Waste Management & Research recent issues

Moving toward COP 15

Savino, A., Hansen, J. A. — 2008-08-04

Modelling waste generation by the telecom sector in Nigeria: the grey side of the impressive outing

Osibanjo, O., Nnorom, I.C., Ogbonna, K.C. — 2008-08-04

Since the introduction of digital mobile technology into Nigeria in 2001, there has been a phenomenal improvement in mobile subscription, service delivery and in the overall penetration of mobile telecommunication into rural areas in the country. For instance, the country's teledensity increased from less than 1% in 2001 to about 25% in 2006 — an increase of more than 3000%. The aim of this paper is to predict improvements in telephone penetration and waste generation by the Nigerian telecommunications sector. This was achieved by regression analysis of available data on telephone subscription in the country. Our estimations indicate that an average of 3 million phones will be retired annually in the country. Considering an economic phone life of 4 years, the over 32 million phones, (weight estimated at about 3200 tons) in use in 2006 would be at their end-of-life (EoL) by 2010. This volume of waste may contain up to 1800 tons of waste plastics, 15 tons of lead and 124 tons of copper. Our derived regression equation also indicates that mobile phone penetration in the country would be about 40% by 2010. This implies that over 55 million mobile phones would be in use by 2010. The grey side of this impressive statistics is that waste generation by the telecommunications sector will also follow this trend. This paper also highlights the need to introduce a framework for the effective management of waste from this sector considering the toxicity of some of the components of mobile phones and accessories and the prevailing inappropriate disposal practices for such potentially `toxic' materials.

The performance of Spanish solid waste collection

Garcia-Sanchez, I.M. — 2008-08-04

In this paper we examine street cleaning and waste collection services in Spanish municipalities with a population exceeding 50 000. The purpose is to identify factors that influence the efficiency of these services. Three input variables (staff, vehicles and containers) and four outputs variables (tonnage, collection points, collection point density and kilometres of surface area washing) are analyzed using an analytical model based on Data Envelopment Analysis (DEA) methodology. These variables, along with non-controllable input variable (Tourist Index), were chosen because they were shown, based on a Tobit regression analysis, to have a statistically significant impact on municipality behaviour. The results obtained show that scale inefficiency was lower than pure technical efficiency, the latter is linked to service management. It was observed that the street-cleaning activity was performed more inefficiently than that of waste collection. Furthermore, it was detected that municipalities can reduce the resources used in rendering this service by 8%. Finally, an estimation using the Mann—Whitney test allows us to conclude that there is no difference between the inefficiencies observed in municipalities managed directly by town councils and those which have been transferred to private companies.

GIS-based modelling for the estimation of municipal solid waste generation and collection

Karadimas, N. V., Loumos, V. G. — 2008-08-04

In the present paper, an innovative model for the estimation of municipal solid waste generation and collection is proposed. This model is part of an extended solid waste management system and uses a spatial Geodatabase, integrated in a GIS environment. It takes into consideration several parameters of waste generation, such as population density, commercial activities, road characteristics and their influence on the location and allocation of waste bins. Ground-based analysis was applied for the estimation of the inter-relations between the aforementioned factors and the variations in waste generation between residential and commercial areas. Therefore, the proposed model follows a unified categorization approach for residential and commercial activities and focuses on the dominant factors that determine waste generation in the area under study. The most important result of the research work presented in the current paper is an accurate estimation of the optimal number of waste bins and their allocation. A new methodology and an appropriate algorithm have been developed for this purpose in order to facilitate routing and waste collection. By using these results, municipalities aware of social, economical and environmental factors, related to waste management, can achieve optimal usage of their resources and offer the best possible services to their citizens.

Nutrients and heavy metals distribution in thermally treated pig manure

Kuligowski, K., Poulsen, T. G., Stoholm, P., Pind, N., Laursen, J. — 2008-08-04

Ash from pig manure treated by combustion and thermal gasification was characterized and compared in terms of nutrient, i.e., potassium (K), phosphorus (P) and heavy metal, i.e., cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni) and zinc (Zn) contents. Total nutrient and metal concentrations were measured using energy dispersive X-ray fluorescence analysis. Acid (HNO₃, H₂SO₄) and water-extractable concentrations were also measured both in non-classified ash and in selected ash particle size fractions using flame atomic absorption spectrometry and colorimetric spectrometry. Results indicate that ash from gasified manure contained more water-extractable K in comparison with combusted manure whereas the opposite was the case with respect to P. Heavy metals Ni, Cr and Cd were present in higher concentrations in the fine particle size fractions (< 30 µm of particle diameter), whereas K, P, Zn and Cu exhibited higher concentrations in the coarser particle size fractions (> 30 µm).

Describing variability of MSW composition data with the log-logistic distribution

Milke, M. W., Wong, V., McBean, E. A. — 2008-08-04

Variations in solid waste composition data are necessary as inputs to solid waste planning, yet uncertainty exists regarding which probability distributions might be generally valuable to describe the variability. Twenty-two detailed analyses of solid waste from British Columbia, Canada, were fitted to distributions using the BestFit software. Alternative distributions were ranked based on three goodness-of-fit parameters and twelve waste fractions. The log-logistic distribution was found to be the most able to fit over the wide range of composition types considered. The results were demonstrated to be insensitive to the number of waste components or to the choice of a two- or three-parameter distribution. Although other distributions were able to better match the waste composition for individual waste types, the log-logistic distribution was demonstrated to fit, overall, a wide variety of waste composition types.

Utilization of kaolin processing waste for the production of porous ceramic bodies

2008-08-04

The kaolin processing industry generates large amounts of waste in producing countries such as Brazil. The aim of this study was to characterize kaolin processing waste and evaluate its suitability as an alternative ceramic raw material for the production of porous technical ceramic bodies. The waste material was physically and chemically characterized and its thermal behaviour is described. Several formulations were prepared and sintered at different temperatures. The sintered samples were characterized to determine their porosity, water absorption, firing shrinkage and mechanical strength. Fired samples were microstructurally analysed by X-ray diffraction and scanning electron microscopy. The results indicated that the waste consisted of quartz, kaolinite, and mica, and that ceramic formulations containing up to 66% of waste can be used for the production of ceramics with porosities higher than 40% and strength of about 70 MPa.

Volatility of heavy metals during incineration of tannery sludge in the presence of chlorides and phosphoric acid

Tang, P., Zhao, Y.C., Chen, D.Z., Xia, F.Y. — 2008-08-04

Knowledge of the behaviour of heavy metals in the combustion process is a most important factor in selecting disposal alternatives for waste materials. Accordingly, in this work, the vaporization behaviour of highly concentrated heavy metals (Pb, Zn, Cu and Cr) in tannery sludge were investigated experimentally. The sludge was spiked with various chlorine compounds (i.e. PVC, FeCl₃, CaCl₂ and NaCl) and pre-treated with phosphoric acid in order to evaluate the capacity of enhancement and weakening of the volatility of the heavy metals contained in tannery sludge. The experimental results show that the vaporization percentages increased with increasing ratio of Cl/sludge and temperature, and the accelerating and increasing effect of the addition of chlorides on the vaporization percentage of heavy metals was dependent on the release capacity of chlorine radicals. The vaporization percentages of lead and zinc increased by 15—20%, whereas those of copper and chromium increased by only about 3 and 10% at 800 °C. However, heavy metals were not expected to be completely released in the combustion process in spite of the high ratio of Cl/sludge. Alternately, heavy metals contained in tannery sludge can be immobilized effectively by pre-treatment with phosphoric acid. When the 85% phosphoric acid accounted for 10% of dry basis of tannery sludge, the phosphate-treated sludge showed the lowest vaporization percentage of about 3—15% with formation of Ca₁₈Cu₃(PO₄)₁₄, Ca₉Cr(PO₄)₇, Ca₁₉Zn₂(PO₄)₁₄ and PbMgP₂O₇ in the bottom ash.

Metal releases from a municipal solid waste incineration air pollution control residue mixed with compost

Van Praagh, M., Persson, K.M. — 2008-08-04

The influence of 10 wt.% mature compost was tested on the heavy metal leachate emissions from a calcium-rich municipal solid waste incineration air pollution control residue (MSWI APC). Apart from elongated columns (500 and 1250 mm), an otherwise norm compliant European percolation test setup was used. More than 99% of the metals Al, As, Cd, Cr, Cu, Fe and Ni were left in the APC residue after leaching to a liquid-to-solid ratio (L/S) of 10. Apparent short-term effects of elevated leachate DOC concentrations on heavy metal releases were not detected. Zn and Pb leachate concentrations were one order of magnitude lower for L/S 5 and 10 from the pure APC residue column, which suggests a possible long-term effect of compost on the release of these elements. Prolonging the contact time between the pore water and the material resulted in elevated leachate concentrations at L/S 0.1 to L/S 1 by a factor of 2. Only Cr and Pb concentrations were at their maxima in the first leachates at L/S 0.1. Equilibrium speciation modelling with the PHREEQC code suggested portlandite (Ca(OH)₂) to control Ca solubility and pH.

Chemical sequential extraction of heavy metals and sulphur in bottom ash and in fly ash from a pulp and paper mill complex

Nurmesniemi, H., Poykio, R., Kuokkanen, T., Ramo, J. — 2008-08-04

A five-stage sequential extraction procedure was used to determine the distribution of 11 metals (Cd, Cr, Cu, Mo, Pb, Zn, As, Co, V, Ni, Ba), and sulphur (S) in bottom ash and in fly ash from a fluidized bed co-combustion (i.e. wood and peat) boiler of Stora Enso Oyj Oulu Mill at Oulu, Northern Finland, into the following fractions: (1) water-soluble fraction (H₂O); (2) exchangeable fraction (CH₃COOH); (3) easily reduced fraction (NH₂OH—HCl); (4) oxidizable fraction (H₂O₂ + CH₃COONH₄); and (5) residual fraction (HF + HNO₃ + HCl). Although metals were extractable in all fractions, the highest concentrations of most of the metals occurred in the residual fraction. From the environmental point of view, this fraction is the non-mobile fraction and is potentially the least harmful. The Ca concentrations of 29.3 g kg^—1 (dry weight) in bottom ash and of 68.5 g kg^{— 1} (dry weight) in fly ash were correspondingly approximately 18 and 43 times higher than the average value of 1.6 g kg^{— 1} (dry weight) in arable land in Central Finland. The ashes were strongly alkaline pH (~ 12) and had a liming effects of 9.3% (bottom ash) and 13% (fly ash) expressed as Ca equivalents (dry weight). The elevated Ca concentrations indicate that the ashes are potential agents for soil remediation and for improving soil fertility. The pH and liming effect values indicate that the ashes also have a pH buffering capacity. From the environmental point of view, it is notable that the heavy metal concentrations in both types of ash were lower than the Finnish criteria for ash utilization.

Effect of drying on leaching testing of treated municipal solid waste incineration APC-residues

Yuyan Hu, , Hyks, J., Astrup, T., Christensen, T. H. — 2008-08-04

Air-pollution-control (APC) residues from waste incinerators are hazardous waste according to European legislation and must be treated prior to landfilling. Batch and column leaching data determine which type of landfill can receive the treated APC-residues. CEN standards are prescribed for the batch and column leaching test; however, these standards do not specify whether or not the residue samples should be dried prior to the leaching testing. Laboratory tests were performed in parallel (dried/nondried) on treated APC-residue samples and evaluated with respect to Cr, Cd, Cu, Pb and Zn leaching. The effect of drying of the wet APC-residue samples was particularly dramatic regarding the leaching of Cr. Drying resulted in 10—100 times more Cr leaching in both batch and columns test. Drying also affected the leaching of Cd, Cu and Pb. Initial Cd leaching was up to 100 times higher in column tests with dried APC-residue than in tests with wet residues. The effect of drying appeared to be a combination of decreasing the reduction capacity of the sample (Cr), decreasing pH (Cd, Cu) and in column tests also a wash-out of salts (probably affecting Cd and Pb). If the leaching tests are intended to mimic landfill conditions, the results of this paper suggest that the tests should be done on wet, non-dried residue samples, although this may be less practical than testing dried samples.

Honours and achievements

2008-08-04

Editorial: Healthcare waste management -- the global paradox

Townend, B., Vallini, G. — 2008-06-02

Resolving complexities in healthcare waste management: a goal programming approach

Chaerul, M., Tanaka, M., Shekdar, A. V. — 2008-06-02

The wide variety of activities at healthcare facilities generates different types of waste. There is always a danger of spreading infection due to mishandling of infectious waste or sharps. Hence, a variety of policies and actions have been taken to improve healthcare waste management systems. A large body of literature is available which suggests methods for tackling different problematic situations but management is confronted with a variety of complex problems, such as the choice of technological options to control infection, legal and budget restrictions and the timely removal of waste, which can, at times, conflict with each other. Hence, a planning model is presented that is based on a trans-shipment goal programming approach wherein the waste flow is optimized for multiple objectives under different priority structures or with different relative importance (weights). The use of the model is demonstrated as a decision-making tool that would help the management to understand the effects of their policies on the system performance. The model is validated for a case application representing a real-life situation. It can be easily seen that, in the case in which the management is biased toward a higher level of safety protection towards infection control, they have to compromise on cost control and to some extent on environmental pollution control.

Utilizing a `systems' approach to improve the management of waste from healthcare facilities: best practice case studies from England and Wales

2008-06-02

Changes in environmental legislation and standards governing healthcare waste, such as the Hazardous Waste Regulations are expected to have a significant impact on healthcare waste quantities and costs in England and Wales. This paper presents findings from two award winning case study organizations, the Cardiff and Vale NHS Trust and the Cornwall NHS Trust on `systems' they have employed for minimizing waste. The results suggest the need for the development and implementation of a holistic range of systems in order to develop best practice, including waste minimization strategies, key performance indicators, and staff training and awareness. The implications for the sharing of best practice from the two case studies are also discussed.

Modelling seasonal variation in biomedical waste generation at healthcare facilities

Katoch, S. S., Kumar, V. — 2008-06-02

A mathematical model can help waste planners to optimize waste management systems related to environmental protection. It can also help government bodies set guidelines and regulations, and evaluate prevailing strategies for handling and disposal of waste. In this paper, a technique to develop a mathematical model to correlate the generation rate of biomedical waste (contaminated with blood and body fluid) as a function of bed occupancy and type of ailment (in terms of seasonal changes) using data for two consecutive years from three different healthcare facilities is presented. The data exhibit different trends in biomedical waste generation rates and number of beds occupied in two different years. However, the seasonal variation in biomedical waste production rate remained nearly the same during these 2 years. The fixed trend in biomedical waste generation rate in two consecutive years could be due to similar seasonal illnesses pattern and social factors.

Metal leachability, heavy metals, polycyclic aromatic hydrocarbons and polychlorinated biphenyls in fly and bottom ashes of a medical waste incineration facility

Valavanidis, A., Iliopoulos, N., Fiotakis, K., Gotsis, G. — 2008-06-02

Medical waste from hospitals and other healthcare institutions has become an imperative environmental and public safety problem. Medical waste in Greece has become one of the most urgent environmental problems, because there are 14 000 tons produced annually, of which only a small proportion is incinerated. In the prefecture of Attica there is only one modern municipal medical waste incinerator (started 2004) burning selected infectious hospital waste (5—6 tons day^{— 1}). Fly and bottom residues (ashes) are collected and stored temporarily in barrels. High values of metal leachability prohibit the landfilling of these ashes, as imposed by EU directives. In the present study we determined quantitatively the heavy metals and other elements in the fly and bottom ashes of the medical waste incinerator, by inductively coupled plasma emission spectrometry (ICP) and by energy dispersive X-ray analysis (EDAX). Heavy metals, which are very toxic, such as Pb, Cd, Ni, Cr, Cu and Zn were found in high concentrations in both fly and bottom ashes. Metal leachability of fly and bottom ashes by water and kerosene was measured by ICP and the results showed that toxic metals in both ashes, such as Pb, Cr, Cd, Cu and Zn, have high leaching values. These values indicate that metals can become soluble and mobile if ash is deposited in landfills, thus restricting their burial according to EU regulations. Analysis of polychlorinated biphenyls and polycyclic aromatic hydrocarbons in fly and bottom ashes showed that their concentrations were very low. This is the first known study in Greece and the results showed that incineration of medical waste can be very effective in minimizing the most hazardous and infectious health-care waste. The presence of toxic metals with high leachability values remains an important draw back of incineration of medical waste and various methods of treating these residues to diminish leaching are been considered at present to overcome this serious technical problem.

Production of biologically safe digested manure for land application by a full-scale biogas plant with heat-inactivation

2008-06-02

Inactivation of indigenous indicator micro-organisms such as faecal coliforms, coliphages, and faecal streptococci was investigated in a full-scale biogas plant that mainly digested cow manure. The biogas plant consisted principally of a feed reservoir, fermentation tank (37 °C), heat-inactivation process (70 °C), and five reservoirs for the heat-inactivated, digested manure that was used by a local livestock farmer as liquid fertilizer. Although all the indicators tended to exhibit stepwise decreases with each stage of treatment, coliphages were found to be more capable of surviving than faecal coliforms and faecal streptococci under mesophilic anaerobic conditions as well as high temperature conditions (heat-inactivation at 70 °C). Liquid fertilizer produced at the biogas plant had faecal coliform densities less than the stipulations of the US EPA 40 CFR 503 Class A limits. Heat-inactivation tests indicated that although coliphages exhibited more tolerance than other bacterial indicators between 37 and 70 °C, they were more sensitive to continuous temperature increase than faecal coliforms and faecal streptococci.

Microbial characteristics associated with six different organic wastes undergoing anaerobic decomposition in batch vial conditions

In Chul Kong, — 2008-06-02

In this study, the biodegradation characteristics of six plant-based wastes were compared in anaerobic batch vial systems. The highest gas accumulation and methane (CH₄) concentrations (approximately 70%) were observed in samples containing copy paper, newspaper and box paper materials, whereas the lowest were observed in samples containing wood and leaves. In samples containing steamed rice and fruit, the methanogenic activity was inhibited, which resulted in acid accumulation. The high biodegradation activity of newspaper samples was also associated with high adenosine triphosphate levels and dehydrogenase activity. No significant differences were, however, observed in the dehydrogenase activity of the samples. High bioluminescence was observed in samples with high biodegradation activities, indicative of low toxicity.

Preliminary study for the management of construction and demolition waste

2008-06-02

This paper refers to the management of the construction and demolition (C&D) waste since, according to the EU Waste Strategy, C&D waste is considered to be one of the priority waste streams and appropriate actions need to be taken with respect to its effective management. Initially, the paper presents the state-of-the-art of the problem of C&D waste, including the amount and composition of C&D waste in EU countries, differences in the characteristics of this waste stream depending on its origin, as well as collection and management practices that are applied. A methodology is described for the estimation of the quantities of the waste stream under examination, since in most cases quantitative primary data is not available. Next, the fundamentals for the development of an integrated scheme for the management of C&D waste are presented and discussed, such as appropriate demolition procedures and location of waste management (off-site waste management, on-site waste management, direct on-site recovery, centralized on-site recovery). Finally, taking into consideration all relevant parameters, alternative systems that could be applied for the management of the C&D waste are suggested.

Mathematical modelling of a composting process, and validation with experimental data

Gomes, A. P., Pereira, F. A. — 2008-06-02

The present study aimed to develop a mathematical model of composting which, while not overlooking the fundamental principles of physical and microbiological chemistry, could be easily applied in practice and be validated by experimental data. The experimental results of the biological aerobic decomposition of a mixture consisting of rice and rice husks, could be explained in terms of the parameter aggregation model, assuming a set of pseudo-first-order reactions in series, in which a hydrolysis step is followed by a biochemical oxidative step with formation of compost, biomass and biological gases (CO₂, O₂). The corresponding kinetic parameters and their temperature dependence were determined. These parameters indicated that the hydrolysis step was always the slowest one, and, therefore, the overall rate-determining step. This is in substantial agreement with our experimental observations of a non-dependency of the overall rate on the oxygen concentration, and suggests that rather than using mesophilic and thermophilic bacteria and fungi for seeding or accelerating the process, adequate hydrolytic enzymes (or related micro-organisms) should be added, instead.

Report: Medical students for monitoring biomedical waste segregation practices -- why and how? Experience from a medical college

2008-06-02

The cornerstone for an effective biomedical waste (BMW) management is appropriate waste segregation. Improper waste segregation practices can have an adverse impact on public health and increase the cost of treatment. Deficiencies in waste segregation practices can be corrected by continuous monitoring and education. Manpower for monitoring waste segregation in a large teaching hospital is scanty. We utilized the undergraduate medical students as monitors and studied the impact on waste segregation practices. A prospective observational study was carried out from August 2004 to January 2005. For monitoring waste segregation, the different areas of the hospital were divided amongst the II M.B.B.S students. They were provided with an observation sheet wherein the status of waste segregation and overall hygiene was recorded on a scale of 1—5. The impact of this programme was then analysed over the study period. The results indicated that a statistically significant improvement in waste segregation practices occurred in all areas. Thus, a large hospital with a medical college can identify students or a similar group for monitoring waste segregation or other aspects of biomedical waste management. This will improve their understanding of good practice in BMW management in future.

Report: Healthcare waste characterization in Chittagong Medical College Hospital, Bangladesh

2008-06-02

Healthcare waste management (HCWM) options are inconsistent in Bangladesh. One of the first critical steps in the process of developing a reliable waste management plan requires a comprehensive understanding of the quantities and characteristics of the waste that needs to be managed. This study took into consideration both the quantity and quality of the generated waste to determine the generation rates and physical properties of healthcare waste (HCW) in Chittagong Medical College Hospital (CMCH) and also to estimate the amount of infectious and non-infectious waste generated in different wards. CMCH, the second largest hospital in Bangladesh, comprises 34 wards, 12 of which were selected randomly. Waste materials were collected from these wards and then segregated and weighed. Waste generation per day was found to be 73.22 kg/ward, 1.28 kg/bed and 0.57 kg/patient. A total of 2490 kg of HCW was produced each day in CMCH (37% being infectious and the rest being non-infectious waste). Infectious waste was 27.07 kg per ward, 0.47 kg per bed and 0.21 kg per patient and the non-infectious waste was 46.15 kg per ward, 0.81 kg per bed and 0.36 kg per patient per day. HCW comprised eight categories of waste materials with vegetable/food waste being the largest component (50.21%) and varied significantly (P < 0.05) among the 12 different wards studied. The greatest amount of HCW was recorded (154 kg) in Orthopaedics followed by 96.66 kg in the Medicine Unit-3 and the smallest amount was recorded in Casualty (8.79 kg). The amount of HCW was positively correlated with the number of occupied beds (r_xy = 0.79, P < 0.01). There is no structured form of medical waste treatment in CMCH and most waste materials are dumped in open areas for natural degradation or re-sold by scavengers. It is essential to develop a national policy and implement a comprehensive action plan for HCWM that will provide environmentally sound technological measures to improve HCWM in Bangladesh.

Report: Hospital waste management -- awareness and practices: a study of three states in India

Hanumantha Rao, P. — 2008-06-02

The study was conducted in Andhra Pradesh, Maharashtra and Uttar Pradesh in India. Hospitals/nursing homes and private medical practitioners in urban as well as rural areas and those from the private as well as the government sector were covered. Information on (a) awareness of bio-medical waste management rules, (b) training undertaken and (c) practices with respect to segregation, use of colour coding, sharps management, access to common waste management facilities and disposal was collected. Awareness of Bio-medical Waste Management Rules was better among hospital staff in comparison with private medical practitioners and awareness was marginally higher among those in urban areas in comparison with those in rural areas. Training gained momentum only after the dead-line for compliance was over. Segregation and use of colour codes revealed gaps, which need correction. About 70% of the healthcare facilities used a needle cutter/destroyer for sharps management. Access to Common Waste Management facilities was low at about 35%. Dumping biomedical waste on the roads outside the hospital is still prevalent and access to Common Waste facilities is still limited. Surveillance, monitoring and penal machinery was found to be deficient and these require strengthening to improve compliance with the Bio-medical Waste Management Rules and to safeguard the health of employees, patients and communities.

Report: The assessment of hospital waste management: a case study in Tehran

2008-06-02

Hospital waste management is an important process that must be dealt with diligently. The management of hazardous waste material requires specific knowledge and regulations and it must be carried out by specialists in the field. In this cross-sectional study, we assessed the main stages of hospital waste management including separation, containment, removal and disposal of waste materials in public hospitals affiliated with Tehran University of Medical Sciences (TUMS). We selected 108 units of six hospitals (three general hospitals and three subspecialty hospitals) from those hospitals supervised by TUMS using the cluster sampling method. The measurement was conducted through a questionnaire and direct observation by researchers. Association analysis was done by statistical tests; Fisher exact test and chi-squared using SPSS software. According to the results obtained by the questionnaire, most of the studied wards scored moderately in terms of quality of their performance in all stages of waste management. About one-fifth of the wards were suffering from poor management of their medical waste and only a minority of wards obtained good scores for managing their waste materials. The findings also revealed significant associations between temporary waste storage and collection and the level of education of the managers (P = 0.040, P = 0.050, respectively). In summary, the study indicated a moderate management in all processes of separation, collection, containment, removal and disposal of waste materials in hospitals with several observed problems in the process.

Report: Treatment of medical waste in Nisava and Toplica districts, Serbia

Stankovic, A., Nikic, D., Nikolic, M. — 2008-06-02

If there are no clearly defined management procedures, medical waste may represent a source of serious health hazards. Medical waste management was evaluated at the three hospitals in the Nisava and Toplica district, in Serbia. All the stages of existing waste management (segregation, collection, storage, transportation and disposal of waste) were examined by interviewing the personnel involved in the management of waste. The generated waste was a mixture of hazardous and non-hazardous waste. The study found that waste management performance in this district was poor and that there were problems in every stage of management. The results indicate that the waste generation rate was 1.92 kg bed^{— 1} day^—1 and consisted of 98.7% general waste and 1.3% sharps. Inappropriate segregation practices were the biggest problem and led to increased quantities of general waste. There were no specific regulations for the segregation of the medical waste. None of the surveyed hospitals have a system to refine wastewater and there were no training courses about hospital waste management.

Editorial

Iskandar, L., Tjell, J. Chr. — 2008-04-09

Lateral migration and offsite surface emission of landfill gas at City of Montreal landfill site

Franzidis, J.-P., Heroux, M., Nastev, M., Guy, C. — 2008-04-09

An evaluation of lateral landfill gas migration was carried out at the Saint-Michel Environmental Complex in Montreal, City of Montreal Landfill Site, Canada, between 2003 and 2005. Biogas concentration measurements and gas-pumping tests were conducted in multilevel wells installed in the backfilled overburden beside the landfill site. A migration event recorded in autumn 2004 during the maintenance shutdown of the extraction system was simulated using TOUGH-LGM software. Eleven high-density instantaneous surface monitoring (ISM) surveys of methane were conducted on the test site. Gas fluxes were calculated by geostatistical analyses of ISM data correlated to dynamic flux chamber measurements. Variograms using normal transformed data showed good structure, and kriged estimates were much better than inverse distance weighting, due to highly skewed data. Measurement-based estimates of yearly off-site surface emissions were two orders of magnitude higher than modelled advective lateral methane flux. Nucleodensimeter measurements of the porosity were abnormally high, indicating that the backfill was poorly compacted. Kriged porosity maps correlated well with emission maps and areas with vegetation damage. Pumping tests analysis revealed that vertical permeability was higher than radial permeability. All results suggest that most of the lateral migration and consequent emissions to the atmosphere were due to the existence of preferential flow paths through macropores. In December 2006, two passively vented trenches were constructed on the test site. They were successful in countering lateral migration.

Evaluation of human urine as a source of nutrients for selected vegetables and maize under tunnel house conditions in the Eastern Cape, South Africa

Mnkeni, P. N. S., Kutu, F. R., Muchaonyerwa, P., Austin, L. M. — 2008-04-09

The introduction of ecological sanitation (ECOSAN) toilets in South Africa has created opportunities for safer sanitation and recycling of human excreta, as fertilizers, in rural and peri-urban areas. A study was carried out to evaluate the fertilizer value of human urine (0 to 400 kg N ha^—1) for maize and tomato, compared to urea, in a tunnel house. Dry matter yield of both maize and tomato, harvested at 9 and 10 weeks after planting, respectively, increased with increasing N rate (both as urine or urea) up to 200 kg N ha^—1. Urea reduced soil electrical conductivity (EC) whereas urine increased it. Leaf tissue Na, in both crops, also increased with urine application. A follow-up study was carried out with two crops with contrasting sensitivity to salinity and using a wider range of N application (0 to 800 kg N ha^—1). The results indicated increased root and leaf dry-matter yield of beetroot (tolerant to salinity) with increased urine rates up to the highest rate of 800 kg N ha^—1 , whereas the leaf and root dry-matter yield of carrot, which is sensitive to salinity, peaked at the low urine application rate of 50 kg N ha^{— 1}. Soil EC increased with urine application up to 4.64 and 13.35 mS cm^—1, under beetroot and carrot, respectively. Generally the results showed that human urine compared well with urea as a source of N for crops but optimum rates depend on the sensitivity of the crops to soil salinity, which should be monitored where human urine is regularly used for fertilizing crops.

Factors influencing households' participation in recycling

Vicente, P., Reis, E. — 2008-04-09

The success of a recycling programme depends on the active and sustained participation of citizens in the correct separation and collection of recyclable waste. An effective study of strategies aimed at augmenting people's involvement in recycling involves understanding which factors influence the decision to co-operate with a recycling programme. This research investigates the influence of attitudes, incentives, presence of children in household and information through direct media, on households' participation in recycling. The results suggest that positive attitudes toward recycling and information are important factors in explaining recycling participation. Some guidelines that may be considered in future communication and intervention strategies designed to promote recycling participation are discussed.

Environmental impacts and costs of solid waste: a comparison of landfill and incineration

Rabl, A., Spadaro, J. V., Zoughaib, A. — 2008-04-09

The methodology for evaluating the impacts and damage costs (`external costs') due to pollution from waste treatment is described and the results are presented, based on the ExternE project series of the European Commission. The damage costs of landfill and incineration of municipal solid waste are compared, with due account for energy and materials recovery, as well as possible differences in transport distance. We have not been able to quantify the total damage costs of leachates because of the complexity of the environmental pathways and of the long time horizon of some persistent pollutants, but we consider an extreme scenario to show that they are not worth worrying about in the sense that reducing the pollutants in leachates beyond current regulations would bring negligible benefit in comparison with the abatement of other sources of the same pollutants. The damage costs due to the construction of the waste treatment facility are negligible. The damage costs of waste transport, which are illustrated by an arbitrary choice of a 100 km round trip by a 16 tonne truck, are also negligible. The benefits of materials recovery make a small contribution to the total damage cost. The only significant contributions come from direct emissions (of the landfill or incinerator) and from avoided emissions due to energy recovery (from an incinerator). Damage costs for incineration range from about 4 to 21 tonne_waste^—1, and they are extremely dependent on the assumed scenario for energy recovery. For landfill the cost ranges from about 10 to 13 tonne_waste^—1 ; it is dominated by greenhouse gas emissions because only a fraction of the CH₄ can be captured (here assumed to be 70%). Amenity costs (odour, visual impact, noise) are highly site-specific and we only cite results from a literature survey which indicates that such costs could make a significant contribution, very roughly on the order of 1 tonne_waste^—1.

Release of nitrogen and trace metal species from field stacked biosolids

Peckenham, J. M., Nadeau, J. A., Amirbahman, A., Behr, R. S. — 2008-04-09

Concerns over elevated nitrate (NO₃^—) levels found in groundwater near former biosolid stockpiling locations resulted in the Maine Department of Environmental Protection (MDEP) imposing stricter regulations governing the stockpiling of biosolids in October 2002. The goals of this study were to measure the amount and speciation of nitrogen (N) and trace metals leaving stockpiled biosolids and travelling through the soil column. The biosolids were placed on plastic-lined cells to collect all leachate. Ammonium (NH₄⁺), ranging from 2000 to 4900 mg L^{— 1}, was the dominant N species (90% of total N) in the leachate from the Class B lime-stabilized biosolids in the lined cell experiment. Nitrate (NO₃^—) and nitrite (NO₂^— ) concentrations were negligible, remaining below 0.25 and 0.1 mg L^—1, respectively. Dissolved organic carbon (DOC) concentrations as high as 8900 mg L^—1 and chemical oxygen demand (COD) as high as 37 000 mg L^—1 were measured in the leachate leaving the lined cell. Fifteen zero-tension pan lysimeters (ZTP-lysimeter) were installed in a 90 m² plot at depth intervals of 30, 60, and 100 cm. Leachate passing through the soil column underlying the biosolids stockpile was collected in the ZTP-lysimeters. The average ZTP-lysimeter NH₄⁺ concentrations ranged from 1400 mg L^{— 1} at 60 cm depth to 145 mg L^—1 at 90 cm depth. The average ZTP-lysimeter DOC concentrations ranged from 2000 mg L^—1 at 60 cm to 525 mg L^{— 1} at 90 cm. Trace metal determinations of the leachate collected from the lined cell and ZTP-lysimeters showed arsenic loading rates exceeded the state limits of 0.5 kg ha^—1 year^{— 1} by an order of magnitude. Arsenic concentrations were in excess of several thousand milligrams per litre in the lined-cell leachate and several hundred milligrams per litre in the ZTP-lysimeters as deep as 90 cm under the biosolid stockpile. Phosphorus, iron and manganese in excess of several thousand milligrams per litre were observed in both the lined-cell leachate and ZTP-lysimeters. Significant concentrations of other trace metals were found at depth in the zero-tension ZTP-lysimeter plot. Trace metals were largely mobilized by the DOC from the biosolids and due to the presence of anaerobic environment, especially in the underlying soil.

Bacterial community patterns and thermal analyses of composts of various origins

Klammer, S., Knapp, B., Insam, H., Dell'Abate, M. T., Ros, M. — 2008-04-09

During composting, the degradation of organic waste is accompanied and driven by a succession of microbial populations exhibiting a broad range of functional capabilities. Detailed inventories of the microbial communities in mature compost, however, are not available. Mature composts, originating from biowaste as well as sewage sludge and anaerobic sludge, were studied by denaturing gradient gel electrophoresis-fingerprints after polymerase chain reaction (PCR) amplification of the 16S rRNA genes using three different universal primer pairs, as well as by differential scanning calorimetry and thermogravimetry. The composts of different origin had different bacterial communities. The influence of different 16S rDNA primer sets on the same batches of compost DNA was evaluated. The clearest separation of different compost types was obtained by using the PCR primer pair 338f + 518r which is suggested for future applications. Communities from the different biowaste compost samples clustered together and could be separated from sewage sludge communities indicating the establishment of different microbial consortia. A similar differentiation of composts was found with the thermogavimetric analyses. It may thus be concluded that the resulting humus quality is closely linked to the microbial communities involved.

Sources and factors controlling the disposal of biodegradable municipal solid waste in urban and rural areas of Cyprus

Skourides, I., Smith, S. R., Loizides, M. — 2008-04-09

An inventory of sources of biodegradable municipal soil waste (BMSW) was constructed for urban and rural areas in the EU accession region of Cyprus. Composition analysis was performed on source-separated BMSW collected from households in the rural Ergates Community and an urban area within the Agglanjia Municipality. The data were statistically scrutinized to identify the main factors influencing the quantities of BMSW disposed by urban and rural communities in Cyprus. The results were extrapolated to predict the quantities and types of BMSW disposed by the entire communities. Significantly more BMSW was disposed in the urban area compared to the rural community due to lower diversion rates for green waste and the disposal of food waste from commercial sources. The quantity of food waste collected from households was influenced by socio-economic (household size, income, percentage of children) and behavioural (feeding of food waste to domestic animals, consuming processed `ready' food) factors, whereas garden size, the type of vegetation, the reuse of trimmings and home composting were the main factors controlling the disposal of green waste.

Assessment of microbiological and parasitological quality of composted wastes: health implications and hygienic measures

2008-04-09

Feedstock and compost samples were collected from twenty composting plants and analysed from the microbiological point of view. Faecal indicator organisms were determined in order to evaluate the efficacy of processes for the removal of pathogenic micro-organisms with similar survival characteristics and to verify their suitability as appropriate markers of microbial quality of composted products. In addition to the classical bacterial indicators, selected organisms, such as Salmonella, Giardia , Cryptosporidium, Clostridium spores and helminth ova, were investigated. Statistically significant differences in the removal of the different micro-organisms were observed with regard to both the different composting plants (P < 0.05) and feedstock composition (P < 0.05). In fact, compost obtained by feedstock containing sewage sludge was shown to have a better hygienic quality in comparison with compost containing green discards and municipal solid waste as raw matter. Giardia cysts, Cryptosporidium oocysts and helminth ova were not effective indicators of hygienic quality of compost, whereas Clostridium perfringens spores, because of their high resistance to treatments, could be considered as an additional model for assessing the composting process, especially with regard to more resistant pathogen reduction.

Synergism effects of phenol-degrading yeast and ammonia-oxidizing bacteria for nitrification in coke wastewater of Esfahan Steel Company

Ghanavati, H., Emtiazi, G., Hassanshahian, M. — 2008-04-09

Ammonia-oxidizing bacteria and phenol-degrading yeast were isolated in order to study the synergism effects of phenol-degrading yeast and ammonia-oxidizing bacteria for enhancing the nitrification in coke wastewater from the Isfahan Steel Company. The influent and effluent samples with ~ 600—1200 mg L^{— 1} ammonium and 550—2350 mg L^—1 phenol were collected aseptically in sterile flasks. The biodegradation of phenol and nitrification were studied with different treatments. The results showed that addition of Na₂CO₃ and autotrophic bacteria to wastewater increased the ammonium removal by 100%. Furthermore, the synergism effects of phenol-degrader yeast and autotrophic bacteria reduced the time for ammonium removal.

Use of glazed ceramic waste as additive in mortar and the mathematical modelling of its strength

Altin, Z. G., Erturan, S., Tepecik, A. — 2008-04-09

This study investigated the reusability of waste material from the tile manufacturing industry as an alternative material to natural pozzolan trass. Yield strength values of mortar made from Portland cement (CEM I 42.5), were measured by adding glazed ceramic waste and trass at various weight ratios (5 to 40%). The test results proved that the strength values at 2, 7, and 28 days gave good results for concentrations of waste materials less than 5—10% in the cement. A decrease in strength was observed at higher concentrations. Mathematical modelling results showed a logarithmic correlation between the mortar strength and weight fraction of cement.

Obituary

Hahn, N. J., Aage Hansen, J., Berridge Dean, P. — 2008-02-25

Editorial: Waste management: stepping up to the climate change challenge

Ragossnig, A., Hilger, H. — 2008-02-25

Role of waste management with regard to climate protection: a case study

Hackl, A., Mauschitz, G. — 2008-02-25

According to the Kyoto Protocol and the burden-sharing agreement of the European Union, Austria is required to cut greenhouse gas (GHG) emissions during the years 2008 to 2012 in order to achieve an average reduction of 13%, based on the level of emissions for the year 1990. The present contribution gives an overview of the history of GHG emission regulation in Austria and identifies the progress made towards the realization of the national climate strategy to attain the GHG emission targets. The contribution uses Austria as an example of the way in which proper waste management can help to reduce GHG emissions. The GHG inventories show that everything must be done to minimize the carbon input due to waste deposition at landfill sites. The incineration of waste is particularly helpful in reducing GHG emissions. The waste-to-energy by incineration plants and recovery of energy yield an ecologically proper treatment of waste using state-of-the-art techniques of a very high standard. The potential for GHG reduction of conventional waste treatment technologies has been estimated by the authors. A growing number of waste incinerators and intensified co-incineration of waste in Austrian industry will both help to reduce national GHG emissions substantially. By increasing the number and capacity of plants for thermal treatment of waste the contribution of proper waste management to the national target for reduction of GHG emissions will be in the range of 8 to 14%. The GHG inventories also indicate that a potential CO₂ reduction of about 500 000 t year^—1 is achievable by co-incineration of waste in Austrian industry.

Mitigation of global greenhouse gas emissions from waste: conclusions and strategies from the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report. Working Group III (Mitigation)

2008-02-25

Greenhouse gas (GHG) emissions from post-consumer waste and wastewater are a small contributor (about 3%) to total global anthropogenic GHG emissions. Emissions for 2004-2005 totalled 1.4 Gt CO₂-eq year^—1 relative to total emissions from all sectors of 49 Gt CO₂-eq year^{— 1} [including carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O), and F-gases normalized according to their 100-year global warming potentials (GWP)]. The CH₄ from landfills and wastewater collectively accounted for about 90% of waste sector emissions, or about 18% of global anthropogenic methane emissions (which were about 14% of the global total in 2004). Wastewater N₂O and CO₂ from the incineration of waste containing fossil carbon (plastics; synthetic textiles) are minor sources. Due to the wide range of mature technologies that can mitigate GHG emissions from waste and provide public health, environmental protection, and sustainable development co-benefits, existing waste management practices can provide effective mitigation of GHG emissions from this sector. Current mitigation technologies include landfill gas recovery, improved landfill practices, and engineered wastewater management. In addition, significant GHG generation is avoided through controlled composting, state-of-the-art incineration, and expanded sanitation coverage. Reduced waste generation and the exploitation of energy from waste (landfill gas, incineration, anaerobic digester biogas) produce an indirect reduction of GHG emissions through the conservation of raw materials, improved energy and resource efficiency, and fossil fuel avoidance. Flexible strategies and financial incentives can expand waste management options to achieve GHG mitigation goals; local technology decisions are influenced by a variety of factors such as waste quantity and characteristics, cost and financing issues, infrastructure requirements including available land area, collection and transport considerations, and regulatory constraints. Existing studies on mitigation potentials and costs for the waste sector tend to focus on landfill CH₄ as the baseline. The commercial recovery of landfill CH₄ as a source of renewable energy has been practised at full scale since 1975 and currently exceeds 105 Mt CO₂ -eq year^—1. Although landfill CH₄ emissions from developed countries have been largely stabilized, emissions from developing countries are increasing as more controlled (anaerobic) landfilling practices are implemented; these emissions could be reduced by accelerating the introduction of engineered gas recovery, increasing rates of waste minimization and recycling, and implementing alternative waste management strategies provided they are affordable, effective, and sustainable. Aided by Kyoto mechanisms such as the Clean Development Mechanism (CDM) and Joint Implementation (JI), the total global economic mitigation potential for reducing waste sector emissions in 2030 is estimated to be > 1000 Mt CO₂-eq (or 70% of estimated emissions) at costs below 100 US$ t^{— 1} CO₂-eq year^—1. An estimated 20—30% of projected emissions for 2030 can be reduced at negative cost and 30—50% at costs < 20 US$ t^—1 CO₂-eq year^—1. As landfills produce CH₄ for several decades, incineration and composting are complementary mitigation measures to landfill gas recovery in the short- to medium-term — at the present time, there are > 130 Mt waste year^{— 1} incinerated at more than 600 plants. Current uncertainties with respect to emissions and mitigation potentials could be reduced by more consistent national definitions, coordinated international data collection, standardized data analysis, field validation of models, and consistent application of life-cycle assessment tools inclusive of fossil fuel offsets.

Biotic systems to mitigate landfill methane emissions

Huber-Humer, M., Gebert, J., Hilger, H. — 2008-02-25

Landfill gases produced during biological degradation of buried organic wastes include methane, which when released to the atmosphere, can contribute to global climate change. Increasing use of gas collection systems has reduced the risk of escaping methane emissions entering the atmosphere, but gas capture is not 100% efficient, and further, there are still many instances when gas collection systems are not used. Biotic methane mitigation systems exploit the propensity of some naturally occurring bacteria to oxidize methane. By providing optimum conditions for microbial habitation and efficiently routing landfill gases to where they are cultivated, a number of bio-based systems, such as interim or long-term biocovers, passively or actively vented biofilters, biowindows and daily-used biotarps, have been developed that can alone, or with gas collection, mitigate landfill methane emissions. This paper reviews the science that guides bio-based designs; summarizes experiences with the diverse natural or engineered substrates used in such systems; describes some of the studies and field trials being used to evaluate them; and discusses how they can be used for better landfill operation, capping, and aftercare.

Green house gas emissions from composting and mechanical biological treatment

Amlinger, F., Peyr, S., Cuhls, C. — 2008-02-25

In order to carry out life-cycle assessments as a basis for far-reaching decisions about environmentally sustainable waste treatment, it is important that the input data be reliable and sound. A comparison of the potential greenhouse gas (GHG) emissions associated with each solid waste treatment option is essential. This paper addresses GHG emissions from controlled composting processes. Some important methodological prerequisites for proper measurement and data interpretation are described, and a common scale and dimension of emission data are proposed so that data from different studies can be compared. A range of emission factors associated with home composting, open windrow composting, encapsulated composting systems with waste air treatment and mechanical biological waste treatment (MBT) are presented from our own investigations as well as from the literature. The composition of source materials along with process management issues such as aeration, mechanical agitation, moisture control and temperature regime are the most important factors controlling methane (CH₄), nitrous oxide (N₂O) and ammoniac (NH₃) emissions. If ammoniac is not stripped during the initial rotting phase or eliminated by acid scrubber systems, biofiltration of waste air provides only limited GHG mitigation, since additional N₂O may be synthesized during the oxidation of NH₃, and only a small amount of CH₄ degradation occurs in the biofilter. It is estimated that composting contributes very little to national GHG inventories generating only 0.01—0.06% of global emissions. This analysis does not include emissions from preceding or post-treatment activities (such as collection, transport, energy consumption during processing and land spreading), so that for a full emissions account, emissions from these activities would need to be added to an analysis.

The potential role of compost in reducing greenhouse gases

Favoino, E., Hogg, D. — 2008-02-25

The contribution of the agricultural sector to emissions of climate change gases is becoming better understood. At the same time, the potential role of the sector as a means through which to tackle climate change, widely neglected in the past, is becoming more widely acknowledged. The absorption potential of agricultural soils could contribute significantly to constraining growth in greenhouse gas emissions, while also contributing to improvements in soil quality in some areas. In addition to the measures listed above, other benefits of compost application may have some relevance. Some of these measures include replacement of chemical fertilizers (implying avoidance of greenhouse gases related to their production) reduced use of pesticides (avoiding emissions associated with their production), improved tilth and workability (less consumption of fuels). Typically, life-cycle analyses (LCAs) exhibit limitations related to assessing the effects of `time-limited' carbon sequestration in soils. This has tended to obscure the potentially important effect of composting, in which biogenic carbon is held in soils for a period of time before the carbon is released. The paper seeks to understand these effects and offers comments on the contribution of biological treatments to tackling climate change issues. Key issues include the replacement of fertilizers, reduction of N₂O emissions, and peat replacement.

Energy efficiency in waste-to-energy and its relevance with regard to climate control

Ragossnig, A. M., Wartha, C., Kirchner, A. — 2008-02-25

This article focuses on systematically highlighting the ways to optimize waste-to-energy plants in terms of their energy efficiency as an indicator of the positive effect with regard to climate control. Potentials for increasing energy efficiency are identified and grouped into categories. The measures mentioned are illustrated by real-world examples. As an example, district cooling as a means for increasing energy efficiency in the district heating network of Vienna is described. Furthermore a scenario analysis shows the relevance of energy efficiency in waste management scenarios based on thermal treatment of waste with regard to climate control. The description is based on a model that comprises all relevant processes from the collection and transportation up to the thermal treatment of waste. The model has been applied for household-like commercial waste. The alternatives compared are a combined heat and power incinerator, which is being introduced in many places as an industrial utility boiler or in metropolitan areas where there is a demand for district heating and a classical municipal solid waste incinerator producing solely electrical power. For comparative purposes a direct landfilling scenario has been included in the scenario analysis. It is shown that the energy efficiency of thermal treatment facilities is crucial to the quantity of greenhouse gases emitted.

Methods for determining the biomass content of waste

Staber, W., Flamme, S., Fellner, J. — 2008-02-25

As CO₂ emission trading in Europe has been established it is of essential importance to distinguish between biogenic and fossil emissions. Emissions resulting from bio-fuels and biogenous fractions are categorized as climate-neutral. Determination of plants using only fossil or bio-fuels is simple but categorization becomes more difficult for plants using a mix of fossil and biofuel such as solid recovered fuels. In the meantime, different methods for solving this problem have been developed. Using different approaches and technologies, all of these methods have the same goal: determining the biomass content (biogenic fraction), for example, in solid recovered fuels or in the off-gas of a mono- or co-incineration plant in order to calculate the biogenic carbon dioxide emissions. In the following article, the most common methods for determining the biogenic fraction of fuels, namely the Selective Dissolution Method, the Balance Method and the ¹⁴C-Method will be explained in detail.

Hazardous waste incineration in context with carbon dioxide

Reinhardt, T., Richers, U., Suchomel, H. — 2008-02-25

The Kyoto Protocol of 1997 demands an emission reduction of climate-affecting gases in various industrial sectors. In this context CO₂ is one of the relevant gases and waste management is one of the relevant sectors. Referring to the situation in Europe, waste incineration is one of the major sources of CO₂ in the waste management sector. The Kyoto Protocol, however, only covers CO₂-emissions originating from fossil fuels, whereas the incineration of renewable materials, e.g. wood, is considered to be climate-neutral since it does not make any net contribution to the CO₂ inventory of the atmosphere. Unlike the situation with municipal waste, there is little if any information on the CO₂-emissions caused by the incineration of hazardous waste in specialized plants, and the renewable fraction in these materials. The present paper focuses on this gap of knowledge. Taking the full-scale hazardous waste incineration plant in Biebesheim, Germany, as an example, a carbon balance was set up for the whole plant taking into account all other material flows. Afterwards the determination of the proportion of renewable materials in the hazardous waste incinerated by means of the radiocarbon method (¹⁴C) is reported. On the basis of the results, optimization potentials are discussed.

Environmental assessment of waste incineration in a life-cycle-perspective (EASEWASTE)

Riber, C., Bhander, G. S., Christensen, T. H. — 2008-02-25

A model for life-cycle assessment of waste incinerators is described and applied to a case study for illustrative purposes. As life-cycle thinking becomes more integrated into waste management, quantitative tools for assessing waste management technologies are needed. The presented model is a module in the life-cycle assessment model EASEWASTE. The module accounts for all uses of materials and energy and credits the incinerator for electricity and heat recovered. The energy recovered is defined by the user as a percentage of the energy produced, calculated on the lower heating value of the wet waste incinerated. Emissions are either process-specific (related to the amount of waste incinerated) or input-specific (related to the composition of the waste incinerated), while mass transfer to solid outputs are governed by transfer coefficients specified by the user. The waste input is defined by 48 material fractions and their chemical composition. The model was used to quantify the environmental performance of the incineration plant in Aarhus, Denmark before and after its upgrading in terms of improved flue gas cleaning and energy recovery. It demonstrated its usefulness in identifying the various processes and substances that contributed to environmental loadings as well as to environmental savings. The model was instrumental in demonstrating the importance of the energy recovery system not only for electricity but also heat from the incinerator.

Clean development mechanism: an incentive for waste management projects?

Plochl, C., Wetzer, W., Ragossnig, A. — 2008-02-25

The Clean Development Mechanism (CDM) was introduced by the Kyoto Protocol to provide a financial incentive to establish project activities in developing countries for reducing greenhouse gas emissions while also fostering sustainable development. This article shows that waste management project activities play an important role in achieving the aims of the CDM. It describes how these activities have to prove additionality, how the emission reductions must be calculated and monitored in order to be eligible and in order to lead to Certified Emission Reductions (CERs). The article further provides an analysis about the various challenges that are involved in applying the CDM scheme to waste management project activities, which require a new specific set of technical skills and regulatory standards.

Exploring the clean development mechanism: Malaysian case study

Pedersen, A. — 2008-02-25

During 2006 the CDM market in Malaysia became established and by December 2007 a total of 20 Malaysian projects had registered with the CDM Executive Board.The Kyoto Protocol defines the Annex 1 countries, as countries that are obliged to reduce their greenhouse gas (GHG) emissions and the clean development mechanism (CDM) allows Annex 1 countries to develop projects, which contribute to emission reduction, in non-Annex 1 (developing) countries. Currently, two projects have been corrected due to request for review and there is one project for which review is requested. Two projects have been rejected by the Executive Board. The broad knowledge of CDM in Malaysia and the number of successful projects are partly due to the well-functioning CDM institutional framework in Malaysia. As an illustration this article focuses on a Malaysian—Danish project and describes the implementation of CDM in Malaysia and refers to this specific project. The project was registered with the CDM Executive Board in May 2007 and is a methane avoidance project in which methane is captured from a landfill and used to generate electricity.