Results 1 - 10 of 337
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[en] Soil washing is one of the decontamination techniques to remove radioactive materials from the surrounding soil of nuclear power plants in the soil remediation stage. The nature of this work is repetitive and requires significant resources, and it has uncertainty due to lack of domestic experience. This study suggests the application of a discrete event simulation model to the site remediation work, especially the soil washing process. In this study, we investigated the applicability of a simulation model of soil washing process used in the site remediation project. Although safety against dose exposure is the primary concern in soil remediation, efficient allocation of resources and efficient waste management including volume reduction are also the main objectives in the soil remediation process. These objectives can be achieved by use of logistical simulation model in the planning stage. Detailed input data are required for more accurate and optimized planning, and it is expected to obtain practical operating data through the management of various properties and parameters in the model
[en] Sea level change over the global system has been studied by various observations during the historical period. Sea level rise would be one of the most significant potential impacts of climate change if the current trend of sea level rise (SLR) due to global warming continues to increase for the upcoming decades. The objective was to identify spatial and temporal of radioactive waste facilities that would be affected if sea level rise to happen. Data on contour was obtain from ASTERGDEM NASA, relevant government agency and was also mapped digitally. GIS application is very useful for the radioactive waste sector in planning of facing a geomorphological evolution. (author)
[en] The function of a sewage treatment plant is to treat the sewage to acceptable standards before being discharged into the receiving waters. To design and operate such plants, it is necessary to measure and predict the influent flow rate. In this research, the influent flow rate of a sewage treatment plant (STP) was modelled and predicted by autoregressive integrated moving average (ARIMA), nonlinear autoregressive network (NAR) and support vector machine (SVM) regression time series algorithms. To evaluate the models’ accuracy, the root mean square error (RMSE) and coefficient of determination (R2) were calculated as initial assessment measures, while relative error (RE), peak flow criterion (PFC) and low flow criterion (LFC) were calculated as final evaluation measures to demonstrate the detailed accuracy of the selected models. An integrated model was developed based on the individual models’ prediction ability for low, average and peak flow. An initial assessment of the results showed that the ARIMA model was the least accurate and the NAR model was the most accurate. The RE results also prove that the SVM model’s frequency of errors above 10% or below − 10% was greater than the NAR model’s. The influent was also forecasted up to 44 weeks ahead by both models. The graphical results indicate that the NAR model made better predictions than the SVM model. The final evaluation of NAR and SVM demonstrated that SVM made better predictions at peak flow and NAR fit well for low and average inflow ranges. The integrated model developed includes the NAR model for low and average influent and the SVM model for peak inflow.
[en] Environmental cleanup may involve decontaminating an area affected by a radiological release, containing an oil spill, or remediating a Superfund site or brownfield. It is a key component of how environmental agencies work to protect public health and the environment. There are many publications on technical protocols for cleanup and waste disposal. Additionally, there has been much social science work on the social problems of environmental contamination. However, social science research on cleanup itself has been much more scattered across disciplines and incidents. To date, there has not been a comprehensive review of the social factors that affect cleanup processes and outcomes. Such social factors may include cultural worldviews that shape stakeholder perspectives on ‘how clean is clean’ and social relationships among stakeholders. This article fills this gap by providing an interdisciplinary literature review of the social science of environmental cleanup. Three principal themes emerged from the 97 articles that met selection criteria: effects on cleanup worker health, public engagement and decision-making, and societal benefits of cleaned-up sites. The review points to areas where further research is needed. For example, there is a lack of mixed methods and interdisciplinary engagement within the literature. Additionally, few articles compare cleanup situations. There is also a need for further investigation into specific social science topics such as labor practices, gender, race, and power relationships. To address these gaps, we argue for the development of a comprehensive framework or model as well as the exploration of broader questions complicating cleanups. Overall, this area of research has significant potential to benefit environmental cleanup policy and practice worldwide, while advancing social theory about people and the environment. (topical review)
[en] Different types of NORM residues are generated in many industries and most of them require appropriate management. The paper discusses the classification of the materials, especially the differences between ‘NORM residue’ and ‘NORM waste’ and between relevant management strategies. Several practical examples are also provided. The management of NORM residues may involve immediate removal or alternatively long term storage, prior to reprocessing. The management of NORM waste may involve long term storage prior to disposal. There are three optional strategies for disposal: (i) concentrate and contain, (ii) delay and decay, or (iii) dilute and disperse. Additional information is also provided for the dilute and disperse management option, as in many cases it is selected as the preferred one, both for NORM residues (that are blended with other materials in the process of their use) and for NORM waste (as no radiologically contaminated legacy sites are created after blended material is disposed of in mining voids and landfills). (author)
[en] The main objective of this study was to obtain a conservative forecast of the expected spread of the contamination plume towards the intake of the water supply wellfield. The forecast was made with two assumptions, namely that from 2015, the collection of waste into the storage facilities is stopped and that the interception of contaminated water by drainage wells below the cinder storage dam is also stopped. This conservative approach assumes that the concentration of pollutants in the sources remained at a constant level for the entire forecast period.
[en] Large quantities of construction and demolition (C&D) waste are generated in China every year, but their potential environmental impacts on the surrounding areas are rarely assessed. This study focuses on metals contained in C&D waste, characterizing the metal concentrations and their related environmental risks. C&D waste samples were collected in Shenzhen City, China, from building demolition sites, renovation areas undergoing refurbishment, landfill sites, and recycling companies (all located in Shenzhen city) that produce recycled aggregate, in order to identify pollution levels of the metals As, Cd, Cr, Cu, Pb, Ni, and Zn. The results showed that (1) the metal concentrations in most demolition and renovation waste samples were below the soil environmental quality standard for agricultural purposes (SQ-Agr.) in China; (2) Cd, Cu, and Zn led to relatively higher environmental risks than other metals, especially for Zn (DM5 tile sample, 360 mg/kg; R4 tile sample, 281 mg/kg); (3) non-inert C&D waste such as wall insulation and foamed plastic had high concentrations of As and Cd, so that these materials required special attention for sound waste management; and (4) C&D waste collected from landfill sites had higher concentrations of Cd and Cu than did waste collected from demolition and refurbishment sites.