Landfill Material Research Articles

Experimental Study on the Mechanical Property of Loess Mixed with Bentonite‐HDTMA

Malan loess in the middle and lower reaches of the Yellow River after mixed with different bentonite and HDTMA ratios was selected to carry out shear and consolidation tests for discussing the influence of bentonite‐HDTMA on the mechanical property of loess lining material in landfills. Studies have shown that, after mixing 6% to 14% bentonite, the cohesive force of modified loess is significantly increased, the friction angle is reduced and remains stable, and the shear strength is improved. The compressibility of materials slightly decreases with the increase of bentonite ratio. The addition of 2%–4% HDTMA weakens the increment for the cohesive force caused by bentonite, but the friction angle is effectively recovered. The compressibility of materials increases with the increase of HDTMA ratio. As the dry density increases, the shear strength of the modified loess increases, and the compressibility coefficient decreases. The mechanical property of loess lining material can be optimized by adding 6%–14% bentonite. The incorporation of 2%–4% HDTMA does not have a significant negative impact on the optimization effect of bentonite. From the perspective of the mechanical property, it is recommended that the dry density of modified loess is 1.70 g/cm3, the bentonite ratio is 10%–14%, and the HDTMA ratio is 2%–4%.

Swelling Potential of Clayey Soil Modified with Rice Husk Ash Activated by Calcination for Pavement Underlay by Plasticity Index Method (PIM)

Volume change in expansive soils is a problem encountered in earth work around the world. This is prominent with hydraulically bound structures or foundations subjected to prolonged moisture exposure. This behavior of clayey used as subgrade, foundation, landfill, or backfill materials causes undesirable structural functionality and failures. To prevent this happening, clayey soils are studied for possible volume change potential and degree of expansion. Consequently, the problematic soils are stabilized. In this work, the stabilization of clayey highly expansive soil classified as A‐7‐6 soil and highly plastic with high clay content was conducted under laboratory conditions. The treatment exercise was experimented using quicklime‐activated rice husk ash (QARHA), hydrated lime‐activated rice husk ash (HARHA), and calcite‐activated rice husk ash (CARHA) at the rates of 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, and 10%. Upon treatment with the three calcium compounds to produce three sets of treated experimental specimens, the plasticity index was observed and recorded and swelling potentials were evaluated using the plasticity index method (PIM). The results showed a consistent improvement on the properties of the treated soil with the addition of the different activated admixtures. While the utilization of CARHA and HARHA improved the clayey soil to medium expansive soil, the treated clayey soil substantially improved from highly expansive soil with a potential of 23.35% to less expansive with a final potential of 0.59% upon the addition of 10% QARHA. Finally, QARHA was adjudged as the best binding composite due to the highest rate of reduction recorded with its utilization.

Current Status and Development Trends of Sludge Disposal Technology

Sludge is a typical solid waste of sewage treatment plants, and its disposal methods have attracted much attention. This paper summarized the current technical routes for sludge disposal in China, including anaerobic digestion, anaerobic fermentation, incineration, landfill, land utilization, and building materials utilization. In the context of energy saving and carbon reduction and the promotion of resource recovery, enhanced pretreatment technology of sludge anaerobic digestion and anaerobic fermentation technology for fuel gas production are the first choices for sludge disposal and resource utilization. In addition, the development trend of sludge disposal technology was analyzed.

Enhanced GPR data interpretation to estimate in situ water saturation in a landfill

Research was completed to show that using the complex refractive index model (CRIM) to interpret GPR data can improve the estimation of in situ water content of the waste in the landfill. Literature shows that the Topp equation is normally used to analyse GPR data, despite the fact it fails to consider porosity and other properties of the landfill material or soil that can affect the electromagnetic properties of the material. The application of (CRIM) overcomes these limitations and more. Previously measured field GPR data were reanalyzed with CRIM and supported by synthetic GPR data to show that CRIM provides a better prediction of the water content of the landfill material.Further enhancement of GPR data interpretation was implemented by optimizing the frequency of the GPR scan and determining the ideal offset separation distance between the transmitter and the receiver using sensitivity tests. The sensitivity tests were based on synthetic 2D surface based-reflection GPR data sets generated by MATLAB®. The sensitivity results showed that the optimum frequency was 1 GHz, with an ideal offset distance of 0.75 m. After using the optimized values, it was possible to obtain a percentage of error of 1% between modelled water saturation and GPR measured water saturation.

Utilization of discarded foundry sand (DFS) and inorganic waste from cellulose and paper industry for the manufacture of glass-ceramic materials

Abstract Recycling has been pointed out as an alternative to the disposal of waste materials in industrial landfills. In the present study, the transformation of residues (discarded foundry sand - DFS, grits, and lime mud) in glass-ceramic materials is shown. The glasses were obtained by the melting/cooling method. The precursor materials, glasses, and glass-ceramics were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), and differential scanning calorimetry/thermal gravimetric analysis (DSC/TGA). The glassy materials were milled, pelleted, and thermally treated at the crystallization temperatures given by DSC data to obtain the glass-ceramics (885, 961, and 1090 ºC). The main formed phases were cristobalite, α-wollastonite (parawollastonite), and β-wollastonite (pseudowollastonite). The glass-ceramics showed very low water absorption and apparent porosity (0.26 to 0.88 wt% and 0.66 to 1.77 vol%, respectively). The results confirmed that the studied residues can be used as raw materials for the manufacture of vitreous and glass-ceramic materials.

INFLUENCE OF STRESS RATIO IN SHEAR SURFACE ON SHEAR STRENGTH OF DEPOSITED MATERIAL

<p>The "Ribnica" landfill of the "Vrtlište" surface mine bordered the river Ribnica until during 2017, a landslide was started and the river Ribnica was interrupted, and a water reservoir was formed. After the completion of the tunnel that diverted the river Ribnica, its previously interrupted riverbed in the downstream part is planned for continuation of the disposal of masses from the surface mine "Vrtlište" by making an earth dam. The dam has the role of retaining large waters in case of exceeding the maximum tunnel flow, as well as in cases of monitoring and construction work in the tunnel.</p><p>The requirement to use landfill material for the construction of the dam poses a significant risk due to the lack of data on its shear strength. This paper presents the results of research on the shear strength of materials in the conditions of dam construction, under optimal moisture conditions and maximum compaction and analyzes the obtained results, which should define the behavior of the tested materials in the conditions of dam construction. The conducted research represents the first phase of the research, which will be followed by research into the shear strength of completely saturated materials, which will determine the behavior of deposited materials in the dam body and the final slopes.</p>

Engineering geological evaluation of Mfensi and Afari clay deposits for liner application in municipal solid waste landfills

Mfensi and Afari clay deposits in the Ashanti Region of Ghana were evaluated for their suitability as liner materials to curtail leachate migration in municipal solid waste landfills. Chemical, mineralogical, physicochemical, geotechnical, and thermal analyses were conducted to characterize the clays as well as to evaluate their potential as suitable barrier materials. The test results were compared with standard requirements for clay liner applications. The findings revealed that the chemical compositions of both clays were analogous with dominant oxides being silica, aluminum, and iron. Quartz, kaolinite, and magnetite were the minerals identified in both clays. The effective cation exchange capacity of the Mfensi and Afari clays was 5.45 meq/100 g and 28.99 meq/100 g, respectively. The clays were fine-grained (< 0.06 mm), with fines contents of approximately 80% and 56% for Mfensi and Afari clays, respectively. The Atterberg limits consisting of the liquid limits and plasticity indices of the Mfensi and Afari clays were 42.85%, 22.43%, and 64.78%, 40.52%, respectively. The unconfined compressive strengths were 331.73 kPa and 242.92 kPa for Mfensi and Afari clays, respectively. The hydraulic conductivities of the clays were of the order × 10−7 cm/s. The average thermal conductivities of the clays were found to be $$0.025\,{\text{Wm/K}}$$ for Afari clay and $$0.215\,{\text{Wm/K}}$$ for Mfensi clay. The results demonstrate that both clays generally passed the requirements for clay liner application and hence could be used as liner materials in municipal solid waste landfills to minimize leachate migration.

Framework, method and case study for the calculation of end of life for HWL and parameter sensitivity analysis

Mass construction and operation of hazardous waste landfill infrastructure has greatly improved China’s waste management and environmental safety. However, the deterioration of engineering materials and the failure of landfill may lead to the release of untreated leachate rich in persistent toxic pollutants to the soil and shallow groundwater. Accordingly, we develop the framework and process model to predict landfill life by coupling the landfill hydrological performance model and material degradation model. We found that the decrease rate of the concentration of persistent pollutants in leachate was significantly slower than the deterioration rate of the landfill engineering materials. As a result, when the materials failed, the leachate with high concentrations of persistent pollutants continued to leak, resulting in the pollutants concentration in surrounding groundwater exceeding the acceptable concentration at around 385 a, which is the average life of a landfill. Further simulation indicated that hydrogeological conditions and the initial concentration of leachate will affect landfill lifespan. The correlation coefficients of concentration, the thickness of vadose zone and the thickness of aquifer are − 0.79, 0.99 and 0.72 respectively, so the thickness of vadose zone having the greatest impact on the life of a landfill. The results presented herein indicate hazardous waste landfill infrastructure reinvestment should be directed toward long-term monitoring and maintenance, waste second-disposal, and site restoration.

Geophysics for urban mining and the first surveys in Denmark: rationale, field activity and preliminary results

Geophysical methods have been widely used in recent decades to investigate and monitor landfill sites for environmental purposes. With the advent of the circular economy, waste contained in old landfills may be considered a resource that can be developed. Since the content of old landfills is largely unknown, the occurrence and quantity of valuable materials must be investigated before embarking on any development activity. Two landfills on Sjælland, Denmark (located at Hvalsø and Avedøre) were selected for a pilot study to characterise their content. At both locations, a set of geophysical surveys is underway. Here, we present the data obtained from magnetic and 2D seismic refraction surveys. Magnetic data show various anomalies that can be interpreted as caused by iron-rich waste. At both sites, the landfill material results in generally low P-wave velocity (&lt;400 m/s), lower than those obtained for Quaternary sediments at Avedøre. The seismic velocities appear to increase in the presence of metals or by compaction with depth (&gt;550 m/s). We propose that seismic refraction can thus define the bottom of the landfill and possibly its internal structure, especially when combined with other methods.

Emissions of non-methane volatile organic compounds from a landfill site in a major city of India: impact on local air quality

Emissions from landfills are a significant source of non-methane volatile organic compounds (NMVOCs) in urban environments. NMVOCs play an important role in atmospheric chemistry, and elevated concentrations of some compounds are responsible for air quality deterioration. This study is based on the measurements of a suite of 20 C2–C8 NMVOCs at 21 upwind and downwind sites of the largest landfill in western India. Ethane, ethylene and aromatics were the dominant compounds; the concentrations of BTEX in the downwind regions were up to three times higher than their concentrations at upwind sites. The emission ratios of BTEX and other NMVOCs were different from those for residential, commercial, and industrial sources characterizing the emissions from burning and decomposition of organic material. The slope of ΔToluene/ΔBenzene of 0.64 is about three times higher than that determined at the main road junctions of the city. Ranking by Prop-Equiv, the top NMVOCs were isoprene, cis-2-Butene, m + p-xylenes, propylene, ethylene and trans-2-Butene account for 72–75% of the total Prop-Equiv concentrations. Alkenes played the dominant role in ozone formation, followed by aromatic and alkane groups. In addition to landfill emissions, contributions from traffic-related emissions to ambient concentrations of aromatic VOCs were also significant at some sites. Although the experiment was not designed to characterize the emissions from a specific source, the analysis suggests the substantial contributions from both decomposition and burning of landfill materials. The main difficulty in characterizing VOC emissions from landfills is the spatial and temporal variability of emissions from a large area.

К вопросу утилизации свалок методом аэробного биореактора

Обосновывается постановка новой научной и производственной задачи трансформации содержащих органическое вещество свалок в управляемые аэробные биоректоры с целью: (а) устранения в теле свалки анаэробного гниения, порождающего зловонные запахи, пожароопасный свалочный газ и другие вредные последствия анаэробных условий и (б) создание контролируемых аэробных условий для ускоренной экологически безопасной трансформации органического вещества в неопасное состояние для последующей возможности утилизации всего материала свалки с ее ликвидацией или использования ставшей не опасной свалки в качестве элемента рельефа. Формулируется междисциплинарный подход к обоснованию режимов и параметров свалки-биореактора на основе сочетания методов моделирования тепломассопереноса в теле свалки со сложной морфологией, неоднородной проницаемостью на протяжении всего ее жизненного цикла и методов сопряженных микробиологических исследований оптимального состава целевого сообщества популяций микроорганизмов и требований к условиям для их жизнедеятельности в теле свалки (влажность, температура, концентрация кислорода). Учтен опыт США по созданию и эксплуатации свалок-биоректоров. Приводится план действий по реализации пилотного проекта, который может стать прототипом для утилизации свалок методом аэробного биореактора, и на этой основе решение в короткие сроки и с низкими затратами острых экологической и земельной проблем, вызванных созданными ранее и вновь создаваемыми свалками в различных регионах страны.

Perspectives of Using Lignin as Additive to Improve the Permeability of In-Situ Soils for Barrier Materials in Landfills

Very often, in-situ soil does not meet the requirements for landfill barriers; therefore, it is necessary to purchase the material from quarries. An increasing number of by-products have been proposed as alternative landfill barrier materials. The present study investigated the performance of two soils of Central Italy (alluvial and volcanic soils) with an organosolv lignin (sulfur-free lignin (SFL)), a widespread by-product in the world. Laboratory investigations indicated that the volcanic soil mixed with 10% in weight of lignin did not reach the permeability value required for landfill bottom liners, also showing high compressibility. On the contrary, the addition of 20% to 30% lignin to the alluvial soil reached the permeability value recommended for the top-sealing layer of landfills: scanning electron microscope analysis indicated that the improvement was due mainly to the physical binding. Large-scale investigations should be carried out to evaluate the long-term performance of the mixtures. The increasing production of organosolv lignin worldwide gives this by-product the opportunity to be used as an additive for the realization of the top-sealing layer. The approach can save the consumption of raw materials (clayey soils from quarries), giving lignin a potential new field of application and recovering in-situ soils.

Analysis of melting reconstruction treatment and cement solidification on ultra-risk municipal solid waste incinerator fly ash-blast furnace slag mixtures.

High temperature melting treatment and cement solidification are technologies currently used to reduce the leaching of heavy metals in municipal solid waste incinerator (MSWI) fly ash. In this paper, to ascertain the feasibility of melting MSWI fly ash with blast furnace (BF) slag, ultra-risk MSWI(U-MSWI) fly ash having high heavy metal (Zn, Pb, Cu, and Cr) contents were blended with BF slag, then melted and quenched into water to prepare reconstructed slag. The melting and solidification behaviors, phase composition and microstructure, and heavy metal leachability of reconstructed slag were studied. In addition, to study the further solidification and utilization of reconstructed slag in cement, the compressive strength and leaching concentration of cement composites with reconstructed slag were also investigated. The results indicate that the presence of heavy metals in the U-MSWI fly ash had a little influence on the microstructure and phase composition of reconstructed slag. The leaching concentration of heavy metals in the reconstructed slag increased with the increasing of U-MSWI fly ash content, and when the content of U-MSWI fly ash was less than 50 wt%, the reconstructed slag could meet the environmental requirements. The reconstructed slag further solidified by cement could be applied to landfill and construction materials. The technology of melting reconstruction treatment with cement solidification was a technical-economical choice for the industrial treatment of U-MSWI fly ash.

Assessment of the use of dredged marine materials in sanitary landfills: A case study from the Marmara sea

Worldwide production of large volumes of dredged materials (DMs) has become a pressing environmental problem. In Turkey, the government has yet to develop management strategies that successfully prevent or minimize dumping into the Marmara Sea. One potential solution is the utilization of the DMs as a source of material for earthworks, particularly in sanitary landfills in Istanbul and Kocaeli. The most economically developed cities in Turkey, they were evaluated in terms of potential environmental impacts and regulatory compliance. Five ports/harbors representing specific portions of the study area and different industrial activities were selected as pilot regions. Physical, chemical, mineralogical, toxicological, and leaching potential measurements of DMs dredged from the seabed revealed they qualify as non-hazardous waste. Index and engineering tests performed on raw and processed DMs were assessed to determine the geotechnical requirements for soil-based materials (SBM) used in sanitary landfills. The results showed that non-hazardous DMs could be utilized as a cover, base/cap liner, and/or fill material at various sections within the landfills. This method provides environmental advantages not seen with other management strategies for DMs such as dumping at sea or upland disposal.

Baseline Study of Heavy Metal Pollution in a Tropical River in a Developing Country

Massive load of toxic heavy metals is discharged by human activities, as well as by natural actions, give rise to metal contamination in water body. Sg. Sembilang is one of the rivers that is receiving effluent from various sources such as landfill, industrial, residential, and agricultural runoff. In this study, the concentration of heavy metals in nine stations along the Sg. Sembilang was collected for one year period to evaluate their levels of pollution. Ten heavy metals were analyzed using inductively coupled plasma optical emission spectroscopy (ICP-OES). The mean concentrations of Fe, Mn, Zn, Al, and Cu were 3.01, 0.68, 0.29, 0.007, and 0.027 mg/L respectively, were below the National Water Quality Standards of Malaysia (NWQS), with the exception of Cd, Cr, Pb, Mg, and Ni. Calculated HPI based on the mean concentration of heavy metals, was found to be 6.05, that is below the critical pollution index value of 100. With respect to sampling locations, station J03 registered the highest value of 7.989. This is probably due to the location of J03 which is very near to the effluent discharge point. The analysis indicates the present scenario of water quality of Sg. Sembilang due to the effect of effluent from the landfill material, and waste water from industry, agricultural runoff and residential area. Required steps should be taken to conserve this river from pollution, and also to lessen the environmental risk.

ANALISIS KANDUNGAN LOGAM BERAT ABU BATUBARA PLTU BANGKO BARAT KAB. MUARA ENIM SUMATERA SELATAN

Coal combustion product (CCP) from Bangko Barat Power Plant is used as landfill material in acidic overburden layers. CCP is categorized as hazardous and toxic waste (PP No.101/2014) from specific sources and is known to contain heavy metals. This study aims to analyze the heavy metal content of coal combustion product from Bangko Barat Power Plant, Muara Enim Regency, South Sumatra Province. Heavy metal content of CCP includes Hg, Cd, Cu, Ag, Ni, Pb, As, Cr, Sn, Zn dan Mn. Heavy metal content analysis to ensure overburden piling by utilizing CCP, either with a long-term safe coating or mixing scheme. The analysis was carried out by using ICP-MS test, XRF test, XRD test, analysis of grain size and grain morphology. Samples of fly ash and bottom ash were categorized as non- hazardous and toxic waste based on the results of the ICP-MS test compared to the values of TK-A, TK-B and TK-C. Heavy metal content that needs attention from coal ash is As (4.4-20 ppm), Cr (26-43 ppm), Cu (30.7-42.6 ppm), Pb (22,2-29,3 ppm), Zn (77.5-128 ppm), Ni (10,6-24,8 ppm) and Mn (144-396 ppm). The content of other heavy metals is relatively low (Hg, Cd, Ag and Sn) and the threshold is not exceeded. Monitoring the quality of runoff water from landfill area using CCP to be controlled so that the heavy metal content does not endanger the health of living things.

Assessing the Regulatory Requirements of Lead-Based Perovskite Photovoltaics

Nicole Moody, Samuel Sesena, Dane W. deQuilettes, Benjia Dak Dou, Richard Swartwout, Anna Johnson, Udochukwu Eze, Roberto Brenes, Matthew Johnston, Vladimir Bulovic, and Moungi G. Bawendi are members of Tata-MIT GridEdge Solar, an interdisciplinary research program at the Massachusetts Institute of Technology working toward scalable design and manufacturing of lightweight, flexible solar cells. Joseph T. Buchman and Christy L. Haynes are part of the Center for Sustainable Nanotechnology, a multi-institutional partnership aimed at understanding the fundamental chemical and physical processes that govern the transformations and interactions of nanoparticles in the environment.

Evaluation of the use of crushed returned concrete as recycled aggregate in ready-mix concrete plant

Every year, a significant amount of waste is generated in ready-mix concrete (RMC) plants. Further, the environmental and economic consequences of the disposal of this residue are relevant. Therefore, crushing and sieving the hardened concrete returned to the plant has emerged as a possible and interesting alternative to recycle RMC residue for use as aggregates. This paper presents an experimental study performed by one of the largest producers of RMC in Brazil. The recycled aggregates were evaluated through laboratory analysis and industrial-scale production, to verify their technical impact and applicability in new concrete formulations. The tests demonstrate that recycled aggregate, when used within 48 h after production, has good application potential because no differences in pumpability were found. The standard deviation of the recycled aggregate concrete is slightly higher than that of concrete produced only with natural aggregates, which affects the average compressive strength needed to achieve the same characteristic strength. This condition may increase the production costs of RMC. However, in the case studied, this cost increment was less than the costs associated with disposing of the material in landfills and those related to the purchase of conventional aggregates. Therefore, this study concludes that concretes with recycled aggregates have conditions to be economically viable, especially for classes with a characteristic strength of less than 30 MPa.

Shear Testing of the Interfacial Friction Between an HDPE Geomembrane and Solid Waste.

High-density polyethylene (HDPE) geomembrane is often used as an anti-seepage material in domestic and industrial solid waste landfills. To study the interfacial shear strength between the HDPE anti-seepage geomembrane and various solid wastes, we performed direct shear tests on the contact interface between nine types of industrial solid waste or soil (desulfurization gypsum, fly ash, red mud, mercury slag, lead-zinc slag, manganese slag, silica fume, clay and sand) and a geomembrane with a smooth or rough surface in Guizhou Province, China. Friction strength parameters like the interfacial friction angle and the apparent cohesion between the HDPE geomembrane and various solid wastes were measured to analyze the shear strength of the interface between a geomembrane with either a smooth or a rough surface and various solid wastes. The interfacial shear stress between the HDPE geomembrane and the industrial solid waste increased with shear displacement and the slope of the stress-displacement curve decreased gradually. When shear displacement increased to a certain range, the shear stress at the interface remained unchanged. The interfacial shear strength between the geomembrane with a rough surface and the solid waste was higher than for the geomembrane with a smooth surface. Consequentially, the interfacial friction angle for the geomembrane with a rough surface was larger. The geomembrane with a rough surface had a better shear resistance and the shear characteristics fully developed when it was in full contact with the solid waste.

Gas and liquid permeability in the variably saturated compacted loess used as an earthen final cover material in landfills

Landfill final covers are crucial to mitigating both the emission of landfill gases and surface water infiltration into solid wastes. Loess that is widely distributed in Northwest China has been transformed into earthen final cover (EFC), although not yet on a large scale. There remains a need for laboratory bench-testing in assessing the performance of this loess as an EFC material, particularly with respect to gas and liquid permeability. To evaluate gas and liquid permeability in the variably saturated loess at the laboratory scale, loess specimens with various resultant dry densities and post-compaction water contents were prepared. Laboratory tests were performed including constant gas pressure-gradient tests and wetting tests in a step-wise fashion to measure gas and liquid permeability as well as water retention behaviours. Large differences were found between intrinsic permeability to gas and liquid, and an empirical power relationship was proposed to characterize the measured intrinsic permeability to gas and liquid relative to the void ratio. The data of relative gas permeability as a function of liquid saturation plotted nearly along a single curve for all dry densities; this was also the case for the relative liquid permeability. Based on the regression results of water retention curves, the measured relative gas permeability values were well described by the van Genuchten–Mulaem (vG-M) model, and a certain difference between the relative liquid permeability evaluated by the vG-M model and the modified Childs and Collis-George equation. An unique relationship was found between the ratio of liquid to gas permeability and liquid saturation for all dry densities, in a range of residual liquid to gas saturation. An empirical model was proposed to efficiently describe gas and liquid permeability of the compacted loess at various liquid saturations and dry densities as well as the data of the loam from another experimental program.