Waste Disposal In China Research Articles

Research insights of argillaceous-based site for high-level radioactive waste disposal in China

Research insights of argillaceous-based site for high-level radioactive waste disposal in China

Risk assessment and source analysis of trace elements in soils around county landfills in Tibet.

The ecology of the Qinghai‒Tibet Plateau is fragile, and the ecosystems in the region are difficult to remediate once damaged. Currently, landfilling is the mainstay of domestic waste disposal in China, and numerous, widely distributed county landfills exist. trace elements (TEs) in waste are gradually released with waste degradation and cannot be degraded in nature, affecting environmental quality and human health. To reduce the chance bias that exists in studies of individual landfills, we selected 11 representative county landfills in Tibet, total of 76 soil samples were collected, eight TEs (arsenic (As), mercury (Hg), chromium (Cr), copper (Cu), lead (Pb), cadmium (Cd), nickel (Ni), and zinc (Zn)) were determined, and analysed for the current status of pollution, risk to human health, and sources of TEs to explore the impact of the landfills. The results showed that only a few landfills had individual TEs exceeding the risk screening value of the Soil Environmental Quality Risk Control Standard for Soil Contamination (GB 15618-2018) (pH > 7.5). Most of the soils around the landfills had moderate levels of pollution, but some individual landfills had higher levels, mainly due to Cd and Hg concentrations. Source analysis showed that Hg originated mainly from atmospheric transport; the other TEs came mainly from the weathering of soil parent material and bedrock. The potential risk from TEs to human health was low, and the risk to children was greater than the risk to adults. Among the three exposure routes, oral ingestion resulted in the highest carcinogenic risk and noncarcinogenic risk, with a contribution rate of more than 95%. Among the TEs, Ni had the highest carcinogenic risk, followed by Cr and As, and As had the highest noncarcinogenic risk.

New Trends in Pollution Prevention and Control Technology for Healthcare and Medical Waste Disposal in China

This study explores the progression of global healthcare and medical waste (HMW) disposal technologies and emerging practices in China including the COVID-19 pandemic period through patent technology innovation analysis. Trends were identified through both the Derwent Innovation Index database and bibliometric methods. Based on the bibliometric analysis of 4128 patents issued from 2002 to 2021, the development status and research trends of HMW disposal technology were revealed. Regarding patents, China significantly advanced post-2011. However, a large number of applications are filed only in China and are more focused on domestic rather than overseas markets. As the pandemic remains a threat, and increasing amounts of medical waste are generated, new technologies are being sought in China that will be safer for humans and the environment, and will also be in line with the zero waste technology trend. Incineration and waste crushing are core methodologies in medical waste disposal. Future directions pivot towards innovations in large-scale and distributed processing equipment, automation and unmanned systems and high-temperature steam disinfection collaborative disposal methods—including the “High temperature steam–municipal solid waste incineration collaborative technology” and the “High temperature steam–thermal magnetic gasification collaborative technology”. This patent analysis enhances our understanding of the impact of COVID-19 on HMW disposal practices, guiding improved policymaking and research in the HMW sector.

How trade liberalization shapes pro-environmental behavior? An analysis of residents’ waste disposal in China

ABSTRACT With the rapid development of the economy, individuals are gradually raising awareness of the impacts of their daily behaviors on the environment. This paper uses household survey data from China Family Panel Studies to investigate the influence of trade liberalization on Chinese residents’ pro-environmental behaviors. The results first reveal that trade liberalization has a significant positive impact on residents’ pro-environmental behaviors, implying that trade liberalization is conducive to promoting residents’ daily behaviors in a less environmentally harmful manner. Second, the impacts of trade liberalization on residents’ pro-environmental behaviors are heterogeneous depending on regions, household sizes, and household incomes per capita. Third, trade liberalization helps residents form environmentally friendly living habits by the mechanisms of improving income, promoting urbanization, and increasing the government’ss investment in waste disposal. Our study provides insights into regulating residents’ pro-environmental behaviors and improving environmental quality in emerging economies.

Determination of heat transfer representative element volume and three-dimensional thermal conductivity tensor of fractured rock masses

The natural fracture system exerts a significant influence on the physical and mechanical properties of rock masses. The heat transfer in fractured rock masses is much more complicated than that of intact rock due to the thermal contact resistance induced by natural fractures with varying size, aperture, roughness, and orientation. This work describes a method for determining the representative element volume (REV) of heat transfer and the 3D thermal conductivity tensor of fractured rock masses. The method is based on the element-wise averaging of temperature and heat flux, which can be obtained from a finite element solution to a steady state heat transfer problem with specific boundary conditions. A case study was conducted based on the geological data of a potential area for high level radioactive waste disposal in China. The results indicate that the size of heat transfer REV of the rock masses in the study area is approximately 18 m × 18 m × 18 m. 3D thermal conductivity tensor, the magnitudes and directions of the three principal thermal conductivities, and anisotropy of the fractured rock masses were obtained. Influences of main fracture parameters including density, disc diameter, and thermal contact resistance on the heat transfer characteristics were investigated. The research results in this work can provide a better understanding of the discontinuous heat transfer processes in fractured rock masses and their homogenization methods.

Quantifying the effect of socio-economic-geo drivers on the change of municipal waste disposal in China by an integrated TWFE-PRF-SDM methodology

Municipal solid waste management and disposal in China have significantly evolved since 2000. Due to China's vast land area and significant socioeconomic and geographic disparities, nationwide waste management strategies need to be further evaluated. This study quantified the effect of social, economic, and geographic drivers on municipal waste disposal activities in 31 provincial-level administrative regions from 2003 to 2020, by establishing a methodology integrated by two-way fixed effects regression model, panel random forest, and spatial Durbin model. The results showed, in the past two decades, socio-economic-geo indicators significantly co-decided the landfill and incineration activities. In particular, the explanatory ability of GDP per capita was above 45%, while land resources and city size also showed great significance. Spatial autocorrelation analysis showed that the relationship between landfill/incineration rates and socio-economic-geo drivers changed notably from unobvious to significant with economic growth. Furthermore, the local economy and land resources displayed more impact than those of the neighboring regions, while sci-tech and education showed clear spatial spillover effects. Chinese government would carefully assess the full-scale promotion policy of incineration plants, landfill is still hold as a reasonable option for regions with specific socio-economic-geo conditions.

Quantifying the Effect Socio-Economic-Geo Drivers on the Change of Municipal Waste Disposal in China by an Integrated Twfe-Prf-Sdm Methodology

Quantifying the Effect Socio-Economic-Geo Drivers on the Change of Municipal Waste Disposal in China by an Integrated Twfe-Prf-Sdm Methodology

The Study on the Way of Radioactive Waste Disposal in China

The Study on the Way of Radioactive Waste Disposal in China

Thermo-mechanical effect on the anisotropic permeability of a mudstone

Tamusu mudstone is a candidate geological medium for high-level radioactive waste disposal in China. This paper investigates its anisotropic hydraulic properties. Permeability measurements were conducted on two kinds of samples, i.e., along the directions perpendicular and parallel to the beddings, under different stress conditions with heating-cooling cycles (20 → 40→60 → 80→60 → 40→20 °C). The results confirmed the hydraulic anisotropy of Tamusu mudstone. Increasing lithostatic pressure decreases the intrinsic permeability k and hydraulic conductivity K and decreases the hydraulic anisotropy of Tamusu mudstone. The temperature significantly affects the hydraulic properties: the k values exhibit a negative correlation with temperature. A notable variation in parallel hydraulic properties upon temperature elevation indicates that the thermal effect is more crucial in the direction parallel at low lithostatic pressure. A notable effect of thermal paths on the hydraulic properties of Tamusu mudstone was exhibited through the different K or k at the same temperatures before and after heating-cooling cycles.

Health Risk Assessment and Projection of Municipal Solid Waste Disposal in China

Background China’s Municipal solid waste (MSW) is growing rapidly. Incineration and landfill are two main approaches of MSW disposal and both of them emit different types of ambient pollutants and threaten human health. There lacks systematic health risk assessment and projections of MSW incineration and landfill in China. Methods We established the historical MSW incineration and landfill emission inventories from 2015 to 2017 and used the Gaussian Diffusion Model to simulate the spatial distribution of ambient pollutants. We then used Risk Quotients Model to assess the non-carcinogenic and carcinogenic health risks through inhalation exposure. Besides, we set seven possible MSW incineration development scenarios to predict health risk levels in 2035, considering the effect of population growth, incineration rate, waste classification and recycling, and technology progress. Results The results show that non-carcinogenic risk caused by MSW incineration from 2015 to 2017 was lower than landfill at the national level. Both of them were meet the maximum acceptable level (HI ≤ 1). From 2015 to 2017, carcinogenic risks caused by landfill were 9.42 × 10-6, 9.40 × 10-6, 9.37 × 10-6, nine times larger than the maximum acceptable level (CR ≤ 1×10-6). Carcinogenic risks caused by incineration were 5.71 × 10-6, 7.92 × 10-6, 9.44 × 10-6, five to nine times larger than the maximum acceptable level. Projection results show that compared to the baseline scenario, through classification and recycling, changing incinerator furnace, and improving, national health risk levels will be decreased by 24%, 94% and 97%. Conclusions We assessed the health risks caused by MSF disposal and found MSF incineration a relatively low risk alternative disposal approach compared to waste landfill. In the future, local government should reduce MSF disposal health risks by optimizing the selection of incinerators locations, improving the garbage sorting recycling system, and strengthening information disclosure and communications.

Evolutionary Game Analysis of Medical Waste Disposal in China under Different Reward and Penalty Models

Although local governments have issued relevant reward and penalty policies, there are still problems of medical waste disposal in China, particularly in light of the special situation of the COVID-19 pandemic. Furthermore, these problems are generated in the game between local governments and disposal enterprises. Accordingly, based on the evolutionary game theory, this paper establishes and analyzes the game system between local governments and disposal enterprises under four modes: static reward and static penalty, dynamic reward and static penalty, static reward and dynamic penalty, and dynamic reward and dynamic penalty. The theoretical analysis is verified through numerical simulation of a medical waste disposal case in China. The results showed that when local governments choose the static reward and static penalty mode, the game system hardly always has an evolutionary stable state, and the dynamic reward or dynamic penalty mode can make up for the shortcomings of the static reward and static penalty mode. The static reward and dynamic penalty mode is considerably better than the other two dynamic reward and penalty modes, which has the best effect on improving the quality of medical waste disposal. Additionally, if the reward or penalty increases dynamically, local governments tend to implement a “relaxed supervision” strategy, and disposal enterprises will still improve the disposal quality of medical waste. The suggestions proposed based on the research conclusions offer some enlightenment for policymakers to formulate reasonable reward and penalty measures.

Exploration of bacterial communities in products after composting rural wastes with different components: Core microbiome and potential pathogenicity

The co-treatment of solid waste has become a new trend of rural waste disposal in China in the future. However, the quality of compost products after co-treatment remains still ill-defined, especially the characteristics of microbiome related to the environmental safety of organic fertilizer. Here we investigated the composition and structure of bacteria in the composted products with different components based on 16S high-throughput sequencing. The results indicated that the bacterial communities of the products were not explained by the physicochemical proprieties of raw materials and the bacterial community changes in compost products were mainly driven by microorganisms in swine manure, while kitchen waste and rice straw, as composite additive materials, have little effect on the microbial composition of the composted products. A total of 38 OTUs affiliated with 4 phyla (Proteobacteria, Bacteroidetes, Firmicutes and Actinobacteria) were observed in more than 60% compost products, which were considered as core microbiomes. PICRUSt’s prediction of microbial function found that average 8.1% of bacteria in the compost products were associated with human diseases, and 13.27% potential pathogenic bacteria were detected, such as Pseudomonas , Flavobacterium , Clostridium_sensu_stricto_1 , Actinomadura , Corynebacterium_1 and Bacillus , suggesting that existing compost products still posed a risk of disease. The study provides basic data for the profile of core microorganisms and pathogenicity in composting products with different components of rural wastes. • Bacterial communities in composted products with different components was explored. • The bacterial communities of the products were not explained by raw materials. • Core microbiome consisting of 38 OTUs affiliated with 4 phyla were identified. • An average of 8.1% of bacteria in composted products were related to human diseases.

Energetic and financial analysis of solar landfill project: a case study in Qingyuan

Abstract Landfilling is the most commonly used option for waste disposal in China but occupies massive land resources and solar landfills could be a win-win solution by installing photovoltaic (PV) systems on the closed landfills. This paper theoretically studies the feasibility of solar landfills and compares two possible PV technologies, which are polycrystalline silicon (p-Si) and thin film PVs, from the aspects of energy and financial performance. Based on the research, the capacity factors of p-Si and thin film PV are 19.706% and 17.825%, while the conversion efficiency of them are 12.52% and 10.05%, respectively. The financial analysis indicates that the discounted payback period of p-Si PV is 13.42 years while that of thin film PV is 18.56 years. From another aspect, the levelized cost of electricities of p-Si and thin film PV are 0.87 and 0.92 CNY. The conclusion that can be drawn from the above research is that solar landfills are feasible for the case in Qingyuan energetic and financially. Compared with the thin film PV, the p-Si PV is the optimal choice for solar landfills no matter from the aspects of performance or financial consideration.

Experimental Investigation on Drying and Wetting of GMZ Bentonite Using X-Ray Tomography and Volumetric Digital Image Correlation Technique

To investigate the shrinking and swelling properties of Gao-Miao-Zi (GMZ) bentonite, which has been considered as engineering barriers for high-level radioactive nuclear waste disposal in China, drying and wetting tests were carried out. The microstructure of the material at each hydric state was recorded using X-ray tomography (X-CT). The 3D images of the material were analyzed using digital volume correlation (DVC) technique, and the full-field strains at mesoscale (i.e., in the order of clay aggregate) during drying and wetting were quantified. The results show that the GMZ bentonite exhibits notable swelling characteristics during wetting and the swelling strain of the material is up to 8% at mesoscale. The full-field strain in 3D of the material is heterogeneous, anisotropic, and irreversible during drying and wetting. The corresponding deformation mechanisms are discussed. Two different swelling mechanisms were also identified: traction occurs in the interface between the matrix and inclusions during swelling; pre-existing fissure closes during swelling.

Effect of heat exposure on anisotropic mechanical properties of host rock in the Tamusu pre-selected area for high-level radioactive waste disposal in China

As a typical sedimentary rock, clay rock with bedding structure shows clear anisotropy in its mineral composition and mechanical properties. When the clay rock is selected as the host rock for a high-level radioactive waste (HLW) geological repository, its temperature rises because of the continuous release of heat by the HLW. To examine the influence of temperature on the anisotropic mechanical properties of clay rock in the Tamusu pre-selected area for HLW repository in China, a series of direct shear tests in different directions were conducted on the Tamusu clay rock exposed to a range of temperatures. The microstructural characteristics were observed by scanning electron microscopy, and the morphology of the shear failure surfaces was analyzed with the help of 3D laser scanning. The results show that the shear strength parameters of specimens sheared perpendicular to the bedding plane were significantly higher than those of specimens sheared parallel to the bedding plane, and the former specimens exhibited a more rugged failure surface. Strength of both types of specimens increased with the increase in temperature from 30°C to 200°C because of water evaporation and mineral expansion. The mechanical anisotropy was also enhanced by heat exposure. These findings provide key information for the site characterization of the HLW repository, and a reference for the design and construction of underground engineering structures in layered clay rock.

Modeling Damage Evolution in Heterogeneous Granite Using Digital Image-Based Grain-Based Model

A particle-based discrete element model combined with digital image processing to take into account the grain geometry and size distribution is used to investigate the mechanical and microcracking behavior of Beishan granite (BG), a typical crystalline rock potential for nuclear waste disposal in China. First, the procedure to construct a digital image-based grain-based model is introduced. The unsupervised K-means clustering algorithm is used to determine mineral boundaries, and four micro-parameters are assigned according to the Weibull distribution to reflect micro-heterogeneity of rock. Then, the model is calibrated to the macro-properties of BG obtained from laboratory tests, and consistency between model simulation and laboratory test results of both microcracking processes and failure modes is found. It is shown that intragrain cracks are initiated successively in quartz, feldspar, and mica; and their numbers in quartz and feldspar are much more than that in mica. Crack cluster, forking cracks and cataclastic microcracking are typical in quartz, while the “voids” is found in mica. Grain property heterogeneity has a significant impact on micro-cracking behavior and macro-properties of the model, with greater heterogeneity resulting in a lower uniaxial compression strength and elastic modulus, and a more scattered distribution of microcrack inclination. The modeling procedures presented here provide an effective method for investigating mechanical and damage behavior of granites, with specific consideration of heterogeneity involving the distribution of mineral grains and their mechanical properties.

Reduction potential of GHG emissions from municipal solid waste incineration for power generation in Beijing

Abstract With rapid economic growth and massive urbanization, China faces the problem of municipal solid waste (MSW) disposal and the pressing need for development of alternative energy. MSW incineration for power generation is playing an increasingly important role in MSW management in China. In order to study the reduction of GHG emissions caused by MSW incineration for power generation, the GHG emissions under the baseline level is calculated by using Clean Development Mechanism (CDM) methodology. Then, the GHG emission reduction is estimated based on the improved upstream-operation-downstream (UOD) framework. Finally, the GHG emission reduction in Beijing is studied and forecasted through grey prediction model and scenario analysis, and the main factors affecting the reduction potential are identified. The results show that the GHG emission reduction target can be achieved through MSW incineration for power generation. Direct and alternative GHG emissions from MSW incineration are the main sources of emissions, while indirect emissions account for a small proportion. The MSW disposal volume, the moisture content of MSW, the installed capacity of biomass energy, the average line loss of power generation and the quantity of fossil fuels consumed by power generation are five important factors that affecting GHG emission reduction potential. It is recommended that the dominant form of waste disposal in China should be replaced by MSW incineration for power generation, and the full classification of MSW needs to be promoted. Furthermore, the installed capacity of biomass energy should be increased and the average line loss of power generation should be reduced.

Study on Domestic Waste Treatment of Urban Residents in China

With the increase of urban population and the expansion of urban scale in China, the number of domestic waste of urban residents has been increasing year by year. The current main method of domestic waste disposal in China is landfill and incineration power generation. However, compared with foreign countries, there are still many problems in the treatment of municipal solid waste in China. For example, the nature and classification of domestic wastes make it more difficult to dispose of domestic waste, the overall level of municipal solid waste disposal is low, and some foreign waste disposal technologies are implemented in China. supervision and planning of the waste treatment industry in China need to be strengthened, and it is necessary to reduce the amount of household waste, pay attention to the classification of domestic waste, encourage the recycling of domestic waste, increase the use of municipal solid waste, and increase investment in research. The development of technology and the strengthening of the government departments' standard management of waste disposal companies will improve the scientific and resourceful treatment of municipal solid waste.

Spectral Characteristics of Dissolved Organic Matter in Landfill Groundwater

Landfills have been the most common methods of organized waste disposal in China posing an incredible groundwater pollution threat. Dissolved organic matter (DOM) can be used to trace the source, species and migration of contaminants in groundwater, and the investigations of its composition, structure, and distribution play a role in environmental protection. This study investigated the DOM source, composition, and molecular structure in groundwater at landfills for different years of operation, and explored the dynamics of groundwater DOM evolution over time, usingmodern spectroscopy in combination with multivariate statistical analysis. The results showed that DOM in landfill groundwater was initially dominated by outputs from microbial activities, and this was followed by autogenous terrigenous input. In the early stages of landfilling, the DOM of microbial origin was significant; however, towards the late stages of landfilling, the presence of microbial DOM has weakened. The groundwater DOM with short landfill times were mainly composed of newly produced tryptophan and tyrosine, which had low humification, aromaticity, and molecular weight. Microbial activity was strong, and while there were initial, significant differences between sampling points, evidence of its presence could be used for early warning of contamination and monitoring should be conducted for its presence. Microbial activity weakened with longer landfill operation time, landfill waste tended towards stability, and the DOM in groundwater with high humification, aromaticity and molecular weight, was able to reduce the landfill impact on groundwater.

Analysis of Development of Hazardous Waste Disposal Technology in China

With the rapid development of science and technology and economy, the rapid increase of hazardous waste has become the common environmental problems facing the whole world. China is the world’s manufacturing power, with the accelerating process of urbanization, the resulting number of hazardous waste more and more. However, hazardous materials such as toxic, corrosive, flammable, reactive and infectious, and other dangerous characteristics if not properly handled, will cause serious harm to the environment, ecology and human health. Therefore, hazardous waste disposal research has extremely important practical significance. In this paper, the basic summary of hazardous waste, while the status of hazardous waste disposal in China to make an analysis of hazardous waste disposal in China to provide value for reference.