Solid Waste Components Research Articles

Influence of heterogeneity and elevated temperatures on the seismic translational stability of engineered landfills

This paper proposes a new generalised closed-form solution to estimate the safety factors for translational failure of landfills considering the effects of heterogeneity and temperature variation with the depth of the landfill. The influence of heterogeneity was considered in the form of a shear wave velocity profile, while the influence of temperature was accounted for by considering the temperature-dependent shear strength properties. The proposed method also considered the influence of material damping and the mode change behaviour of the landfill. The safety factor for translational failure of the landfill was estimated using the limit equilibrium-based two-part wedge method. The proposed method was validated by comparing the safety factor obtained from this method with comparable analytical solutions. An extensive parametric study was conducted to demonstrate the influences of the landfill geometry, shear strength properties of municipal solid waste and liner components, parameters of strong ground motion, heterogeneity, and landfill temperature on the calculation of safety factors. The interfacial shear strength properties of liner components played a vital role in the translational stability of landfills compared to the shear strength properties of municipal solid waste. The frequency of base excitation showed a strong influence on landfill stability, while the material damping displayed a nominal effect. For the cases considered in this study, when the frequency of base excitation was close to the fundamental frequency of the landfill, the base acceleration was amplified by 6.7 times which reduced the safety factor by approximately 1.6 times. Heterogeneity and temperature have a significant influence on landfill stability. The increased degree of heterogeneity caused an approximately 27% reduction in the safety factor. For the given set of input parameters, the elevated temperature in the landfill alone decreased the safety factor by a maximum of 18%, while it reduced by approximately 60% under the combined influence of seismic, heterogeneity, and elevated temperature.

Exploitation of plastic bags in roadway blocks

Plastics are an increasingly important component of urban solid waste. The disposal of waste materials, such as used plastic bags, has become a major issue. The vast amount of waste plastic bags collected in the twenty-first century has posed significant challenges for their disposal. The amount of waste plastic in the home is substantial and growing. Our results indicate cement blocks are ideal for laying and finishing pathways and streets because they are easy to lay and finish. This study was carried out on experimenting the substitute materials in the mixture of cement blocks a component of building materials which is normally manufactured using the mixture of cement, fine aggregate and water, following a certain ratio. A series of three different percentages of plastics bags were added with the mix and certain quantities were replaced by quarry dust instead of Fine aggregate. Tests were done on the blocks to study its compressive strength, split tensile strength the water absorption percentage and acid test. Both the test compressive and split tensile tests were conducted on the seventh and 28th day. Based on the results acquired, for compressive strength tests on the 28th day, the result a good indication is that the blocks can be produced by replacing the cement and fine aggregate with utilizing the plastic for and effective way of 1:1 and 1:2, with 10& 20% replacing with quarry dust having strength 10.7 and 9.5 N/mm 2 respectively Which is 165 more than the conventional type of blocks. Similarly the water percentage is also nil and very marginal in the same proportions. The decrease in weight is existed in all the samples tested the result is equal in all mix compositions. This is uniform rate implies block undergo certain abrasion. Conclusions were drawn for utilising the above composition in a suitable non structured places and minimizing the plastic waste.

Investigation of the polystyrene combustion completeness increasing method in the environmentally safe waste disposal installation

The article presents the study results of the solid waste components (on the example of polystyrene) combustion optimizing based on traditional solutions used in the furnaces organization (stratified combustion, combustion in a vortex flow, combustion products recirculation), as well as due to the electrostatic field impact. Relative changes in the CO and NO emissions values were obtained for various methods of air supply to the combustion chamber and electrostatic field parameters. The use of an electrostatic field with a potential difference of 3–4 kV made it possible to increase the combustion efficiency, which led to a decrease in the formation of CO by up to 40%, and NO to almost zero.

Composition of Domestic Solid Waste and the Determination of its Density & Moisture Content: a Case Study for Tikrit City, Iraq

This research has been done to know the physical composition of domestic solid waste and to determine the percentages of domestic solid waste components in Tikrit City. Food wastes comprises the highest percentage among other components (about 55.331 % from the total weight of the domestic solid waste). The research also examined the seasonal variations of domestic solid waste components percentages which be considered to be critical when a composting plant or a recycling facility is to be planned to use within the solid waste management system. The main seasonal variation is in food wastes that were typically larger at summer. Packaging wastes like paper and cardboard tended to increase at the winter. The density and moisture content of domestic solid waste were (229.088 kg/m3 and 27.419 %), respectively.

Comparative Studies of Biodegradation of Wastes Using Cellulase from Garden Snails (Limicolaria flammea) and Giant African Snails (Archachatina marginata)

The generation of solid waste is a massive and ever-growing problem that affects the entire world, particularly developing countries. In Africa, waste recycling is not fully embraced and performed; as a result, these waste products are viewed as physical contaminants that can harm the ecosystem, generate pollution, and cause a lot of environmental risks. The use of synthetic compounds in the decomposition of wastes could harm the ecosystem and lead to global warming, thus biocatalysts are a preferred option. Cellulase, a hydrolytic enzyme, could digest cellulose, a main component of solid waste. Garden snail (Limicolaria flammea) and Giant Africa snail (Archachatina marginata) are organisms that feed on dead, decaying and actively growing plants due to their possession of cellulolytic enzyme. Cellulase from the gut of Archachatina marginata haemolymph and Limicolaria flammea had specific activities of 1.15 U/mg and 1.14 U/mg respectively. It also showed high level of degradation. Limicolaria flammea haemolymph showed high activity of 504.11% on soluble starch, 529.39% on kick tree and 993.77% on carton paper. This study suggests that cellulase from both Limicolaria flammea and Archachatina marginata has biodegrading potentials on waste materials. While their effects and the rate of degrading wastes differ, they could both be relevant in waste management especially on kitchen waste.

Exploring Key Components of Municipal Solid Waste in Prediction of Moisture Content in Different Functional Areas Using Artificial Neural Network

Moisture content is a very important parameter for municipal solid waste (MSW) treatment technology selection and design. However, the moisture content of MSW collected from different urban areas is influenced by its physical composition in these areas. The aim of this study was to analyze the key components of MSW for predicting moisture content in different functional areas via the development of an artificial neural network (ANN) model. The dataset used in this study was collected in Shanghai from 2007 to 2019. Considering the influence of functional areas, the model obtained the performance with MAE of 2.67, RMSE of 3.29, and R2 of 0.83, and an eight-fold cross validation showed acceptable results. The inter-quartile range (IQR) and isolation forest were compared to detect and remove outliers. In descending order, the moisture content was ranked as commercial/residential > office > cleaning areas. Based on a parameter exclusion method, kitchen, rubber, and plastic wastes show the greatest influence on moisture content in residential and commercial areas. In cleaning and office areas, paper, wood and bamboo waste products were the most important components. The determination of key components in different functional areas is of benefit for reducing the workload of moisture content estimation.

Combination of hyperspectral imaging and machine learning models for fast characterization and classification of municipal solid waste

Determining thermochemical properties and eliminating inorganic components of municipal solid waste (MSW) are crucial to its thermochemical treatment. Traditional characterization and classification technologies have shortcomings including long duration, complex operation, and inevitable sample consumption. This study proposed a hyperspectral imaging and machine learning models based method to solve these problems. Under the optimal parameter conditions, the identification accuracy of inorganic components by F1 scoring reached nearly 100% in MSW, and the prediction accuracy of carbon, hydrogen, oxygen, nitrogen contents and low heating value (LHV)of organic components by mean relative error value reached 92.6%, 86.9%, 80.4%, 54.7% and 90.5%, respectively. The results validated the hypothesis that combination of hyperspectral imaging and machine learning models are promising to accomplish fast characterization and classification of components in MSW, where principal component analysis was capable to abstract crucial information from the spectral pattern, and artificial neural network presented satisfactory classification and regression performance.

Food Waste Treatments and the Impact of Composting on Carbon Footprint in Canada

Forty percent of the food generated in Canada is wasted, making it the most significant component of municipal solid waste. Food waste characteristics, such as high moisture and oil content, and variable composition, make it difficult to manage with conventional waste treatment methods. Part of food waste is disposed of in landfills, generating greenhouse gases and significantly increasing the carbon footprint. Various treatment methods such as composting and anaerobic digestion have been employed to treat and manage the remaining waste efficiently. This study provides an overview of the impact of composting as a food waste treatment method in Canada and paves way for the research of the usefulness of composting in addition to other food waste treatment methods such as anaerobic digestion. Average composting data for Canada was used to determine the change in the carbon footprint by the diversion of food waste using CCaLC2 software. It was determined that the overall carbon footprint of 1.38 and 1.33 mega-tons of CO2 was reduced from the composting of food waste in the years 2014 and 2016, which were approximately 18% and 20% of the total footprint of Canada municipal solid waste, respectively. The carbon footprint data collected herein were compared to the data from England, Sweden, and the USA to reveal the high effectiveness of composting in Canada.

Dynamics of microbiota and physicochemical characterization of food waste in a new type of composter

Organic wastes are considered the most significant components of urban solid waste, negatively affecting the environment. It is essential to use renewable resources to minimize environmental risks. Composting is one of the most sustainable methods for managing organic waste and involves transforming organic matter into a stable and nutrient-enriched biofertilizer, through the succession of microbial populations into a stabilized product. This work aimed to evaluate the efficiency of the new type of composter and the microbial and physiochemical dynamics during composting aiming to accelerate the degradation of organic waste and produce high-quality compost. Two inoculants were evaluated: (1) efficient microorganisms (EM); (2) commercial inoculum (CI), which were compared to a control treatment, without inoculation. Composting was performed by mixing organic waste from gardening with residues from the University's Restaurant (C/N ratio 30:1). The composting process was carried out in a 1 m3 composter with controlled temperature and aeration. The thermophilic phase for all treatments was reached on the second day. Mature compost was obtained after an average of 120 days, and composting in all treatments showed an increase in the availability of P and micronutrients. The new composter helped to accelerate the decomposition of residues, through the maintenance of adequate oxygen content and temperature control inside the cells, providing high metabolic activity of microorganisms, contributing to an increase in physicochemical characteristics, also reducing the composting time in both treatments. During composting, the bacteria and actinobacteria populations were higher than yeasts and filamentous fungi. The inoculated treatments presented advantages showing more significant mineralization of P-available and micronutrients such as Mn and Zn in terms of the quality of the final product in comparison to the control treatment. Finally, the new composter and the addition of inoculants contributed significantly to the efficiency of the process of composting organic waste.

PEMANFAATAN ENDAPAN LIMBAH CAIR (ELC) INDUSTRI KULIT UNTUK PUPUK TANAMAN CABAI

The purpose of this study was to utilize solid waste from wastewater treatment sludge for red chili fertilizer by finding the proportion/ratio of solid waste components with soil to obtain the most optimal composition. The materials used are solid waste sediment leather tannery, soil, chili seedlings, pesticides, and water. The tools used are plant pots (pots made of clay with a diameter of ± 25 cm and a height of ± 20 cm). The method used was planting red chili seeds on 6 types of planting media, namely control pots, 1,2,3,4,5 pot which were sequentially controlled (without solid waste), and the ratio of solid waste: soil with a ratio of 1:2, 1: 3, 1:4, 1:5, 1:6. The results of the data obtained were analyzed using a T test and completely random design. furthermore, duncan test was conducted to determine the best dose (ratio) for chili plants if previously (in the unidirectional variance test) there was a ratio effect. The results obtained were pots 1, 2, 4 had a higher plant height than the control. Pots 1,2,3,4 had more leaves than the control. The conclusion that can be obtained is that the solid waste sediment on chili planting media affects height increase, number of chili leaves, and quantitatively not all of them have a significant effect. Giving solid waste sediments with a ratio of 1: 3 showed the fastest increase in height and number of leaves.

LAND REMEDIATION AND RECLAMATION TECHNIQUES THROUGH THE BIODEGRADATION OF WASTE PAPERS

Waste materials are one of the major components of solid organic waste that pollutes land. Inappropriate disposal of municipal waste (solid) not only affects land but is also a source of danger to inhabitants. The management of residue from incineration is an integral part of waste disposal/management systems. This research provides a collection and bio-treatment technologies for various types of waste paper such as office paper and newspaper as feedstock using two microorganisms: Serratia and Rhizopus to convert them to reducing sugars. The percentages of reducing sugar present in the samples before, during and after hydrolysis were determined using the dinitrosalicylic (DNS) acid test method. The effect of temperature on the substrate was analyzed at 37, 40, and 45°C. This research shows that waste paper can be converted into useful materials.

Optimal utilization of solid residue from phase-separation pretreatment before food waste anaerobic digestion

Food waste (FW) is a significant component of municipal solid waste (MSW) with high recycling value. In FW treatment plants, FW is separated into crude oil, liquid part and solid residue (SR) after pretreatment. Crude oil is used to process biodiesel, liquid part is sent to Anaerobic digestion (AD), but there are different technical options for SR utilization. In this study, four common methods, incineration, AD, composting, and feed processing, are compared in terms of carbon emissions and economic performance. The results show that AD is the best treatment choice for the lowest net carbon emission of −79.28 to −118.73 kg CO2-eq/t SR because of its high efficiency of electricity generation. Composting of SR has the highest net carbon emission with 19.24–116.40 kg CO2-eq/t SR because the carbon reduction effect from compost replacing chemical fertilizers is less than the direct greenhouse gas emissions. Feed processing remains almost all the biogenic carbon in the product, and hence it is the priority option if taking the short-term contribution of biogenic sources to carbon emissions. As for economic performance, feed processing is the best choice with a benefit of 225 CNY/t SR, while incineration of SR results in a high expenditure. From a comprehensive point of view, feed processing and AD are the best choices due to their carbon reduction effects and relatively low treatment cost. These results provide an essential reference for the decision making of FW treatment processes.

Review on Anaerobic Digestion and Disposal Technology of Solid Waste

This paper reviews the solid waste disposal technologies at home and abroad. Solid waste is rich in a large amount of organic matter. If discarded or landfilled, it will cause serious environmental problems such as greenhouse gas emissions, landfill leachate emissions, pathogen transmission and groundwater pollution. Common disposal methods of solid waste include sanitary landfill, incineration, compost fermentation, anaerobic digestion, etc. Among them, anaerobic digestion technology is an economical and efficient solid biological treatment technology, which can not only realize the degradation of organic matter components in solid waste and the removal of toxic and harmful pollutants, but also obtain biogas to realize energy recovery.

CFD Simulation Analysis of Sub-Component in Municipal Solid Waste Gasification Using Plasma Downdraft Technique

Plasma gasification technology is one of the potential methods to decompose dangerous wastes and turn them into non-leachable slag due to it greater energy efficiency and bottom ash prevention concerns. However, a fundamental study of CFD simulation on the reaction flow characteristic using the operational of plasma gasification process was scarce. The present study aims to investigate the gasification characteristic of municipal solid waste (MSW) component including food waste, paper, and yard waste to produce synthesis gas using a 3-dimensional CFD simulation method in the downdraft plasma gasifier. The reaction model of non-premixed combustion, Euler-Lagrangian approach and K- ε turbulence model was used as a setup parameter. Plasma being consider as hot gas with 1173K, coal as 293K and air inlet on 673K. Flowrate of feedstocks, plasma gas flow and air flowrate are set to 0.029 kg/s, 0.0438kg/s, and 0.0029kg/s respectively. Based on the result and comparison between those feedstocks, food waste typically produced higher CH4, CO, and CO2 than paper and yard. Yard wastes yield the highest H2 content which consist of 0.544 mole fraction, with 539.24% higher than food waste and 79.76% higher than paper. The result showed that gasification of different component from MSW produced different characteristic of syngas based on the properties of the feedstock.

Thermodynamic assessment of iron and the expansion behavior of porous ceramsite in pure mineral systems relating to solid waste components

Herein, Factsage software and sintering experiment were conducted to predict and correlate thermodynamic calculations of Fe in a synthetic solid waste and the expansion behavior of ceramsite. With the increase of Fe2O3 content, the liquid phase content and viscosity in the multi-component system gradually decreased and the melting temperature range became wider. This can match with the generation of the liquid phase with proper viscosity in the ceramsite and the full expansion properties. At 400–1000 °C, iron as a network former was tetrahedrally coordinated with oxygen to form Hercynite (Al2FeO4) phase; at 1180–1200 °C, iron as a network modifier dissolved into the silicate mineral structure to form the eutectic composition of Diopside (Ca4Mg3.62Fe0.78Si7.6O24) and Ferrosolite (Si16Mg5.09Fe10.66Ca0.26O48). The formation of iron-bearing silicate facilitated the generation of the viscous layer, so that the outer layer of the ceramsite exhibited sealing performance. Finally, a preferable porous ceramsite with compressive strength of 10.7 MPa and an apparent density of 708 kg/m3 was obtained. This study analyzes the effect of Fe2O3 on the expansion behavior of porous ceramsite and provides new insight into how to analyze different solid wastes to produce ceramsite in a predictable way.

Characteristics and health effects of particulate matter emitted from a waste sorting plant

Solid waste components can be recycled in waste paper and cardboard sorting plants (WPCSP) through a multistep process. This work collected 15 samples every six days from each of the 9 points selected to study the processes taking place in a WPCSP (135 particulate matter samples total). Examining the concentration and size fraction of particulate matter (i.e., PM1, PM2.5 and PM10) in WPCSP is an essential issue to notify policy makers about the health impacts on exposed workers. The major activities for increasing of the concentration of PM in various processing units in the WPCSP, especially in hand-picking routes I and II were related to manual dismantling, mechanical grinding, mechanical agitation, and separation and movement of waste. The results of this work showed that a negative correlation between temperature and particulate matter size followed the order PM10 > PM2.5 > PM1. Exposure to PM2.5 and PM10 in the WPCSP lead to possible risk (HI = 5.561 and LTCRs = 3.41 × 10−6 to 9.43 × 10−5 for PM2.5 and HI = 7.454 for PM10). The exposure duration and the previous concentrations had the most effect on the ILCRs and HQs for PM2.5 and PM10 in all sampling sites. Hence, because WPCSP are infected indoor environments (I/O ratio > 1), the use of control methods such as isolation of units, misting systems, blower systems equipped with bag houses, protective equipment, a mechanical ventilation system, and additional natural ventilation can reduce the amount of suspended PM, enhance worker safety, and increase the recycling rate.

Environmental and Economic Life-Cycle Assessments of Household Food Waste Management Systems: A Comparative Review of Methodology and Research Progress

Household food waste (HFW) is the main component of municipal solid waste (MSW). Appropriate HFW management strategies could reduce the environmental burdens and economic costs to society. Life-cycle thinking is an effective decision-making tool for MSW management. This paper compares the three main environmental and economic assessment methodologies, i.e., societal life-cycle costing (societal LCC), environmental cost-effectiveness (ECE) analysis, and multicriteria analysis (MCA) in terms of the definitions, method frameworks, and their advantages/disadvantages. Most reviewed studies applied the environmental life-cycle costing (ELCC) method, a simplified ECE, which does not involve interactive quantitative comparisons between environmental and economic benefits. Further attention should be paid to the coordination between life-cycle assessment (LCA) and life-cycle costing (LCC), the monetization coefficient in external cost calculation of societal LCC, and the standardization and evaluation approaches of ECE. HFW prevention is rarely considered in the reviewed literature but was demonstrated as the best route over treatment or utilization. Anaerobic digestion is environmentally preferable to composting and landfilling; it is comparable to biodiesel production, feeding conversation, and incineration. From the perspective of economic costs (including societal LCC), the ranking of treatment technologies varied a lot from one study to another, attributable to the diverse evaluation methods and different data sources. To improve the environmental and economic assessment approaches to HFW management, an inventory database (e.g., food waste properties, technical treatment parameters, material flow, and fund flow data) suitable for HFW should be constructed. When establishing the system boundaries, the processes of source sorting, collection and transportation, and by-product handling should be coherent with the investigated treatment technology.

Reaction performance and mechanism of a NiO/Ca2Fe2O5 oxygen carrier in Chemical looping gasification of cellulose

Chemical looping gasification (CLG) is a novel technology created to realize the clean and efficient utilization of solid fuels, where the syngas product avoids dilution by N2 and the pollutants are inhibited by using metal oxide as oxygen carrier (OC) instead of molecular oxygen. Cellulose, as the main component of biomass-based solid waste, was evaluated in the CLG process with NiO/Ca2Fe2O5 prepared by the impregnation method. Reaction mechanism and morphology evolution of the OC as well as the influence of key reaction parameters were investigated by fixed-bed reactor and thermogravimetric analysis experiments coupled with various characterization techniques. The results indicated that the addition of Ni not only improved the oxygen release performance of Ca2Fe2O5 but also helped tar cracking and carbon conversion. On the other hand, the excellent activity in the solid–solid reaction of Ca2Fe2O5 promoted the performance of the Ni-based OC. The test results revealed that Ca2Fe2O5 was a better base than CaFe2O4, and the carbon conversion efficiency reached 98% with the OC sample at 850 °C. NiO markedly improved the reactivity of Ca2Fe2O5 after 10 cyclic reactions. The temperature notably affected activity below temperatures of 850 °C and slightly above. Due to the limited reduction of Ca2Fe2O5 below 800 °C and the redox behavior improvement being minor above 850 °C, the temperature of 850 °C was marked as the optimum for the studied process Addition of water inhibited OC inactivation in cyclic reactions, which was mainly attributed to the crystal separation and agglomeration of OC particles. However, water inhibited the deep reduction of metal on the surface, which reduced the activity on tar cracking and carbon conversion to a certain extent.

Multi-criteria assessment of food waste and waste paper anaerobic co-digestion: Effects of inoculation ratio, total solids content, and feedstock composition

Food waste and waste paper are the two largest components of municipal solid waste, and many previous studies found that their co-digestion improved methane yield. This study investigated the anaerobic co-digestion of 0–100% food waste with paper food packages on lab-scale with feedstock-to-inoculum (F/I) ratios from 0.5 to 6 (based on volatile solids, VS) and total solids contents from 8% to 28%. In addition to methane yield, volumetric productivity and process economics were also used to evaluate the operating parameters. Results showed that the highest cumulative methane yield of around 530 L/kg-VSfeed was obtained from 100% food waste at F/I ratios of 0.5, 1, and 2; the highest volumetric methane productivity of 44.2 L/Lwork was achieved with 25% food waste at an F/I ratio of 6; and the highest annual net profit was obtained from 75% food waste at an F/I ratio of 2, which also achieved the highest internal rate of return (20.7%) and the shortest payback period (5 years). Addition of waste paper packages to food waste could enhance the digester stability, and it is beneficial to allow certain amount of paper packages and tissues to be collected together with food waste during the initial source separation.

Quantitative Analysis of Industrial Solid Waste Based on Terahertz Spectroscopy

Industrial solid waste refers to the solid waste that is produced in industrial production activities. Without correct treatment and let-off, industrial solid waste may cause environmental pollution due to a variety of pollutants and toxic substances that are contained in it. Conventional detection methods for identifying harmful substances are high performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS), which are complicated, time-consuming, and highly demanding for the testing environment. Here, we propose a method for the quantitative analysis of harmful components in industrial solid waste by using terahertz (THz) spectroscopy combined with chemometrics. Pyrazinamide, benazepril, cefprozil, and bisphenol A are four usual hazardous components in industrial solid waste. By comparing with the Raman method, the THz method shows a much higher accuracy for their concentration analysis (90.3–99.8% vs. 11.7–86.9%). In addition, the quantitative analysis of mixtures was conducted, and the resulting prediction accuracy rate was above 95%. This work has high application value for the rapid, accurate, and low-cost detection of industrial solid waste.