Waste Treatment Problems Research Articles

Combined preparation and application of geopolymer pavement materials from coal slurry-slag powder-fly ash mining solid waste: A case study

The solid waste treatment problem generated in the process of coal mining has always been an important factor restricting safe and environmentally friendly production, and the coal slurry from the coal mine road surface is a new type of mine solid waste, so it is of great significance to treat and efficiently utilize the coal slurry. Currently, a common method of solid waste utilization is to add modifying reagents to prepare functional materials. Select coal slurry, slag powder and fly ash as raw materials, and sodium sulfate and sodium hydroxide were used as alkali exciters to prepare coal slurry based geopolymer pavement material (CSGPM). Response surface methodology was used to establish regression equations between the design optimization objectives (coagulation time, compressive strength) and the variables (mass fraction, mass ratio of slag powder to fly ash, mass ratio of sodium sulfate to sodium hydroxide). The effects of two-by-two interactions of the factors on the optimization objective were explored, and the use of different raw materials was obtained. Under the optimal proportioning parameters, the coagulation time of CSGPM was 33 min and the compressive strength of 24 h of curing was 11.20 MPa. In addition, the generation mechanism of AFt and C-S-H gel substances inside the specimen was explained with the help of microscopic scanning. CSGPM showed good mechanical properties in both load-bearing numerical simulations and acoustic emission tests. Numerical simulation was used to establish the relationship between the design objective of the roadbed (maximum subsidence of the roadbed after bearing) and the design variable (thickness of CSGPM paving). Comparative analyses yielded an optimal subgrade surface layer design thickness of 5 cm, with a maximum subsidence of 0.0033 m after bearing vehicles. Synchronization of roadbed material and concrete damage in combined specimen acoustic emission tests with uniform load transfer. The final coal mine pavement was successfully paved and the total cost of CSGPMD is 63.2 per cent of C30 concrete. Those results are important for the preparation of new pavement functional materials.

Preparation of MgAl-LDHs loaded with blast furnace slag and its removal of Cu(II) and methylene blue from aqueous solution

ABSTRACT Blast furnace slag (BFS) is a kind of waste produced in industrial production, as well as a valuable secondary resource. In this paper, layered double hydroxides composites (BFS/LDHs) were prepared by aqueous polymerization, with industrial waste BFS as modifier and magnesium nitrate, aluminium nitrate, and urea as raw materials. BFS/LDHs have been characterized by using scanning electron microscopy (SEM), fourier infrared spectrometer (FT IR), x-ray diffraction (XRD), and the specific surface area analyser (BET). The adsorption of BFS/LDHs on Cu (II) and methylene blue (MB) was investigated by batch experiments. The results showed that the adsorption capacity of BFS/LDHs to Cu (II) is stronger than that of MB. What’s more, the solid concentration effect was found in the process of sorption kinetics and sorption isotherms. The sorption kinetics curves of Cu (II) and MB on BFS/LDHs were well fitted by the quasi-second-order kinetics under different adsorbent concentrations. Langmuir and Freundlich sorption isotherm models were used to analyse the adsorption. It showed that the adsorption conforms to Langmuir and Freundlich’s adsorption isotherm models. The BFS/LDHs composites have good recycling availability in this adsorption process of Cu (II) and MB, the removal capacity of which was reduced by 16.1% and 3.8% after being recycled for six times, respectively. More importantly, BFS/LDHs composites are not only expected to become a sewage treatment agent, but also to solve the problem of industrial waste treatment, which is a win–win strategy.

Present situation of comprehensive utilization of coal-based solid waste

At present, the annual discharge of coal-based solid waste in China has exceeded 800 million tons, but the mainstream treatment methods are still simple treatment methods such as goaf backfilling and openpit stacking. The massive stacking of coal-based solid waste is not only a serious waste of resources itself, but also brings a series of problems such as environmental pollution. Under the “Carbon Peak” and “Carbon Neutrality” strategy in China, in order to achieve green and rapid development of the coal industry, it is necessary to solve the problem of coal-based solid waste treatment and achieve green and comprehensive utilization of coal-based solid waste. Taking coal gangue, gasification slag and fly ash as representative coal-based solid waste, the present situation of coal-based solid waste production in China and the basic properties of coal-based solid waste are introduced. The utilization status and application characteristics of coal-based solid waste in cement concrete, roadbed materials, soil improvement and so on are focused on, and the resource utilization potential of coal-based solid waste is analyzed and summarized. Then the application prospect of coal-based solid waste in high-value utilization in the future is analyzed and prospected.

Israel’s largest landfill rehabilitation: creative landscape design as a catalyst for a functioning metropolis

ABSTRACT Urban rehabilitation of brownfields advances cities' resilience and contributes to residents' wellbeing and nature preservation. This article explores the transformation of one such site-Hiriya, once the largest landfill in Israel-into a large metropolitan park. The rebirth of the area, taken to new levels by the design of German landscape architect Peter Latz, combines a regional solution to problems exacerbated by climate change, drainage, and transportation and brings social recovery to neglected neighbourhoods in the southern Tel Aviv metropolis. We argue that the success of Hiriya's transformation was a national-scale event, resulting not only from an evolved Israeli environmental discourse but from parallel processes including a maturing national planning system, a new approach to water and streams, and an overdue national plan for waste treatment problems resulting from threats to vital infrastructures. Using a range of textual and visual documents, the article examines the processes that led to the transformation of Hiriya and looks at how an excellent design turned Hiriya from a brownfield on the outskirts of the cities into a lively, green, functioning space in an urban setting, thereby providing a regional, even a global, model for creating sustainable spaces.

Investigation of sodium bicarbonate media blasting technology for achieving the cleaner production of graphite deposition reactor cleaning process: Process optimization and simulation

The periodic cleaning of silicon nitride residues on the graphite deposition reactor surface is a critical process for producing silicon wafers in the photovoltaic manufacturing industry. A green, non-erosive and sustainable sodium bicarbonate media blasting technology (SBMBT) was investigated in this research, aiming for providing an alternative to the widely-used polluting liquid hydrofluoric acid soaking method in the industry. By comparing the cleaning behavior of different blasting media (sodium bicarbonate, alumina, glass bead and walnut shell) under various blasting angles and pressures, the most appropriate cleaning process parameters (30° and 0.3 MPa) and efficient removal rate (0.085 cm2/s) of SBMBT were determined based on the statistical characterization of surface roughness data. Under the most appropriate cleaning process parameters, the mean value of roughness (Ra = 2.119 μm) and cleanliness of graphite deposition reactor surface that was cleaned by SBMBT could meet industry standards. Based on the stress sample data provided by the six identical simulations on each of the nine parameter combinations, the multiple-impact cleaning mechanism of SBMBT was revealed using the LSTC dynamics (LS-DYNA) particle impact model and a high-speed camera. Based on five sets of the recovery experiments data, the mean value of blasting media recovery rate obtained in the validation of the designed sodium bicarbonate media recovery scheme was 79.98%, and the consistency of the media crystal form before and after recovery was confirmed by PXRD. As the experimental results indicate, SBMBT is a green technology with low damage, no residue, and can effectively alleviate the problem of solid waste treatment, which is worthy of being applied in graphite deposition reactor cleaning processes.

Problems of Food Waste Treatment аnd Ways of Their Resolving

The problem of food waste treatment has attracted serious attention lately, as such wastes are regarded as a source of valuable biological matters. We should consider them as a resource, which can be used in the future to produce forage, fertilizers, etc. The authors carried out investigations aimed at revealing problems of food waste treatment. Analysis of the effective legal acts allows us to draw a conclusion, that the major part of these acts cannot create conditions directed to preferable and priority utilization of food wastes, therefore recommendations aimed at elimination of gaps in the field of waste regulation are advanced. First of all it is necessary to specify available definitions and introduce new ones in the field of food waste management, to ban destruction and burial of food waste, build infrastructure for separate garbage collection with obligatory use of bins for food waste. At the same time it is needed to adopt a law about food-sharing, to insert amendments into the Tax Code of the Russian Federation and to remove from the list of taxation entities food stuffs with expiring BBD in case of their free transfer. These changes could release trade enterprises from taxes and thus motivate companies not to reduce foods to the condition of food waste. Serious attention should be paid to technologies of their utilization and assessment of efficiency of technological solutions on their use in the field of food stuffs management in the Russian Federation in order to decrease amounts of food with expiring BBD and food waste.

S-doped biomass catalyst triggered peroxydisulfate activation for methyl orange degradation

Utilizing biomass as carbon precursor for peroxydisulfate (PDS) catalyst preparation could solve the problem of solid waste and water pollution treatment synergistically. However, the poor activity of pure biomass catalyst (BC) still needs further improvement. In this study, novel S-doped BC (S-BC) was prepared from chitosan (waste from agriculture and food industry) for PDS activation. With S doping, superior conductivity and defect (active sites) degree were achieved in S-BC. About 99.73% removal efficiency of methyl orange (MO) could also be achieved under the conditions of 3 mM PDS, 1.0 g L−1 S-BC, 10 mg L−1 MO, and initial pH of 3. This removal efficiency is higher than that of BC at 58.46%. Density functional theory calculation showed that the S2O82− ions were favorably adsorbed on the S-BC surface due to the negative adsorption energy of −3.048 eV. The O atoms in S–O bond (in S2O82−) could capture electrons from S atoms (in S-BC), leading the favorable breaking of this bond. Thus, resulting in the formation of surface attached radicals, O2·− and 1O2 for MO degradation, rather than SO4−· radicals in solution.

EXAFS investigation of strontium adsorption onto weathered biotite

The efficiency of the sorption of Sr2+ on weathered biotite (WB), a type of clay mineral, was investigated. Removal of Sr2+ and Cs+ is important in the treatment of contaminated water from the 1F accident, which is one of the radionuclide waste treatment problems. We focused on developing an adsorption method for Sr ions using WB, which is abundant in Fukushima. Applying a molten salt treatment, the amount of sorbed Sr2+ simply increased as the added mass ratio of strontium chloride (SrCl2) increased from 1:1, 1:5, and 1:10 for the onefold, fivefold, and tenfold additions of SrCl2, respectively. Then, the crystal structure of WB as an adsorbent was evaluated by x-ray diffraction (XRD) analysis. Thus, it was observed that the WB retained its original crystal structure even after the sorption of Sr2+. Extended x-ray absorption fine structure (EXAFS) analysis was performed to investigate the local sorption structure of Sr2+ in the WB. The results revealed that Sr2+ was preferentially sorbed into the SiO4 and Al2O3 layers when Sr2+ was in the low mass ratio, whereas it was mainly sorbed into the SiO4 layer when the ratio was high.

Medical-Waste Chain: A Medical Waste Collection, Classification and Treatment Management by Blockchain Technology

To prevent the spread of the COVID-19 pandemic, 2019 has seen unprecedented demand for medical equipment and supplies. However, the problem of waste treatment has not yet been given due attention, i.e., the traditional waste treatment process is done independently, and it is not easy to share the necessary information. Especially during the COVID-19 pandemic, the interaction between parties is minimized to limit infections. To evaluate the current system at medical centers, we also refer to the traditional waste treatment processes of four hospitals in Can Tho and Ho Chi Minh cities (Vietnam). Almost all hospitals are handled independently, lacking any interaction between the stakeholders. In this article, we propose a decentralized blockchain-based system for automating waste treatment processes for medical equipment and supplies after usage among the relevant parties, named Medical-Waste Chain. It consists of four components: medical equipment and supplies, waste centers, recycling plants, and sorting factories. Medical-Waste Chain integrates blockchain-based Hyperledger Fabric technology with decentralized storage of medical equipment and supply information, and securely shares related data with stakeholders. We present the system design, along with the interactions among the stakeholders, to ensure the minimization of medical waste generation. We evaluate the performance of the proposed solution using system-wide timing and latency analysis based on the Hyperledger Caliper engine. Our system is developed based on the hybrid-blockchain system, so it is fully scalable for both on-chain and off-chain-based extensions. Moreover, the participants do not need to pay any fees to use and upgrade the system. To encourage future use of Medical-Waste Chain, we also share a proof-of-concept on our Github repository.

Solid municipal waste treatment problems and responsible consumption in a green economy

Improving the life quality of the Russian Federation population is especially relevant in the green economy in general, in the housing and communal utilities sector (further HCUS), in particular, and in the process of solving the problem of solid municipal waste (further SMW) management, in particular. The transition to a green economy is also based on responsible consumer behavior, which is an urgent and difficult task, since the theoretical and methodological basis of research is still being formed here. The purpose of the study is to identify the key problems of SMW circulation and identify the main problems of responsible consumption in the green economy. Research methods: analysis of domestic and foreign authors’ works on the stated problems; surveys of the population and experts; correlation and qualimetric analysis. Issues considered: (1) HCUS, regulatory support for responsible consumption and the problem of SMW circulation in the green economy; (2) the attitude of the population to SMW and the problems of modeling responsible consumption in the green economy. It is revealed that both abroad and in Russia there is a growing attention from the state and society to responsible consumption. It is shown that the majority of respondents noted the high efficiency of the national project "Ecology" activities. It is expected that in the very near future the business will be forced to introduce environmental standards and environmental management, create "clean" technologies, recycle and dispose of waste. The attitude of the population to SMW was studied based on the model of the individual's pro-ecological behavior: (1) identification of the behavior to be changed; (2) study of the main indicators influencing this behavior; (3) development and application of intervention tools to change behavior and reduce environmental impact; (4) evaluation of the results of the intervention. It is revealed that in Russia there is an insufficiently high level of environmental education of the population, which is associated with indicators of quality of life. The most effective ways to stimulate responsible consumption are social marketing activities and the implementation of economic tools to encourage and punish consumers.

Insight into the self-assembly process of bamboo lignin purified by solvent fractionation to form uniform nanospheres with excellent UV resistance

Lignin exhibits some antioxidant and UV protection due to its large number of phenolic hydroxyl and methoxy groups, which can be used in the field of sun protection. However, its complex macromolecular structure, high polydispersity, low solubility and deep coloration limit their development in the sunscreen field. In this work, we purified and separated lignin by solvent fractionation so that its phenolic hydroxyl content could be retained or even increased without modification. Consequently, by controlling environmental factors, lignin rapidly self-assembles into nanospheres without changing its structure, which not only achieves the standard of light-colored lignin but also meets the requirement of high sunscreen performance. It was measured that the lignin nanospheres formed by this method could meet more than 90% of UV blocking, especially for ultraviolet (UVA) fragments, when mixed with commercially available creams. It not only promotes the application of lignin in the field of sun protection, realizes the sustainable development of lignin, but also alleviates the problem of solid waste treatment and disposal.

Pythagorean fuzzy entropy measure-based complex proportional assessment technique for solving multi-criteria healthcare waste treatment problem.

With the increasing risk to human health and environmental issues, the selection of appropriate management and treatment of healthcare waste has become a major problem, especially in developing countries. There are various alternatives to dispose of health care waste. The important is to assess the best alternative among them. The assessment of each alternative should be done based on public health, psychological, economic, environmental, technological, and operational aspect. The selection of the best health care waste treatment (HCWT) alternative is a complicated, multi-criteria decision-making (MCDM) problem involving numerous disparate qualitative and quantitative features. Hence, in this research article, the MCDM method is presented for estimating and choosing the best alternative of HCWT by COPRAS technique in a Pythagorean fuzzy set (PFS). Here, in this paper, first of all, a new entropy measure on PFSs is proposed and its validity is studied. Thereafter, the MCDM technique Complex Proportional Assessment (COPRAS) is discussed in which the criteria weights are assessed by the proposed entropy measure and score function to enhance an efficacy and efficiency of the proposed technique. Furthermore, the above-defined technique is employed to resolve the real-life problem to obtain the best treatment alternative to disposal of the health care waste. Finally, sensitivity analysis is presented to rationale the proposed viewpoint for prioritizing HCWT alternatives.

The Effect of Biogas Purification Process Using Calcium Oxide-Based Sorbents on the Diffusion Flame Combustion Characteristics

Biogas is an alternative energy source that could solve two problems at once, the problem of environmentally friendly energy needs and the problem of waste treatment. One of the sources of biogas is obtained from anaerobic bacterial fermentation of cow dung waste. The biogas fermentation process produces impurities such as carbon dioxide (CO2) as a combustion inhibitor. Carbon dioxide will inhibit the combustion reaction, resulting in incomplete combustion. The biogas purification process is needed to reduce the amount of carbon dioxide in the biogas. The purification process is carried out using an absorbent compound of calcium oxide (CaO) to bind carbon dioxide contained in the biogas. Thus, the purpose of this study was to analyze the effect of the biogas purification process using calcium oxide on the characteristics of the diffusion flame produced by combustion. The research was conducted experimentally using the physicochemical-absorption method of purification by flowing biogas through a purificator device that contained a purification solution. After passing through the purification solution, the biogas was regulated at a fuel flow rate of 3 liters/min and then proceed to the bunsen burner. The results showed that purification affected increasing the characteristics of the diffusion flame combustion due to the reduced amount of carbon dioxide in the biogas. This is indicated by increasing the purification molarity, it also increases the flame speed of combustion and the flame angle, as well as a decrease in the flame height.

Utilization of producing biogas from food waste in anaerob biodegester at thermophilic temperature

The problem of food waste is increasing as food needs increase as a source of human protein. Therefore, biogas conversion can also answer the problem of household food waste treatment. The purpose of this study is to find out the producing of biogas from a mixture of food waste and liquid waste tofu in anaerobic biodegester at thermophylic temperature. The manufacture of biogas in this study using batch feeding, which is a type of digester that replenishes organic matter is done once full and then waited until biogas is produced. The manufacture of biogas is carried out for 5 weeks. The observed parameters are COD, BOD, TS, VS, and the resulting volume of biogas. From the observations obtained that, by varying substrate can decrease COD, BOD, TS, while substrate temperature can increase VS. The volume of biogas produced in the mixture of liquid waste tofu 60% and food waste 30% is 22.600 ml. The results showed that the percentage of substrate from the mixture of food waste with liquid waste tofu had an effect on increasing biogas production.

Intelligent monitoring system for biogas detection based on the Internet of Things: Mohammedia, Morocco city landfill case

Mechanization is a depollution activity, because it provides an energetic and ecological response to the problem of organic waste treatment. Through burning, biogas from mechanization reduces gas pollution from fermentation by a factor of 20. This study aims to better understand the influence of the seasons on the emitted biogas in the landfill of the city Mohammedia. The composition of the biogas that naturally emanates from the landfill has been continuously analyzed by our intelligent system, from different wells drilled in recent and old waste repositories. During the rainy season, the average production of methane, carbon dioxide, and oxygen and nitrogen are currently 56%, 32%, and 1%, respectively, compared to 51%, 31%, and 0.8%, respectively, for old waste. Hazards levels, potential fire, and explosion risks associated with biogas are lower than those of natural gases in most cases. For this reason a system is proposed to measure and monitor the biogas production of the landfill site remotely. Measurement results carried out at various sites of the landfill in the city of Mohammedia by the system show that the biogas contents present dangers and sanitary risks which are of another order.

Synthesis of microcrystalline cellulose from raw feed stock – A Review

Reduction of waste and minimizing the cost of synthesis of products are the most important aspects of research and development in chemical and allied fields. Solid waste treatment is gaining importance due to its effect on the groundwater quality and soil quality. Solid waste can be dealt with by three principles, reduce, recycle and reuse. Reduction of solid waste by dewatering, reuse solid waste and recycling of non putrescible waste can reduce the solid waste treatment and disposal problem significantly. Many products like ethanol, acetic acid, microcrystalline cellulose, citric acid, pectic acids etc can be derived from waste materials. The use of agricultural materials for synthesizing various products is increasing. Microcrystalline cellulose (MCC) is one such product useful in bakery, dairy and beverage industry. It has also found applications in pharmaceutical industry. This product can be derived lignocellulosic biomass. Various treatment technologies can be use for pretreatment of biomass. Selection of raw material for MCC is based on factors such as raw material, composition, availability, toxicity, cost, byproduct generation, socioeconomic aspects. Acid hydrolysis is used for converting cellulose to MCC. This review aims to study various raw materials and methods for obtaining MCC from low cost feed stock.

Continuous Self-Cycling Fermentation Leads to Economical Lycopene Production by Saccharomyces cerevisiae

The economic feasibility and waste treatment problem are challenges to the industrialization of lycopene production from Saccharomyces cerevisiae. In this study, fermentation wastewater, biomass residue, and residual D-galactose are recycled for lycopene production. Results show that when fresh water is totally replaced by wastewater, lycopene titer attains 1.21 ± 0.02 g/L, which is 14.2% higher than the fresh water group (P < 0.05). An 80% replacement ratio of yeast extract by biomass residue causes no significant difference to lycopene production while 100% replacement ratio significantly lowers lycopene titer compared with the yeast extract group. Then, a novel fermentation medium containing wastewater and biomass residue with supplementing 3 g/L yeast extract and D-galactose is used for lycopene production. Lycopene titer increases 22.4% than the traditional fermentation in shake flasks (P < 0.05). Continuous self-cycling strategy using wastewater and biomass residue was tested in shake flasks. The mean lycopene titer of the first five recycles shows no significant difference with the start batch. Scaling up to 70 L fermenter, the mean lycopene titer attains 5.88 ± 0.15 g/L in three recycles, which is 22.25% higher than the start batch (P < 0.05). Economic analysis shows that the lowest unite product cost is achieved when four recycles are accomplished, which is 29.6% lower than the traditional fermentation while the chemical oxygen demand decreases 64.0%. Our study shows that continuous self-cycling fermentation process for lycopene production is feasible for the first time. The comprehensive utilization of wastewater and biomass residue from lycopene production by S. cerevisiae and achievement of high lycopene titer will hopefully accelerate industrialization of microbial production of lycopene.

An eco-friendly novel technique for power generation utilising municipal waste water and sludge recycling

Presently world is in need of more energy and drinking water due to the increase in population, industrialisation and urbanisation. Conventional sources of energy are limited, non-renewable, and health hazardous. There are verities of power plants, like thermal, hydro, wind, etc., running all around the world, however they need large infrastructure, create ecological imbalance and waste a lot of energy in form of heat, sound, etc. The present work aims to combine various power plants in a single unit system, utilising the waste energy loss, resulting augmentation in the efficiency of plant. It reduces the energy losses and provides pure drinking water from the municipal waste water. It solves the problem of solid waste treatment, because the domestic solid waste materials have been utilised to generate valuable products like oil, charcoal etc. along with power. It works continuously throughout the year, reduces infrastructures, as well as economical and eco-friendly too.

An eco-friendly novel technique for power generation utilising municipal waste water and sludge recycling

Presently world is in need of more energy and drinking water due to the increase in population, industrialisation and urbanisation. Conventional sources of energy are limited, non-renewable, and health hazardous. There are verities of power plants, like thermal, hydro, wind, etc., running all around the world, however they need large infrastructure, create ecological imbalance and waste a lot of energy in form of heat, sound, etc. The present work aims to combine various power plants in a single unit system, utilising the waste energy loss, resulting augmentation in the efficiency of plant. It reduces the energy losses and provides pure drinking water from the municipal waste water. It solves the problem of solid waste treatment, because the domestic solid waste materials have been utilised to generate valuable products like oil, charcoal etc. along with power. It works continuously throughout the year, reduces infrastructures, as well as economical and eco-friendly too.

Study on recovery of biogas from mixed biowaste for regional biogasification system

Even in Japan, the energy recovery from a waste became the importance by not only wastetreatment problem but also environmental problem which carbon dioxide (CO2) causes. Theenergy recovery is being measured from organic waste. However, the construction of thedisposing facility does not advance in actually various factors. As the one factor, the property ofa organic waste variously changes by the discharge source such as home, food shop, supermarket, farm, sewage treatment plant, etc., and the energy recovery ratio changes with it. In thisstudy, the biogas generation of the waste which arose actually was obtained experimentally. Inaddition, the following were examined using waste generation in the region and the biogas frombiowaste : Electric power recovery, heat recovery, CO2 emission. In the garbage discharged, thegas generation magnification showed the very high, The gas yields seemed to be very high forbiowastes, since these is originally offered as foods. In case of the livestock manure, the gasyield over about 16 times per manure was obtained. The gas yield is not very dependent on theorganic substance content. This cause the bedding was included in the manure, and it seemed toaffect the organic substance content by the content and type. In case of the sewage sludge, thegas yield of about 3.5 times per sludge was got. As a result of the trial based on the wastegeneration in the region, electric power, heat can be utilized effectively. In addition, that thereduction was also possible on CO2 emission clarified.