used to assess the new ideas. A list of factors to be considered in evaluating the design of SSIs exists. There should be high enough stacks to direct emissions away from operators, but which can allow the flue gas to pass through and not to accumulate. Any designs in SSIs must be tested to prove their performance. Locally built SSIs should be certified to recognizable standards. Moreover engineering standards must be highly observed to minimize mishaps. Still the site where SSI is installed must be protected against unauthorized access. Mismanagement of MW is not only practiced in Tanzania, but also in other places. In India, for example, 3.08 billion injections were administered in However, only 0.8 billion disposal procurements were performed (Lloyd, 2003). This shows that either the 3.0 billion was recycled, lost in the community or reused. During the training sessions, the trainees were encouraged to raise awareness in their respective work-stations by writing and posting written instructions, information 19

20 or pictures for display. Moreover, proper home-based healthcare waste management practices were introduced. 3.7 Monitoring and Control of MW and the National Regulatory Framework Medical waste as a hazardous waste requires monitoring, i.e. to make sure that the whereabouts of such wastes are known at all times (van Veen, 1988), that is, from cradle to grave. Control of medical waste can be fully achieved when adequate monitoring facilities are available. Control means that competent authorities can act rapidly to ensure that the possibilities for inappropriate handling of wastes or dumping are minimized. This means also that the authorities have the power, both legally and financially, to act quickly in order to reduce dangers posed to human health and the environment (van Veen, 1988). For adequate monitoring and control, Tanzania needs proper national legislation on hazardous waste. In the legislation, the two terms waste and hazardous must be clearly defined. A survey conducted in other countries shows that environmental laws covering hazardous waste differ in several aspects. In most Western European countries, for example, definitions exist, but differ from country to country, which may lead to all kinds of problems and misunderstandings in, for example, transboundary shipments of hazardous wastes. Also, because hazardous waste is an international problem, then international agreements on definitions are recommended (van Veen, 1988). Thus as Tanzania develops her national legal framework, on MWM, well-synthesized laws must be acquired by critically looking into the details of the laws from developed countries. Efforts in to regulatory response in Tanzania (problems of biomedical and hazardous waste) comprised false starts and miss steps. The forerunners in this field comprise of USA, Sweden, and Canada. Developing countries are making new efforts for developing more comprehensive schemes, Tanzania being among of them. These countries have learned much from the experience of forerunners. However, they should not merely adopt the approaches used in those days, they must learn and implore upon. Examples of counter productive approaches can be found in the initial efforts by US-EPA, in the 1970 s. EPA launched an extensive campaign in television and press, leading to hysteria concerning anything related to hazardous wastes. As a result, the public opposition blocked even well designed hazardous waste treatment, storage and disposal facilities. This led to an increased industrial reliance on existing, less technologically advanced facilities. In Tanzania, for instance, all hazardous wastes and biomedical wastes are competing for scarce capacity at the best treatment disposal facilities. There is a need for classifying wastes as less toxic or more toxic and put corresponding efforts on its management. There are few threads numbing through all issues related to hazardous waste management. (a) The importance of prioritizing regulatory activities, whereby the government, industry and the public must cope with these problems using limited resources. This is possible if the resources are directed to the most important problems. (b) Regulation myopia, which means failure to look beyond the immediate issue to see the full effects of the regulatory actions. For example, rules on safe storage of hazardous waste must also encourage less desirable activities like disposal into city sewers. (c) The need to facilitate and encourage proper waste handling or cleanup, even if the provisions necessary to encourage proper handing will also allow less than-perfect handing methods. (d) Regulatory agencies should not underestimate the power of public opinion and economic incentives. (e) Overemphasizing the dangers of hazardous waste to the public can be counterproductive. The question is who must know the dangers of dangers and threats to the human health. 20