Medical wastes characterisation in healthcare institutions in Mauritius

This study was initiated to characterize solid and liquid wastes generated in healthcare institutions and to provide a framework for the safe management of these wastes. The project was carried at three major medical institutions, namely, the Jeetoo Hospital, the Sir Seewoosagur Ramgoolam National (SSRN) Hospital and the Clinic Mauricienne. A waste audit carried out at these sites revealed that approximately 10% of solid wastes was hazardous in nature, consisting mainly of infectious, pathological and chemical wastes. The average amount of hazardous wastes per patient per day was found to be 0.072 kg at Jeetoo hospital, 0.091 kg at SSRN hospital and 0.179 kg at the clinic. The amount of hazardous wastes generated as a function of the number of occupied beds was found to follow a relationship of type y=0.0006x-0.19, where y was the amount of hazardous wastes generated per bed per day and x was the number of occupied beds. The waste quantifying process also revealed that at SSRN Hospital, 0.654 m(3) of water was being consumed per patient per day and the amount of wastewater produced was 500 m(3)/day. Further analysis revealed that the wastewater was polluting with chemical oxygen demand (COD), biological oxygen demand (BOD(5)), total suspended solids (TSS) and coliform content well above permissible limits.     

Hazardous medical waste generation rates of different categories of health-care facilities

Goal of this work was to calculate the hazardous medical waste unit generation rates (HMWUGR), in kg bed(-1)d(-1), using data from 132 health-care facilities in Greece. The calculations were based on the weights of the hazardous medical wastes that were regularly transferred to the sole medical waste incinerator in Athens over a 22-month period during years 2009 and 2010. The 132 health-care facilities were grouped into public and private ones, and, also, into seven sub-categories, namely: birth, cancer treatment, general, military, pediatric, psychiatric and university hospitals. Results showed that there is a large variability in the HMWUGR, even among hospitals of the same category. Average total HMWUGR varied from 0.012 kg bed(-1)d(-1), for the public psychiatric hospitals, to up to 0.72 kg bed(-1)d(-1), for the public university hospitals. Within the private hospitals, average HMWUGR ranged from 0.0012 kg bed(-1)d(-1), for the psychiatric clinics, to up to 0.49 kg bed(-1)d(-1), for the birth clinics. Based on non-parametric statistics, HMWUGR were statistically similar for the birth and general hospitals, in both the public and private sector. The private birth and general hospitals generated statistically more wastes compared to the corresponding public hospitals. The infectious/toxic and toxic medical wastes appear to be 10% and 50% of the total hazardous medical wastes generated by the public cancer treatment and university hospitals, respectively.     

Disposal of solid waste in Istanbul and along the Black Sea coast of Turkey

The increasing amount of solid waste arising from municipalities and other sources and its consequent disposal has been one of the major environmental problems in Turkey. Istanbul is a metropolitan city with a current population of around 14 million, and produces about 9000 ton of solid waste every day. The waste composition for Istanbul has changed markedly from 1981 to 1996 with large decreases in waste density, much of which is related to decreased amounts of ash collected in winter. In recent years, the Istanbul region has implemented a new solid waste management system with transfer stations, sanitary landfills, and methane recovery, which has led to major improvements. In the Black Sea region of Turkey, most of the municipal and industrial solid wastes, mixed with hospital and hazardous wastes, are dumped on the nearest lowlands and river valleys or into the sea. The impact of riverside and seashore dumping of solid wastes adds significantly to problems arising from sewage and industry on the Black Sea coast. Appropriate integrated solid waste management systems are needed here as well; however, they have been more difficult to implement than in Istanbul because of more difficult topography, weaker administrative structures, and the lower incomes of the inhabitants.     

Composition and production rate of dental solid waste in Xanthi, Greece: variability among dentist groups

The objective of this work was to determine the composition and production rate of dental solid waste, produced by dental practices in the Prefecture of Xanthi, a multicultural area in Northeast Greece with a population of 102,000. For the study, 22 private dental practices and 1 public dental practice were selected of the 48 private and 5 public dental practices in operation. The 22 private dental practices included 16 owned by Christian Greek-born dentists, 3 by Moslem dentists and 3 by Christian dentists repatriated from the former Soviet Union. Differentiation on the basis of religion is directly related to the countries from which dentists received their training, e.g., Greece-European Union, Turkey and former Soviet Union. Thus, including the one public dental practice, 4 study groups were considered. Waste collection took place for 22 working days, from 20 May to 27 June 2002. This period was considered to be a representative one for a semi-rural area, such as Xanthi. Dentists were instructed to collect the total amount of waste they produced. A total of 260 kg dental solid waste was collected during the study period and was manually separated. Dental solid waste was classified in three main categories: (1) Infectious and potentially infectious waste, accounting for 94.7% by weight. (2) Non-infectious waste accounting for 2.0%. (3) Domestic-type waste, accounting for 3.3% by weight. The category of infectious waste is classified as hazardous and includes components containing metal (8.51%), components without metal (91.18%) and amalgam (0.33%). Using the weight data, the production rate of dental solid waste for the study period in the Prefecture of Xanthi was determined to be 513 g/practice/day and of infectious and potentially infectious waste 486 g/practice/day. The latter includes the production rate of sharps (9.8 g/practice/day), non-sharps (31.6), infectious waste without metal (443) and amalgam (1.6 g/practice/day). Since dental solid waste is currently disposed of in landfills together with the municipal solid waste, the results of the study were used to suggest an appropriate management scheme. The results were also used to compare the composition and production rates of dental solid waste produced by the 4 study groups.     

Composition analysis of dental solid waste in Brazil

When developing proper waste management strategies, it is essential to characterize the volume and composition of solid waste. The aim of this work was to evaluate the composition of dental waste produced by three dental health services in Belo Horizonte, Minas Gerais State, Brazil. Two universities, one public and one private, and one public dental health service were selected. Waste collection took place from March to November 2007. During this period, three samples were collected from each dental health service. The total amount of dental waste produced in one day of dental work was manually separated into three categories: infectious and potentially infectious waste, accounting for 24.3% of the total waste; non-infectious waste, accounting for 48.1%; and domestic-type waste, accounting for 27.6% (percentages are for mean weights of solid waste). Our results showed that most of the waste considered as biomedical may be misclassified, consequently making the infectious waste amount appear much larger. In addition, our results suggest that the best waste minimization method is recycling, and they help to define an appropriate waste management system in all three of the dental health services involved in this study.     

Composition and production rate of solid waste from dental laboratories in Xanthi, Greece

The composition and production rate of solid waste produced by four dental laboratories were measured in the Prefecture of Xanthi (Greece) during 2002. The selected dental labs in Xanthi were expected to produce approximately 75% of the waste produced from of all seven dental laboratories in the Xanthi Prefecture. Sampling was performed during a 2-month period. Solid waste was categorized into three major categories: (a) infectious and potentially infectious waste, (b) non-infectious toxic waste and (c) household type solid waste. Dental laboratories solid waste (DLSW) was produced at a rate of 0.059 g/cap/day (or 22 g/cap/year) at the time of the study. Household type waste, infectious and potentially infectious waste and non-infectious toxic waste comprised approximately 74%, 26% and less than 0.5% of the total DLSW weight produced, respectively. DLSW was estimated to be approximately 0.007% of the amount of municipal solid waste produced in the Prefecture of Xanthi.     

Medical waste production at hospitals and associated factors

This study was conducted to evaluate the quantities of medical waste generated and the factors associated with the generation rate at medical establishments in Taiwan. Data on medical waste generation at 150 health care establishments were collected for analysis in 2003. General medical waste and infectious waste production at these establishments were examined statistically with the potential associated factors. These factors included the types of hospital and clinic, reimbursement payment by National Health Insurance, total number of beds, bed occupancy, number of infectious disease beds and outpatients per day. The average waste generation rates ranged from 2.41 to 3.26kg/bed/day for general medical wastes, and 0.19-0.88kg/bed/day for infectious wastes. The total average quantity of infectious wastes generated was the highest from medical centers, or 3.8 times higher than that from regional hospitals (267.8 vs. 70.3Tons/yr). The multivariate regression analysis was able to explain 92% of infectious wastes and 64% of general medical wastes, with the amount of insurance reimbursement and number of beds as significant prediction factors. This study suggests that large hospitals are the major source of medical waste in Taiwan. The fractions of medical waste treated as infectious at all levels of healthcare establishments are much greater than that recommended by the USCDC guidelines.     

Medical waste generation in selected clinical facilities in Taiwan

This study investigated the type and amount of medical waste generated from small clinical facilities in Taiwan. We sampled 200 small medical establishments, with few or no patient beds, to survey the wastes generated and disposed. The surveyed medical facilities consisted of four groups including private clinics, medical laboratories, blood centers and public clinics. Private clinics providing surgical, dental, obstetrical, and dialysis services were included in this survey because they may generate higher amounts of infectious waste than other specialties. The overall mean general waste production rate was 3.97 kg/bed/day (or 0.075 kg/patient/day) at all the surveyed facilities, higher than that obtained from larger hospitals in Taiwan, which ranged from 2.41 to 3.26 kg/bed/day. The highest amount of infectious wastes generated among the four groups of facilities were from blood centers (3.14 kg/bed/day), followed by private clinics, medical laboratories and public clinics (1.91, 1.07, and 0.053 kg/bed/day, respectively). The overall average was 2.08 kg/bed/day. This study suggests that the waste generated at small medical facilities ranged widely.     

Consumption patterns and household hazardous solid waste generation in an urban settlement in México

Mexico is currently facing a crisis in the waste management field. Some efforts have just commenced in urban and in rural settlements, e.g., conversion of open dumps into landfills, a relatively small composting culture, and implementation of source separation and plastic recycling strategies. Nonetheless, the high heterogeneity of components in the waste, many of these with hazardous properties, present the municipal collection services with serious problems, due to the risks to the health of the workers and to the impacts to the environment as a result of the inadequate disposition of these wastes. A generation study in the domestic sector was undertaken with the aim of finding out the composition and the generation rate of household hazardous waste (HHW) produced at residences. Simultaneously to the generation study, a socioeconomic survey was applied to determine the influence of income level on the production of HHW. Results from the solid waste generation analysis indicated that approximately 1.6% of the waste stream consists of HHW. Correspondingly, it was estimated that in Morelia, a total amount of 442ton/day of domestic waste are produced, including 7.1ton of HHW per day. Furthermore, the overall amount of HHW is not directly related to income level, although particular byproducts do correlate. However, an important difference was observed, as the brands and the presentation sizes of goods and products used in each socioeconomic stratum varied.     

Accelerated carbonation treatment of industrial wastes

The disposal of industrial waste presents major logistical, financial and environmental issues. Technologies that can reduce the hazardous properties of wastes are urgently required. In the present work, a number of industrial wastes arising from the cement, metallurgical, paper, waste disposal and energy industries were treated with accelerated carbonation. In this process carbonation was effected by exposing the waste to pure carbon dioxide gas. The paper and cement wastes chemically combined with up to 25% by weight of gas. The reactivity of the wastes to carbon dioxide was controlled by their constituent minerals, and not by their elemental composition, as previously postulated. Similarly, microstructural alteration upon carbonation was primarily influenced by mineralogy. Many of the thermal wastes tested were classified as hazardous, based upon regulated metal content and pH. Treatment by accelerated carbonation reduced the leaching of certain metals, aiding the disposal of many as stable non-reactive wastes. Significant volumes of carbon dioxide were sequestrated into the accelerated carbonated treated wastes.     

Hospital solid waste management practices in Limpopo Province, South Africa: a case study of two hospitals

The shortcomings in the management practices of hospital solid waste in Limpopo Province of South Africa were studied by looking at two hospitals as case studies. Apart from field surveys, the generated hospital waste was weighed to compute the generation rates and was followed through various management practices to the final disposal. The findings revealed a major policy implementation gap between the national government and the hospitals. While modern practices such as landfill and incineration are used, their daily operations were not carried according to minimum standards. Incinerator ash is openly dumped and wastes are burned on landfills instead of being covered with soil. The incinerators used are also not environmentally friendly as they use old technology. The findings further revealed that there is no proper separation of wastes according to their classification as demanded by the national government. The mean percentage composition of the waste was found in the following decreasing order: general waste (60.74%)>medical waste (30.32%)>sharps (8.94%). The mean generation rates were found to be 0.60kg per patient per day.     

Overview of waste disposal and landfills/dumps in Asian countries

Many cities in developing Asian countries face serious problems in managing solid wastes. The annual waste generation increases in proportion to the rises in population and urbanization. Asian countries with greater rural populations produce more organic waste, such as kitchen wastes, and fewer recyclable items, such as paper, metals, and plastics. Reliable data on solid waste compositions are difficult to obtain, and even if available, they are often not updated. We report the most recent waste composition data in some developing Asian countries. We suggest that a better classification system for landfills is needed to address inconsistencies in data for sanitary landfill sites versus waste dumps. We also discuss the information on waste disposal trends and problems associated with general solid waste management in developing Asian countries.     

Characteristics of healthcare wastes

A comprehensive understanding of the quantities and characteristics of the material that needs to be managed is one of the most basic steps in the development of a plan for solid waste management. In this case, the material under consideration is the solid waste generated in healthcare facilities, also known as healthcare waste. Unfortunately, limited reliable information is available in the open literature on the quantities and characteristics of the various types of wastes that are generated in healthcare facilities. Thus, sound management of these wastes, particularly in developing countries, often is problematic. This article provides information on the quantities and properties of healthcare wastes in various types of facilities located in developing countries, as well as in some industrialized countries. Most of the information has been obtained from the open literature, although some information has been collected by the authors and from reports available to the authors. Only data collected within approximately the last 15 years and using prescribed methodologies are presented. The range of hospital waste generation (both infectious and mixed solid waste fractions) varies from 0.016 to 3.23kg/bed-day. The relatively wide variation is due to the fact that some of the facilities surveyed in Ulaanbaatar include out-patient services and district health clinics; these facilities essentially provide very basic services and thus the quantities of waste generated are relatively small. On the other hand, the reported amount of infectious (clinical, yellow bag) waste varied from 0.01 to 0.65kg/bed-day. The characteristics of the components of healthcare wastes, such as the bulk density and the calorific value, have substantial variability. This literature review and the associated attempt at a comparative analysis point to the need for worldwide consensus on the terms and characteristics that describe wastes from healthcare facilities. Such a consensus would greatly facilitate comparative analyses among different facilities, studies and countries.     

Medical wastes management in the south of Brazil

In developing countries, solid wastes have not received sufficient attention. In many countries, hazardous and medical wastes are still handled and disposed together with domestic wastes, thus creating a great health risk to municipal workers, the public and the environment. Medical waste management has been evaluated at the Vacacai river basin in the State of Rio Grande do Sul, Brazil. A total of 91 healthcare facilities, including hospitals (21), health centers (48) and clinical laboratories (22) were surveyed to provide information about the management, segregation, generation, storage and disposal of medical wastes. The results about management aspects indicate that practices in most healthcare facilities do not comply with the principles stated in Brazilian legislation. All facilities demonstrated a priority on segregation of infectious-biological wastes. Average generation rates of total and infectious-biological wastes in the hospitals were estimated to be 3.245 and 0.570 kg/bed-day, respectively.     

Management of hazardous waste in Thailand: present situation and future prospects

 This paper deals with the present scenario of hazardous waste management practices in Thailand, and gives some insights into future prospects. Industrialization in Thailand has systematically increased the generation of hazardous waste. The total hazardous waste generated in 2001 was 1.65 million tons. It is estimated that over 300 million kg/year of hazardous waste is generated from nonindustrial, community sources (e.g., batteries, fluorescent lamps, cleansing chemicals, pesticides). No special facilities are available for handling these wastes. There are neither well-established systems for separation, storage, collection, and transportation, nor the effective enforcement of regulations related to hazardous wastes management generated from industrial or nonindustrial sectors. Therefore, because of a lack of treatment and disposal facilities, these wastes find their way into municipal wastewaters, public landfills, nearby dump sites, or waterways, raising serious environmental concern. Furthermore, Thailand does not have an integrated regulatory framework regarding the monitoring and management of hazardous materials and wastes. In addition to the absence of a national definition of hazardous wastes, limited funding has caused significant impediments to the effective management of hazardous waste. Thus, current waste management practices in Thailand present significant potential hazards to humans and the environment. The challenging issues of hazardous waste management in Thailand are not only related to a scarcity of financial resources (required for treatment and disposal facilities), but also to the fact that there has been no development of appropriate technology following the principles of waste minimization and sustainable development. A holistic approach to achieving effective hazardous waste management that integrates the efforts of all sectors, government, private, and community, is needed for the betterment of human health and the environment. Received: February 26, 2001 / Accepted: October 11, 2002     

Count, identification and antimicrobial susceptibility of bacteria recovered from dental solid waste in Brazil

In Brazil, few studies on microbial content of dental solid waste and its antibiotic susceptibility are available. An effort has been made through this study to evaluate the hazardous status of dental solid waste, keeping in mind its possible role in cross-infection chain. Six samples of solid waste were collected at different times and seasons from three dental health services. The microbial content was evaluated in different culture media and atmospheric conditions, and the isolates were submitted to antibiotic susceptibility testing. A total of 766 bacterial strains were isolated and identified during the study period. Gram-positive cocci were the most frequent morphotype isolated (48.0%), followed by Gram-negative rods (46.2%), Gram-positive rods (5.0%), Gram-negative-cocci (0.4%), and Gram-positive coccobacillus (0.1%). Only two anaerobic bacteria were isolated (0.3%). The most frequently isolated species was Staphylococcus epidermidis (29.9%), followed by Stenotrophomonas maltophilia (8.2%), and Enterococcus faecalis (6.7%). High resistance rate to ampicillin was observed among Gram-negative rods (59.4%) and Gram-positive cocci (44.4%). For Gram-negative rods, high resistance was also noted to aztreonam (47.7%), cefotaxime (47.4%), ceftriaxone and cefazolin (43.7%), and ticarcillin-clavulanic acid (38.2%). Against Gram-positive cocci penicillin exhibit a higher resistance rate (45.0%), followed by ampicillin, erythromycin (27.2%), and tetracycline (22.0%). The present study demonstrated that several pathogenic bacteria are present in dental solid waste and can survive after 48 h from the waste generation time and harbor resistance profiles against several clinical recommended antibiotics.     

Proximate composition of household waste and applicability of waste management technologies by source separation in Hanoi,Vietnam

The organic fraction of municipal solid wastes in Southeast Asia, which has a high moisture content, accounts for a large proportion of total waste. Local governments need to pay adequate attention to the composition of wastes to determine alternative waste management technologies. This study proposed the use of a triangle diagram to describe changes in proximate composition and rates of successful source separation of municipal solid waste and to identify technical challenges about alternative waste management technologies such as incineration, composting, and refuse-derived fuel production based on physical and proximate composition analysis of household waste sampled in Hanoi, Vietnam, as a case study. The analysis indicated the effectiveness of different types of source separation as well as different levels of successful achievement of source separation as an adjustment mechanism for the proximate composition of waste. Proper categorization of wastes for source separation is necessary for the appropriate use of alternative waste management technologies. The results showed that, at a source separation rate of just greater than 0.52 in a three-way separation scheme, the waste separated as combustible waste would be suitable for incineration with energy recovery. Based on well-designed schemes of source separation, alternative waste management technologies can be applied.     

Assessment and analysis of industrial liquid waste and sludge disposal at unlined landfill sites in arid climate

Municipal solid waste disposal sites in arid countries such as Kuwait receive various types of waste materials like sewage sludge, chemical waste and other debris. Large amounts of leachate are expected to be generated due to the improper disposal of industrial wastewater, sewage sludge and chemical wastes with municipal solid waste at landfill sites even though the rainwater is scarce. Almost 95% of all solid waste generated in Kuwait during the last 10 years was dumped in five unlined landfills. The sites accepting liquid waste consist of old sand quarries that do not follow any specific engineering guidelines. With the current practice, contamination of the ground water table is possible due to the close location of the water table beneath the bottom of the waste disposal sites. This study determined the percentage of industrial liquid waste and sludge of the total waste dumped at the landfill sites, analyzed the chemical characteristics of liquid waste stream and contaminated water at disposal sites, and finally evaluated the possible risk posed by the continuous dumping of such wastes at the unlined landfills. Statistical analysis has been performed on the disposal and characterization of industrial wastewater and sludge at five active landfill sites. The chemical analysis shows that all the industrial wastes and sludge have high concentrations of COD, suspended solids, and heavy metals. Results show that from 1993 to 2000, 5.14+/-1.13 million t of total wastes were disposed per year in all active landfill sites in Kuwait. The share of industrial liquid and sludge waste was 1.85+/-0.19 million t representing 37.22+/-6.85% of total waste disposed in all landfill sites. Such wastes contribute to landfill leachate which pollutes groundwater and may enter the food chain causing adverse health effects. Lined evaporation ponds are suggested as an economical and safe solution for industrial wastewater and sludge disposal in the arid climate of Kuwait.     

Leaching behaviour of hazardous demolition waste

Demolition wastes are generally disposed of in unlined landfills for inert waste. However, demolition wastes are not just inert wastes. Indeed, a small fraction of demolition waste contains components that are hazardous to human health and the environment, e.g., lead-based paint, mercury-contained in fluorescent lamps, treated wood, and asbestos. The objective of this study is to evaluate the release potential of pollutants contained in these hazardous components when they are mixed with inert wastes in unlined landfills. After identification of the different building products which can contain hazardous elements and which can be potentially pollutant in landfill scenario, we performed leaching tests using three different lysimeters: one lysimeter containing only inert wastes and two lysimeters containing inert wastes mixed with hazardous demolition wastes. The leachates from these lysimeters were analysed (heavy metals, chlorides, sulphates fluoride, DOC (Dissolved Organic Carbon), phenol index, and PAH). Finally, we compared concentrations and cumulative releases of elements in leachates with the limits values of European regulation for the acceptance of inert wastes at landfill. Results indicate that limit values are exceeded for some elements. We also performed a percolation column test with only demolition hazardous wastes to evaluate the specific contribution of these wastes in the observed releases.     

Cement clinker: An environmental sink for residues from hazardous waste treatment in cement kilns

About 70% of all of the liquid and solid hazardous wastes commercially incinerated in the United States is being burned in cement kilns. The process inevitably results in residues, primarily heavy metals, entering the clinker and waste dusts (cement kiln dust, CKD) produced by these kilns. The effects of this trend on the nature and chemical composition of cement, actual and future, are discussed. The wastes burned by cement kilns are expected to increasingly have higher levels of heavy metals per Btu. In general, the effects are very simple to describe but have as yet unknown consequences. The present American Society for Testing and Materials (ASTM) standard does not effectively control hazardous waste burning residues in Portland Cement.The regulatory and economic pressures on CKD disposal suggest that much of it, and its heavy metal residues, will, in time, end up in the clinker and the resultant cement. The end point to the trend is the ability to make cement that passes the performance specifications while containing high levels of heavy metals. The only other alternative is to maximize the levels of heavy metals in the CKD, minimize the amount of CKD, and dispose of its as a hazardous waste.It is recommended that an effort to correlate heavy metal levels in clinker with adverse effects be undertaken, a new standard for cement containing hazardous and other waste residuals be developed, and labeling be required.