Mixture Of Solid Waste Research Articles

Kinetic evaluation and applicability analysis on direct aqueous carbonation of industrial/mining solid wastes

CO2 mineralization combined with goaf backfilling is an effective pathway for alkaline solid waste recycling and CO2 emission reduction. Determining the kinetics of solid waste mixtures during direct aqueous carbonation is therefore important. Here, carbonation behavior and kinetics of carbide slag and its mixes with iron tailing are examined using a kinetic model based on the two-film theory. The impact of important operation parameters is assessed through model fitting as well. Results show that there is an excellent fitting accuracy to the carbonation of carbide slag and its 50 % mixtures by the model (average R2 =0.999) although a limitation is observed when the IT blending ratio is very high. Additionally, the change of gas-liquid mass transfer flux is compatible with the theory, and the ideal parameters are determined to be a reaction temperature of 65 °C, a solid-liquid ratio of 100 g/L, and a CO2 concentration of 15 %. Difference between the experimental and predicted value is controlled within 10 %. The above results are beneficial to revealing the microscale carbonation mechanism of mixed solid waste and may offer theoretical backing for industrial applications.

From the solid waste mixture of coal hydrogasification residue and red mud to efficient Fe3O4/C- and Fe/C-based composite microwave absorbents

Following the concept of sustainable development, magnetic particles/C-based composite microwave absorbing materials were prepared through reactions between two solid wastes: coal hydrogasification residue (CHR) and red mud (RM). At a fixed mass ratio of CHR to RM of 0.6:1, Fe3O4/C- and Fe/C-based composites could be obtained at 700 and 900 °C, respectively. A minimum microwave reflection loss of −48.3 dB and a largest effective absorption bandwidth of 4.5 GHz were achieved for the Fe/C-based composite with a simulated thickness of 1.5 mm. The Fe3O4/C-based composite exhibited slightly poorer performance because the fixed initial system could not guarantee impedance matching for both products. The strong intrinsic attenuation capacity of the materials mainly resulted from the dielectric loss, including conduction loss caused by graphite carbon as well as interfacial polarization relaxation loss arising from the numerous phase boundaries.

GENERATION AND CHARACTERISTICS OF HOUSEHOLD SOLID WASTE IN KHULNA CITY, BANGLADESH

For growing cities, solid waste management is a serious concern, focusing on household waste because it accounts for a significant portion of municipal solid waste. An accurate estimation of the quantity and characteristics of solid waste mixtures from diverse income levels is required for effective city-wide solid waste management planning. The purpose of this study is to assess the production and characteristics of domestic solid waste produced by different socio-economic groups in three wards (no. 17, 23 and 24) of Khulna city. Moreover, various factors that influence the pace of waste production have been critically investigated. The finding suggests that, household waste generation rate ranges from 0.421 to 5.81 kg/day, average of 1.917 kg/day and 0.476 kg/capita/day. The waste composition analysis depicts that kitchen garbage is the most prevalent component. The waste generation rate has a positive relationship with income level and household size. Nonetheless, the findings and proposed essential steps of this study would be beneficial in assisting policymakers in refining plans for controlling the municipal waste effectively.

From Solid Waste Mixture of Coal Hydrogasification Residue and Red Mud to Efficient Fe3o4/C- and Fe/C-Based Composite Microwave Absorbents

From Solid Waste Mixture of Coal Hydrogasification Residue and Red Mud to Efficient Fe3o4/C- and Fe/C-Based Composite Microwave Absorbents

Influence and microscopic mechanism of the solid waste-mixture on solidification of Cu2+-contaminated soil

In this paper, two aspects of studies are carried out: (1) synthesis of solid waste-mixture solidifier by using red mud, calcium carbide residue, and phosphogypsum; (2) solidification behaviors of the solid waste-mixture in the presence of Cu2+ ion. The performance of solidified soil was assessed by performing mechanical, permeability, and microstructure tests on samples. The results show that solid waste-mixture can improve the strength, brittleness, and impermeability of the contaminated soil, while the effect of Cu2+ ion is completely opposite. Additionally, the dominant heavy metal form in the solid waste-mixture solidified soil is iron-manganese oxide. The addition of solid waste is more conducive to the transformation of heavy metals to a stable form. The leaching toxicity values of solid waste-mixture solidified soil all meet the relevant standard and the effect is better than that of cement. Besides, the heavy metal can be fastened in the solidified soil through the precipitation, absorption of calcium silicate hydrate (C-S-H), and ion exchange of ettringite (AFt). In sum, it implied that the solid waste mixture had a potential application for the solidification of Cu2+-contaminated soil.

The influence of PET and PBT contamination during transportation fuel production via pyrolysis

The pyrolysis of plastic waste is a promising method to reduce waste accumulation while it could provide value-added transportation fuels. The main goal of this study is to investigate the influence of PET and PBT contamination during plastic pyrolysis oil production utilizing HDPE, LDPE, PP, and PS mixtures as these plastics are good candidates for transportation fuel production via pyrolysis and distillation. Seven different waste blends were prepared and pyrolyzed in a laboratory-scale batch reactor equipped with reflux. Mass balance, gas analysis, thermogravimetric analysis, and deposit formation were evaluated. It was concluded that by increasing the PET or PBT concentration in the initial solid waste mixtures, the oil production decreases while the amount of gases increases. Additionally, either PET or PBT generates operational difficulties due to they form deposits in piping system in form of benzoic acid. The maximum concentration of these plastic waste materials was 20% (PET) and 25% (PBT) in this study as further increase blocked the cross-section of piping, causing operational difficulties. Based on the obtained results the concentration of PET and PBT should be limited in waste mixtures when transportation fuel production is desired.

Valorisation of biomass and diaper waste into a sustainable production of the medical mushroom Lingzhi Ganoderma lucidum

Global solid waste is expected to increase by at least 70% annually until year 2050. The mixture of solid waste including food waste from food industry and domestic diaper waste in landfills is causing environmental and human health issues. Nevertheless, food and diaper waste containing high lignocellulose can easily degrade using lignocellulolytic enzymes thereby converted into energy for the development and growth of mushroom. Therefore, this study explores the potential of recycling biomass waste from coffee ground, banana, eggshell, tea waste, sugarcane bagasse and sawdust and diaper waste as raw material for Lingzhi mushroom (Ganoderma lucidum) cultivation. Using 2% of diaper core with sawdust biowaste leading to the fastest 100% mushroom mycelium spreading completed in one month. The highest production yield is 71.45 g mushroom; this represents about 36% production biological efficiency compared to only 21% as in commercial substrate. The high mushroom substrate reduction of 73% reflect the valorisation of landfill waste. The metabolomics profiling showed that the Lingzhi mushroom produced is of high quality with a high content of triterpene being the bioactive compounds that are medically important for treating assorted disease and used as health supplement. In conclusion, our study proposed a potential resource management towards zero-waste and circular bioeconomy for high profitable mushroom cultivation.

Co-Composting of Khat-Derived Biochar with Municipal Solid Waste: A Sustainable Practice of Waste Management

Biochar is a way to improve the performance of the composting process and the quality of compost. This study was aimed to investigate the optimum ratio of khat straw (Catha edulis) biochar and organic municipal solid waste mixtures to improve the quality of the resulting co-composts. Khat-derived biochar during pyrolysis at 350 °C was added to organic municipal solid waste mix and four co-composting treatments were prepared with the compositions (% w/w): control compost (no biochar) and 5%, 15%, and 25% co-composted biochar in three replicates. The total organic carbon, organic matter, total nitrogen, available phosphorus, and potassium values ranged as 16.76–21.45%, 30.77–40.26%, 0.97–1.68%, 0.58–0.76%, and 12.72–15.29%, respectively. The results confirmed that 5% and 15% co-composted khat biochars had significantly reduced (p < 0.05) organic matter loss and increased the contents of cation exchange capacity, pH, phosphorous, potassium, calcium, magnesium, and zinc compared to the control compost, while some heavy metals (Fe, Cu, and Mn) and EC values in co-composted biochars are lower than the control compost. Khat-derived biochar could be added to municipal organic waste mix at 5–15% (w/w) in order to get better quality of compost, which can be used as biofertilizer.

Mechanical properties test of pavement base or subbase made of solid waste stabilized by acetylene sludge and fly ash

As a sustainable development requirement, rational utilization of solid waste has been paid more and more attention, such as acetylene sludge (AS), fly ash (FA), coal gangue, and construction waste used in civil engineering. The comprehensive utilization of the solid waste has already been developed for road engineering recently. This study focuses on the properties of base or subbase that are made of coal gangue and construction waste stabilized by AS and FA. The base or subbase material with various volumetric ratios of AS:FA:stacked coal gangue (SCG), AS:FA:air-washed coal gangue (ACG), AS:FA:recycled brick, and concrete debris (RBCD) were designed. In addition, their properties were tested, including unconfined compressive strength (UCS), indirect tensile strength (ITS), and compressive resilient modulus. The results showed that the UCS and ITS of the SCG stabilized by AS–FA are higher than that of the ACG stabilized by AS–FA. However, there was no significant correlation between UCS, ITS, compressive resilient modulus, and binder content of the AS/FA-stabilized RBCD. Even though the properties of the solid waste mixture were not stable enough, it could be potentially used in the base or subbase of the pavements.

DEFINITIONS OF A RATIONAL INDICATOR OF HUMIDITY AT COMBUSTION OF MUNICIPAL SOLID WASTE

The article deals with the current issue of solid waste management for today and emphasizes that heattreatment is the most effective method of waste reduction. Under the heat treatment, the combustion process isconsidered. The impact of pollutants released during the incineration of household waste is reviewed. It is revealedthat a number of certain parameters are taken into account while planning the process of incineration of a mixtureof solid waste. Such as technology that will dispose of debris, morphological composition, the need for pre-treatment(sorting, grinding), the aggregate state of waste, fractional composition, heat of combustion of waste, etc. Equallyimportant is the humidity of the waste to be recovered through incineration. Humidity is the amount of waterabsorbed into the material in the form of steam or liquid. It can be expressed in two separate ways, as a percentageof the wet weight of the sample or as a percentage of the dry weight of the sample. Therefore, this paper focuses onsuch an important parameter when burning solid waste as humidity, and presents typical humidity data. The analysisof the concentration of basic chemical compounds during the incineration of municipal solid waste, depending onthe degree of their humidity was done. The acceptable waste incineration humidity is calculated, with minimumemissions. Microsoft Excel and MathCad software were used to simplify the calculation. Real values of humidityand emission concentration were used in the determination. The transformations, ratios and calculations determinethe dependencies for each emission were established. Using the factors that take into account the hazard class ofthe substances and adding all the values, the minimum emission value and the humidity at which this value isobserved were found. A calculation algorithm has been developed to determine the amount of emissions that will begenerated by burning a specific mixture of solid waste.

MATHEMATICAL APPROACH ON HOUSEHOLD WASTE CAUSING ENVIRONMENTAL POLLUTANTS DUE TO LANDFILL AND TREATMENTS

Household solid waste is the solid waste mixture of garbage and rubbish which comes during the use of various products in daily life. It also called as domestic waste or residential waste. It may fall into two categories either hazardous or non-hazardous which are stored and forsaken directly to the landfills. This is how household solid waste plays vital role in spreading environmental pollutants. For reduction of the pollution, treatment plant is constructed for hazardous solid waste and compost plant is organized for non-hazardous solid waste. In this paper, we have developed a system of non-linear differential equations to analyse the household solid waste storage. In order of preventive measures, five various controls are given to the different compartments. The basic reproduction number and the stability are derived to check the endurance of the model. The numerical simulation is also done using validated data.

SYNTHESIS AND CHARACTERIZATION OF GREENER CERAMIC MATERIALS WITH LOWER THERMAL CONDUCTIVITY USING OLIVE MILL SOLID BYPRODUCT

In the current research, the valorization of olive mill solid waste as beneficial admixture into clay bodies for developing greener ceramic materials with lower thermal conductivity, thus with increased thermal insulation capacity towards energy savings, is investigated. Various clay/waste mixtures were prepared. The raw material mixtures were characterized and subjected to thermal gravimetric analysis, in order to optimize the mineral composition and maintain calcium and magnesium oxides content to a minimum. Test specimens were formed employing extrusion and then sintering procedure at different peak temperatures. Apparent density, water absorption capability, mechanical strength, porosity and thermal conductivity were determined on sintered specimens and examined in relation to the waste percentage and sintering temperature. The experimental results showed that ceramic production from clay/olive-mill solid waste mixtures is feasible. In fact, the mechanical properties are not significantly impacted with the incorporation of the waste in the ceramic body. However, the thermal conductivity decreases significantly, which can be of particular interest for thermal insulating materials development. Furthermore, the shape of the produced ceramics does not appear to change with the sintering temperature increase.

Co-gasification and co-combustion of industrial solid waste mixtures and their implications on environmental emissions, as an alternative management

The primary sludge produced by the wastewater treatment plant of a pulp and paper mill has high physicochemical heterogeneity, which limits the efficiency of thermochemical methodologies for the final disposal of this residue. As a solution, co-pelletization of the Primary Sludge (PS) with two other principal Industrial Solid Residues (ISRs) of the plant, Coal Boiler Ashes (CBA) and Wood Waste chips (WW), was proposed as a way to valorize the PS for energy use, while reducing dewatering costs. The energy potential was evaluated through a series of thermal co-processing tests of disaggregated and pelletized mixtures. Due to their differing fixed-carbon-to-volatile-material ratios, combining the ISRs resulted in a reduction of up to 45% of the mass of the ISR generated, improving the disposal conditions and achieving a minimum thermal power of 5.0 MJ/Nm3 through gasification. Finally, the environmental implications of the thermal co-processing of the wastes were assessed, finding very low impacts due to pollutant emissions, in accordance with the legal environmental regulations in force in Colombia.

Characterizing the implications of waste dumping surrounding the Yangtze River economic belt in China

China has prohibited an extensive list of solid waste from abroad since 2017. While China seeks to move away from being the world's dumping ground, cleaning up its own backyard is proving to be a great challenge. China’s Yangtze River economic zone, which covers 11 provinces and accounts for 40% of the country's Gross Domestic Product, has been found to be alarmingly polluted: 74 million metric tons of solid wastes, including industrial solid waste, construction debris, municipal solid waste, and hazardous waste, have been disposed of by dumping. In this study, the statistics and spatial patterns of waste dumping were determined and mapped, and then the subsequent environmental impacts on the local and downstream marine ecosystem were evaluated. The results indicated the largest dumped-waste volume was found in Sichuan province (industrial solid waste) and Hubei province (solid waste mixture). The potential environmental impacts aroused by waste dumping in Hubei, Jiangxi and Sichuan provinces were serious, while the impacts in Yunnan and Zhejiang were slight. It is imperative for the Yangtze River Economic Zone to develop stringent measures for curbing the dumping of solid waste, assessing the implications from existing dumping activities, and enhancing the capacity for responsible waste management.

Optimising mixture of agricultural, municipal and industrial solid wastes for the production of alternative fuel

The valorisation of waste is often represented through the form of energy recovery, nutrient reclamation and other by-products. Solid Recovered Fuel (SRF) or Refuse Derived Fuel (RDF) as a solid alternative fuel has shown promising results for waste management and enhancing the energy security. The energy recovered is dependent on the quality of the solid fuel, which is evaluated by several parameters, including the calorific value, the moisture content, the density, the oxygen content and the gas emissions. The parameters varied following different types of wastes, which increase the complexity in producing high quality of solid fuel from a mixture of solid waste. This study aims to compare different mixtures of alternative fuel composed of municipal solid waste (MSW), non-hazardous industrial waste and agricultural waste. The selected wastes have high calorific value (2,601-8,657 cal/g), low moisture content (0.06 - 9.86 %), various density (63 - 910 kg/m 3 ), high carbon (C) of 45 - 67 %, low nitrogen (N) of 0.15 - 2.22 %, low sulphur (S) of 0.01 - 0.80 %, moderate hydrogen (H) of 4.9 - 8.21 % and high oxygen (O) of 25 - 45.5 %. The high C and O content indicated high energy and combustibility, whereas low N and S concentration can reduce the emissions of unwanted gas. The selection of the optimised mixture is based on technical and economic feasibility assessment. The technical score is calculated over seven criteria, including calorific value, moisture content, density, O and gas emissions (COx, NOx, SOx). Based on the assessment on these parameters, the optimum mixture consists of 23.00 % rice straw, 19.52 % wood, 24.58 % plastics, 18.43 % cotton stalks, and 14.47 % used tires. The optimum mix has a calorific value of 5,272 cal/g, density of 311 kg/m 3 , and moisture content of 1.94 %. The analysis demonstrated that mixture with high proportion of plastics, rice, wood and cotton stalk ranked high as preferable alternative fuel. The analysis also showed that the ranking of the alternative fuel decreases following an increase of sludge and olive pomace in the mixture. The proposed selling price of the alternative fuel produced is 135.47 USD/t covering all capital costs and operational and maintenance costs.

Biogas from anaerobic co-digestion of chrome and vegetable tannery solid waste mixture: Influence of the tanning agent and thermal pretreatment

Abstract Mesophilic anaerobic co-digestion of mixtures of solid wastes from tanneries containing chromium and vegetable tannins was investigated in an orthogonal array. The effect of thermal pretreatment on shavings was evaluated as well. The biogas and methane productivity in terms of VSS was assessed. The treatment efficiency was also evaluated in terms of variation of organic and inorganic load. All assays with chromium-containing sludge showed on average 19.6 ml of biogas/gVSS added, 8.15 ml of methane/gVSS added, 4.8% VSS reduction, 60.4% BOD5 reduction, 55% TOC reduction, 67% IC increase and 54.6% TN increase, showing greater mineralization of the residue when compared to the assays with vegetable tannin sludge, which has proven to be toxic. The origin of shavings was not significant in any parameter due to the small proportion of this residue in assays. The thermal pre-treatment was beneficial only for assays with vegetable tannins, since there was evidence that the heating mechanism degraded part of the phenolic organic matter and consequently reduced its toxicity.

Biogas production from tannery solid wastes – Scale-up and cost saving analysis

Abstract This work proposes a laboratory and semi-pilot scales procedure for the evaluation of biogas production potential and waste biodegradation efficiency from mixtures of solid wastes from tanneries as well as the evaluation of the energy saving. Leather shavings and sludge from wastewater treatment plants substrates were considered in the study. A theoretical model was employed for calculations of the disintegration kinetic constant (kdis). Biogas yields between 21 and 30 mL/kgVSS, maximum methane content of 59% v/v, and a TOC reduction between 68 and 76% were obtained on both scales. A linear consistency was found in the assessed scale up and a two-fold biodegradation rate to a five-fold volume of treated waste. In the conditions studied in semi-pilot scale, a midsize tannery could reduce 6.8% of electric and 1.6% of thermal energy consumption besides the great cost saving of disposal of this waste.

Biofuel from Co-pyrolysis of Solid Tire Waste and Rice Husk

Abstract In this study the conversion of solid tire waste and rice husk into biofuels and chemicals by externally heated fixed-bed co-pyrolysis reactor have been taken into consideration. The solid tire waste and rice huskwere characterized through proximate and ultimate analysis, gross calorific values and thermo-gravimetric analysis to investigate their suitability as feedstock for this consideration. The collected solid tire waste chipped and then mixed with rice husk at different blends. The mixtures of solid wastes were fed into the reactor and the products were oil, char and gases. The liquid and char products were collected separately while the gas was flared into the atmosphere. The process conditions were varied by the percentage oftire in the blends at reactor temperature 450 °C. The variation of tire waste in feed blends was found to influence the product yields and feedstock to oil energy conversion efficiency (FOECE) significantly. The maximum liquid yields were 52wt% for50% tire and 50% rice husk blend at reactor temperature 450 °C for zeroN 2 gas flow, feed size 1800-2300 μm for rice husk and 2cm×1cm×1 cm for tire waste and running time 60 min. Liquid products obtained at these conditions were characterized by physical properties, chemical analysis and fractional distillation. The results show that it is possible to obtained liquid products that are comparable to petroleum fuels and valuable chemical feedstock from the selected wastes if the pyrolysis conditions are chosen accordingly.

Solid Waste Mixtures Combustion in a Circulating Fluidized Bed: Emission Properties of NOx, Dioxin, and Heavy Metals

Abstract To efficiently and environment friendly combust the domestic garbage, sludge, and swill waste fuels, five different fuels are prepared by mixing the waste fuels together with coal, and grass biomass at different mixing ratios, and finally those fuels were combusted in a circulating fluidized bed (CFB) reactor. The emission performances of NOx, dioxin, and heavy metal during the combustion tests are studied. The results showed that a stable furnace temperature can be reached at approximately 850 °C when combusting all studied mixed fuels, benefiting the thermal processes of sludge and domestic garbage and thus realizing the purpose of waste-to-fuel. In addition, the dioxin emissions are much lower than the emission standards, and NOx emissions could be reduced significantly by adjusting the ratio of waste fuels. However, the emissions of mercury, lead, and the combinations of chromium, tin, antimony, cupper and manganese components all exceeded the pollution control standard for hazardous wastes incineration, a further technology is required for heavy metal reductions to achieve the emission standards.

Thermodynamic Equilibrium Model Applied To Predict the Fouling Tendency in a Commercial Fluidized-Bed Boiler, Combusting Solid Waste

A thermodynamic equilibrium model, combined with an advanced fuel analysis, was applied to predict the fouling tendency in a commercial bubbling fluidized-bed (BFB) boiler, combusting a mixture of solid waste. In order to enhance the performance of the model, further modifications were made, considering the combustion pattern in the fluidized-bed system and also the temperature profile in the combustion zone. The modeling was performed using Factsage, and experimental data obtained during the full-scale measurements were used as input for the model, simulating the deposit formation in the real boiler. The simulation results were then compared with the results obtained during the full-scale combustion tests to estimate the accuracy and validity of the applied model. The thermodynamic equilibrium modeling proved to be a reliable tool for predicting the fouling in the BFB boiler, thus determining the fraction of the melt in the deposited salts formed on the heat transfer surfaces during the flue gas condensation. The calculations showed that the ratio of the SO2 to alkali chloride concentration in the flue gas was the decisive factor that affected the rate of the deposit formation in the boiler. Both the simulation and the experimental results indicated that lower bed temperatures and cocombustion of P-rich fuels decrease the deposition buildup in the boiler.