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Industrial processes and municipal wastes largely contribute to the fluctuations in iron (Fe) content in soils. Fe, when present in unfavorable amount, causes harmful effects on human, flora, and fauna. The present study is an attempt to evaluate the composition of Fe in surface soils from paper mill and municipal landfill sites and assess their potential ecological and human health risks. Geochemical fractionation was conducted to explore the chemical bonding of Fe across different fractions, i.e., water-soluble (F1) to residual (F6). Different contamination factors and pollution indices were evaluated to comprehend Fe contamination extent across the study area. Results indicated the preference for less mobile forms in the paper mill and landfill, with 26.66% and 43.46% of Fe associated with the Fe–Mn oxide bound fraction (F4), and 57.22% and 24.78% in the residual fraction (F6). Maximum mobility factor (MF) of 30.65% was observed in the paper mill, and 80.37% in the landfill. The enrichment factor (EF) varied within the range of 20 < EF < 40, signifying a high level of enrichment in the soil. The individual contamination factor (ICF) ranged from 0 to >6, highlighting low to high contamination. Adults were found to be more vulnerable towards Fe associated health risks compared to children. The Hazard Quotient (HQ) index showed the highest risk potential pathways as dermal contact > ingestion > inhalation. The study offers insights into potential Fe contamination risks in comparable environments, underscoring the crucial role of thorough soil assessments in shaping land use and waste management policies. [Display omitted] • Geochemical fractionation unveils less bioavailable Fe in contaminated soil. • EF, ICF, and I geo indicate high Fe contamination. • Adults are more susceptible to potential health risks from surplus Fe exposure. • HQ analysis pinpoints dermal contact as the primary pathway for Fe exposure risks. [ABSTRACT FROM AUTHOR]

Waste generated from developed states often ends its journey inside the waste management facilities of developing states and, ultimately, their landfills. Developing states end up bearing the risk of devastating their own ecological systems and poisoning their populace, while developed states are unequivocally better off. Recognizing this problem, the international community responded by adopting the Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and their Disposal (1989), the most significant international treaty governing the global waste trade. However, the Convention has not resolved the problem of fairness posed by the global waste trade. This Note argues that the Basel Convention erroneously assumes that consent is meaningful in a transaction between a developed state and developing state--when the developing state is instead incentivized to weaken its own environmental protections to participate in the global waste trade. Although the Basel Convention requires that waste be disposed in an environmentally sound manner, the Convention's explanation should go into further detail to fulfill the objectives of the Convention. Specifically, the Convention should set explicit standards for different types of waste to ensure that they are disposed of in an environmentally sound manner. Additionally, the parties to the Convention should provide more resources to developing states who participate in the global waste trade. [ABSTRACT FROM AUTHOR]

Indonesian municipal solid waste (MSW) is dominated by biodegradable MSW (organic and paper). Due to the degradation process, the physical and hydraulic characteristics of these components can change. It is important to study the physical and hydraulic characteristics of MSW, because landslides occurred in several landfills in Indonesia after heavy rains. Field observations showed that landslides occur due to reduced paper components in the landfill (due to high recycling activities), and cause high percolation of water into the landfill. In the research, 38 samples consisting of two variants of MSW samples (organic and 80% organic + 20% paper), were prepared under the conditions of optimum moisture content. The organic sample of MSW is leaf, while the paper sample of MSW is newspaper, which were shredded to a diameter of about 1 cm. The tests of moisture content, bulk density (in the mould of permeameter), particle size distribution, and permeability were carried out on both sample variants for 90 days, with a test frequency of once in 5 days. The results showed that there was an increase in the moisture content and density, and a decrease in particle size and permeability in both variants of MSW sample. Organic MSW + paper has lower permeability and higher density than organic MSW. This requires further study, because a high paper recycling ratio can lead to a change in the landfill characteristics. [ABSTRACT FROM AUTHOR]

Waste from the global paper life cycle can be a lost economic opportunity and a risk to the natural environment and human health. This study assesses the recovery potential of major waste flows in the global paper life cycle to support improvements in material use. The “recovery potential” indicator shows the technical possibility for extracting value from waste through recycling and other forms of recovery. The potential is identified through a review of recovery technologies that are currently applied or likely to be commercially available by the year 2050. The analysis compares current material use in the global paper life cycle with an ideal scenario in which the recovery potential of all major waste flows is fulfilled. In the ideal scenario, the Recycled Input Ratio (RIR) is increased from 38% to 67%–73% and the landfill intensity is reduced from 331–473 kg/t paper to 0–2.6 kg/t paper. The reduction in required landfill space is achieved mainly through increased consumer waste recycling. Better management of industrial waste from the paper sector has a rather limited impact on the RIR and landfill intensity. The conditions for successful recovery of waste are discussed separately. The analysis shows that the recovery potential indicator can be usefully applied to estimate potential improvements in complex material systems and the findings may inform policies for resource efficiency and the circular economy. [ABSTRACT FROM AUTHOR]

• Characterization of solid wastes is an important to analysis of the final disposal. • Chemical, thermal, mineral, physical and environmental conditions were evaluated. • Waste from the paper industry is classified as non-inert non-harmful; • The best disposal methodology from the paper industry waste is sanitary landfills. • Some exceptions of disposal can be found, depending on the type of paper. The world paper industry produces a great amount of industrial solid waste that undergoes a treatment process that can be either primary, secondary, or tertiary, in order to adapt the waste for correct disposal. The paper manufacturing industries search for the best way to dispose of their wastes, generally in landfills, but there are few studies proving the effectiveness of such measure from the environmental, technological and economic points of view. Knowing the characteristics of this waste and understanding the treatment process it is submitted to are fundamental issues to manage it and comply with environmental demands. The purpose of this paper is to perform a chemical, mineralogical, thermal, morphological, physical and environmental characterization of the paper and pulp industry wastes, in order to assess alternatives for their adequate disposal, such as controlled landfills, sanitation, incineration, and sea dumping. It was observed that the material presents physical, chemical, and morphological features that indicate the possibility of reusing it in other production chains, such as the ceramic industry, besides being classified as non-hazardous wastes. Furthermore, disposal in sanitary landfills presents advantages in environmental and technological terms. [ABSTRACT FROM AUTHOR]

Copyright of Desenvolvimento e Meio Ambiente is the property of Universidade Federal do Parana and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Green liquor dregs wastes coming from pulp and paper production are currently disposed in landfills at a huge cost for industry and the environment. In this work, a novel and more sustainable waste management strategy is proposed. Dregs were used for the first time as fine filler in the production of biomass fly ash-based geopolymeric mortars. The influence of the dregs incorporation amount on the fresh (geopolymer kinetics and mortars workability) and hardened-state (mechanical resistance, water absorption and capillary water absorption) properties of the mortars was evaluated. Although dregs incorporation reduce the flow workability (up to 19%), their presence and amount did not significantly alter the geopolymerization kinetics. Additionally dregs-containing mortars exhibited enhanced tensile (up to 71%) and compressive strength (up to 34%), and lower water absorption in comparison with the reference mortar. These results demonstrate the feasibility of using dregs as fine filler in geopolymers production. Moreover the mortars were produced using mainly biomass fly ash waste as aluminosilicate source which further reduces the environmental impact of the pulp and paper industry. [ABSTRACT FROM AUTHOR]

Recycling programs have significantly reduced the amount of waste sent to landfills, but recycling contamination rates have risen, reducing the environmental benefit of recycling collection. In this work, we investigate the prevalence of food-stained recyclable material contaminating recycling by evaluating disposal decisions of food-stained paper items. Consumers are more likely to contaminate recycling with food-stained items that have a low (vs. high) degree of dirtiness. We argue that consumers may dispose food-stained paper items into recycling out of a desire to avoid the anticipated negative feelings of not recycling. Consistent with this argument, we demonstrate that consumers with higher environmental values are less influenced by the degree of dirtiness of food-stained paper items and feel more negatively about not recycling food-stained paper items. We further demonstrate that disposal informational campaigns can reduce recycling contamination and increase composting by changing how consumers feel about recycling food-stained paper items. [ABSTRACT FROM AUTHOR]

In 2012 the City of Flagstaff partnered with researchers at the Dept. of Civil and Environmental Engineering at Northern Arizona University to successfully develop a mix design utilizing sludge derived from the manufacturing of recycled paper pulp sludge (PPS) and fly ash as a component of a landfill cap. This research has been extended to explore the addition of polymers to the mix of waste materials in order to optimize a design that would be suitable as a component for an EPA Subtitle D-approvable landfill liner. Cinder Lake Landfill (CLL) serves several communities in Northern Arizona and is managed by the City of Flagstaff. CLL does not have a reliable source of clay needed to construct a required landfill liner, which is necessary for the upcoming 108-acre landfill expansion. However, CLL receives approximately 80 tons of recycled PPS daily from the local tissue manufacturing plant. PPS is currently used as daily cover and was tested for use as part of a landfill cap, as noted above. Incorporating polymers in alternative materials such as PPS and fly ash has the potential to meet performance criteria and be approved by state and federal regulators, and has the potential to save the City millions of dollars over conventional composite liners of geomembrane and clay. Different mixtures of PPS, fly ash and three different polymers are currently being subjected to testing for the following: Water Content, Specific Gravity, Porosity, Organic Content, Atterberg Limits (plasticity), Proctor Compaction, Consolidation, California Bearing Ratio, Shear Strength, Gas Permeability, and Liquid Permeability. The optimal mixture of PPS and fly ash will be blended with a range of polymer concentrations. The goal is to find an optimal mix of PPS, fly ash, and polymer to achieve regulatory standards related to permeability, along with other desirable properties such as strength and flexibility. The optimum mixture(s) will then be subjected to field trials, scheduled to begin in 2016, in which test cells will be created at CLL. The liner will be constructed with the optimized mixture(s), and the cells will be operated as landfills for 1-2 years. Results from lab and field testing will be submitted to federal and state regulators for consideration as an alternative liner approach. [ABSTRACT FROM AUTHOR]

Paper waste sludge (PWS) is a waste produced in large quantities by the pulp and paper industry, and is usually disposed by landfilling. This study investigates the pyrolytic conversion of PWS as an alternative to its valorisation. Low and high ash PWSs (8.5 and 46.7 wt%) were subjected to fast pyrolysis conversion to maximise the bio-oil yield by optimising the reactor temperature and pellet size. Maximum bio-oil yields of 44.5 ± 1.7 daf, wt% at 400 °C, and 59.9 ± 4.1 daf, wt% at 340 °C, for an intermediate pellet size of 4.84 ± 0.15 mm, were attained from the conversion of the low and high PWS, respectively. The low optimal reactor temperatures, as well as the high bio-oil yields, make valorisation via fast pyrolysis conversion promising. A significant reduction in the O/C molar ratio of up to 35%, from the high ash PWS to its bio-oil product, led to a 65% increase of the higher heating value. A thermogravimetric study was implemented to investigate the pyrolytic mechanisms behind the increase in bio-oil yield with intermediate pellets sizes. It revealed that the observed increase in non-condensable gas yield, which corresponded to a decrease in the bio-oil yield, was due to the promotion of exothermic reactions for high heating rates using smaller pellet sizes. [ABSTRACT FROM AUTHOR]

This article presents the results of the study of the morphological composition of municipal solid waste (MSW) from the landfill of Atyrau city, and the waste's energy characteristics and presence of microorganisms, including bacteria, fungi and viruses. This study was carried out under a government order to determine the feasibility of recycling accumulated and incoming waste into electricity and its hazard to the environment and the workers involved in handling it. At the moment, there is no MSW recycling in Kazakhstan, which has led to the accumulation of more than 125 million tons of waste with an annual increase of 5 million tons. The research included four major cities (Almaty, Shymkent, Atyrau and Astana), which were selected not only on the basis of population, but also because the cities were located in different climatic zones. Samples were collected at the city landfills: 10 samples with an average distance of 100 m from each other were collected to provide a maximum coverage of both recently received waste and long-time stored waste. The research showed that neither climatic conditions nor the population size had a significant impact on MSW density, the values of which ranged from 120.1 kg/m3 to 145.4 kg/m3, as this indicator directly depends on the quality of life. The mass of the combustible fraction ranged from 39.41% to 54.62% and was mainly represented by plastic, textile and paper waste. The average value for the four cities was 50.30%. The higher calorific value fell in the range of 24.22–30.49 MJ/kg, with an average value of 26.71 MJ/kg. Microbiological studies showed little difference in average composition regardless of climatic conditions. Thus, no sharp differences in MSW composition, its energy characteristics and microbiological composition were found. The results of this study may be useful for optimising MSW recycling and disposal processes, as well as for developing measures to reduce their negative impact on the environment and human health. [ABSTRACT FROM AUTHOR]

Paper mill sludge (PMS) is a residual biomass that is generated at paper mills in large quantities. Currently, PMS is commonly disposed in landfills, which causes environmental issues through chemical leaching and greenhouse gas production. In this research, we are exploring the potential of fast pyrolysis process for converting PMS into useful bio-oil and biochar products. We demonstrate that by subjecting PMS to a combination of acid hydrolysis and torrefaction pre-treatment processes it is possible to alter the physicochemical properties and composition of the feedstock material. Fast pyrolysis of pretreated PMS produced bio-oil with significantly higher selectivity to levoglucosenone and significantly reduced the amount of ketone, aldehyde, and organic acid components. Pretreatment of PMS with combined 4% mass fraction phosphoric acid hydrolysis and 220 °C torrefaction processed prior to fast pyrolysis resulted in a 17 times increase of relative selectivity towards levoglucosenone in bio-oil product along with a reduction of acids, ketones, and aldehydes combined from 21 % to 11 %. Biochar, produced in higher yield, has characteristics that potentially make the solid byproduct ideal for soil amendment agent or sorbent material. This work reveals a promising process system to convert PMS waste into useful bio-based products. More in-depth research is required to gather more data information for assessing the economic and sustainability aspects of the process. [ABSTRACT FROM AUTHOR]

Almost 36 million tons of paper and yard trimmings are not currently being recycled or composted annually and likely end up in landfills. One approach to valorize these resources would be for biofuels production. Nonrecyclable municipal solid waste (MSW) paper and yard trimmings were assessed for their suitability as feedstocks to produce biofuels from sugars. Both materials met the cost target of less than $85.51/ton ($2016) with MSW paper ranging from $36.40 to $62.18/dry ton and grass clippings from $25.64 to $45.86/dry ton. MSW paper exceeded the carbohydrate requirement of 59% while grass clippings had significantly lower amounts of carbohydrates (30%). However, both types of MSW had ash contents significantly above the required 5% total ash with paper at 22% ash and grass clippings at 16%. While neither waste material was individually found to be suitable for biofuels production based on compositional requirements, it was determined that blending either waste with corn stover would produce materials that met carbohydrate, ash, and cost targets. The higher carbohydrate and lower ash stover compensated for the lower carbohydrates and high ash of the waste materials, while the lower cost waste materials offset the higher cost of corn stover. [ABSTRACT FROM AUTHOR]

Municipal waste management is a major challenge for local governments in South Africa and Namibia, as in other developing countries. The circular economy concept in waste management is an alternative sustainable development framework that has the potential to combat resource depletion, pollution, and poverty while achieving the SDGs. The purpose of this study was to investigate the current waste management systems in Langebaan and Swakopmund municipalities resulting from municipal policies, procedures, and practices in the context of a circular economy. A mixed method approach was used to collect qualitative and quantitative data through structured in-depth interviews, document analyses, and direct observation. The study found that the Langebaan and Swakopmund municipalities have not yet fully implemented the circular economy concept into their waste management systems. A mix of waste consisting of papers, plastics, cans, tyres, and organic products is dumped into landfills weekly at a rate of about 85%. The main challenges to implementing the circular economy concept include: lack of technical solutions, inadequate regulatory frameworks, insufficient financial resources, lack of private sector involvement, insufficient human resource capacity, and inadequate information and knowledge. A conceptual framework was therefore proposed to guide the municipalities of Langebaan and Swakopmund in implementing the circular economy concept in their waste management systems. [ABSTRACT FROM AUTHOR]

Copyright of Ceramica is the property of Associacao Brasileira de Ceramica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study aimed to investigate the beneficial reuse of paper mill sludge as landfill cover and bottom liner material in municipal solid waste landfills. For this purpose, two-dimensional finite element analyses of a typical landfill geometry were carried out using PLAXIS finite element program. The results of the analyses were evaluated in terms of displacement and factor of safety (FS) values, and compared with those of the compacted clay. The results of this study showed that, vertical and lateral displacements of the landfill slightly increased while the FS of the landfill slopes decreased with increasing surface loading. However, for all the cases studied, lower vertical and lateral displacements and higher FS values were obtained for the landfills with paper mill sludge as the cover and bottom liner material in comparison to those of the compacted clay. Besides, for all the cases studied, FS values greater than 1.5 were obtained, indicating that the landfill slopes were stable under the proposed loadings and landfill cover and bottom liner materials. Based on these results, it can be stated that the paper mill sludge examined in this paper has geotechnical properties that are desirable for a landfill cover and bottom liner material for use as a substitute of compacted clay in municipal solid waste landfills. [ABSTRACT FROM AUTHOR]

• Co-landfilling of PMS with MSW showed reduction in bioavailability of heavy metals. • Movable forms of Cu, Cr, Pb and Zn increased in MSW disposed landfill bioreactor. • ETS co-disposal decreased toxicity of all analyzed heavy metals after landfilling. • Bioavailabilities of Cr, Pb and Ni were unaltered in case of DPS co-disposal. • Transformation of heavy metals were greatly influenced by pH, VS and MC. Speciation of heavy metals (Cu, Cr, Pb, Ni, Cd and Zn) during anaerobic co-disposal of two distinct paper mill sludges viz. effluent treatment plant sludge and de-inking plant sludge with municipal solid waste in anaerobic landfill bioreactor was investigated. Effects of moisture content, volatile solids and pH on fractionation of heavy metals over the course of landfilling were also analyzed. Study revealed enhancement in bioavailability of Cu, Cr, Ni and Cd on sole disposal municipal solid waste in bioreactor landfill over 300 days. However, co-disposal of effluent treatment plant sludge with municipal solid waste showed reduction in bioavailability of every analyzed heavy metals with maximum increment in stable residual forms of Cu, Cr, Pb, Ni and Zn by 3.70 %, 0.73 %, 3.08 %, 1.17 % and 3.45 % (dry weight), respectively. De-inking sludge co-disposal was also found effective for reducing bioavailability of Cu, Cd and Zn while bioavailability of Cr, Ni and Pb was unaltered. Strong correlations between increase in residual forms of heavy metals and volatile solid reduction obtained for both co-disposed bioreactors. [ABSTRACT FROM AUTHOR]

Large volumes of engineered wood products (EWPs) and paper are routinely placed in landfills in Australia, where they are assumed to decay. However, the extent of decay for EWPs is not well-known. This study reports carbon loss from EWPs and paper buried in landfills in Sydney, Brisbane and Cairns in Australia, located in temperate, subtropical and tropical climates, respectively. The influence of pulp type (mechanical and chemical) and landfill type (municipal solid waste – MSW and construction and demolition – C&D) on decay levels were investigated. Carbon loss for EWPs ranged from 0.6 to 9.0%; though there is some uncertainty in these values due to limitations associated with sourcing appropriate controls. Carbon loss for paper products ranged from 0 to 58.9%. Papers produced from predominantly mechanical pulps generally had lower levels of decay than those produced via chemical or partly chemical processes. Typically, decay levels for paper products were highest for the tropical Cairns landfill, suggesting that climate may be a significant factor to be considered when estimating emissions from paper in landfills. For EWPs, regardless of the landfill type and climate, carbon losses were low, confirming results from previous laboratory studies. Lower carbon losses were observed for EWP and paper excavated from the Sydney C&D landfill, compared with the Sydney MSW landfill, confirming the hypothesis that conditions in C&D landfills are less favourable for decay. These results have implications for greenhouse gas inventory estimations, as carbon losses for EWPs were lower than the commonly assumed values of 23% (US EPA) and 50% (Intergovernmental Panel on Climate Change). For paper types, we suggest that separate decay factors should be used for papers dominated by mechanical pulp and those produced from mostly chemical pulps, and also for papers buried in tropical or more temperate climates. [ABSTRACT FROM AUTHOR]

The objective of this study was to measure the anaerobic biodegradation of different types of paper products in laboratory-scale landfill reactors. The study included (a) measurement of the loss of cellulose, hemicellulose, organic carbon, and (b) measurement of the methane yields for each paper product. The test materials included two samples each of newsprint (NP), copy paper (CP), and magazine paper (MG), and one sample of diaper (DP). The methane yields, carbon storage factors and the extent of cellulose and hemicellulose decomposition all consistently show that papers made from mechanical pulps (e.g., NPs) are less degradable than those made from chemical pulps where essentially all lignin was chemically removed (e.g., CPs). The diaper, which is not only made from chemical pulp but also contains some gel and plastic, exhibited limited biodegradability. The extent of biogenic carbon conversion varied from 21 to 96% among papers, which contrasts with the uniform assumption of 50% by the Intergovernmental Panel on Climate Change (IPCC) for all degradable materials discarded in landfills. Biochemical methane potential tests also showed that the solids to liquid ratio used in the test can influence the results. [ABSTRACT FROM AUTHOR]

Fermentation of Klebsiella pneumoniae was conducted using crude glycerol fortified with secondary paper mill sludge as a carbon source in 5 L fermenter. After 96 hours of fermentation, the fermented broth contained mostly microbial cells surrounded by extracellular polymeric substances (EPS) and other particulate residues from paper mill sludge and glycerol. When this fermented broth is used as it is, it is called broth EPS (B-EPS). When the fermented broth is centrifuged, the supernatant solution is separated from the rest of the microbial cells and from sludge residues. This supernatant is called Slime-EPS (S-EPS). Both types of EPS were used for treatment of landfill leachate. S-EPS showed better flocculation activity (85%) than B-EPS (70%). EPS was also used in combination of Al2(SO4)3 or FeSO4. The removal efficiency of COD with use of S-EPS combined with FeSO4 (more than 80% of COD removal) was higher than with S-EPS alone (48% of COD removal). Better results were recorded when S-EPS (0.015 g/L) was combined with FeSO4 (2 g/L) at pH 8. A remarkable reduction of the following parameters was recorded: COD (82%), total nitrogen (44%), phosphorus (50%) and removal of metals such as Ca (64.3%) and Mg (62.4%). [ABSTRACT FROM AUTHOR]

Background: There has been growing interest in the development of waste-specific decay factors for estimation of greenhouse gas emissions from landfills in national greenhouse gas inventories. Although engineered wood products (EWPs) and paper represent a substantial component of the solid waste stream, there is limited information available on their carbon dynamics in landfills. The objective of this study was to determine the extent of carbon loss for EWPs and paper products commonly used in Australia. Experiments were conducted under laboratory conditions designed to simulate optimal anaerobic biodegradation in a landfill.Results: Methane generation rates over incubations of 307-677 days ranged from zero for medium-density fibreboard (MDF) to 326 mL CH4 g−1 for copy paper. Carbon losses for particleboard and MDF ranged from 0.7 to 1.6%, consistent with previous estimates. Carbon loss for the exterior wall panel product (2.8%) was consistent with the expected value for blackbutt, the main wood type used in its manufacture. Carbon loss for bamboo (11.4%) was significantly higher than for EWPs. Carbon losses for the three types of copy paper tested ranged from 72.4 to 82.5%, and were significantly higher than for cardboard (27.3-43.8%). Cardboard that had been buried in landfill for 20 years had a carbon loss of 27.3%—indicating that environmental conditions in the landfill did not support complete decomposition of the available carbon. Thus carbon losses for paper products as measured in bioreactors clearly overestimate those in actual landfills. Carbon losses, as estimated by gas generation, were on average lower than those derived by mass balance. The low carbon loss for particleboard and MDF is consistent with carbon loss for Australian wood types described in previous studies. A factor for carbon loss for combined EWPs and wood in landfills in Australia of 1.3% and for paper of 48% is proposed.Conclusions: The new suggested combined decay factor for wood and EWPs represents a significant reduction from the current factor used in the Australian greenhouse gas inventory; whereas the suggested decay factor for paper is similar to the current decay factor. Our results improve current understanding of the carbon dynamics of harvested wood products, and allow more refined estimates of methane emissions from landfills. [ABSTRACT FROM AUTHOR]

The USA, China and India are the top three producers of municipal solid waste. The composition of solid wastes varies with income: low-to-middle-income population generates mainly organic wastes, whereas high-income population produces more waste paper, metals and glasses. Management of municipal solid waste includes recycling, incineration, waste-to-energy conversion, composting or landfilling. Landfilling for solid waste disposal is preferred in many municipalities globally. Landfill sites act as ecological reactors where wastes undergo physical, chemical and biological transformations. Hence, critical factors for sustainable landfilling are landfill liners, the thickness of the soil cover, leachate collection, landfill gas recovery and flaring facilities. Here, we review the impact of landfill conditions such as construction, geometry, weather, temperature, moisture, pH, biodegradable matter and hydrogeological parameters on the generation of landfill gases and leachate. Bioreactor landfills appear as the next-generation sanitary landfills, because they augment solid waste stabilization in a time-efficient manner, as a result of controlled recirculation of leachate and gases. We discuss volume reduction, resource recovery, valorization of dumped wastes, environmental protection and site reclamation toward urban development. We present the classifications and engineered iterations of landfills, operations, mechanisms and mining. [ABSTRACT FROM AUTHOR]

A new landfill cover system, biochar-methanotrophs-clay (BMC) cover is recommended for reducing methane emissions at landfills. It also contributes to decreasing soil permeability and improving soil water retention in a long time, due to highly porous structure of biochar and the growth metabolism of methanotrophs. To determine the effects of biochar content, oxidation aging times and methane-filled days on hydraulic properties, a total of 60 groups of experiments were conducted. The saturated hydraulic conductivity (ksat) was obtained by flexible wall permeameter with controllable hydraulic head pressure. The results showed that the ksat of BMC increased with increasing biochar content and oxidation aging times, while decreased with adding methane-filled days. The soil-water characteristic curves (SWCCs) were obtained with soil suction measured by the filter paper method. The results indicated the water retention capacity of MBC reduced with increasing oxidation aging times but increased with adding methane-filled days. Detected by mercury intrusion porosimetry (MIP), fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM), the differences displayed the changes of pore structures and extracellular polymeric substances (EPS). The oxidation aging of biochar increased the volume of pores, resulting in the increased ksat and the decreased water retention capacity. However, the growing of methanotrophs decreased the volume of pores, resulting in the ksat decreased and the water retention capacity increased due to EPS. No matter how many times the oxidation aging process was experienced, the BMC with longer methane-filled days exhibited relatively lower ksat and better water retention capacity. This implied a more stable barrier capacity to reduce water infiltration in the long term. By combing a series of macro and micro experiments, this paper provides theoretical guidance for the application of biocharmethanotroph- clay mixture to landfill covers. [ABSTRACT FROM AUTHOR]

[Display omitted] • Effluent treatment sludge was found virtuous accompanying waste for co-landfilling. • Equal proportion of wastes produced maximum methane after 300 days of landfilling. • Reduced leachate strength was attained by ETPS co-disposal in bioreactor landfill. • Gompertz growth model showed excellent fit for experimental methane data. The study aims to investigate the feasibility of anaerobic co-landfilling of effluent treatment plant sludge (ETPS) from paper mill and municipal solid waste (MSW) in prismoidal shaped simulated anaerobic landfill bioreactors. Both ETPS and MSW were co-disposed in 0:100 (R1), 25:75 (R2), 50:50 (R3) and 75:25 (R4) ratios. Periodic assessments of leachate characteristics and biomethane production were carried out for 300 days. ETPS co-disposal with MSW showed considerable reduction in biochemical oxygen demand of leachate (R2: 95.9%, R3: 97.5% and R4: 93.2%). Moreover, cumulative methane gas generations were 2.974, 6.085 and 4.653 times more in R2, R3 and R4 bioreactors as compared to R1. Gompertz growth model was found in well-fitting for methane generation with the observed data. Correlogram plotted among leachate parameters exhibited exclusive relationships and justified leachate trends. This simulation of co-landfilling could be baseline study for the implementation of technology at pilot scale. [ABSTRACT FROM AUTHOR]

A detailed characterization of municipal solid waste (MSW) beyond a standard compositional analysis may offer insights useful for improving waste management systems. The present paper contributes to the scarce literature in the field by presenting new data from a rapidly developing Central Asian city, the capital of Kazakhstan, Nur-Sultan. Three sampling campaigns (each 1 week long) have been conducted at the city landfill over a 1-year period (2018–2019), and a detailed characterization for selected waste components and sub-components has been performed. The major fractions of MSW were organics (46.3%), plastics (15.2%), paper (12.8%), and diapers (5.9%). The detailed composition analysis showed high LDPE (low-density polyethylene) content (5.5%) mostly comprised of plastic bags (4.5%), transparent glass (3.2%), pharmaceuticals (0.4%), and fine (i.e., < 12 mm) organic fraction content (29%). The MSW generation rate of Nur-Sultan was estimated as 1.47 kg capita−1 day−1 based on the field collection as well as literature data. Among sustainable waste management recommendations addressed for Nur-Sultan and applicable to other cities in Central Asia, composting is recommended due to high organics fraction in MSW and its great potential to reduce the landfilled waste volume and to help valorizing the waste. [ABSTRACT FROM AUTHOR]

Landfills are engineered, heterogeneously contaminated sites containing large reservoirs of paper waste. Cellulose degradation is an important process within landfill microbial ecology, and these anoxic, saturated environments are prime locations for discovery of cellulases that may offer improvements on industrial cellulose degradation efforts. We sampled leachate from three locations within a municipal landfill, a leachate collection cistern, and groundwater from an adjacent aquifer to identify cellulolytic populations and their associated cellulases. Metagenomic sequencing identified wide-spread and taxonomically diverse cellulolytic potential, with a notable scarcity of predicted exocellulases. 16S rRNA amplicon sequencing detected nine landfill microorganisms enriched in a customized leachate medium amended with microcrystalline cellulose or common paper stocks. Paper-enrichment cultures showed competition dynamics in response to the specific composition (lignin: hemi-cellulose: cellulose) of the different paper stocks. From leachate biomass, four novel cellulolytic bacteria were isolated, including two with the capacity for cellulolysis at industrially relevant temperatures. None of the isolates demonstrated exocellulase activity, consistent with the metagenome-based predictions. However, there was very little overlap between metagenome-derived predicted cellulolytic organisms, organisms enriched on paper sources, or the isolates, suggesting the landfill cellulolytic community is at low abundance but able to rapidly respond to introduced substrates. [ABSTRACT FROM AUTHOR]

A rapid upsurge in urban and industrial developments leads to increased generations of solid wastes. The most accepted technique of waste discarding around the world is landfilling. Leaching chemicals from municipal dumping grounds can pollute the groundwater source and the surrounding environment without appropriate precautionary measures. Bentonite is a low-cost constituent used as a liner material in landfills due to its low permeability, high sealing ability, high specific surface area, and the ability to hold up the impurity migration through adsorption. However, leachate interaction with bentonite may alter its properties and reduce its usefulness as a barrier material in the long term. Also, bentonite having different chemical and mineralogical compositions will behave differently due to the leachate interaction. Therefore, it is necessary to compare the performance of various bentonites in the presence of leachates. In the present investigation, two Indian bentonites of different mineralogical compositions were studied for their change in the index properties, swelling, swelling potential, swelling pressure, hydraulic conductivity, consolidation parameters and shear strength properties in the presence of fly ash, sewage sludge and paper mill leachates. The outcomes showed that in the presence of all the leachates, liquid limit, free swell, compression index, swelling potential, swelling pressure, time to complete 90% of consolidation and shear strength dropped; whereas, hydraulic conductivity and coefficient of consolidation increased. Besides, the quality of bentonite prominently influenced the hydraulic, strength and swelling behaviour. The bentonite having a higher cation exchange capacity, liquid limit, specific surface area, and swelling capability undergoes a higher variability in the free swell (80.0, 73.8 and 76.9% decline), liquid limit (73.5, 61.7 and 69.2% decline), swelling potential (61.3, 55.7 and 51.0% decline), swelling pressure (53.3 and 56.4% decrease), and hydraulic conductivity (57.5, 8.6 and 41.1 times increase at a void ratio of 1.2) values when infused with fly ash, sewage sludge and paper mill leachates, respectively. The study also showed that the fly ash leachate interaction causes a higher variation in bentonite behaviour than sewage sludge and paper mill leachates. The study's findings would prove beneficial to design engineers for selecting bentonite types for landfill liners. • Engineering properties of two Indian bentonites are presented. • Unconfined compressive strength reduced in the presence of all three leachates. • Hydraulic conductivity of the bentonites increased due to leachates. • Concentration level of metals and bentonite's composition greatly influenced engineering properties. • Influence of the fly ash leachate is the most among all three. [ABSTRACT FROM AUTHOR]

Historically solid waste was commonly landfilled in the coastal zone in sites with limited engineering to isolate waste from adjacent coastal environments. Climate change is increasing the likelihood that these historic coastal landfills will erode releasing solid waste to the coastal zone. Historic coastal landfills are frequently located near designated ecological sites; yet, there is little understanding of the environmental risk posed by released waste. This research investigated inorganic and organic contaminant concentrations in a range of solid waste materials excavated from two historic coastal landfills, and the potential ecological impact should eroded waste be released to the coastal environment. Contaminant concentrations in the analysed waste materials exceeded sediment quality guidelines, indicating erosion of historic coastal landfills may pose a significant environmental threat. Paper and textile wastes were found to make a significant contribution to the total contaminant load, suggesting risk assessments should consider a wide range of solid waste materials. • Climate change may increase the risk of historic waste eroding into the coastal zone. • Contaminant concentrations are highly variable between and within historic landfills. • Release of solid waste would have significant ecological impact. • Release of textiles, paper and wood may all present significant contamination risk. • A screening risk assessment method needs to be developed to prioritise management. [ABSTRACT FROM AUTHOR]

Improper solid waste management poses adverse health effects and pollution challenges in both developed and developing countries. The present study is aimed to evaluate the fate of municipal solid waste (MSW) and household waste behaviors in Tabriz megacity. A questionnaire survey was performed to evaluate the knowledge, attitudes and practices of residents toward MSW reduction, source separation, recycling and collection. The results indicated that food wastes make up the highest portion of MSW, and high moisture content of waste leads to low heating value which is below than average heating value for applicability of incineration. Potentially recyclable wastes such as paper and cardboard, plastics, metals, textiles, glass, wood and others make up a total of 33% of the household solid wastes. Investigation of the fate of MSW revealed that about 55.5% of generated waste ends up in landfill sites, 20.5% is separated by itinerant buyers and separation facility just before landfilling, and 24% is converted into compost. The evaluation of resident's behaviors toward MSW demonstrated the low knowledge of respondents and their high willingness to segregate solid wastes. [ABSTRACT FROM AUTHOR]

Much of what ends up in our landfills is recyclable material, exposing the urgent need to understand the psychological processes behind recycling behavior. Results from four studies suggest that consumers often trash well-known recyclable products due to the product being erroneously categorized as trash after it has been distorted (e.g., paper after it has been cut, torn, or crumpled). However, this categorization error can be somewhat mitigated by the presence of signage depicting the different distorted forms the recyclable product can take. Through prompting, consumers are able to correctly categorize a recyclable product when disposing of it, regardless of the level of distortion. These results provide an explanation for, and potential solution to, the issue of recyclable materials making their way into our landfills every day. [ABSTRACT FROM AUTHOR]

The unit weight of municipal solid waste is a critical parameter in engineering analyses of landfills execution, design, and stability of landfills, but significant uncertainty as of now exists with respect to its value. By using synthetic municipal solid waste (SMSW) that replicates the typical composition of waste produced in India. To determine the relation between Maximum Dry Density (MDD) & Optimum Moisture Content (OMC) of fresh SMSW "Modified Proctor Test" has been performed. MSW is a very heterogeneous material, numerous efforts have been made in the past to generalize the density of MSW, but still, the effect of each material on the density is Obscure. In this paper, the variation in MDD & OMC has been provided depending on the varying percentage of each material (Paper, Plastic & Organic Content) present in it. As a result of regulations and shifting consumer habits, waste is continually changing. Engineers must therefore be mindful of the evolving mechanical characteristics of trash, and it's possible that prior findings may not be a reliable indicator of how waste will behave in the future. Therefore, Calculating the variation in unit weight can be useful in designing engineered MSW landfills and for future references. [ABSTRACT FROM AUTHOR]

There is a great demand for human–machine interfaces (HMIs) in emerging electronics applications. However, commercially available plastic-based HMIs are primarily rigid, application-specific, and hard to recycle and dispose of due to their non-biodegradability. This results in electronic and plastic waste, potentially damaging the environment by ending up in landfills and water resources. This work presents a green, capacitive pressure-sensitive (CPS), touch sensor-based keypad as a disposable, wireless, and intelligent HMI to mitigate these problems. The CPS touch keypads were fabricated through a facile green fabrication process by direct writing of graphite-on-paper, using readily available materials such as paper and pencils, etc. The interdigitated capacitive (IDC) touch sensors were optimized by analyzing the number of electrode fingers, dimensions, and spacing between the electrode fingers. The CPS touch keypad was customized to wirelessly control a robotic arm's movements based on the touch input. A low-pressure touch allows slow-speed robotic arm movement for precision movements, and a high-pressure touch allows high-speed robotic arm movement to cover the large movements quickly. The green CPS touch keypad, as a disposable wireless HMI, has the potential to enforce a circular economy by mitigating electronic and plastic waste, which supports the vision of a sustainable and green world. [ABSTRACT FROM AUTHOR]

Waste generation has seen a significant surge in the last decade, presenting an urgent need for efficient and sustainable waste management strategies. The mounting piles of landfill waste underscore the criticality of segregating recyclable from non-recyclable waste, a measure that could alleviate numerous global environmental challenges. The increasing necessity to differentiate waste into specific categories such as paper, plastic, and metal is becoming evident; these categories demand distinct disposal and recycling methods. Addressing this automatic detection and segregation issue calls for an automated garbage classification system, achievable through computer vision. This paper introduces a deep learning and computer vision-based Smart Ensembled Framework for Waste Management (SEFWaM) to categorize garbage into various classes for improved waste management. This innovative model employs a fusion of transfer learning—a deep learning technique and boosting to devise an ensembled approach for efficient waste classification. Our proposed approach, trained on the Trashnet 2.0 dataset, has demonstrated superior performance over competing algorithms in terms of Weighted Macro Precision (WMP), Weighted Macro Recall (WMR), Weighted Macro F1-Score (WMF), and test accuracy. The proposed SEFWaM model achieves an accuracy of 94.2% for the considered dataset, proving its superior efficiency over other deep learning-based models. This research thereby contributes to a pressing environmental issue by offering an automated, efficient solution for waste management. [ABSTRACT FROM AUTHOR]

Low-permeability liners are required at the base of municipal solid waste (MSW) landfills to minimize leachate leakage and contaminant migration into groundwater. This paper uses a two-dimensional coupled groundwater flow and contaminant transport model to examine the performance of three types of low-permeability liners specified by the current Chinese landfill standard: (1) a compacted clay liner (CCL), (2) a geomembrane (GMB) overlying a CCL, and (3) a GMB overlying a geosynthetic clay liner (GCL) on a CCL. The model simulates leachate leaking and contaminant migrating over the entire base of the landfill for the CCL and through the holed GMB wrinkles for the GMB composite liners. The performance of each type of low-permeability liners was evaluated and compared in terms of leakage rate and peak impact of chloride on the aquifer. Based on liner cases and conditions examined in this paper, the results show that the three types of low-permeability liners are not equivalent for minimizing the leakage rate and chloride impact on the aquifer. The GMB + GCL + CCL performs the best among the three low-permeability liners, and is effective for limiting the peak chloride impact on the aquifer below the acceptable level in drinking water. [ABSTRACT FROM AUTHOR]

This paper reviews recent research on biopolymer and biotechnology-based bioplastics as a solution to plastic pollution. Plastics are becoming a substantial issue as society progresses, particularly with single-use variants. These packaging films are primarily composed of petroleum and refined with high heat, releasing carbon dioxide pollutants in the process. At the end of its lifespan, plastic is regularly thrown away in landfills and the environment, posing risks to human and ecosystem health. While bioplastics are prevalent in the market today, their lack of biodegradability and high costs prevent widespread use. As a result, studies about novel methods of producing biodegradable bioplastics have emerged. This paper reviews research concerning E. coli, chitosan, keratin, cellulose, and alginate as unconventional methods of synthesizing a new strand of bioplastics -- rigid 3D monoliths and flexible packaging films. Alginate composite films show the most promise in terms of sustainability, cost, mechanical properties, and ease of scalability but are restricted to low-humidity environments. Thus, additional research and field testing is needed before widespread adoption. [ABSTRACT FROM AUTHOR]

This paper investigates a waste landscape in the Marston Vale, Bedfordshire, UK, consisting of a range of landfill hills. The hills originated as vast holes in the ground created by clay extraction, which presented suitable receptacles for the dumping of landfill waste. Although of much larger scale than evidence normally dealt with by archaeologists, these are treated here as archaeological features within an archaeological landscape. While other papers deal with important aspects of political ecology of waste landscapes, the present focus is on the upscaling of methods that is necessary to cope with such mega-scale contemporary waste landscapes, in order to make them more susceptible to archaeological analysis. [ABSTRACT FROM AUTHOR]