bluuebunny/crossref_metadata_2025 huggingface dataset:
Program Variation in Treatment Outcomes Among Women in Residential Drug Treatment
Authors: Grella Christine E. , Joshi Vandana , Hser Yih-Ing
Published: April 2009

Multilevel modeling was used to assess the program characteristics associated with treatment retention among 637 women in 16 residential drug treatment programs in the Drug Abuse Treatment Outcome Study. Women who were pregnant or had dependent children had higher rates of retention in programs in which there were higher percentages of other such women. Longer retention was associated with higher rates of posttreatment abstinence. Bivariate analyses showed that programs with higher proportions of pregnant and parenting women provided more services related to women's needs. The findings support the provision of specialized services and programs for women in order to improve outcomes of drug abuse treatment.
Statistical Power for Nonequivalent Pretest-Posttest Designs
Authors: Oakes J. Michael , Feldman Henry A.
Published: April 2009

Nonequivalent controlled pretest-posttest designs are central to evaluation science, yet no practical and unified approach for estimating power in the two most widely used analytic approaches to these designs exists. This article fills the gap by presenting and comparing useful, unified power formulas for ANCOVA and change-score analyses, indicating the implications of each on sample-size requirements. The authors close with practical recommendations for evaluators. Mathematical details and a simple spreadsheet approach are included in appendices.
A Review of Temporal Effects and Outcome Predictors in Substance Abuse Treatment Studies With Long-Term Follow-Ups
Authors: McKay James R. , Weiss Richard V.
Published: April 2009

This article is an initial report from a review of alcohol and drug treatment studies with follow-ups of 2 years or more. The goals of the review are to examine the stability of substance use outcomes and the factors that moderate or mediate these outcomes. Results from 12 studies that generated multiple research reports are presented, and methodological problems encountered in the review are discussed. Substance use outcomes at the group level were generally stable, although moderate within-subject variation in substance use status over time was observed. Of factors assessed at baseline, psychiatric severity was a significant predictor of outcome in the highest percentage of reports, although the nature of the relationship varied. Stronger motivation and coping at baseline also consistently predicted better drinking outcomes. Better progress while in treatment, and the performance of pro-recovery behaviors and low problem severity in associated areas following treatment, consistently predicted better substance use outcomes.
Probabilistic Cost-Effectiveness Analysis of HIV Prevention
Authors: Johnson-Masotti Ana P. , Laud Purushottam W. , Hoffmann Raymond G. , Hayat Matthew J. , Pinkerton Steven D.
Published: April 2009

In cost-effectiveness analysis, the incremental cost-effectiveness ratio is used to measure economic efficiency of a new intervention, relative to an existing one. However, costs and effects are seldom known with certainty. Uncertainty arises from two main sources: uncertainty regarding correct values of intervention-related parameters and uncertainty associated with sampling variation. Recently, attention has focused on Bayesian techniques for quantifying uncertainty. We computed the Bayesian-based 95% credible interval estimates of the incremental cost-effectiveness ratio of several related HIV prevention interventions and compared these results with univariate sensitivity analyses. The conclusions were comparable, even though the probabilistic technique provided additional information.
A Design for a Relational Database for the Calculation and Storage of Greenhouse Gas Emissions
Authors: Newcomb Theodore M.
Published: April 2009

The Intergovernmental Panel on Climate Change (IPCC) has published guidelines for the development of national greenhouse gas-emissions inventories and recommendations for collecting data necessary to calculate greenhouse gas emissions. Many regional and local jurisdictions will be performing inventories of greenhouse gas emissions and estimating the benefits of mitigation strategies to reduce emissions. This article advocates the development of relational databases to calculate and store emissions estimates based on IPCC guidelines and quantities of precursors of greenhouse gases. Specific examples of tables and queries are used to illustrate calculation methods and formulae, the choice of database keys, and the choice of methods for joining tables to construct queries.
Do Participation Rates Change when Active Consent Procedures Replace Passive Consent
Authors: Pokorny Steven B. , Jason Leonard A. , Schoeny Michael E. , Townsend Stephanie M. , Curie Carrie J.
Published: April 2009

Researchers face considerable ambiguity and controversy regarding the issue of informed consent. Decisions about consent procedures can affect study participation rates and prevalence estimates among specific populations. Changing from passive to active parental consent procedures was examined in a case study with an anonymous survey of sixth- through eighth-grade students' substance use. Four types of procedures for obtaining parental consent were examined. Results suggest that certain types of consent procedures can yield high levels of participation. This study also demonstrates that low participation rates with some active consent procedures can cause biases in sample characteristics and outcome data.
Reducing Overclaiming in Needs Assessment Studies an Experimental Comparison
Authors: Calsyn Robert J. , Kelemen William L. , Jones E. Terrence , Winter Joel P.
Published: April 2009

A randomized experiment investigated the effect of various instructional sets on reducing agency awareness overclaiming, that is, claiming knowledge of fictitious agencies. As predicted, respondents who were warned that the list contained fake agencies exhibited less agency awareness overclaiming than respondents who were not warned. However, providing respondents a memory retrieval strategy had no effect on agency awareness overclaiming. A multivariate model, which included demographic variables, response style variables, and knowledge variables, explained 40% of the variance of agency awareness overclaiming.
The American Stop Smoking Intervention Study
Authors: Stillman Frances , Hartman Anne , Graubard Barry , Gilpin Elizabeth , Chavis David , Garcia John , Wun Lap-Ming , Lynn William , Manley Marc
Published: April 2009

Reducing tobacco use, especially cigarette smoking, is a public health priority. The American Stop Smoking Intervention Study (ASSIST) was initiated in 1991 to prevent and reduce tobacco use primarily through policy-based approaches to alter the social-political environment. This article describes the conceptual design, research framework, evaluation components, and analytic strategies that are guiding the evaluation of this demonstration research endeavor. The ASSIST evaluation is a unique analysis of the complex relationships between the social context, public health activity at the state level, tobacco use, and individual behavior. The measures of tobacco control activity developed for this evaluation may be useful in ongoing national cancer control surveillance efforts, and the lessons learned will enhance the development of tobacco control programs.
Informed Policy Making for the Prevention of Unwanted Pregnancy
Authors: Chetkovich Carol , Mauldon Jane , Brindis Claire , Guendelman Sylvia
Published: April 2009

California health and welfare officials asked the authors to identify ways that their programs could encourage service use among low-income women. The project posed a challenge: The clients wanted to identify supply-side barriers amenable to intervention, but prior research suggested other factors might be more influential. The approach was to examine service-related issues, but in the broader context of women's experiences. The authors identify factors amenable to intervention, including inaccurate beliefs about methods. Other important influences—such as instability of relationships, skepticism about planning, or unsatisfactory method experiences—may be beyond the reach of specific policies, but are nevertheless critical to understanding program context. Findings suggest that punitive messages and policies based on a simplistic model of behavior may be unrealistic and ineffective.
Decisions on Placement and Family Preservation
Authors: Schuerman John , Rossi Peter H. , Budde Stephen
Published: April 2009

Vignettes presented to experts and workers in the child welfare field were used to explore the degree of agreement on decisions to place children in substitute care or to refer them to family preservation services. The design allowed for investigation of the problem of targeting in family preservation programs. Findings indicate considerable inconsistency in decisions among experts and workers, particularly in decisions to refer to family preservation and other in-home services. Contrary to the stated intentions of family preservation services, a majority of the referrals to these programs do not involve children who would have been placed in the absence of these programs.
Influence of Assessment Methods on Reports of Gender Differences in AMI Symptoms
Authors: Ju Young Shin  , Martin René , Bryant Howren M.
Published: April 2009

The purpose of this secondary analysis was to compare gender differences in retrospective reports of acute myocardial infarction (AMI) symptoms resulting from two different assessment methods: the open-ended inquiry and the combined assessment approach. Women reported more atypical symptoms in their responses to the open-ended inquiry and a greater number of typical, atypical, and total symptoms in the combined assessment approach in which the open-ended inquiry was followed by a series of closed-ended questions. Women reported more jaw/neck pain, dyspnea, and palpitations in response to the open-ended inquiry. In the combined assessment, men reported more chest pain/discomfort than women, whereas women were more likely to report jaw/neck pain, dyspnea, back pain, fatigue, paroxysmal nocturnal dyspnea, and palpitations. The data suggest that careful attention to the type of questions used to assess AMI symptoms could lead to more definitive conclusions regarding gender differences in AMI symptoms.
More Than Just Free Content
Authors: Cenite Mark , Wanzheng Wang Michelle , Chong Peiwen  , Shimin Chan Germaine
Published: April 2009

This study explores file sharers' reported motivations for downloading and uploading content on peer-to-peer networks, including ethical obligations guiding file sharing. Drawing on Lessig's classification of purposes of file sharing and Giesler's theoretical framework of gifting systems, 40 in-depth interviews were conducted with file sharers in Singapore using a standard protocol, then transcripts were analyzed using qualitative content analysis. Downloading is perceived as an alternative through which users satisfy desires that existing markets do not meet. Respondents reported downloading to avoid long waits for content to arrive in Singapore; to access difficult-to-find and censored content; to sample content, including content outside their usual tastes; and because downloading is convenient and free. Respondents reported a norm of reciprocity and sense of community that motivated them to upload and an obligation to purchase content they liked. Implications for understanding and combating file sharing during the inevitable transition to other business models are discussed.
An exploratory qualitative study of equity and the social care needs of visually impaired older people in England
Authors: Charles Nigel , Manthorpe Jill
Published: April 2009

This article describes the findings of a small study of the ways in which social care practitioners describe their assessment practice with visually impaired older people in England. The study interviewed 14 social care staff in three local authorities that had different organizational arrangements for assessments. Using a vignette method, the study explored staff's definitions of social care needs. Possible differences between the practice of specialists in visual impairment and those who were not working or trained specifically in the area of visual impairment are explored, as is the context of policy assessments for social care services. The potential impact of differences and context on equity is discussed.
Archives and Records Management Education and Training: what can Africa learn from Europe and North America?
Authors: Katuu Shadrack
Published: April 2009

While education and training of archives and records professionals within Sub Saharan Africa has a history of about five decades, elsewhere professional development has a history lasting several centuries. In Europe, archivists have been in existence since the 17th century while in North America, while the history is just about one century old, within that time a lot of innovation has been evident. This article provides a summary of developments in the two continents, drawing lessons that could be useful in reinvigorating discussion within the African continent.
The Institutional Foundations of Materialism in Western Societies
Authors: Kilbourne William E. , Dorsch Michael J. , McDonagh Pierre , Urien Bertrand , Prothero Andrea , Grünhagen Marko , Jay Polonsky Michael , Marshall David , Foley Janice , Bradshaw Alan
Published: April 2009

Studies of materialism have increased in recent years, and most of these studies examine various aspects of materialism including its individual or social consequences. However, understanding, and possibly shaping, a society’s materialistic tendencies requires a more complete study of the relationship between a society’s institutional patterns and the acceptance of materialism by its members. Consequently, the current study examines five of the institutional antecedents of materialism to understand better how and why it develops as a mode of consumption within a society. More specifically, a model relating materialism and a set of institutionalized patterns of social behavior referred to as the dominant social paradigm was developed and tested in a study of seven industrial, market-based countries. The results suggest that the economic, technological, political, anthropocentric, and competition institutions making up the dominant social paradigm are all positively related to materialism. The implications of the relationship are then discussed.
Stormwater run-off and pollutant transport related to the activities carried out in a modern waste management park
Authors: Marques M. , Hogland W.
Published: April 2009

Stormwater run-off from twelve different areas and roads has been characterized in a modern waste disposal site, where several waste management activities are carried out. Using nonparametric statistics, medians and confidence intervals of the medians, 22 stormwater quality parameters were calculated. Suspended solids, chemical oxygen demand, biochemical oxygen demand, total nitrogen and total phosphorus, as well as run-off from several areas, showed measured values above standard limits for discharge into recipient waters - even higher than those of leachate from covered landfill cells. Of the heavy metals analyzed, copper, zinc and nickel were the most prevalent, being detected in every sample. Higher concentrations of metals such as zinc, nickel, cobalt, iron and cadmium were found in run-off from composting areas, compared to areas containing stored and exposed scrap metal. This suggests that factors other than the total amount of exposed material affect the concentration of metals in run-off, such as binding to organic compounds and hydrological transport efficiency. The pollutants transported by stormwater represent a significant environmental threat, comparable to leachate. Careful design, monitoring and maintenance of storm-water run-off drainage systems and infiltration elements are needed if infiltration is to be used as an on-site treatment strategy.
Experimental generation of organic dust from compostable household waste
Authors: Heldal Kari Kulvik , Breum Niels O. , Nielsen Birgitte H. , Wilkins Ken
Published: April 2009

The objective was to assess the influence of different waste storage systems on the emission of bioaerosols and gases from compostable household waste. Batches of waste were stored for 14 days in different storage systems: ventilated containers (compostainers) with or without added structure material and closed containers with or without a preservation additive. The microbial potential of the waste was measured with a rotating drum after storage. The weight loss in the compostainers (39%) was higher than in the closed containers (9%). Hydrogen sulphide and mercaptans developed in the closed container, and the concentration of ammonia increased continuously in both systems to 140 ppm. The microbial content for the incubated waste was high for closed containers compared to compostainers, and waste in closed containers generated a liquid rich in endotoxin and bacteria. The aerosols emitted from the waste consisted mainly of fungal spores, especially Aspergillus fumigatus, and no significant differences were observed between the systems. The endotoxin potential was high for waste stored in closed containers. The use of a preservative prevented microbial growth and reduced the emission of bioaerosols and gases substantially.
Lateral gas transport in soil adjacent to an old landfill: factors governing emissions and methane oxidation
Authors: Christophersen Mette , Kjeldsen Peter , Holst Helle , Chanton Jeffrey
Published: April 2009

Field investigations of lateral gas transport and subsequent emissions in soil adjacent to an old landfill in Denmark were conducted during a 1-year period. A significant seasonal variation in the emissions with high carbon dioxide and low methane fluxes in the summer (May to October) was observed. This was attributed to methane oxidation. Diurnal measurements during a drop in barometric pressure showed that the fluxes of landfill gas changed dramatically within a very short time. The concentrations and the soil moisture content in the upper part of the soil profile had significant influence on the fluxes, as did the distance from the landfill border, temperature, barometric pressure and the pressure gradient. Statistical analyses proved that soil moisture described the largest part of the variation. No methane is emitted during the summer. Calculations and isotope analyses showed that very high fractions of the laterally migrating methane were oxidised.
Design of landfill daily cells
Authors: Panagiotakopoulos D. , Dokas I.
Published: April 2009

The objective of this paper is to study the behaviour of the landfill soil-to-refuse (S/R) ratio when size, geometry and operating parameters of the daily cell vary over realistic ranges. A simple procedure is presented (1) for calculating the cell parameters values which minimise the S/R ratio and (2) for studying the sensitivity of this minimum S/R ratio to variations in cell size, final refuse density, working face length, lift height and cover thickness. In countries where daily soil cover is required, savings in landfill space could be realised following this procedure. The sensitivity of minimum S/R to variations in cell dimensions decreases with cell size. Working face length and lift height affect the S/R ratio significantly. This procedure also offers the engineer an additional tool for comparing one large daily cell with two or more smaller ones, at two different working faces within the same landfill.
Waste benefits of CO2 policies in Japan
Authors: Gielen D. J. , Moriguchi Y.
Published: April 2009

A linear programming model REAP (Regional Environmental strategy Analysis Program) has been developed for the analysis of the consequences of a CO2 tax for petrochemical products such as plastics (CO2, carbon dioxide, is the most important greenhouse gas). Special attention has been paid to the impacts on waste management.

The results suggest that a 10,000 Y t-1 CO2 tax would result in a significant reduction of CO2 emissions in the petrochemical life cycle, ranging from 40 Mt in 2015 to 70 Mt CO2 in later decades (more than 50% emission reduction). Waste quantities will be reduced simultaneously. The CO2 tax results in an 18% reduction of plastic waste weight in 2015 (3 Mt waste). Lower tax levels that may be politically more acceptable would result in proportionally lower environmental benefits. CO2 benefits and waste benefits of a CO2 tax are of equal importance in policy terms.

Apart from changes in waste volume, CO2 taxes would affect the cost-effectiveness of waste handling technologies. Energy recovery in industrial kilns may replace conventional waste incineration. Recycling constitutes half of the total waste treatment. Given these results, current investments in new incineration capacity may suffer from insufficient waste availability during the next two decades in case CO2 taxes are introduced.

A third effect of a CO2 tax is a significant increase of waste transportation. The results show that this increase is concentrated in the central part of Honshu (Kinki, Chubu & Kanto). Such transportation can result in new local environmental impacts that should be analysed in more detail. Given the strong impact of CO2 taxes on waste quantities and waste treatment it is recommended to co-ordinate CO2 policies and solid waste policies.
Life cycle inventory for Municipal Solid Waste management Part 2: MSW management scenarios and modeling
Authors: Wilson E. J.
Published: April 2009

Evaluating the environmental performance of municipal solid waste management options is a complex task. Part 1 of this study presents the municipal solid waste management program of the Pamplona Region in Spain and explores the operational, economic, and environmental factors of the program. In Part 2, alternative waste management scenarios that include the selective collection of organic material and composting are illustrated. The use of a Life Cycle Inventory model for waste management allows for the comparison of the environmental burdens of the different scenarios. This use of a Life Cycle Inventory model for solid waste management lets program managers and decision makers include energy use, final solid waste, and Greenhouse gas emissions in the decision making process. Additionally, the different management scenarios are evaluated on their ability to fulfil Pamplona regional objectives and meet European Packaging and Landfill Directive targets.
Treatment of waste incinerator air-pollution-control residues with FeSO4: Concept and product characterisation
Authors: Lundtorp K. , Jensen D. L. , Sørensen M. A. , Christensen T. H. , Mogensen E. P. B.
Published: April 2009

This paper describes a new concept for treatment of air-pollution-control (APC) residues from waste incineration and characterises the wastewater and stabilised residues generated by the process. The process involves mixing of APC-residues with a ferrous sulphate solution and subsequent oxidation of the suspension (Ferrox-process 1996). The process results in a significant reduction in the leaching of salts and heavy metals from the residue, by washing out most of the salts and by binding the heavy metals in the iron oxides formed. In the laboratory, a semidry gas-cleaning residue and a fly ash were treated by the process. The generated wastewater contained low concentrations of heavy metals (e.g. Pb: 27-39 μg l-1 and Cd: 2.6-4.6 μg l-1), but high concentrations of salts (e.g. Cl, Na, K, and Ca). The treatment process reduced the leaching of Pb from the residues by more than two orders of magnitude at fixed pH as determined by pH-static leaching tests. Likewise, the leaching of Cd, Zn and Cu was significantly reduced. The effect on elements that form oxyanions (e.g. Cr) is marginal and in the current process there is no reduction in the release of Hg.
Vienna’s biowaste compost - quality development and effects of input materials
Authors: Plahl F. , Rogalski W. , Gilnreiner G. , Erhart E.
Published: April 2009

Extensive chemical analyses were conducted during the last decade to assess the heavy metal content of the finished compost as well as of biowaste and other input materials. Twenty six percent of the compost lots were class I according to ÖNORM S2200, 70% class II and 4% did not reach class II. If the compost lots were classified according to the new Austrian compost ordinance, 22% would conform to class A+ and 78% to class A. These data are put into relation with heavy metal contents of soil, of yard wastes and of biowastes without contaminants. In the soil samples particularly nickel and lead exceeded the limits for class A+ (compost ordinance). In the yard wastes, more than 90% of the samples met the limits for all heavy metals. Biowaste without contaminants conformed to class A+ on average. In biowaste without contaminants no influence of the housing structure on the heavy metal content was observed. The compost produced only from biowaste from areas with high building density, after undergoing the normal process of metal removal, however, was significantly higher contaminated than that of compost of the whole city of Vienna. The impact of specific input materials, such as Christmas trees or wooden crates, was investigated by chemical analyses before and after controlled composting experiments with those materials. In both experiments the compost quality did not reach the limits for heavy metals of class I (ÖNORM S2200).
A Fuzzy Markov approach for assessing groundwater pollution potential for landfill siting
Authors: Chen Wei-Yea , Kao Jehng-Jung
Published: April 2009

This study presents a Fuzzy Markov groundwater pollution potential assessment approach to facilitate landfill siting analysis. Landfill siting is constrained by various regulations and is complicated by the uncertainty of groundwater related factors. The conventional static rating method cannot properly depict the potential impact of pollution on a groundwater table because the groundwater table level fluctuates. A Markov chain model is a dynamic model that can be viewed as a hybrid of probability and matrix models. The probability matrix of the Markov chain model is determined based on the groundwater table elevation time series. The probability reflects the likelihood of the groundwater table changing between levels. A fuzzy set method is applied to estimate the degree of pollution potential, and a case study demonstrates the applicability of the proposed approach. The short- and long-term pollution potential information provided by the proposed approach is expected to enhance landfill siting decisions.
Material and energy balances in a large-scale aerobic bioconversion cell
Authors: Themelis Nickolas J. , Kim Young Hwan
Published: April 2009

On the basis of earlier experimental studies of the aerobic bioconversion of organic wastes, the preferred values of operating parameters and the biochemical rate constants of oxidation to CO2 and H2O were identified. Energy and material balances were then constructed for a large, 3 m deep aerobic cell holding 1,440 tons of the ‘wet’ component of organic wastes (major organic constituent: [C6H10O4]n). It was found that conduction/convection and radiation losses to the surroundings amount to a relatively small fraction of the chemical heat released by oxidation. Therefore, the surplus chemical heat must be removed by means of an upward water-saturated air flow that is several-fold the stoichiometric requirement for biodegradation. This study has quantified a basic process difference between anaerobic and aerobic bioconversion of organic matter: In the former, most of the chemical energy in the converted organic matter is stored chemically in the generated methane gas. In the latter, this energy is released in the cell and must be carried out in a relatively large air/water vapour flow through the cell.
Long-term settlement behaviour of MSW landfills with various fill ages
Authors: Park H. I. , Lee S. R.
Published: April 2009

MSW landfill settlement characteristics are peculiar because a considerable amount of settlement occurs due to the decomposition of waste organic solids for very long duration. The total amount of settlement that occurs due to this decomposition in a MSW landfill is mainly dependent upon the amount of biodegradable solid waste and hence the fill age of the MSW landfill. The settlement stabilisation period is also dependent upon the decomposition condition. In order to investigate the settlement characteristics of MSW landfills, a mathematical model was proposed and applied to settlement data of MSW landfills which have various fill ages. A data bank of model parameters were obtained and the trends were analysed. The long-term settlement behaviour of MSW landfills can be fairly well estimated by the proposed model. It is supposed that the total remaining amount of settlement might be predicted on the basis of the fill age with two appropriate design parameters.
Determination of chlorine and bromine in automotive shredder residues by oxygen bomb and ion chromatography
Authors: Cortés-Peña M. A. , Pérez-Arribas L. V. , León-González M. E. , Polo-Díez L. M.
Published: April 2009

An analytical procedure, oxygen bomb combustion-ion chromatography (IC), has been developed for the determination of total chlorine in Automotive Shredder Residues (ASR). Samples of these residues are fired under elevated oxygen pressure (30 atm) and the combustion products are transferred into a Na2 CO3/NaHCO3 absorbent solution containing 1% of H2 O2; the chlorine contents are then evaluated by ion chromatography. The use of the non-suppressed IC determination with a conductivity detector provides a rapid, sensitive and selective method for chlorine determination in ASR, allowing determinations of this heteroatom at levels below 1% in the presence of bromine and sulfur. Moreover, the proposed method allows the simultaneous determination of chlorine, bromine and sulfur which are potential environmental hazards.
A model for the reallocation of recycling containers: application to the case of glass
Authors: González-Torre Pilar L. , Adenso-Díaz Belarmino
Published: April 2009

From both the social as well as the economic perspective, the recycling of household waste products is of growing importance. The recycling of glass in particular is one of the most successful as far as public collaboration is concerned, as well as due to the demand for recycled material on the part of glass manufacturers. This article presents a model for designing the first stage in the reverse logistics chain, i.e. the collection of material (in our case, applying the model to the collection of glass) directly from the consumer by means of containers. The aim of this model is to determine how to distribute the recycling containers in a specific region in the most efficient way possible, taking into account the economic and sociological characteristics of the population (level of education, number of catering establishments, etc.), while attempting to maximise the material collected and reducing the logistics costs. The model has been applied to the case of the Principality of Asturias, Spain, obtaining estimations that improve the performance of the system.
Adding crumb rubber into exterior wall materials
Authors: Zhu Han , Thong-On Norasit , Zhang Xiong
Published: April 2009

In Arizona US, most houses are built with walls covered by stuccos/coatings/mortars. This paper presents an explorative investigation of adding crumb rubber into stuccos/coatings/mortars. A series of experiments are conducted to examine the thermal and mechanical performance of the crumb rubber mixes. The results show that, the mixes with crumb rubber do exhibit more desirable performances like being high in crack-resistance and thermal insulation, and low in thermal expansion/contraction. The drawback for the crumb rubber mixes is the reduction in compressive strength, but which can be compensated by other means. As a site experiment, an area of 100 square-feet of crumb rubber coatings for two mix designs is sprayed on a tire-adobe wall. After being sprayed more than 14 months, the coatings apparently are in good condition. Significance of this study is that this practice, if accepted, will yield improved products that consume large quantities of crumb rubber.
Carbide sludge management in acetylene producing plants by using vacuum filtration
Authors: Ramasamy Palanisamy , Periathamby Agamuthu , Ibrahim Shaliza
Published: April 2009

Carbide sludge (10.4-11.5 tonnes day-1) is generated from the reaction of calcium carbide (900 kg) and water (6,000 L) in the production of acetylene (2400 m3), in three selected acetylene manufacturing plants. The sludge (of pH 12.2 and containing Cu, Pb, Fe, Mn, Ni and Zn ions whose concentrations exceed the Department of Environment limits for industrial wastewater) was treated by vacuum filtration as a substitute for the ponding system, which is environmentally less acceptable. A similar system by flocculation was also developed. The filtration system represents an improvement over the ponding method, as shown by a pH of 7 for the clear filtrate; the solid cake, which contains 98% of the metals, can be conveniently disposed at an integrated scheduled waste treatment centre.
Re-use of stabilised flue gas ashes from solid waste incineration in cement-treated base layers for pavements
Authors: Cai Zuansi , Jensen Dorthe L. , Christensen Thomas H. , Bager Dirch H.
Published: April 2009

Fly ash from coal-burning power plants has been used extensively as a pozzolan and fine filler in concrete for many years. Laboratory experiments were performed investigating the effect of substituting the coal-based fly ash with chemically stabilised flue gas ashes (FGA) from waste incineration.

Two types of FGA were treated by the Ferrox-process, which removes the majority of the easily soluble salts in the FGA and provides binding sites for heavy metals in terms of ferrihydrite. Cubes of cement treated base layer materials containing 5% stabilised FGA were cast, sealed and cured for two weeks. Cylinders (diameter 100 mm, length 150 mm) were drilled from these cubes for tank leaching experiments. Duplicate specimens were subject to compression strength testing and to tank leaching experiments. The compressive strength of the CTB fulfilled the Danish requirements for CTB, i.e. strength more than 5 MPa after 7 days. The tank leaching tests revealed that leaching of heavy metals was not significantly affected by the use of chemically stabilised flue gas ashes from waste incineration. Assuming that diffusion controls the leaching process it was calculated that less than 1% of the metals would leach during a 100-year period from a 0.5 m thick concrete slab exposed to water on one side. Leaching of the common ions Ca, Cl, Na and SO4 was increased 3-20 times from the specimens with chemically stabilised flue gas ashes from waste incineration. However, the quantities leached were still modest.

These experiments suggest that FGA from waste incineration after Ferrox-treatment could be re-used in CTB without compromising the strength and leaching from the base layer.
Kinetics of anaerobic treatment of landfill leachates combined with urban wastewaters
Authors: Fueyo Gema , GutiéRrez Antonio , Berrueta José
Published: April 2009

The anaerobic degradation of landfill leachates mixed with domestic wastewater has been studied in a pilot-scale Upflow Anaerobic Sludge Blanket (UASB) reactor. A previous work in laboratory-scale had shown that a fraction (5%) of the refractory organic matter could be additionally degraded when these two substrates were treated in conjunction, but this synergistic effect in the Chemical Oxygen Demand (COD) removal was not reproduced. However, the mass loading rate for which the maximum degradation was obtained was higher for the mixtures (0.5 kg COD/kg SSV·d) than for the separated components (0.18 and 0.19), allowing an increase in the treatment capacity of the leachates. The methane productivity (304 L/kg COD) was close to the theoretical maximum and independent of the proportion of the mixture components. The experimental data were fitted to a modification of Haldane’s kinetic model, in which the parameters depend on the hydraulic residence time and the biomass concentration.
Magnetic susceptibility variation of MSW compost-amended soils: In-situ method for monitoring heavy metal contamination
Authors: Yoshida Mitsuo , Jedidi Naceur , Hamdi Helmi , Ayari Fethia , Hassen Abdennaceur , M’Hiri Ali
Published: April 2009

Magnetic susceptibility was measured for agricultural soils in Mornag area, Tunisia, where the soils were partly amended by manure or compost obtained from municipal solid waste stabilisation (‘MSW compost’). Our study indicates that natural non-treated soils and manure-amended soils are always low in magnetic susceptibility, but MSW compost-amended soils show higher values of this parameter. Actually, the increase of magnetic susceptibility shows a direct correspondence with the increasing of the amount of MSW compost added to the soil. According to the magnetic mineralogical investigation carried out by isothermal remanent magnetisation acquisition technique, higher magnetic susceptibility values are depending on an increase in ferromagnetic components such as either magnetite (-Fe3 O4) or maghemite (-Fe2 O3) particles. The growth in content of these ferromagnetic components corresponds to an increase of the concentration of heavy metals in soils, which means that magnetic susceptibility indirectly indicates the concentration of heavy metals in MSW compost-amended soils.
Don’t ban PVC: Incinerate and recycle it instead!
Authors: Menke Doris , Fiedler Hiltrud , Zwahr Heiner
Published: April 2009

Plastics are making a growing contribution to sustainable development. For example, over an expected lifetime of 50 years, the use of window frames and insulating materials made of plastic in buildings save many times the energy required to manufacture them. Plastics for packaging purposes provide protection against damage and dirt contamination, thereby saving considerable amounts of material and energy. Choosing appropriate disposal strategies for plastic waste also helps to protect the environment (Mark 2000).
Hospital waste operational procedures: A case study in Brazil
Authors: Ferreira Aldo Pacheco , Veiga Marcelo Motta
Published: April 2009

This study analysed the hospital waste management practices and their implications to public health in the city of Belo Horizonte, south eastern Brazil. Belo Horizonte is a regional capital city located 300 miles from the famous city of Rio de Janeiro, Brazil. It is only 100 years old and is the first city planned in Brazil. It was originally planned for 300,000 people but, today, it is home to more than 2 million people.

This study assessed the operational procedures at five hospitals (170 to 450 beds) with different medical specialties in order to analyse their major waste problems. This study also gathered data on different types of treatment and disposal procedures used by waste generators, which enabled an estimate on the amount of on-site and off-site waste generated.
Design of a reverse osmosis plant for leachate treatment aiming for safe disposal
Authors: Thörneby Lars , Hogland William , Stenis Jan , Mathiasson Lennart , Somogyi Pernilla
Published: April 2009

Leachate treatment is one of the major environmental issues faced by landfill owners. One promising method for reduction of pollutant discharge is reverse osmosis (RO). RO technology was tested at a pilot plant at Hedeskoga Landfill in southern Sweden. This landfill receives municipal solid waste (MSW) and industrial, commercial and institutional (IC&I) waste, and produces about 3000 m3/ha of leachate annually.

Annual variations in the volume of leachate produced, estimated from changes in leachate electrical conductivity, were relatively small and should therefore have a minor effect on the main performance parameter of an RO plant, i.e., the achievable volume reduction. The volume reduction (Vpermeate/Vfeed) of polluted water achieved in batch experiments with 200-1000 litres of raw leachate was more than 80% (4MPa) and the remaining 20% was left as retentate. However, raw leachate caused severe fouling problems in a continuous flow run and after 24 hours, the flux had decreased to about 20% of the initial value. By pre-treating the leachate in a storage pond combined with a wetland, the situation was significantly improved and the decrease in membrane flux was only 0.2% per hour during a 200 hour run. The retention in terms of total solids and chemical oxygen demand was 90%, and for ammonia, it was 82%, at a volume reduction of 50%.

The HELP-model was used for prediction of the water balance for the Hedeskoga landfill, with special focus on estimation of potential evapotranspiration. With different types of vegetation and a volume reduction of 75% in the RO plant, it was found possible to achieve safe disposal by irrigating 25% to 40% of the leachate-producing landfill area with pre-treated leachate.

Pre-treatment with wetlands and nature based systems reduce the need of detergents for cleaning of the membranes and water only can be used. Short pre-treatment by aeration is not sufficient to bring leachate to a condition sustainable for RO-treatment. In that case, it was found necessary with alkaline-acid-alkaline treatment to restore the permeability. The total treatment cost for a full scale treatment plant at Hedeskoga was estimated to be approximately 30 SEK/m3, of which 25 is capital and 5 is operational costs. This can be compared to the total treatment costs for municipal sewage in Sweden, which is 8 SEK/m3.
Automobile shredder residue gasification
Authors: De Filippis Paolo , Pochetti Fausto , Borgianni Carlo , Paolucci Martino
Published: April 2009

Automobile Shredder Residue (ASR) shows a broad chemical composition owing to the presence of different materials, and its high organic content makes it interesting as a source of energy.

In this work, a bench scale two-stage reactor is used for gasifying ASR. The reactor shows an efficient ASR gasification, avoiding the formation of difficult to manage char and tar and allowing an easy recovery of energy. The results of the investigation were used to test a simple model based on mass and energy balances and chemical equilibrium, predicting syngas composition including the presence of problematic elements such as sulphur and chlorine.

Gasification data calculated by the model agree in a satisfactory way with the experimental ones. Due to the large variation in ASR composition, the model predicts that ASR gasification is industrially feasible only if a blend of ASR and RDF is used as a reactor feed.
How model-based systems analysis can be improved for waste management planning
Authors: Eriksson Ola , Olofsson Mattias , Ekvall Tomas
Published: April 2009

Waste management models have been developed worldwide since the late 1960s. The overall aim of the models is to assist decision makers who are facing a complex task in order to handle waste in a cost-efficient and environmentally sound way. International research publications regarding waste management models point out the major benefits to be their capacity to deal with complexity and uncertainty and of finding benefits of co-operation and handling different goals. Such models have been developed and used successfully in Swedish research projects since the beginning of the 1990s, but the current situation is that such models are rarely requested for waste management planning in the country. Based on case studies (with the waste management models MIMES/Waste and ORWARE) in the Swedish municipality of Jönköping and a follow-up study, the paper discusses and draws conclusions on how to improve and increase the use of models to better correspond to the needs of decision makers involved in waste management planning.
Removal of ammonia in a modified two-phase food waste anaerobic digestion system coupled with an aerated submerged biofilter
Authors: Wang Jing-Yuan , Zhang Hua , Stabnikova Olena , Tay Joo-Hwa
Published: April 2009

Anaerobic digestion of food waste can reduce its volume, generate fuel biogas containing methane, and produce solid organic residue that can be used as a soil conditioner or fertiliser. Anaerobic digestion is more promising food waste disposal method than incineration and landfilling. The hybrid anaerobic solid-liquid (HASL) system, enhanced with a submerged biofilter for ammonia removal, was proposed for food waste digestion. Application of the submerged biofilter in the HASL system operated in batch mode increased concentrations of dissolved COD and volatile fatty acids in an acidogenic reactor, and total COD removal and methane production in a methanogenic reactor. The gas production in the enhanced HASL system was 86 l while in the conventional HASL system it was 54 l after 14 days of batch process. Methane production in the enhanced HASL system was increased by 26% in comparison with the conventional HASL system.
Solubility and adsorption characteristics of Pb in leachate from MSW incinerator bottom ash
Authors: Kim Sang-Yul , Tanaka Nobutoshi , Matsuto Toshihiko
Published: April 2009

The solubility and adsorption characteristics of Pb in leachate from municipal solid waste incineration (MSWI) bottom ash was studied by batch experiments. The solubility of Pb in leachate was 1-2 orders of magnitude lower than that of Pb in carbonate solutions. Adsorption experiments showed bottom ash have high adsorption capacity for Pb. To evaluate a controlling component in bottom ash, quartz, Al and Fe powder as well as their ions were examined over wide ranges of pH at 25°C. The results showed that only Fe powder had high adsorption capacities for Pb, indicating that iron oxides in bottom ash would be one major adsorbent for Pb. Adsorption diagram, constructed by using the data of adsorption experiments, fitted the experimental data of Pb in leachate very well. It suggests that the decrease of Pb solubility in leachate is mainly due to adsorption reaction.
Predicting Arithmetic Abilities
Authors: Stock Pieter , Desoete Annemie , Roeyers Herbert
Published: April 2009

Arithmetic abilities acquired in kindergarten are found to be strong predictors for later deficient arithmetic abilities. This longitudinal study ( N = 684) was designed to examine if it was possible to predict the level of children's arithmetic abilities in first and second grade from their performance on preparatory arithmetic abilities in kindergarten. Furthermore, the role of intelligence in the assessment of developing mathematical reasoning and numerical facility was investigated. The results showed that good predictions of beginning arithmetic abilities can be made. Even in the long term, it was possible to make predictions of later arithmetic performances, especially for the domain of arithmetical reasoning. Logic thinking abilities such as seriation and classification and counting knowledge may be assessed in kindergarten as possible markers for at-risk development. Furthermore, it is important to take into account intelligence when looking for useful predictors of arithmetical reasoning.