RESUMEN
To safely protect workplaces and the workforce during and after the COVID-19 pandemic, a scalable integrated sensing solution is required in order to offer real-time situational awareness and early warnings for decision-makers. However, an information-based solution for industry reopening is ineffective when the necessary operational information is locked up in disparate real-time data silos. There is a lot of ongoing effort to combat the COVID-19 pandemic using different combinations of low-cost, location-based contact tracing, and sensing technologies. These ad hoc Internet of Things (IoT) solutions for COVID-19 were developed using different data models and protocols without an interoperable way to interconnect these heterogeneous systems and exchange data on people and place interactions. This research aims to design and develop an interoperable Internet of COVID-19 Things (IoCT) architecture that is able to exchange, aggregate, and reuse disparate IoT sensor data sources in order for informed decisions to be made after understanding the real-time risks in workplaces based on person-to-place interactions. The IoCT architecture is based on the Sensor Web paradigm that connects various Things, Sensors, and Datastreams with an indoor geospatial data model. This paper presents a study of what, to the best of our knowledge, is the first real-world integrated implementation of the Open Geospatial Consortium (OGC) Sensor Web Enablement (SWE) and IndoorGML standards to calculate the risk of COVID-19 online using a workplace reopening case study. The proposed IoCT offers a new open standard-based information model, architecture, methodologies, and software tools that enable the interoperability of disparate COVID-19 monitoring systems with finer spatial-temporal granularity. A workplace cleaning use case was developed in order to demonstrate the capabilities of this proposed IoCT architecture. The implemented IoCT architecture included proximity-based contact tracing, people density sensors, a COVID-19 risky behavior monitoring system, and the contextual building geospatial data.
Asunto(s)
COVID-19/prevención & control , Restauración y Remediación Ambiental/normas , Internet de las Cosas/normas , Pandemias/prevención & control , Lugar de Trabajo/normas , Conductas de Riesgo para la Salud , Humanos , Estándares de Referencia , Programas Informáticos/normasRESUMEN
Titanate nanomaterials have been outstanding in the removal of emerging contaminants by the photocatalysis process. These photocatalysts, when modified through techniques such as doping with metals, they have advantages over TiO2, especially in the region of visible light. In this work, the photocatalytic performance of four recent reported catalysts, pristine titanate nanowires, cobalt-doped titanate nanowires, iron-doped titanate nanowires and ruthenium-doped titanate nanowires, for the removal of the antidepressant trazodone under visible light radiation was compared. The iron-doped titanate nanowires presented the best catalytic activity by the catalyst surface area. Additionally, thirteen transformation products (TPs) were identified by high-resolution mass spectrometry and, to the best of our knowledge, nine of them have never been described in the literature. It was shown that for each catalyst different TPs were formed with distinct time profiles. Finally, toxicity assessment by computational methods showed that TPs were not readily biodegradable and they presented toxicity to aquatic organisms with mutagenic potential. These findings reinforce the importance of taking into consideration the TPs formed during the removal of pollutants since many of them may be toxic and can be produced during photocatalysis.
Asunto(s)
Contaminantes Ambientales/química , Restauración y Remediación Ambiental/métodos , Nanocables/química , Fotólisis , Titanio/química , Trazodona/química , Antidepresivos de Segunda Generación/química , Antidepresivos de Segunda Generación/efectos de la radiación , Biotransformación , Contaminantes Ambientales/toxicidad , Restauración y Remediación Ambiental/normas , Cinética , Luz , Metales Pesados/química , Mutágenos/toxicidad , Fotólisis/efectos de los fármacos , Fotólisis/efectos de la radiación , Trazodona/efectos de la radiaciónRESUMEN
Polycyclic aromatic hydrocarbons (PAHs) in soil are not only detrimental to environment but also to human health. Double dielectric barrier discharge (DDBD) plasma reactor used for the remediation of pyrene contaminated soil was studied. The performance of DDBD reactor was optimized with influential parameters including applied voltage, type of carrier gas, air feeding rate as well as pyrene initial concentration. The analysis of variance (ANOVA) results showed that input energy had a great effect on pyrene remediation efficiency followed by pyrene initial concentration, while, the effect of air feeding rate was insignificant. More specifically, the remediation efficiency of pyrene under air, nitrogen and argon as carrier gas were approximately 79.7, 40.7 and 38.2% respectively. Pyrene remediation efficiency is favored at high level of applied voltages and low level of pyrene initial concentration (10 mgkg-1) and air feeding rate (0.85 L/min). Moreover, computation of the energy efficiency of the DDBD system disclosed that an optimal applied voltage (35.8 kV) and higher initial pyrene concentration (200 mgkg-1) favored the high energy efficiency. A regression model predicting pyrene remediation under DDBD plasma condition was developed using the data from a face-centered central composite design (FCCD) experiment. Finally, the residual toxicity analysis depicted that the respiratory activity increased more than 21 times (from 0.04 to 0.849 mg O2 g-1) with a pyrene remediation efficiency of 81.1%. The study demonstrated the DDBD plasma technology is a promising method not only for high efficiency of pyrene remediation, but also recovering biological function without changing the physical-chemical properties of soil.
Asunto(s)
Restauración y Remediación Ambiental , Hidrocarburos Policíclicos Aromáticos , Pirenos , Contaminantes del Suelo , Biodegradación Ambiental , Restauración y Remediación Ambiental/instrumentación , Restauración y Remediación Ambiental/normas , Pirenos/metabolismo , Contaminantes del Suelo/metabolismoRESUMEN
Two of the most prevalent Superfund-site contaminants are carcinogenic solvents PCE (perchloroethylene) and TCE (trichloroethylene). Because their cleanup is difficult and costly, remediators have repeatedly falsified site-cleanup data, as Tetra Tech apparently did recently in San Francisco. Especially for difficult-to-remediate toxins, this paper hypothesizes that scientific misrepresentations occur in toxic-site assessments, before remediation even begins. To begin to test this hypothesis, the paper (1) defines scientific-data audits (assessing whether published conclusions contradict source data), (2) performs a preliminary scientific-data audit of toxic-site assessments by consultants Ninyo and Moore for developer Trammell Crow. Trammel Crow wants to build 550 apartments on an unremediated Pasadena, California site - once a premier US Navy weapons-testing/development facility. The paper (3) examines four key Ninyo-and-Moore conclusions, that removing only localized metals-hotspots will (3.1) remediate TCE/PCE; (3.2) leave low levels of them; (3.3) clean the northern half of soil, making it usable for grading, and (3.4) ensure site residents have lifetime cancer risks no greater than 1 in 3,000. The paper (4) shows that source data contradict all four conclusions. After summarizing the benefits of routine, independent, scientific-data audits (RISDA), the paper (5) argues that, if these results are generalizable, RISDA might help prevent questionable toxic-site assessments, especially those of expensive-to-remediate toxins like PCE/TCE.
Asunto(s)
Restauración y Remediación Ambiental/normas , Fraude , Sitios de Residuos Peligrosos/normas , Auditoría Administrativa/organización & administración , Tetracloroetileno/análisis , Tricloroetileno/análisis , California , Humanos , Auditoría Administrativa/normas , Compuestos Orgánicos Volátiles/análisisRESUMEN
Incorporating bioaccessibility into human health risk assessment is recognized as a valid way to reduce the conservative properties of conventional results, where the total concentration of a contaminant analysed by exhaustive chemical extraction is applied. Taking a coke production site in Beijing as an example, a mild chemical extraction technology was employed to profile the bioaccessibility of benzo[a]pyrene (BaP), indeno[1,2,3-cd]pyrene (IcP) and dibenz[ah]anthracene (DBA) in soils. The results that were regressed using two bi-phase desorption models (Karickhoff and Weibull) revealed that the rapid desorption fractions of BaP, IcP and DBA, which are taken for bioaccessible fractions, were basically less than half of the total contents in the soils. Probabilistic analysis (PA) was carried out with pre-set distributions of the exposure parameters to characterize the uncertainty in the assessment. The results incorporating bioaccessibility and PA were several times higher than the generic remediation goals which equal to national screening levels, and orders of magnitude higher than the baselines of the region and nation. The results of the Weibull fit were finally recommended as site-specific remediation goals (SSRGs) (10.59â¯mg/kg, 95.48â¯mg/kg and 9.24â¯mg/kg). Over-remediation was avoided while contributing to considerable economic and environmental benefits.
Asunto(s)
Restauración y Remediación Ambiental/normas , Hidrocarburos Policíclicos Aromáticos , Contaminantes del Suelo , Adulto , Disponibilidad Biológica , Industria Química , Niño , Coque , Ingestión de Alimentos , Humanos , Residuos Industriales , Modelos Estadísticos , Hidrocarburos Policíclicos Aromáticos/química , Hidrocarburos Policíclicos Aromáticos/farmacocinética , Hidrocarburos Policíclicos Aromáticos/normas , Medición de Riesgo , Contaminantes del Suelo/química , Contaminantes del Suelo/farmacocinética , Contaminantes del Suelo/normasRESUMEN
Mineral nutrition of plants greatly depends on both environmental conditions, particularly of soils, and the genetic background of the plant itself. Being sessile, plants adopted a range of strategies for sensing and responding to nutrient availability to optimize development and growth, as well as to protect their metabolisms from heavy metal toxicity. Such mechanisms, together with the soil environment, meaning the soil microorganisms and their interaction with plant roots, have been extensively studied with the goal of exploiting them to reclaim polluted lands; this approach, defined phytoremediation, will be the subject of this review. The main aspects and innovations in this field are considered, in particular with respect to the selection of efficient plant genotypes, the application of improved cultural strategies, and the symbiotic interaction with soil microorganisms, to manage heavy metal polluted soils.
Asunto(s)
Contaminación Ambiental , Metales Pesados , Adaptación Fisiológica , Biodegradación Ambiental , Biotransformación , Restauración y Remediación Ambiental/métodos , Restauración y Remediación Ambiental/normas , Metales Pesados/análisis , Metales Pesados/química , Procesos Fotoquímicos , Plantas/metabolismoRESUMEN
Remediation decisions for contaminated sediment sites are typically based on comparisons of in situ sediment concentrations to preliminary remediation goals (PRGs). Preliminary remediation goals are typically developed for protection of human health and the environment, with consideration of site-specific factors that play an important role in determining the sediment concentrations that are consistent with the human health and environmental protection objectives. Remediation goals are selected from among the PRGs. Sediment remediation goals for 4 common contaminants (PCBs, PAHs, Pb, and Hg) at contaminated sediment sites throughout the United States were compiled to determine significant trends and evaluate causes of those trends. Remediation goals were compiled from Records of Decision (RODs) and 5-year review reports for 77 contaminated sediment sites throughout the continental United States. Remediation goals were developed both as surface-weighted average concentrations (SWACs) and action levels (i.e., not-to-exceed values). One or both may be used to define areas requiring remediation. Remediation goals based on SWACs are typically applied to bioaccumulative chemicals for human health and wildlife receptors, whereas action levels are typically used for chemicals that result in an acute toxicity to small home range, sediment-dwelling biota. The findings from this review of remediation goals indicate that SWACs are an increasingly common approach for developing remediation goals. In addition, the findings from this review indicate that although remediation goals adopted for Pb have become more stringent over time, no trend is evident for PCBs, PAHs, and Hg. Remediation goals for PCBs, PAHs, and Hg vary among a number of factors, such as geography, habitat, human or ecological risks, and other local factors. Integr Environ Assess Manag 2019;15:772-782. © 2019 SETAC.
Asunto(s)
Monitoreo del Ambiente , Restauración y Remediación Ambiental/normas , Sedimentos Geológicos/análisis , Contaminantes Químicos del Agua/análisis , Contaminación Química del Agua/prevención & control , Objetivos , Estados Unidos , Contaminación Química del Agua/análisisRESUMEN
Application of engineered nanomaterials for the treatment of industrial effluents and to deal with recalcitrant pollutants has been noticeably promoted in recent years. Laboratory, pilot and full-scale studies emphasize the potential of this technology to offer promising treatment options to meet the future needs for clean water resources and to comply with stringent environmental regulations. The technology is now in the stage of being transferred to the real applications. Therefore, the assessment of its performance according to sustainability criteria and their incorporation into the decision-making process is a key task to ensure that long term benefits are achieved from the nano-treatment technologies. In this study, the importance of sustainability criteria for the conventional and novel technologies for the treatment of industrial effluents was determined in a general approach assisted by a fuzzy-Delphi method. The criteria were categorized in technical, economic, environmental and social branches and the current situation of the nanotechnology regarding the criteria was critically discussed. The results indicate that the efficiency and safety are the most important parameters to make sustainable choices for the treatment of industrial effluents. Also, in addition to the need for scaling-up the nanotechnology in various stages, the study on their environmental footprint must continue in deeper scales under expected environmental conditions, in particular the synthesis of engineered nanomaterials and the development of reactors with the ability of recovery and reuse the nanomaterials. This paper will aid to select the most sustainable types of nanomaterials for the real applications and to guide the future studies in this field.
Asunto(s)
Restauración y Remediación Ambiental/métodos , Nanotecnología , Aguas Residuales , Purificación del Agua/métodos , Contaminantes Ambientales , Restauración y Remediación Ambiental/normas , Industrias , Nanoestructuras , Nanotecnología/normas , Aguas Residuales/análisis , Purificación del Agua/normasAsunto(s)
Ecosistema , Restauración y Remediación Ambiental/métodos , Restauración y Remediación Ambiental/tendencias , Agricultura Forestal/normas , Agricultura Forestal/tendencias , Árboles , África , Animales , Biodiversidad , Ecología/economía , Ecología/métodos , Ecología/normas , Ecología/tendencias , Restauración y Remediación Ambiental/economía , Restauración y Remediación Ambiental/normas , Agricultura Forestal/economía , Agricultura Forestal/métodos , Bosques , Objetivos , Historia del Siglo XX , América Latina , Filipinas , Especificidad de la Especie , Árboles/clasificación , Árboles/crecimiento & desarrolloRESUMEN
A number of past industrial activities and accidents have resulted in the radioactive contamination of large areas at many sites around the world, giving rise to a need for remediation. According to the International Commission on Radiological Protection (ICRP) and International Atomic Energy Agency (IAEA), such situations should be managed as existing exposure situations (ExESs). Control of exposure to the public in ExESs is based on the application of appropriate reference levels (RLs) for residual doses. The implementation of this potentially fruitful concept for the optimisation of remediation in various regions is hampered by a lack of practical experience and relevant guidance. This paper suggests a generic methodology for the selection of numeric values of relevant RLs both in terms of residual annual effective dose and derived RLs (DRLs) based on an appropriate dose assessment. The value for an RL should be selected in the range of the annual residual effective dose of 1-20 mSv, depending on the prevailing circumstances for the exposure under consideration. Within this range, RL values should be chosen by the following assessment steps: (a) assessment of the projected dose, i.e. the dose to a representative person without remedial actions by means of a realistic model as opposed to a conservative model; (b) modelling of the residual dose to a representative person following application of feasible remedial actions; and (c) selection of an RL value between the projected and residual doses, taking account of the prevailing social and economic conditions. This paper also contains some recommendations for practical implementation of the selected RLs for the optimisation of public protection. The suggested methodology used for the selection of RLs (in terms of dose) and the calculation of DRLs (in terms of activity concentration in food, ambient dose rate, etc) has been illustrated by a retrospective analysis of post-Chernobyl monitoring and modelling data from the Bryansk region, Russia, 2001. From this example, it follows that analysis of real data leads to the selection of an RL from a relatively narrow annual dose range (in this case, about 2-3 mSv), from which relevant DRLs can be calculated and directly used for optimisation of the remediation programme.
Asunto(s)
Restauración y Remediación Ambiental/normas , Dosis de Radiación , Radiometría/métodos , Valores de Referencia , Estudios RetrospectivosRESUMEN
The Beijing Municipal Environmental Protection Bureau (EPB) is considering strengthening the Emission Standard of Air Pollutants for Stationary Gas Turbines, originally published in 2011 (DB11/847-2011), with a focus on reducing nitrogen oxides (NOx) emissions. A feasibility study was conducted to evaluate the current operation of 12 existing combined-cycle gas turbine power plants and the design of two new plants in Beijing and their emission reduction potential, in comparison with a state-of-the-art power plant in California. The study found that best management practices (BMPs) could potentially improve the emission level of the power plants, and should be implemented to minimize emissions under current design characteristics. These BMPs include (1) more frequent tuning of turbine combustors; (2) onsite testing of natural gas characteristics in comparison to turbine manufacturer's specifics and tuning of turbine to natural gas quality; (3) onsite testing of aqueous ammonia to ensure adequate ammonia concentration in the mixed solution, and the purity of the solution; (4) more careful inspection of the heat recovery steam generator (HRSG), and the selective catalytic reduction (SCR) during operation and maintenance; (5) annual testing of the catalyst coupon on the SCR to ensure catalyst effectiveness; and (6) annual ammonia injection grid (AIG) tuning. The study found that without major modification to the plants, improving the management of the Beijing gas turbine power plants may potentially reduce the current hourly average NOx emission level of 5-10 parts per million (ppm; ranges reflects plant variation) by up to 20%. The exact improvement associated with each BMP for each facility requires more detailed analysis, and requires engagement of turbine, HRSG, and SCR manufacturers. This potential improvement is an important factor to consider when strengthening the emission standard. However, note that with the continuous needs of improving air quality within the area, more expensive control measures, such as retrofitting the turbines or the HRSGs, may be considered. IMPLICATIONS: This study analyzed the potential emission reductions associated with implementing the best management practices (BMPs) on the combined cycle and cogeneration power plants in Beijing. It determined that implementing the BMPs could potentially achieve up to 580 metric tonnes, or 0.6%, reductions of all NOx emissions in Beijing. Many other cities in China and Asia battling air quality issues may find the information useful in order to evaluate the emission reduction potential of their own gas turbine power plants.
Asunto(s)
Contaminantes Atmosféricos/análisis , Contaminación del Aire/prevención & control , Restauración y Remediación Ambiental/métodos , Centrales Eléctricas , Contaminación del Aire/análisis , Beijing , California , Monitoreo del Ambiente , Restauración y Remediación Ambiental/normas , Estudios de FactibilidadRESUMEN
A tension arises between society's disposition to protect people at risk from environmental pollution, and an aversion towards the potential harmful side-effects associated with cleanup activities. Here we explore how setting different cleanup standards may influence some of the environmental, social, and economic side-effects of remediation, and how they can be quantified for incorporation into cleanup target setting; these include (1) secondary environmental impacts, assessed by life cycle assessment (LCA); (2) fatalities and injuries, assessed by actuarial risk analysis; and (3) the cost effectiveness of stringent cleanup standards, assessed by the incremental cost-effectiveness ratio (ICER). We argue that only by using optimal cleanup standards that integrate quantified remediation side-effects with health risk assessment (HRA) can the green and sustainable remediation (GSR) movement maximize its potential. Together, the combined approaches may provide a more holistic management of risks for a more sustainable future.
Asunto(s)
Contaminación Ambiental/prevención & control , Restauración y Remediación Ambiental/métodos , Restauración y Remediación Ambiental/normas , Análisis Costo-Beneficio , Restauración y Remediación Ambiental/economía , Humanos , Medición de RiesgoRESUMEN
Green and sustainable remediation (GSR) has become a global trend in the contaminated land remediation field. Growing numbers of countries have adopted GSR procedures published in regulatory and/or technical guidance. China is fast becoming one of the largest remediation markets in the world, and is beginning to engage with GSR. Among other efforts, a taskforce is currently developing the first Chinese technical standard on GSR. This paper presents the context positioning and development of a sustainable remediation assessment indicator set for China. This sustainability indicator set was formed based on existing sustainable remediation guidelines and literature. LCA was used to evaluate environmental impacts, and the results combined with social and economic appraisal via MCA. The indicator set was applied to a remediation 'mega-site' in China. The results showed that compared to excavation and landfill, an alternative treatment strategy of soil washing, thermal desorption and S/S brought about relatively less waste generation, better worker safety, and preferable local impacts, leading to higher scores in the environmental and social-economic domains. However, the social-economic scores were limited by a lack of public engagement. The results of the case study have shown that the indicator set is valid, with lessons learnt and suggestions for improvement discussed.
Asunto(s)
Restauración y Remediación Ambiental/normas , Contaminantes del Suelo/aislamiento & purificación , Suelo/química , China , Conservación de los Recursos NaturalesRESUMEN
The UK Marine Management Organisation (MMO) tasked the Centre for Environment, Fisheries & Aquaculture Science (Cefas) with reviewing the current UK dispersant efficacy testing procedures. The aim was to identify possibilities to increase standardisation, improve health and safety performance and explore harmonisation possibilities with international dispersant efficacy testing procedures. The US EPA 'Baffled Flask Test' (BFT) was adopted, implemented and validated as a new standard method in the UK. The outputs from this study suggest that dispersant efficacy results from the adopted BFT test and the currently used protocol are in a similar range and results presented by the US EPA. As a result, the transition to the adopted BFT test will require minimal changes in the assessment of the results or reporting and increase harmonisation between tests used in the UK and North America.
Asunto(s)
Restauración y Remediación Ambiental/métodos , Contaminación por Petróleo/análisis , Petróleo/análisis , Tensoactivos/química , Contaminantes Químicos del Agua/análisis , Restauración y Remediación Ambiental/normas , Modelos Teóricos , Tensoactivos/normas , Reino UnidoRESUMEN
Hydro-climatic changes and the increasing release of pollutants into rivers by human activities tend to affect the quality of watercourses, to alter aquatic ecosystems and to reduce the amount of useable water. The ecological and chemical states of rivers and their evolution is thus of growing concern. In Europe and Switzerland, water policies are progressively shifting towards a holistic approach of river systems. The European Commission notably established a framework to highlight rivers' ecological deficits and to enhance regional or local water management plans. In Switzerland, a similar framework is currently under development. In this paper, both procedures are compared and implemented in a Swiss catchment dominated by agricultural activities. The aim is to define the challenges that still need to be addressed to assess and sustain river health. The hydromorphological, ecological, and ecotoxicological quality of the river was evaluated. Both frameworks highlighted the fact that no section of the river can currently be classified as being in a good environmental state and that the state deteriorates as tributaries and wastewater discharge flow into the main riverbed. Chemical issues and water quality changes due to hydro-climatic variations and management strategies were also pinpointed. Both frameworks are thus useful tools to survey changes in rivers quality in space and over time. However, challenges remain regarding the appropriate strategies to monitor and analyze chemicals, the definition of target values and conditions, the evaluation and integration of human-induced pressures, and the overall evaluation of the state of a river. The development of integrated indicators or of ecosystem services approaches is considered as a potential solution to explore river health and to define efficient restoration measures by water managers.
Asunto(s)
Monitoreo del Ambiente/legislación & jurisprudencia , Monitoreo del Ambiente/normas , Política Ambiental/legislación & jurisprudencia , Restauración y Remediación Ambiental/legislación & jurisprudencia , Ríos , Contaminantes Químicos del Agua/análisis , Calidad del Agua/normas , Ecología , Restauración y Remediación Ambiental/normas , Europa (Continente) , SuizaRESUMEN
In this study, we evaluated the feasibility of using ferric salts including FeCl3 and Fe(NO3)3 as extracting and oxidizing agents for a soil washing process to remediate Pb-contaminated soils. We treated various Pb minerals including PbO, PbCO3, Pb3(CO3)2(OH)2, PbSO4, PbS, and Pb5(PO4)3(OH) using ferric salts, and compared our results with those obtained using common washing agents of HCl, HNO3, disodium-ethylenediaminetetra-acetic acid (Na2-EDTA), and citric acid. The use of 50 mM Fe(NO3)3 extracted significantly more Pb (above 96% extraction) from Pb minerals except PbSO4 (below 55% extraction) compared to the other washing agents. In contrast, washing processes using FeCl3 and HCl were not effective for extraction from Pb minerals because of PbCl2 precipitation. Yet, the newly formed PbCl2 could be dissolved by subsequent wash with distilled water under acidic conditions. When applying our washing method to remediate field-contaminated soil from a shooting range that had high concentrations of Pb3(CO3)2(OH)2 and PbCO3, we extracted more Pb (approximately 99% extraction) from the soil using 100 mM Fe(NO3)3 than other washing agents at the same process conditions. Our results show that ferric salts can be alternative washing agents for Pb-contaminated soils in view of their extracting and oxidizing abilities.
Asunto(s)
Cloruros/química , Restauración y Remediación Ambiental/métodos , Compuestos Férricos/química , Plomo/aislamiento & purificación , Nitratos/química , Contaminantes del Suelo/aislamiento & purificación , Restauración y Remediación Ambiental/normas , Plomo/química , Oxidantes/química , Contaminantes del Suelo/químicaRESUMEN
Cost-effective and eco-friendly washing agents are in demand for Cd contaminated soils. Here, we used leonardite-derived humic substances to wash different types of Cd-contaminated soils, namely, a silty loam (Soil 1), a silty clay loam (Soil 2), and a sandy loam (Soil 3). Washing conditions were investigated for their effects on Cd removal efficiency. Cadmium removal was enhanced by a high humic substance concentration, long washing time, near neutral pH, and large solution/soil ratio. Based on the tradeoff between efficiency and cost, an optimum working condition was established as follows: humic substance concentration (3150 mg C/L), solution pH (6.0), washing time (2 h) and a washing solution/soil ratio (5). A single washing removed 0.55 mg Cd/kg from Soil 1 (1.33 mg Cd/kg), 2.32 mg Cd/kg from Soil 2 (6.57 mg Cd/kg), and 1.97 mg Cd/kg from Soil 3 (2.63 mg Cd/kg). Cd in effluents was effectively treated by adding a small dose of calcium hydroxide, reducing its concentration below the discharge limit of 0.1 mg/L in China. Being cost-effective and safe, humic substances have a great potential to replace common washing agents for the remediation of Cd-contaminated soils. Besides being environmentally benign, humic substances can improve soil physical, chemical, and biological properties.
Asunto(s)
Cadmio/aislamiento & purificación , Restauración y Remediación Ambiental/métodos , Sustancias Húmicas , Contaminantes del Suelo/aislamiento & purificación , Cadmio/análisis , China , Contaminación Ambiental/prevención & control , Restauración y Remediación Ambiental/normas , Concentración de Iones de Hidrógeno , Contaminantes del Suelo/análisisRESUMEN
To address the issue of membrane fouling by ubiquitous humic substances, a hydrophilic pore-former-blended polyethersulfone UF membrane was successfully synthesized via the phase inversion method. For the first time, extremely high concentrations of polyvinylpyrrolidone (PVP), up to 20 wt%, were tested as the hydrophilic pore-former in order to determine the optimum concentration for humic acid fouling. Intrinsic membrane parameters such as permeability and selectivity were evaluated using a cross-flow UF filtration setup. Interestingly, as little as 1 wt% added PVP can significantly improve membrane permeability. That tiny amount of added PVP increased membrane flux to 1107 L/m2h·bar from zero flux, with over 90% rejection of humic acid. In addition, pure water permeation increased to over 2400 L/m2h·bar without sacrificing humic acid rejection (around 90%) when 10 wt% PVP was added; pure water permeation decreased to around 1000 L/m2h·bar as added PVP was increased to 20 wt%. The order of water flux increased with the amount of added PVP up to 20 wt% during humic acid fouling while maintaining membrane selectivity. However, the membrane with 10 wt% added PVP showed the best fouling resistance in terms of flux recovery ratio (98%), total flux loss, reversible fouling ratio, and irreversible fouling ratio. Therefore, the addition of 10 wt% PVP is recommended considering cleaning efficiency and the moderately high flux during humic acid fouling for field operation in wastewater reclamation and water treatment processes.
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Sustancias Húmicas/análisis , Membranas Artificiales , Ultrafiltración/métodos , Purificación del Agua/métodos , Restauración y Remediación Ambiental/métodos , Restauración y Remediación Ambiental/normas , Interacciones Hidrofóbicas e Hidrofílicas , Permeabilidad , Polímeros , Povidona/química , Sulfonas , Aguas Residuales/químicaRESUMEN
This paper presents the results of implementing an extrajudicial environmental mediation procedure in the socioenvironmental conflict associated with routine operation of the El Cabril Disposal Facility for low- and medium- activity radioactive waste (Spain). We analyse the socio-ethical perspective of this facility's operation with regard to its nearby residents, detailing the structure and development of the environmental mediation procedure through the participation of society and interested parties who are or may become involved in such a conflict. The research, action, and participation method was used to apply the environmental mediation procedure. This experience provides lessons that could help improve decision-making processes in nuclear or radioactive facility decommissioning projects or in environmental remediation projects dealing with ageing facilities or with those in which nuclear or radioactive accidents/incidents may have occurred.