bluuebunny/crossref_metadata_2025 huggingface dataset:
Instruments for sustainable solid waste management in Botswana
Authors: Kgathi D. L. , Bolaane B.
Published: April 2009

Sustainable solid waste management is a strategy for achieving environmental quality in both the developed and the developing world. Environmental quality is a necessary condition for an increase in per capita welfare over time. The paper suggests alternative instruments for solid waste reduction, re-use and recycling. But to be able to apply the suggested economic instruments, the quantities and composition of the waste must be known. Having identified the current instruments of Botswana's solid waste management (regulatory measures, environ- mental education, and economic instruments of property rates, service levy, and sanitation fees), the paper argues that these do not go far enough in enhancing environmental protection. Alternative instruments such as solid waste collection and disposal levies, deposit refund schemes, and product levies are suggested. It is also suggested that public environmental education and regulatory measures should be strengthened.
An integrated programme for municipal solid waste management
Authors: Fabbricino Massimiliano
Published: April 2009

A mathematical model is used in planning an integrated programme for the management of municipal solid waste to solve an economical optimisation problem and allow preliminary decisions to be made at the operational planning phase.

The model, based on networks depicting the municipal solid waste management cycle, is simple to apply and furnishes easily assimilated results that facilitate management choices.

Its application in an optimised area within the Regione Campania in Italy demonstrates how it may be used to evaluate the economic advantages pertaining to different municipal solid waste collection and treatment options.
Compressive strength and heavy metal leaching behaviour of mortars containing spent catalyst
Authors: Rattanasak Ubolluk , Jaturapitakkul Chai , Sudaprasert Tippaban
Published: April 2009

This investigation was set and aimed to study the possibility of using spent catalyst as a concrete constituent which the spent catalyst was used as sand. Besides the spent catalyst was used as sand, it was also ground to very small particle size as small as that of cement and used as 20% replacement of cement by weight. Compressive strengths and leaching characteristics of lead, chromium, cadmium, and nickel in mortars containing spent catalyst and ground spent catalyst were tested.

The results presented revealed that the compressive strength of mortar containing spent catalyst increased with ages. The results also indicated that the compressive strength of mortar containing spent catalyst at the proportion of 1.25 times of cement by weight was strong enough to make a concrete brick. In case of the ground spent catalyst being used to replace cement, it made the compressive strength lower than that of the standard mortar approximately 20%. The leachate results of lead and chromium from spent catalyst were lower than the allowance, but cadmium and nickel exceeded the limits. After the spent catalyst was fixed with cement, the leaching of the heavy metals did not exceed the industrial effluent standard. Therefore, the heavy metals mentioned earlier were not a problem in using spent catalyst as a concrete constituent.
Red mud of aluminium production waste as basic component of new construction materials
Authors: Mymrin Vsevolod A. , Vázquez-Vaamonde Alfonso J.
Published: April 2009

The work presented here shows the possibility of using the red mud waste from the Bayer process used for aluminium production as the main component of new construction materials. It describes some recent experiments lasting 180 days as well as some 1 year old samples. The best part of materials used are industrial wastes, but some of them contain small (no more the 2%) additions of CaO or Portland Cement (PC) to increase the strengthening rate of the samples. The high strength values of these materials allow their use as new materials for road and airfields bases, levee core, dumps, foundations, etc. They can also be used to make bricks, tiles, and similar items. In addition to the economic factors, these materials are very easy to use and no new residues are generated.

The results of the heavy metal leaching tests, not included in this paper, show very low levels of their leachability in acid solutions, far below the demands of the Spanish environmental standards. This can be explained by the strong chemical binding of heavy metals in practically insoluble chemical compositions.
Regional shipping strategy assessment based on installing a refuse-derived-fuel process in a municipal incinerator
Authors: Chang Ying -H. , Chang Ni-Bin
Published: April 2009

The rising prices of raw materials and the concerns of energy recovery have resulted in an increasing interest in processing the waste streams. In recent years, a number of credible surveys have shown that recycling and waste-to-energy processes appear to work well together. Compatibility exists for several reasons related to economic, environmental, political, and social aspects. However, the regional impacts of installing a centralised refused-derived fuel (RDF) process prior to waste-to-energy facilities remain unclear due to the inherent complexity of solid waste composition, generation rate, energy and material recovery goals, and the existing shipping patterns. This paper illustrates a thorough evaluation for a RDF pilot study from both quantitative and qualitative aspects. Such a process, consisting of the standard unit operations of shredding, magnetic separation, trommel screening, and air classification, might be useful for integrating the recycling and presorting efforts with a large-scale municipal incinerator in a region. A series of sampling and analyses of the waste streams were performed in Taipei County, Taiwan in order to characterise its potentials for recycling. Based on the proper estimation of solid waste generation, the goal programming modelling analysis not only focuses on an evaluation of how the waste inflows with different rates of generation, physical and chemical compositions, and heating values in the service areas can be processed by a centralised RDF facility to meet both the energy recovery and throughput requirements in different municipal incinerators but also indicates the optimal shipping pattern associated with several incinerators due to such an installation in a regional sense. A case study designed to explore the regional impacts on shipping patterns in the southwestern of Taipei County, Taiwan verifies the application potential of such a planning methodology.
Co-combustion of shredder residues and municipal solid waste in a Swedish municipal solid waste incinerator
Authors: Redin L. Aae , Hjelt M. , Marklund S.
Published: April 2009

Incinerating automotive shredder residue (ASR) in order to increase the recovery from end of life vehicles (ELVs) is an attractive option when recycling this material. In this study, incineration combined with energy recovery, was investigated. The incineration experiments, where 20% shredder residue (SR) was burnt with conventional municipal solid waste (MSW), were conducted in a full-scale MSW horizontal grate incinerator. Measurements were made before, during and after the incineration. The results showed some minor increases in the emission levels of raw gases sampled after an electrostatic filter, but almost no significant differences when sampled after a wet scrubber. An increased level of ‘nontoxic’ metals was detected within the bottom ash. It was concluded that refined SR, in small quantities, is suitable to add to MSW.
Lateral gas transport in soil adjacent to an old landfill: factors governing gas migration
Authors: Christophersen Mette , Kjeldsen Peter
Published: April 2009

Field experiments investigating lateral gas transport in soil adjacent to an old landfill in Denmark during a one-year period were conducted. A significant seasonal variation, with low concentrations of methane and high concentrations of carbon dioxide in the summer, caused by methane oxidation was observed. There was a good correlation between pressure above the barometric pressure and the methane concentration in the soil, indicating that advective flow was the controlling process. This was confirmed by calculations. Diurnal measurement during a drop in barometric pressure showed that lateral migration of landfill gas was a very dynamic system and the concentrations of LFG at a specific place and depth changed dramatically within a very short time. The experiments showed that change in barometric pressure was an important factor affecting gas migration at the Skellingsted landfill in Denmark.
Fate of heavy metals during municipal solid waste incineration
Authors: Abanades S. , Flamant G. , Gagnepain B. , Gauthier D.
Published: April 2009

A thermodynamic analysis was performed to determine whether it is suitable to predict the heavy metal (HM) speciation during the Municipal Solid Waste Incineration process. The fate of several selected metals (Cd, Pb, Zn, Cr, Hg, As, Cu, Co, Ni) during incineration was theoretically investigated. The equilibrium analysis predicted the metal partitioning during incineration and determined the impact of operating conditions (temperature and gas composition) on their speciation. The study of the gas composition influence was based on the effects of the contents of oxygen (reducing or oxidising conditions) and chlorine on the HM partitioning. The theoretical HM speciation which was calculated in a complex system representing a burning sample of Municipal Solid Waste can explain the real partitioning (obtained from literature results) of all metals among the various ashes except for Pb. Then, the results of the thermodynamic study were compared with those of characterisation of real incinerator residues, using complementary techniques (chemical extraction series and X-ray micro-analyses). These analysis were performed to determine experimentally the speciation of the three representative metals Cr, Pb, and Zn. The agreement is good for Cr and Zn but not for Pb again, which mainly shows unleachable chemical speciations in the residues. Pb tends to remain in the bottom ash whereas thermodynamics often predicts its complete volatilisation under chlorides, and thus its presence exclusively in fly ash.
Mechanisms for the aging-induced reduction of lead solubility in scrubber residues from municipal solid waste combustion
Authors: Shimaoka Takayuki , Miyawaki Kentaro , Soeda Masashi , Hanashima Masataka , Yoshida Tsuneyuki , Uchida Toshihito , Gardner Kevin H. , Eighmy T. Taylor
Published: April 2009

This manuscript elucidates the mechanisms responsible for aging-induced reduction in lead leaching from scrubber residues. Leaching tests (JLT13) were conducted on 48 types of scrubber residues and lead solubility was found to be significantly reduced independent of incinerator type or type of gas treatment method. Reaction kinetics that result in lead solubility reduction were shown to be proportional to carbon dioxide partial pressure and in many cases were limited by mass transfer to the residue. With forced gas convection through the residue and a CO2 partial pressure of 0.3%, the concentration of lead in leachate was reduced from 84 mg L-1 to < 0.5 mg L-1 in two days. Ettringite analogs (Ca6Al2(SO4)3(OH)2•26H2O) were identified by X-Ray Diffraction in the wetted scrubber residues early in the aging process; these appear to have been converted into gypsum (CaSO4•2H2O) and vaterite (CaCO3) in the aged material. All of these solid phases are believed to substitute lead into their crystal structure and evidence for this attenuation mechanism is presented.
Microbial risk assessment of source-separated urine used in agriculture
Authors: Höglund Caroline , Stenström Thor Axel , Ashbolt Nicholas
Published: April 2009

A screening-level quantitative microbial risk assessment (QMRA) was undertaken for a urine separating sewer-age system. Exposures evaluated included the handling of stored and unstored urine as well as consumption of crops fertilised with urine. Faecal cross-contamination was the source of risk and Campylobacter jejuni, Cryptosporidium parvum and rotavirus were the organisms chosen to represent different groups of enteric pathogens. Accidental ingestion of unstored urine implied a high risk (Pinf = 0.56) for infection from rotavirus whereas the risks for infection from bacteria and protozoa were approximately 1:10 000. After six months storage at 20°C the risk for viral infections by accidental ingestion of 1 ml of urine was <10-3, the suggested acceptable risk benchmark. Ingestion of crops contaminated with urine resulted in risks of <10-5 after a 3-week (<10-7 after 4 weeks) withholding period between fertilising and harvesting.
The bioreactor landfill: Its status and future
Authors: Reinhart Debra R. , McCreanor Philip T. , Townsend Timothy
Published: April 2009

The bioreactor landfill provides control and process optimisation, primarily through the addition of leachate or other liquid amendments. Sufficient experience now exists to define recommended design and operating practices. However, technical challenges and research needs remain related to sustainability, liquid addition, leachate hydrodynamics, leachate quality, the addition of air, and cost analysis.
Modelling for environmental assessment of municipal solid waste landfills (Part 1: Hydrology)
Authors: De Cortázar Amaya Lobo García , LantaróN Javier Herrero , Fernández Oscar Montero , Monzón Iñaki Tejero , Lamia Maria Fantelli
Published: April 2009

A three-dimensional dynamic simulation program for the prediction of leachate flows, their organic contamination and the gas generated in municipal waste landfills, (MODUELO) has been developed. It permits the simulation of canyon landfills in which the surface area changes throughout the landfill’s history and of complex drainage systems. The “hydrologic module” calculates, based on the saturated flow equations, the water flow between cells and the overall moisture balance. Its results allow the “contamination module” to carry out the balance of organic material. This paper presents the development of the “hydrologic module”. The contamination models are included in another paper. A preliminary application to the Meruelo Landfill (Spain) is also shown here. The fitting of a data series of leachate flows in Meruelo indicated the existence, in this particular landfill, of unconsidered phenomena. The final adjustment of the results makes it possible to obtain a reliable simulation of the degradation processes.
Energy recovery from New York City municipal solid wastes
Authors: Themelis Nickolas J. , Kim Young Hwan , Brady Mark H.
Published: April 2009

This work was part of a major study that examined the policy and technology implications of alternatives for managing the municipal solid wastes (MSW) of New York City. At this time, of the 4.1 million metric tons of MSW collected by the City annually, 16.6% are recycled, 12.4% are combusted in Waste-to-Energy (WTE) plants, and the remaining 71% are landfilled. Despite the heterogeneity of organic materials in MSW, the composite molecular structure can be approximated by the organic compound C6 H10 O4. A formula was derived that allows the prediction of the heating value of MSW as a function of moisture and glass/metal content and compares well with experimentally derived values. The performance of a leading Waste-to-Energy plant that utilises suspension firing of shredded MSW, processes one million tons of MSW per year, and generates a net of 610 kWh/metric ton was examined. The results of this study showed that WTE processing of the MSW reduces fossil fuel consumption and is environmentally superior to landfilling.
Pilot scale evaluation of sorting technologies for CCA treated wood waste
Authors: Blassino Monika , Solo-Gabriele Helena , Townsend Timothy
Published: April 2009

Two sorting technologies including a chemical stain method and an x-ray fluorescence technique were investigated for separating chromated copper arsenate (CCA) treated wood from other wood types in the wood waste stream. Stains were investigated in both laboratory and field settings. Studies included specially mixed solutions with chrome azurol, 1-(2-pyridylazo)-2-naphthol (PAN) and rubeanic acid chemicals. X-ray fluorescence was tested in the laboratory using a commercially available x-ray fluorescence spectrometer. Laboratory scale experiments showed that both technologies were able to detect CCA treated wood in mixtures of treated wood and untreated wood, with detection limits on the order of 3 to 5% CCA. Results from field experiments at construction and demolition facilities indicate that although the chemical stains can be effectively used to identify CCA treated wood waste in field settings, their use will be limited to sorting relatively small wood waste piles due to increased labor and time needed for processing the wood waste. Operational parameters for sorting using x-ray fluorescence technology were established. These parameters concluded that arsenic was the most sensitive metal for analysis, analysis time was less than 2 seconds per wood sample, and the maximum separation distance between the sample and the x-ray probe was 2.5 cm. X-ray technology shows considerable promise for separating large quantities of CCA-treated wood from other wood types in the field using an on-line sorting system.
Minimisation and utilisation of waste mineral sludge from sodium perborate production
Authors: Grilc Viktor , Jer'san Rok
Published: April 2009

Various approaches to waste minimisation, waste treatment and recycling or safe disposal of the waste mineral sludge from sodium perborate production are presented and critically discussed. Some most promising actions for waste (or its harmful potential) reduction on the production level are identified. These include: a) use of better raw materials (richer boron ore), b) improvement of the ore leaching process, and c) intensification of sludge washing and dewatering. These source reduction measures have already resulted in 50% reduction of boron content in the sludge.

Utilisation of the raw or treated (e.g. dried, compacted) waste sludge could be found in agriculture, civil engineering and construction material production. Agricultural use (as a lime substitute) is based on favourable content of calcium-magnesium minerals and alkali pH value of the sludge, and simultaneous absence of heavy metals. Application in civil engineering (as an aggregate) is possible after calcination, which is costly, or as a cement kiln additive.

Stabilisation of sludge before disposal, when no utilisation is available, is possible by small addition of commercial binders (e.g. Portland cement) or larger amounts of pozzolanic wastes (e.g. coal fly ash).
Methane and leachate pollutant emission potential from various fractions of municipal solid waste (MSW): Effects of source separation and aerobic treatment
Authors: Jokela Jari P. Y. , Kettunen Riitta H. , Rintala Jukka A.
Published: April 2009

The effects of source-separation of putrescibles as well as aerobic pre-treatment and landfill aeration on the pollutant emission potential of methane and leachate pollutants were studied in the fresh (PFMSW) and composted (CPFMSW) source-separated putrescible fraction of municipal solid waste, and in the grey waste, and in lysimeter landfilled grey waste and ten-year-old unsorted MSW from our landfill lysimeter study. After 0, 23 and 51 days, an aerobic lysimeter experiment, an elution test and biochemical methane potential (BMP) test was done on samples. PFMSW had high methane (CH4) potential (410 m3CH4 t-1TS) as well as a high amount of ammonium-nitrogen (3.6 kg NH4-N) was eluted, whereas CPFMSW produced 41 m3CH4 t-1TS and 2.0 kg NH4-N t-1TS. A high nitrogen elution potential was found in the grey waste (2.1 kg NH4-N t-1TS). Aeration for 51 days in lysimeters reduced CH4 potential by more than 68% for the PFMSW and CPFMSW samples, whereas for the lysimeter landfilled grey waste the reduction was 50% indicating the potential of aeration for CH4 emission reduction. The effective separation and biological treatment of the PFMSW are important in reducing the environmental impacts of waste management, especially for minimising the methane potential of MSW fractions.
Linking landfill hydrology and leachate chemical composition at a controlled municipal landfill (Kåstrup, Denmark) using state-space analysis
Authors: Poulsen Tjalfe G. , Moldrup Per , Sørensen Kirsten , Hansen Jens Aa.
Published: April 2009

Leachate production and composition data for a municipal landfill measured over a 25-year period was used to investigate important processes and parameters. Long-term leachate production could be satisfactorily predicted from a simple top-layer landfill hydrology model while short-term predictions were less accurate, likely due to water storage in the waste. State-space and multiple regression modelling were used to identify relations between different parameters. State-space models proved most accurate in fitting measured data, likely because temporal correlation between measurements is accounted for unlike multiple regression.

State-space modelling showed that temporal correlation in leachate production must be taken into account and confirmed that water storage inside the landfill is important. Temporal correlation is also important when predicting pH and chloride concentrations but less so for BOD5 and NH3/NH4+ concentrations. Leachate flow did in general not have a strong impact upon leachate composition, small effects were observed for Cl-, and NH3/NH4+concentrations. It was also observed that the mass load of nitrogen from the landfill was strongly dependent upon leachate nitrogen (ammonia/ammonium) concentrations and to a lesser degree upon leachate flow rates. This study introduces state-space modelling in solid waste management as a powerful tool to identify governing parameters for hydrological and bio-chemical processes.
A review of the UK metals recycling industry
Authors: Emery Andrew , Williams Keith P. , Griffiths Anthony J.
Published: April 2009

This paper reviews the volatile nature of the price of recycled metals over the past decade and examines legislative and fiscal drivers that have affected the industry. Results from this study have shown that the UK scrap metals markets are presently seeing some of the lowest scrap prices for nearly a decade for both ferrous and non-ferrous metals, in many cases halving in value in less than a year. Scrap metals and other recycled materials prices were high in 1994-96, which have since fallen back to more traditional low levels. World recessions and the steady decline of the UK manufacturing and engineering sectors have effected prices. With tougher new Government legislation, such as the Climate Change Levy and the proposed End of Life Vehicles Directive, small and medium sized scrap merchants are finding it increasingly difficult to compete.
Report: Operational experiences and legal aspects of co-combustion in Germany
Authors: Marton Csaba , Alwast Holger
Published: April 2009

From 2000-2001, a project entitled “Analysis of effects on environment from waste incineration in industrial facilities” was undertaken by Prognos AG. The project was funded by the German Environmental Agency and the North Rhine-Westphalian Ministry for Environment and Conservation, Agriculture and Consumer Protection.

This paper presents a summary of the main results. The most important industrial processes with practised waste-to-energy are identified, respectively cement kilns, steel works, installations in the non ferrous industry and large combustion plants.

The amount of waste being co-incinerated is determined in permitting procedures. In general the volume of permitted and practised co-incineration is increasing in Germany.

For the greatest possible use of waste it is necessary to establish suitable measures to prevent or to limit, as far as possible, environmental pollution. Emission limit values are determined according to the requirements set out in the German Standards, 17th BImSchV and TA Luft. Plant operators meet generally the air emission limit values fixed in the respective granted permits.
Factors influencing treatment decisions of hazardous waste generators: A study of factories in the Bangkok region
Authors: Jarusombat Soparatana , Amin A. T.M. Nurul
Published: April 2009

While the developed countries are engaged in developing new technology for waste avoidance, recycling and reuse, developing countries are still wrestling to decide on the best option to treat and dispose of wastes. This is particularly so in the case of hazardous industrial wastes (HIW). In order to ensure safe HIW management, one policy response has been to make available a central treatment facility for HIW generators. Such a facility was established in Thailand - the Bang Khuntien Treatment Facility (BKTF) - for the HIW generators in the Bangkok region. However, this facility operates much below its capacity. A study was therefore undertaken between April 1996 and April 1997 to investigate the factors that influence the HIW producing factories’ decisions regarding the use of this facility. The survey reveals a distinct pattern: the majority of the non-users of the facility are small- and medium-scale factories, small generators of hazardous wastes, non recipients of Board of Investment (BOI) concessions, and located far away from the facility. The results from a multiple regression analysis show that a factory decision on usage of the facility is positively influenced by its size, amount of wastes generated, knowledge of the facility, pressure from regulators, and consideration of employee and community welfare. It is negatively influenced by distance and costs of using the treatment facility.
Kinetics of CH4 oxidation in mixed culture
Authors: Dote Yutaka
Published: April 2009

Microbial cultures used for methane oxidation experiments were prepared by enriching under a 20% CH4 atmosphere either leachate extracts from two different landfill sites or a digested sewage sludge. No microbes were axenically isolated, therefore the cultures were mixtures of CH4 oxidising and other aerobic microorganisms. CH4 oxidation experiments were carried out with a batch reactor, whose change in gas volume could be measured. A mixture of air and methane with CH4 concentrations ranging from 5 to 20% was introduced into the reactor. Methane oxidation rate was expressed as a Monod equation for CH4 and a first order reaction for O2. Maximum oxidation rate ( V max) resulted 2.1x10-13 to 3.4x10-11 hr-1cell-1, and half saturation constant ( K M) was 5.1x10-5 to 6.5x10-4 mol L-1. The molar ratio of consumed O2 to oxidised CH4 was 1.5-1.8
Toxicity assessment of a dye industry treatment sludge
Authors: çElebi Sol , Kendir Sevinç
Published: April 2009

Industrial treatment sludges often contain heavy metals and a variety of other hazardous substances which can cause soil and underground water pollution. In the present work, sludge samples from a dye industry treatment plant were analysed for their heavy metal contents, and three different leaching procedures were used to assess the potential toxicity of the sludge. The sludge samples were also incinerated at 600°C, and the remaining inorganic residues were also tested for their leaching characteristics by using the same leaching procedures. The treatment sludge investigated in this study contained about 55 grams of Fe per kilogram of dry sludge because iron salts are used in the chemical treatment of the wastewater. Excluding iron, the decreasing order of abundance for heavy metals in the sludge samples was found to be: Zn> Mn> Cr> Cu> Ni> Pb> Co> Cd. The average concentration of each of these heavy metals varied between 25-740 mg/kg of dry sludge. The Fe content of the inorganic residues was found to be about 140 g/kg, and the heavy metal content varied between 40-2800 mg/kg. In all the leaching tests, Pb was the most readily extracted metal from the sludge, whereas from the inorganic residue, Cd was leached the most easily. The toxicity of the sludge is estimated according to pertinent legislation.
The relation between education, knowledge and action for better waste management in Poland
Authors: Grodzińska-Jurczak Malgorzata
Published: April 2009

In recent years a significant increase in municipal solid waste (MSW) amount has been noted in Poland, and yet there is no fully efficient system for its treatment. Undertaking projects for rational MSW management requires considering both technical facilities and social barriers (waste reduction, re-use and segregation in households). In Poland, attempts to educate and mobilise society to segregate recyclables have not yet produced satisfactory results. Society’s awareness in this field needs to be raised.

The purpose of this study was to determine the level of knowledge and understanding about MSW management and the relationship between knowledge possessed and actions undertaken for various residential age groups in two Polish provinces.

In all groups, 30% of the respondents showed a satisfactory level of knowledge, whilst an equally small number of individuals had undertaken actions for MSW management at home; people with a higher level of knowledge undertook such actions slightly more often. No significant differences between the provinces were found, but residents of town, where waste segregation has been introduced simultaneously with an information campaign, showed a higher level of knowledge. The study points to the need to further educate people about MSW, and to encourage the teaching of pro-environmental attitudes.
Use of natural zeolites as a landfill liner
Authors: Tuncan Ahmet , Tuncan Mustafa , Koyuncu Hakan , Guney Yucel
Published: April 2009

The purpose of this study is to investigate certain features of a novel material proposed to serve as an impervious liner in landfills. Various ratios of bentonites and zeolites (B/Z) compacted at optimum water content were tested to determine the strength parameters, permeability, pH, heavy metals and other properties. A B/Z ratio of 0.10 was found to be an ideal landfill liner material regarding its low hydraulic conductivity and high cation exchange capacity. The use of B/Z mixtures as an alternative to clay liners would provide potential to significantly reduce the thickness of base liner for landfills.
Report: Valorsul integrated waste management: waste incineration plant
Authors: Rodrigues João P. , Nascimento AntóNio , Penha Ana , Vidal Diogo , Torres Anália , Correia Vera
Published: April 2009

Valorsul, SA, is responsible for the management of waste produced in 5 municipalities in the area of Lisbon. Due to the high density production, a multi-municipal waste management was implemented in which the primary unit is an incineration plant, built in 1999, that produces almost 2% of the national energy demand.

This paper describes the main characteristics of this plant, in particular the treatment of gases and waste management. Apart from that, and because of environmental concern of this type of unit, the monitoring program established one year before the start of the operation is described.
The use of waste materials in asphalt concrete mixtures
Authors: Tuncan Mustafa , Tuncan Ahmet , Cetin Altan
Published: April 2009

The purpose of this study was to investigate (a) the effects of rubber and plastic concentrations and rubber particle sizes on properties of asphalt cement, (b) on properties of asphalt concrete specimens and (c) the effects of fly ash, marble powder, rubber powder and petroleum contaminated soil as filler materials instead of stone powder in the asphalt concrete specimens. One type of limestone aggregate and one penetration-graded asphalt cement (75-100) were used. Three concentrations of rubber and plastic (i.e. 5%, 10% and 20% of the total weight of asphalt cement), three rubber particle sizes (i.e. No. 4 [4.75mm] - 20 [0.85 mm], No. 20 [0.85mm] - 200 [0.075mm] and No. 4 [4.75mm] - 200 [0.075mm]) and one plastic particle size (i.e. No. 4 [4.75mm] - 10 [2.00mm]) were also used. It was found that while the addition of plastic significantly increased the strength of specimens, the addition of rubber decreased it. No. 4 [4.75mm] - 200 [0.075mm] rubber particles showed the best results with respect to the indirect tensile test. The Marshall stability and indirect tensile strength properties of plastic modified specimens increased. Marble powder and fly ash could be used as filler materials instead of stone powder in the asphalt concrete pavement specimens.
Data reconciliation, structure analysis and simulation of waste flows: Case study Vienna
Authors: Matyus Thomas , Gleiß Andreas , Gruber Karl , Bauer Gerd
Published: April 2009

The management of complex waste flow systems requires a systematic approach for the handling of data, for obtaining a consistent picture of the system under consideration, and for simulating various policy scenarios and evaluating material control strategies. In this paper the implementation of a useful methodology is presented, which has been developed in previous works and is further enhanced for modelling, identifying, analysing and simulating material flow systems for which at most one measurement per flow is available for a single balancing period. The methodology enables the analyst to cope with missing data and uncertainty in the measurements. A data reconciliation procedure is used to minimise the uncertainty concerning flows by exploiting the redundancies created by restricting the available data to fulfil the available structural information. Statistical tests are introduced to enable the user to check the compatibility of the data with the a priori information. The origins analysis and destination analysis tools allow for a deeper insight into the system structure. Policy scenarios can be treated using the simulation tools. The waste flow system of the city of Vienna has been chosen to demonstrate step-by-step the procedure for building a reliable model and the effective application of the above mentioned methods and tools. Current and future research focuses on models balancing different interrelated quantities simultaneously and on incorporating stock accumulation and depletion behaviour.
Modelling simplification of landfill processes by using methods of reliability theory
Authors: Hosser Dietmar , Dehne Michael , Ahrens Hermann , Kindlein Jonathan
Published: April 2009

By the year 2005 most landfills in Germany will be closed down and begin the closing phase and later the after-care phase. So far there have been only a few scientific investigations concerning the hazard potential of stored waste for the environment. For this reason, it is necessary to predict how the hazard potential of landfills will vary after closure. The prediction can be made by describing the coupled processes of biodegradation and pollutant transport using models that are currently being developed. These models deal with highly non-linear differential equations having a large number of parameters. In order to permit application of the model in practice, it is necessary to reduce these to parameters which are essential to the reliability of the landfill. They have to be identified by sensitivity investigations with the aid of methods of reliability theory so that models can be limited to these essential parameters and the calculation effort as well as measurement of parameters (monitoring) can be considerably reduced.
Determination of field capacity of municipal solid waste with surcharge simulation
Authors: De Velásquez Ma. Teresa Orta , Cruz-Rivera Reynaldo , Rojas-Valencia Neftalí , Monje-RamíRez Ignacio , SáNchez-GóMez Jorge
Published: April 2009

The following study was carried out as part of the environmental monitoring of a landfill in Nuevo Laredo, Tamaulipas (Mexico). The parameter of field capacity is important in predicting the amount of leachate generated by solid waste disposal sites, because of the polluting potential of leachate.

This paper describes how the field capacity for municipal solid waste was determined, and the purpose of this document is to present a methodology, and to describe the devices designed for determining the field capacity of municipal solid waste.

The method consists of applying a surcharge to a representative sample of rubbish, to simulate the effects of the overlying layers in a landfill. The experimental results showed that the higher the compaction of the sample, the smaller the amount of water required to satisfy the field capacity and thus to start the leaching process. Standardisation of the methodology for determining this parameter is required in order to be able to compare the results with those obtained in other parts of the world.
An in depth study of the effects of socio-economic conditions on household waste recycling practices
Authors: Emery Andrew D. , Griffiths Anthony J. , Williams Keith P.
Published: April 2009

Waste is never consistent. Different areas use different materials, which give rise to waste streams that can vary widely in composition. With the increasing pressure on landfill operators and local governments over the amount and type of waste going to landfill, moves have to be taken to reduce, divert and recover materials. To undertake this function it is necessary to identify the composition of the waste stream.

This paper contains the results of a household waste analysis conducted in a typical unitary authority of South Wales, a traditional industrial community. The waste analysis was conducted to determine whether there was a connection between an area’s socio-economic standing and the quantities of waste produced. A selection of three different household categories were chosen, as described by the UK’s ACORN geodemographical system. The three areas chosen were terracedd, council and semi-detached properties and were selected as they were the most dominant and easily recognised types of dwellings found in the study area. The results of the full waste analysis have been compared against a number of previous household waste characterisation studies.
Assessment of the quantities of Waste Electrical and Electronic Equipment (WEEE) in Scotland
Authors: Feszty Katalin , Murchison Colin , Baird Jim , Jamnejad Gholam
Published: April 2009

The EC Directives on Waste Electrical and Electronic Equipment (WEEE) and on the Restriction of the use of certain Hazardous Substances (RoHS) in electrical and electronic equipment forms the basis of legislative control over the ultimate recovery and disposal of electronic and electrical products.

Understanding the quantities and composition of WEEE arising will be critical in the development of an appropriate collection and recovery infrastructure to meet the requirements of the directive. However in advance of implementation of the directive only limited information is currently available. This paper reviews recent estimates of WEEE arisings, considers the results of trial collection schemes, and presents the findings of the authors own analysis of WEEE arisings in Scotland. The results cover the period of 1998-2008 and suggest that the amount of waste electrical and electronic equipment will increase until 300,000-350,000 metric tons per annum is reached.
Assessing the effects of municipal solid waste incinerator bottom ash on the decomposition of biodegradable waste using a completely mixed anaerobic reactor
Authors: Banks Charles J. , Lo Huang-Mu
Published: April 2009

Experimental lab scale anaerobic reactors were used to assess the effect of municipal solid waste incinerator (MSWI) bottom ash on the process of biodegradation of organic materials typical of those found in municipal solid waste (MSW). Three reactors were used in the trial and each of these received the same daily organic load of simulated MSW but varying loads of MSWI bottom ash. The reactors were monitored over a period of 200 days for pH, alkalinity, volatile acids, total organic carbon (TOC), biogas production, gas composition and heavy metals. The addition of ash appeared to have beneficial effects on the degradation process as there was an increase in gas production, alkalinity, and pH, coupled with a decrease in the TOC concentration of leachate when compared with a control reactor without MSWI ash addition. After 200 days operation, the alkalinity and gas production in the anaerobic reactor receiving 6g ash per day was twice that of the reactor receiving 3g of ash per day and four times that of the control reactor. A number of tests were carried out on the ash sample to investigate the possible reasons for enhancement of the biodegradative process. These included a shake flask batch leaching test using distilled water, determination of the acid neutralising capacity by titration curve, and the quantification of six heavy metals and four light metals. In the reactors receiving ash the concentrations of Ca, Na, K, Mg ions were found to be significantly higher and these may provide a higher alkalinity which could promote the digestion process. Soluble concentrations of Cd, Cr, Cu, Ni, Pb, and Zn were in the range of 0.02-0.2, 0.01-2.5, 0.01-0.3, 0.01-1, 0.01-1.2, and 0.01-1 mgl-1 respectively and at these concentrations it is unlikely that they would prove inhibitory to the digestion process.
Foundry waste recycling in moulding operations and in the ceramic industry
Authors: Zanetti Maria Chiara , Fiore Silvia
Published: April 2009

An industrial treatment was performed by the Sasil plant of Brusnengo (Biella, Northern Italy), which is part of the Gruppo Minerali S.p.A. (Novara, Northern Italy), to consider the reclamation of bentonite bonded moulding sands obtained from the Teksid Italia S.p.A. cast iron foundry plant in Crescentino (Vercelli, Northern Italy). An evaluation of the fine particles produced by the wet-mechanical regeneration treatment was made with the purpose of proposing their recycling as binding agents in moulding operations in the cast iron foundry and for the production of tiles in the ceramic industry. The pre-mixed product sold by bentonite suppliers (35% coal dust and 65% bentonite, 0.15 [UNKNOWN]/kg) could be made from the recovered fine fraction below 0.025 mm with the addition of active clay and coal dust, thus obtaining a product that will have physico-chemical properties similar to those of calcic bentonite. The improvements due to the addition of the fine particles to the usually employed clay for tile production were also underlined from the results of several baking tests.

The recovery and recycling of sands and fine particles obtained from the reclamation of bentonite moulding sands will lead to a saving of raw materials and landfill space, with economic and environmental advantages.
The recycling of MSW incinerator bottom ash by sintering
Authors: Wang Kuen-Sheng , Tsai Chen-Chiu , Lin Kae-Long , Chiang Kung-Yuh
Published: April 2009

In recognition of the trend toward an increased use of bottom ash as construction material, the authors have investigated the feasibility of recovering bottom ash for use as aggregates, by sintering size-fractioned MSW incinerator bottom ash (particle size less than 1.41 mm and between 4.76-1.41 mm) at 400-1,000°C for 60-240 min, and then determining the sintered material characteristics, such as the compressive strength, heavy metal leachability and principal material properties. The results indicate that the pH of the Toxicity Characteristic Leaching Procedure (TCLP) leachate produced from both fine and the coarse ash, ranged from 10.0-11.5, and from 7.5-11.3 respectively, and showed a tendency to decrease with an increasing sintering temperature. In addition, for both types of ash the compressive strength of the sintered monoliths, ranging from 50-55 MPa, decreased slightly when the sintering temperature was increased from 400 to 600°C. Deformation problems may arise from the melting of glassy substances in the ash when bottom ash is sintered at temperatures higher than 700°C. Thus, when sintered between 800 to 1,000°C, the sintered bottom ash pellets might disintegrate due to the formation of aluminium and/or calcium salts. The decomposition of calcium carbonate at 650°C which releases significant amounts of carbon dioxide, may also cause the destruction of a monolith. Based on considerations of loss on ignition, volume changes, water adsorption, soundness, bulk density and the compressive strength of the sintered ash, developed by the sintering of bottom ash between 400 to 600°C after removing its coarse impurities, the general results from the experiments suggest that the aggregates do meet the Chinese National Standards (CNS) for permeable blocks.
A framework to contain a spatially distributed model of the degradation of solid waste in landfills
Authors: White James K. , Ren Qingchao , Robinson John P.
Published: April 2009

This paper describes the concept and development of a generic spatially distributed numerical model that can contain and link sub-models of landfill processes in order to simulate solid waste degradation and gas generation in landfills. The model has been designed to simulate anaerobic degradation of solid waste saturated in leachate, and to reflect the effect on degradation of the control of both the flow and chemistry of the leachate in the pore space of the solids. The model can accommodate different profiles of waste constituents and therefore has the potential to simulate the effects of pre-treatment techniques such as shredding and inoculation. Components of the model simulate the transport of leachate and gases, and the consolidation of the solid waste.

The results of some prototype calculations are presented.
Determination of oxygen consumption for landfilled municipal solid wastes
Authors: Kallel Amjad , Matsuto Toshihiko , Tanaka Nobutoshi
Published: April 2009

One of the serious problems of landfilling is the long time required for stabilisation. Nevertheless, site aeration proved to be effective to attenuate such problems. Oxygen consumption rate and air permeability/diffusion are the key parameters to set up the best allocation and design for vertical pipes to promote aeration and hence stabilisation of waste. This paper presents an investigation into the oxygen consumption for various landfilled wastes in Japan such as incineration ash, incombustible waste and under-sieve fraction of shredded bulky waste. Fresh waste sampled directly from processing facilities, as well as old waste sampled from landfill sites, were subjected to analytical determination and measurement of oxygen consumption. Bulky waste showed the highest oxygen consumption, however the old waste revealed a significant loss of biodegradability potential and lower oxygen consumption records. The oxygen consumption for short testing periods (10-days), tends to increase with the ignition loss (IL). The experimental data of respiratory tests (for old waste) were modelled and the fitting parameters are correlated to waste characteristics.