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Serial water balance method for predicting leachate generation in landfills.

This paper presents the "Serial Water Balance" method for predicting leachate generation in landfills. This procedure makes it possible to calculate the total leachate likely to be generated, by estimating an individual cell by cell water balance. This new development considers the interaction effects between cells, through the execution of simple field capacity tests on solid waste samples under different loading conditions. The procedure described in this paper simulates the effect induced by fluid percolating from a cell at an upper layer to cells in the immediately subjacent layer. The method described here was applied to the landfill in Nuevo Laredo, Tamaulipas (Mexico), after first ascertaining information regarding: duration of construction time, exposure time, surface area, the quantity of waste, number of confining cells, and local weather conditions. In a full-scale test case the suggested method has predicted 67% of the leachate produced in a period of 4 years. Further testing and more detailed analysis of the composition of the waste used in the calculations, may improve the accuracy in predicting leachate production. Even though this SWB methodology was applied to a landfill subject to extreme climatological conditions (high daytime temperatures), it is possible to adapt the methodology to solid waste disposal sites in regions with more humid or moderate climates.

Climate↗

Municipal solid wastes and their disposal.

A brief overview is given of the sources, characteristics, and toxic constituents of municipal solid wastes. Several methods are presented for handling, treating, and disposal of solid wastes. Monitoring the landfill site is necessary; there has been a trend to recognize that municipal solid wastes may be hazardous and to provide separate secure handling, treatment, and disposal for their dangerous constituents. Under current state and Federal regulations, permits are being required to assure that proper handling of conventional solid wastes and more hazardous constituents are carefully managed.

Environmental Pollution↗

Household disposal of pharmaceuticals as a pathway for aquatic contamination in the United kingdom.

Pharmaceuticals are produced and used in increasingly large volumes every year. With this growth comes concern about the fate and effects of these compounds in the environment. The discovery of pharmaceuticals in the aquatic environment has stimulated research in the last decade. A wide range of pharmaceuticals has been found in fresh and marine waters, and it has recently been shown that even in small quantities, some of these compounds have the potential to cause harm to aquatic life. The primary pathway into the environment is the use and disposal of medicines; although much of the research in the area currently focuses on the removal of pharmaceuticals during sewage treatment processes, disposal via household waste might be a significant pathway requiring further research. To investigate the household disposal of unused and expired pharmaceuticals as a source of pharmaceutical compounds in the environment, we carried out a survey and interviewed members of 400 households, predominantly from southeastern England. We used the information on when and how they disposed of unfinished pharmaceuticals to construct a conceptual model to assess the pathways of human pharmaceuticals into the environment. The model demonstrated that disposal of unused pharmaceuticals, either by household waste or via the sink or toilet, may be a prominent route that requires greater attention.

Interviews as Topic↗

[Polycyclic aromatic hydrocarbons in industrial solid waste: a preliminary evaluation of the potential risk of environmental and human contamination in waste disposal areas].

Proper solid waste disposal is important to avoid human and environmental contamination. The NBR 10,004 Waste Classification lists several polycyclic aromatic hydrocarbons (PAHs) and indicates that the presence of at least one PAH in a waste sample is enough to classify it as hazardous. The aim of this study was a preliminary evaluation of PAHs in solid waste samples from selected industries to obtain a preliminary overview of their potential for contamination in case of improper disposal. One or more PAHs listed in NBR 10,004 (benzo[a]anthracene, benzo[a]pyrene, benzo[b]fluoranthene, benzo[k]fluoranthene, indene[1,2,3-c,d]pyrene, chrysene, or fluoranthene) were found in all samples, thus leading to their classification as hazardous waste. Our results showed that toxicologically relevant PAHs were found in all the samples, indicating that their final disposal must be performed in appropriate areas in order to minimize human health risks and environmental contamination from waste disposal areas.

Environmental Monitoring↗

Respiratory and general health impairments of workers employed in a municipal solid waste disposal at an open landfill site in Delhi.

The objective of this study was to examine the respiratory and general health of workers employed in a municipal solid waste (MSW) disposal at an open landfill site in India. Ninety-six landfill workers of Okhla landfill site, Delhi, and 90 controls matched for age, sex, and socioeconomic conditions were enrolled. Health data was obtained from questionnaire surveys, clinical examination and laboratory investigations. Lung function was evaluated by spirometry. Compared with matched controls, landfill workers had significantly higher prevalences of both upper and lower respiratory symptoms, and they suffered more often from diarrhea, fungal infection and ulceration of the skin, burning sensation in the extremities, tingling or numbness, transient loss of memory, and depression. Spirometry revealed impairment of lung function in 62% of the landfill workers compared to 27% of the controls. Sputum cytology showed squamous metaplasia, abundance of inflammatory cells, alveolar macrophages (AM) and siderophages (macrophages with iron deposits), and high elastase enzyme activity in neutrophils and AM of a majority of landfill workers, indicating adverse cellular lung reaction. Hematological profiles of these workers depicted low hemoglobin and erythrocyte levels with high total leukocyte, eosinophil and monocyte counts. Erythrocytes with target cell morphology were abundant in 42% of the landfill workers compared to 10% of the controls. Toxic granulation in neutrophils, an indication of infection and inflammation, was recorded in 94% of the landfill workers and in 49% of the controls. The results demonstrated higher prevalence of respiratory symptoms, inflammation of the airways, lung function decrement and a wide range of general health problems in MSW disposal workers.

Adult↗

Solidification of waste steel foundry dust with Portland cement.

Properties of mixtures of Portland cements and "waste steel foundry dust (WSFD)" from Czech steel works were examined. It was found that WSFDs are formed by microporous clusters of spherical particles of iron oxides, ranging in size from 10 to 100 nm. The content of ZnO in WSFD affects markedly the hydration of cement + WSFD mixtures both in solidification time and strength development. Properties of WSFD are very similar to those of very fine silicon flue dusts formed during Si and FeSi production. Cement + WSFD mixtures show long term strength stability and low heavy metals leaching even at WSFD content of 70-80wt.% The above results document the perspectives of WSFD solidification, disposal and the use of this waste material as a new additive to building materials.

Chemical Phenomena↗

Report: future industrial solid waste management in pars Special Economic Energy Zone (PSEEZ), Iran.

The Pars Special Economic Energy Zone (PSEEZ) is located in the south of Iran, on the northern coastline of the Persian Gulf. This area was established in 1998 for the utilization of south Pars field oil and gas resources. This field is one of the largest gas resources in the world and contains about 6% of the total fossil fuels known. Petrochemical industries, gas refineries and downstream industries are being constructed in this area. At present there are three gas refineries in operation and five more gas refineries are under construction. In this study, different types of solid waste including municipal solid waste (MSW) and industrial wastes were investigated separately. The aim of the study was to focus on the management of the industrial wastes in order to minimize the environmental impact. In the first stage, the types and amounts of industrial waste in PSEEZ were evaluated by an inventory. The main types of industrial waste are oil products (fuel oil, light oil, lubricating oil), spent catalysts, adsorbents, resins, coke, wax and packaging materials. The waste management of PSEEZ is quite complex because of the different types of industry and the diversity of industrial residues. In some cases recycling/reuse of waste is the best option, but treatment and disposal are also necessary tools. Recently a design has been prepared for a disposal site in PSEEZ for the industrial waste that cannot be reused or recycled. The total surface area of this disposal site where the industrial waste should be tipped for the next 20 years was estimated to be about 42 000 m2.

Industrial Waste↗

Managing infection control, hazards communication, and infectious waste disposal.

Dentistry entered a new era in the 1980s when the development of the AIDS crisis targeted dental facilities as one source of potential cross-infection with pathogenic microorganisms. As governmental agencies "discovered" dentistry, regulations forced practitioners to assume duties not previously required. Also, substantial costs of compliance became a significant consideration to employers. Managing the compliance and cost considerations of governmental regulation requires dedicating personnel, preferably one person, to the management of infection control, hazards communication, and infectious waste disposal tasks. predictably, this person--the safety supervisor--will develop into the new auxiliary specialist of the 1990s.

Communicable Disease Control↗

Influence of composition variations on the initial alteration rate of vitrified domestic waste incineration fly-ash.

Vitrification as a waste stabilization technology has often been considered applicable only to high-level radioactive waste for which, with the use of suitable additives, it yields a vitreous material with excellent chemical durability. It has become apparent in recent years that some waste forms-notably domestic waste incineration fly-ash purification residues--contain most of the ingredients of a vitrified material, although their composition variations are difficult to control. It is thus important to ensure not only that the materials are suitable for vitrification, but also that the resulting product exhibits acceptable long-term behavior under all circumstances. An initial study showed that, allowing for the compensation changes inherent in the melting process builtby EDF**, the residue collected by a single fly-ash dust separation defines a composition range within which the suitability of the vitrified material can be verified. "Vitrified material" refers to a melted material that contains no unmelted inclusions after cooling, but that may contain a variable fraction of crystallized phases. Five composition parameters were identified for the long-term behavior assessment: the concentrations of the three major elements (silicon, aluminum and calcium), the total alkali metal (sodium and potassium) concentration, and the sum of the concentrations of two toxic elements (zinc and lead). The other elements were assumed constant at molar ratios representative of industrial wastes. The experimentation plan methodology applied to the composition range identified fourteen materials suilable for developing and validating first-order models of the material components. The fly-ash composition had a very significant effect on the degree and kinetics and crystallization in the vitrified material within the experimental composition range; the cooling rate was the determining factor for some of the fourteen materials studied. Two crystailine phases predominated: spinels rich in chromium, zinc, aluminum, magnesium and iron formed quickly on cooling, and accounted for about 2 vol% of the final material. Gehelenite (Ca2Al2SiO7) crystallized massively in some vitrified materials, accounting for more than half the final product and giving it a rock-like appearance. The effect of composition alone must therefore be distinguished from the effect of crystallization on the leaching behavior. Soxhlet tests were conducted for 14 days according to a protocol based on that of the French AFNOR draft standard NF-M 60313 to determine the maximum alteration rate in pure water at 100 degrees C. The measured rate ranged from 4 to 40 gm(-2) day(-1), illustrating the crucial role of the silicon concentration: within the test composition range, a low silicon content (< 30 wt%) tended to result in a significantly higher initial rate. However, the initial rate alone is not sufficient to assess the chemical durability of the material. Further tests will be carried out at 25 degrees C under conditions approximating those of a proposed disposal site to highlight the role of the alteration layer and the effect of rising concentrations in solution on the decreasing alteration rate.

Crystallization↗

The destruction of halogenated organic chemicals by plasma pyrolysis.

Very high destruction efficiencies for halogenated chemicals have been achieved by plasma pyrolysis. Destruction efficiencies exceeded 99.9999999% for tests with polychlorinated biphenyls (PCBs). Preliminary tests with tetrachloromethane have obtained destruction efficiencies exceeding 99.99%. The plasma pyrolysis process involved the creation of a 250-kW plasma with a temperature in excess of 25 000 degrees C. The toxic material was injected into the plasma zone at a rate between 1 and 2 L/min. Thermochemical and photochemical dissociation of the toxic materials produced atoms and ions which recombined to form primarily H2, CO, HCl, and particulate carbon. The HCl was neutralized by NaOH. The flaring of the H2 and CO should destroy to a high degree any trace residuals. The application of plasma pyrolysis for the ultimate disposal of toxicological waste was also investigated. Rat carcasses containing mean lethal dosage of PCB were pyrolyzed.

Animals↗

Hydraulic activity of cement mixed with slag from vitrified solid waste incinerator fly ash.

This study investigates the effects of the slag composition on the hydraulic activity in slag blended cement pastes that incorporate synthetic slag prepared by melting CaO-modified municipal solid waste incinerator fly ash. Two types of composition-modified slag were prepared for this study. First, fly ash was mixed with the modifier (CaO) at 5% and 15% (by weight) respectively, resulting in two fly ash mixtures. These mixtures were then melted at 1400 degrees C for 30 minutes and milled to produce two types of slag with different modifier contents, designated as C1-slag and C2-slag. These synthetic slags were blended with ordinary Portland cement at various weight ratios ranging from 10% to 40%. The synthetic slags presented sufficient hydraulic activity, and the heavy metal leaching concentrations all met the EPA's regulatory thresholds. The pore size distribution was determined by mercury intrusion porosimetry, and the results correlated with the compressive strength. The results also indicate that the incorporation of the 10% C1-slag tended to enhance the hydration degree of slag blended cement pastes during the early ages (3-28 days). However, at later ages, no significant difference in hydration degree was observed between ordinary Portland cement pastes and 10% C1-slag blended cement pastes. In the 10% C2-slag case, the trend was similar, but with a more limited enhancement during the early ages (3-28 days). Thus vitrified waste incinerator fly ash is a technically useful additive to cement, reducing the disposal needs for the toxic fly ash.

Carbon↗

Needlestick injuries and needle disposal in Minnesota physicians' offices.

Because little is known about needlestick injury and needle disposal in non-hospital settings, we surveyed physicians' offices in Minnesota. Recapping of needles was frequent (51.1%, 72 of 141) and injuries had occurred during the past year in 44.0% of offices. When of known cause, needlesticks were most common during blood drawing and recapping (52.0%, 13 of 25). Small offices more often recapped needles, but only metropolitan small offices reported more frequent injuries. Only 37.6% of offices used a protocol for management of injuries, and in less than half (45.4%) was physician evaluation routine. Although most offices used plastic containers and a majority (73.0%) incinerated or autoclaved needles prior to disposal, small offices more often disposed of sharps in their routine solid waste. Larger metropolitan offices more consistently followed current recommendations for handling and disposing of needles. There is a need for education efforts to address these issues for physicians and their office staff.

Acquired Immunodeficiency Syndrome↗

Studies of channel sediments contaminated with organics and heavy metals.

The paper discusses the geo-environmental studies carried out to revitalise a silted up channel in Guanabara Bay. A dredging operation has been planned to remove about 1.5 million cubic meters of contaminated sediment. Investigations were performed to characterise the sediment in terms of its physical and chemical properties and to evaluate the presence of heavy metals and organic compounds, particularly polycyclic aromatic hydrocarbons PAH. Finally, dredging and disposal schemes are briefly outlined based on measured contamination levels.

Brazil↗

Co-landfilling of pretreated waste: disposal and management strategies at lab-scale.

The present paper deals with the possible advantages that can be obtained by co-landfilling of municipal solid waste organic fraction (MSWOF) and bottom ash (BA) from the incineration of municipal solid waste. In particular, the aim of the research hereby presented is to check the effect exerted by different disposal (mixed or layered) and management strategies (anaerobic or semiaerobic conditions) for landfills in which MSWOF and BA are co-disposed. Three lab-scale reactors were set-up: the reactor A with mixed BA and MSWOF in anaerobic conditions, the reactor B with mixed BA and MSWOF in semiaerobic conditions, the reactor C with layered BA and MSWOF in anaerobic conditions. The results obtained showed that the aeration at the beginning of the experimental period for about 60 days led to a more rapid biodegradation of the organic matter and to an improved leachate quality in terms of both organic load and nitrogen content. Also a significant increase in the settling rate was observed at the end of the aeration phase. Therefore, the aerobic management can be advised as the most available strategy providing a more rapid biological and mechanical stabilization of the bulk waste. Otherwise, the disposal strategy did not exert any significant effect on the leachate characteristics; however, the layered configuration may be adopted in order to accelerate the main settlements.

Anaerobiosis↗

Hazardous materials management and control program at Oak Ridge National Laboratory--environmental protection.

At a large research laboratory facility the management and control of hazardous materials, and their subsequent wastes can be an unmanageable task. Environmental regulations, mandated by the Resource Conservation and Recovery Act of 1976, established a Federal program to provide comprehensive regulation of hazardous solid waste materials from their generation time to their disposal. In an effort to comply with these regulations, a Hazardous Materials Management and Control Program was created at Oak Ridge National Laboratory. The program provides personnel with specific guidelines for the procurement, use, storage, transportation and disposal of hazardous materials/wastes, and ensures that they are managed in a manner which adequately protects all personnel, the general public, and the environment.

Legislation as Topic↗

Disposal of antineoplastic wastes at the National Institutes of Health.

The process of developing disposal guidelines for antineoplastic wastes at the National Institutes of Health (NIH) is described. Because of the large volume of hazardous wastes generated, NIH must comply with Environmental Protection Agency (EPA) guidelines for disposal. Seven antineoplastic agents are defined by EPA as hazardous wastes. Because of the similar toxicities and pharmacologic drugs, NIH officials elected to dispose of all such agents as hazardous wastes. Available options are presented. The NIH procedure divides antineoplastic wastes into trace- and bulk-contaminated categories. Trace-contaminated wastes contain minimal or trace amounts of drugs and are disposed of by one-site incineration. Bulk-contaminated materials (defined as intravenous solutions or containers whose contents weigh more than 3% of the capacity of the container) are disposed of by land internment and incineration at EPA-approved sites. Syringes and i.v. bottles containing antineoplastic drugs are labeled with bright red-orange labels instructing personnel to return the materials to the pharmacy for disposal. General decision-making procedures for other institutions are recommended.

Antineoplastic Agents↗