Development and validation of a novel method for the analysis of chlorinated pesticides in soils using microwave-assisted extraction–headspace solid phase microextraction and gas chromatography–tandem mass spectrometry

A new procedure for determining eleven organochlorine pesticides in soils using microwave-assisted extraction (MAE) and headspace solid phase microextraction (HS-SPME) is described. The studied pesticides consisted of mirex, α- and γ-chlordane, p,p’-DDT, heptachlor, heptachlor epoxide isomer A, γ-hexachlorocyclohexane, dieldrin, endrin, aldrine and hexachlorobenzene. The HS-SPME was optimized for the most important parameters such as extraction time, sample volume and temperature. The present analytical procedure requires a reduced volume of organic solvents and avoids the need for extract clean-up steps. For optimized conditions the limits of detection for the method ranged from 0.02 to 3.6 ng/g, intermediate precision ranged from 14 to 36% (as CV%), and the recovery from 8 up to 51%. The proposed methodology can be used in the rapid screening of soil for the presence of the selected pesticides, and was applied to landfill soil samples.

Caracterização e biodegradação de lodo de estações de tratamento de água para descarte em aterro sanitário

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

An investigation of contaminant distribution in subsurface marine wood waste at Mill-A South Terminal, Port of Everett, Washington

This project investigates the correlation between contaminants and the wood waste present in marine sediments off the shore of the Port of Everett in the former Weyerhaeuser Mill-A pulp mill site. The investigation includes the results of two field studies, which tested contaminant levels in 22 boreholes as well as several surface samples. The contaminants include heavy metals and wood waste byproducts. These results, along with 14 other bore logs, provide the framework for a three-dimensional site model, interpolating the full extent of the depositional units and organic and inorganic chemicals found at Mill-A. The sediments of interest are divided into five depositional units defined by the percent wood content and type of wood: native material (<5% wood), intermediate (<30% wood), sawdust (<30% wood), woodchips (<30% wood), and poorly sorted sands with silt (SM-SP) (0% wood). The contaminants include arsenic, 2,4-dimethylphenol, and total organic carbon. Three-dimensional modeling software, RockWorks, interpolated the discrete borehole data of sediment and contaminants assuming horizontal continuity between sampling locations. The sediment distribution was calculated within concentration ranges for each contaminant of concern. The lowest detection limits, the screening levels, and the cleanup levels defined these ranges. Total organic carbon served as a proxy to estimate the quantity of wood waste in the sediment. As a known byproduct of wood decomposition, 2,4-dimethylphenol was expected to be more prevalent in the depositional units with more wood waste. Finally, arsenic was a proxy for other contaminants to determine if contaminants at Mill-A are dominant in sediments with high percentages of wood waste. The volumetric distribution established that high levels of total organic carbon are present in the sediment with higher percentages of wood waste. This correlation was stronger in the decomposing sawdust-rich sediment than the woodchip-rich sediment. The 2,4-dimethylphenol concentrations above cleanup standards were dominant in the sawdust-rich, intermediate and native sediments. Concentrations of 2,4-dimethylphenol below cleanup levels characterized the native sediment. The distribution of arsenic showed no statistically significant correlation to wood content in sediment. These results do not support the hypothesis of contaminant-rich wood waste, as many of the high concentrations of contaminants were not in the wood-rich sediments. This suggests that the contaminants are more distributed among all depositional units at Mill-A rather than focused within sediments with a high percent of wood waste. Understanding the distribution of potentially toxic compounds with wood waste is important for restoring the Puget Sound waterways to a more habitable environment. Future studies should include new data to validate these results and to limit the uncertainty of the extent of contaminants. Future studies may also find motive in looking for a correlation between contaminants and grain size based on previous studies linking these characteristics. These investigations will benefit the current cleanup effort as well as future cleanup efforts at similarly contaminated waterways.

Studies on Landfill Leachate Transportation and Its Impact on Soil Characteristics

Leachate from an untreated landfill or landfill with damaged liners will cause the pollution of soil and ground water. Here an attempt was made to generate knowledge on concentrations of all relevant pollutants in soil due to municipal solid waste landfill leachate and its migration through soil and also to study the effect of leachate on the engineering properties of soil. To identify the pollutants in soil due to the leachate generated from municipal solid waste landfill site, a case study on an unlined municipal solid waste landfill at Kalamassery has been done. Soil samples as well as water samples were collected from the site and analysed to identify the pollutants and its effect on soil characteristics. The major chemicals in the soil were identified as Ammonia, Chloride, Nitrate, Iron, Nickel, Chromium, Cadmium etc.. Engineering properties of field soil samples show that the chemicals from the leachate of landfill may have effect on the engineering properties of soil. Laboratory experiments were formulated to model the field around an unlined MSW landfill using two different soils subjected to a synthetic leachate. The Maximum change in chemical concentration and engineering property was observed on soil samples at a radial distance of 0.2 m and at a depth of 0.3 m. The pollutant (chemicals) transport pattern through the soil was also studied using synthetic leachate. To establish the effect of pollutants (chemicals) on engineering properties of soil, experiments were conducted on two types soils treated with the synthetic chemicals at four different concentrations. Analyses were conducted after maturing periods of 7, 50, 100 and 150 days. Test soils treated with maximum chemical concentration and matured for 150 days were showing major change in the properties. To visualize the flow of pollutants through soil in a broader sense, the transportation of pollutants through soil was modeled using software ‘Visual MODFLOW’. The actual field data collected for the case study was used to calibrate the modelling and thus simulated the flow pattern of the pollutants through soil around Kalamassery municipal solid waste landfill for an extent of 4 km2. Flow was analysed for a time span of 30 years in which the landfill was closed after 20 years. The concentration of leachate beneath the landfill was observed to be reduced considerably within one year after closure of landfill and within 8 years, it gets lowered to a negligible level. As an environmensstal management measure to control the pollution through leachate, permeable reactive barriers are used as an emerging technology. Here the suitability of locally available materials like coir pith, rice husk and sugar cane bagasse were investigated as reactive media in permeable reactive barrier. The test results illustrates that, among these, coir pith was showing better performance with maximum percentage reduction in concentration of the filtrate. All these three agricultural wastes can be effectively utilized as a reactive material. This research establishes the influence of leachate of municipal solid waste landfill on the engineering properties of soil. The factors such as type of the soil, composition of leachate, infiltration rate, aquifers, ground water table etc., will have a major role on the area of influence zone of the pollutants in a landfill. Software models of the landfill area can be used to predict the extent and the time span of pollution of a landfill, by inputting the accurate field parameters and leachate characteristics. The present study throws light on the role of agro waste materials on the reduction of the pollution in leachate and thus prevents the groundwater and soil from contamination

Biodegradation of blend films PVA/PVC, PVA/PCL in soil and soil with landfill leachate

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The influence of soil and landfill leachate microorganisms in the degradation of PVC/PCL films cast from DMF

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of landfill leachate on cereal nutrition and productivity and on soil properties.

Landfill leachates carry nutrients, especially N and K, which can be recycled in cropping systems. We applied doses of landfill leachate (0 [Control], 32.7, 65.4, 98.1, and 130.8 m3 ha-1 ) three times in 2008 and three times in 2009 on a clay Rhodic Kandiudult soil. In 2009, black oat (Avena strigosa L.) and corn (Zea mays L.) were cropped in succession and assessed for concentration of nutrients in leaves and for shoot biomass and grain yield, respectively. As a positive control, an additional treatment with urea (120 kg ha-1 of N) was studied in corn. Soil was sampled at four depths (down to 60 cm) in three sampling dates to assess chemical and biochemical properties. Concentration of nutrients in leaves, oat biomass (8530?23,240 kg ha-1), and corn grain yield (4703-8807 kg ha-1 ) increased with increasing doses of leachate. There was a transient increase in the concentration of nitrate in soil (3-30 mg kg-1), increasing the risk of N losses by leaching at doses above 120 kg ha-1 N, as revealed by an estimated N balance in the cropping system. Sodium and K in soil also increased with increasing doses of leachate but decreased as rainfall occurred. The activity of dehydrogenase decreased about 30% from the control to the highest dose of leachate and urea, suggesting an inhibitory effect of mineral N on microbial metabolism. Landfill leachate was promising as a source of N and K for crop productivity and caused minor or transient effects on soil properties.

Desarrollo sustentable de geoestructuras compuestas por suelo loéssico compactado mejorado con agregado de materiales estabilizantes. Sustainable development of compacted loess soil geo-structures with addition of stabilizing materials.

Los suelos estabilizados mediante compactación, permiten obtener materiales con ventajas ténicas y economicas en diferentes tipos de obras de ingeniería. Ejemplos de su uso se tiene en bases viales de autopistas, rutas o calles urbanas, pistas de aterrizaje, barreras de contención para enterramientos sanitarios o lagunas de estabilización, apoyos de plateas para fundación de edificios, losas industriales, entre otras aplicaciones. Las fallas en este tipo de construcciones pueden resultar en catástrofes ambientales, sociales y elevadas pérdidas económicas, por lo que resulta de gran importancia optimizar el diseño e incrementar la seguridad de este tipo de construcciones. Las obras con estas características involucran grandes volúmenes y/o superficies que requieren controles sistemáticos durante su desarrollo, a los fines de garantizar el cumplimiento de las propiedades de los materiales establecidos en la etapa de diseño. De esta forma, es necesario contar con ensayos de campo sencillos, confiables y eficientes que permitan identificar propiedades físicas, mecánicas e hidráulicas. Las geoestructuras generadas mediante la compactación del suelo próximo al sector de construcción pueden funcionar adecuadamente, con reducidos costos de material y transporte. Su estabilización puede ejecutarse en forma natural, o con la incorporación de agregados minerales como bentonita, cal o cemento. Estas incorporaciones mejoran las propiedades hidráulicas y mecánicas del material, optimizando el comportamiento requerido para la obra. Para establecer la forma en la que estos minerales modifican el comportamiento del suelo local compactado deben realizarse investigaciones especiales con los materiales involucrados. En el ámbito internacional existen numerosas investigaciones sobre comportamiento de suelos compactados, no obstante, si bien aportan antecedentes para la planificación de estudios locales, sus resultados no pueden trasladarse de manera directa. Las características propias del suelo local constituye la principal variable debido a la diversidad en las propiedades geotécnicas de cada Región. Esta investigación, se focaliza en el empleo de suelos limosos de la formación loéssica de la zona central de Argentina. Los suelos de la llanura cordobesa poseen comportamientos particulares, los cuales son contemplados en los diseños presentados como resutado de las investigaciones internacionales. Esta particularidad se relaciona con su inestabilidad, lo que los clasifica como suelos colapsables. Los resultados obtenidos en este trabajo podrán ser extendidos a una gran superficie de la Provincia de Córdoba y a la Región Pampeana en general, a los fines de establecer recomendaciones de diseño y construcción para la confección de Pliegos de Especificaciones Técnicas de diferentes tipos de obras públicas y privadas. El estudio contempla la ejecución de un plan experimental a escala de laboratorio y campo. Los materiales corresponden a suelo limosos puros, y diferentes agregados tales como bentonita, cal y cemento. Se planifican ensayos para evaluar el desempeño del material, a partir de la confección de muestras preparadas con diferentes condiciones de compactación (energía, humedad y método), y en forma de mezcla con los distintos tipos de agregados. Se realizarán ensayos de permeabilidad en celdas de pared rígida y flexible, junto a ensayos mecánicos de compresión confinada, simple y triaxial. Para el trabajo experimental de campo se prevé la ejecución de terraplenes de prueba instrumentados con tensiómetros e infiltrómetros para evaluar el comportamiento hidraúlico en el tiempo, junto con ensayos de penetración y plato de carga para la caracterización mecánica. En forma conjunta se propone el desarrollo de modelos numéricos de caracterización hidromecánica. Stabilized soils by compaction, produce materials technical and economic advantages in different types of engineering works. For example, road bases in highways, roads or city streets, containment barriers for sanitary landfill or stabilization ponds, foundation support of building, industrial flat, and other applications. Failures can result in environmental catastrophes, social, and economic loss, so it is important to optimize the design and increase the safety of such buildings. These works involve large surfaces that require systematic tests during construction, so it is necessary to have simple field tests, reliable and efficient to identify physical, mechanical and hydraulic properties. The geo-structures generated by local soil compaction have reduced material and transportation costs. Stabilization can be naturally, or with the addition of mineral aggregates as bentonite, lime and cement. These additions improve the hydraulic and mechanical properties of the material. So, special investigations should be conducted with the materials involved. There are many international studies on compacted soils behavior but their results can not be transferred directly due to the particularities of regional soils. For this research silty soils of central Argentina are the main focus. The soils of Córdoba plains are instability, so are classified as collapsible soils. The results obtained in this work may be extended to a large area of the Province of Cordoba and the Pampas region in general, in order to establish design and construction recommendations. The study includes laboratory and field tests. The materials are pure silty soil, and different aggregates such as bentonite, lime and cement. Tests are planned to evaluate the performance. Laboratory includes rigid and flexible wall cells, confined, triaxial and simple compression tests. For field experimental instrumented embankments will be constructed. A numerical hydromechanical model will be developed.

The economics of enhanced landfill mining: private and societal performance drivers

This paper addresses the economics of Enhanced Landfill Mining (ELFM) both from a private point of view as well as from a society perspective. The private potential is assessed using a case study for which an investment model is developed to identify the impact of a broad range of parameters on the profitability of ELFM. We found that especially variations in Waste-to-Energy (WtE efficiency, electricity price, CO2-price, WtE investment and operational costs) and ELFM support explain the variation in economic profitability measured by the Internal Rate of Return. To overcome site-specific parameters we also evaluated the regional ELFM potential for the densely populated and industrial region of Flanders (north of Belgium). The total number of potential ELFM sites was estimated using a 5-step procedure and a simulation tool was developed to trade-off private costs and benefits. The analysis shows that there is a substantial economic potential for ELFM projects on the wider regional level. Furthermore, this paper also reviews the costs and benefits from a broader perspective. The carbon footprint of the case study was mapped in order to assess the project’s net impact in terms of greenhouse gas emissions. Also the impacts of nature restoration, soil remediation, resource scarcity and reduced import dependence were valued so that they can be used in future social cost-benefit analysis. Given the complex trade-off between economic, social and environmental issues of ELFM projects, we conclude that further refinement of the methodological framework and the development of the integrated decision tools supporting private and public actors, are necessary.

Biodegradation of blend films in soil and soil with chorume. I. PVC/PCL

Blends of synthetic and biodegradable polymers can be important in attaining material plastic degradation in the environment. Biodegradation using soil and chorume (liquid waste from landfill) microorganisms is a promising area these days. This paper intends to study the PVC/PCL blend degradation in soil using aerobic biodegradation (Bartha respirometer). The morphology and structural changes of the blends were studied by FTIR, scanning electron microscopy, differential scanning calorimetry and contact angle measurements. Blend films prepared by the casting of dichloroethane solutions were buried in a Bartha respirometer containing soil and soil plus chorume and kept there for 120 days. During this time CO2 evolution was measured from time to time. The results showed that PCL films degrade faster than PVC/PCL and PVC films.

Relationship between age of waste and natural electric potential generation in Sanitary Landfill

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Small-scale landfills: impacts on groundwater and soil

In Brazil, the large quantities of solid waste produced are out of step with public policies, technological developments, and government budgets for the division. In small municipalities, the common lack of technological knowledge and financial conditions for suitable waste disposal has resulted in a large number of illegal dumps. Therefore, small sanitary landfill facilities are working with simplified operations focusing on cost reduction and meeting the economic and technological standards of the city without endangering the environment or public health. Currently, this activity is regulated at a federal level although there is some uncertainty regarding the risk of soil and aquifer contamination as theses facilities do not employ liners. Thus, this work evaluates a small landfill to identify changes in soil and groundwater using geotechnical parameters, monitoring wells, and geophysical tests performed by electrical profiling. It is verified that based on current conditions, no contaminants have migrated via underground water aquifers, and overall no significant changes have occurred in the soil. It is concluded that, despite its simplicity, the method investigated is a viable alternative for the final disposal of municipal solid waste from small cities, especially in developing countries.

Comparative analysis between biogas flow in landfill and electrical resistivity tomography in Rio Claro city, Brazil

The biogas originated from anaerobic degradation of organic matter in landfills consists basically in CH4, CO2, and H2O. The landfills represent an important depository of organic matter with high energetic potential in Brazil, although with inexpressive use in the present. The estimation of production of the productive rate of biogas represents one of the major difficulties of technical order to the planning of capture system for rational consumption of this resource. The applied geophysics consists in a set of methods and techniques with wide use in environmental and hydrogeological studies. The DC resistivity method is largely applied in environmental diagnosis of the contamination in soil and groundwater, due to the contrast of electrical properties frequent between contaminated areas and the natural environment. This paper aims to evaluate eventual relationships between biogas flows quantified in drains located in the landfill, with characteristic patterns of electrical resistivity in depth. The drain of higher flow (117 m3 /h) in depth was characterized for values between 8000 Ω⋅m and 100.000 Ω⋅m, in contrast with values below 2000 Ω⋅m, which characterize in subsurface the drain with less flow (37 m3 /h), besides intermediary flow and electrical resistivity values, attributed to the predominance of areas with accumulation or generation of biogas.

Small-scale landfills: impacts on groundwater and soil

In Brazil, the large quantities of solid waste produced are out of step with public policies, technological developments, and government budgets for the division. In small municipalities, the common lack of technological knowledge and financial conditions for suitable waste disposal has resulted in a large number of illegal dumps. Therefore, small sanitary landfill facilities are working with simplified operations focusing on cost reduction and meeting the economic and technological standards of the city without endangering the environment or public health. Currently, this activity is regulated at a federal level although there is some uncertainty regarding the risk of soil and aquifer contamination as theses facilities do not employ liners. Thus, this work evaluates a small landfill to identify changes in soil and groundwater using geotechnical parameters, monitoring wells, and geophysical tests performed by electrical profiling. It is verified that based on current conditions, no contaminants have migrated via underground water aquifers, and overall no significant changes have occurred in the soil. It is concluded that, despite its simplicity, the method investigated is a viable alternative for the final disposal of municipal solid waste from small cities, especially in developing countries.

Attenuation of pollutants in municipal landfill leachate by clay minerals /

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