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Vulnerability assessment of areas allocated for municipal solid waste disposal systems: a case study of sanitary landfill and incineration Texte intégral
2019
Ngamsang, Thittaya | Yuttitham, Monthira
This study was conducted to assess the vulnerability of areas allocated for sanitary landfill in Nakhon Ratchasima and for incineration in Phuket, Thailand, and to investigate the factors contributing to their vulnerability. Analysis was conducted to develop a vulnerability index using a composite index approach and the Intergovernmental Panel on Climate Change (IPCC) framework approach, while correlation and t tests were applied to identify the relationships and differences between the two systems. Additionally, vulnerability indices were developed using the IPCC vulnerability definition. The results suggested that the vulnerability of the areas allocated for sanitary landfill and incineration were not significantly different. The factor that had the greatest impact on the vulnerability of the sanitary landfill was nuisance, while sub-component correlation analysis revealed that cadmium in groundwater was significantly negatively correlated with vulnerability (r = − 0.958, p < 0.05). Furthermore, the factor that had the greatest effect on vulnerability from incineration was leachate. Similarly, correlation analysis suggested that the chemical oxygen demand in leachate and solid waste residues was significantly positively correlated with vulnerability (r = 0.981, 0.975 respectively, p < .05). It is hoped that these findings can be used to establish measures for preventing environmental problems, as well as to prioritize and identify issues that need to be resolved urgently, and to help policy makers select appropriate systems for different regions of Thailand.
Afficher plus [+] Moins [-]Identification of intermediates, acute toxicity removal, and kinetics investigation to the Ametryn treatment by direct photolysis (UV254), UV254/H2O2, Fenton, and photo-Fenton processes Texte intégral
2019
de Oliveira, Dirce Martins | Cavalcante, Rodrigo Pereira | da Silva, Lucas de Melo | Sans Moyà, Carme | Esplugas, Santiago | de Oliveira, Silvio Cesar | Junior, Amilcar Machulek
This paper reports the degradation of 10 mg L⁻¹ Ametryn solution with different advanced oxidation processes and by ultraviolet (UV₂₅₄) irradiation alone with the main objective of reducing acute toxicity and increase biodegradability. The investigated factors included Fe²⁺ and H₂O₂ concentrations. The effectiveness of the UV₂₅₄ and UV₂₅₄/H₂O₂ processes were investigated using a low-pressure mercury UV lamp (254 nm). Photo-Fenton process was explored using a blacklight blue lamp (BLB, λ = 365 nm). The UV₂₅₄ irradiation process achieved complete degradation of Ametryn solution after 60 min. The degradation time of Ametryn was greatly improved by the addition of H₂O₂. It is worth pointing out that a high rate of Ametryn removal was attained even at low concentrations of H₂O₂. The kinetic constant of the reaction between Ametryn and HO● for UV₂₅₄/H₂O₂ was 3.53 × 10⁸ L mol⁻¹ s⁻¹. The complete Ametryn degradation by the Fenton and photo-Fenton processes was observed following 10 min of reaction for various combinations of Fe²⁺ and H₂O₂ under investigation. Working with the highest concentration (150 mg L⁻¹ H₂O₂ and 10 mg L⁻¹ Fe²⁺), around 30 and 70% of TOC removal were reached within 120 min of treatment by Fenton and photo-Fenton processes, respectively. Although it did not obtain complete mineralization, the intermediates formed in the degradation processes were hydroxylated and did not promote acute toxicity of Vibrio fischeri. Furthermore, a substantial improvement of biodegradability was obtained for all studied processes.
Afficher plus [+] Moins [-]Response of Water Chemistry and Young-of-Year Brook Trout to Channel and Watershed Liming in Streams Showing Lagging Recovery from Acidic Deposition Texte intégral
2019
Josephson, Daniel C. | Lawrence, Greg B. | George, Scott D. | Siemion, Jason | Baldigo, Barry P. | Kraft, Clifford
Reductions in sulfur emissions have initiated chemical recovery of surface waters impacted by acidic deposition in the Adirondack region of New York State. However, acidified streams remain common in the region, which limits recovery of brook trout (Salvelinus fontinalis) populations. To investigate liming as a method to accelerate recovery of brook trout, the channels of two acidified streams were limed annually from 2012 to 2015, and an entire watershed of a third acidified tributary was limed by helicopter in 2013. Stream flow, water chemistry, and density of young-of-year (YOY) brook trout were measured in limed streams, an untreated acidified stream, and a buffered reference stream. Lime additions increased pH and acid-neutralizing capacity and decreased inorganic monomeric aluminum concentrations to less than 2.0 μmol/L, the minimum concentration at which in situ brook trout mortality has been documented. However, of the two channel-limed streams, only stream T8 showed a significant response (P < 0.01) in YOY density, increasing from a mean of 0.4 fish/m² before liming to 2.7 fish/m² after liming. No YOY brook trout response was observed in the stream within the limed watershed. Groundwater inputs to streams were identified by relative differences in temperature and concentrations of silica and sodium. YOY brook trout densities increased only in the channel-limed stream (T8) with suitable groundwater inputs for fall spawning and a summer nursery. Results suggest that targeted liming of acidified streams with the necessary groundwater habitat could be beneficial in accelerating recovery of brook trout populations.
Afficher plus [+] Moins [-]Urbanized Tributary Causes Loss of Biodiversity in a Neotropical River Segment Texte intégral
2019
da Silva Tronco Johann, Adriana | Mangolin, Loana Priscila | Sanches, Paulo Vanderlei | Sebastién, Nyamien Yahaut | Topan, Dhyego Amilton | Piana, Pitágoras Augusto | Gomes, Benedito Martins
We used the community of benthic macroinvertebrates, alongside physical and chemical characteristics of the water, to verify the influence of an urbanized tributary on a Neotropical river. Specifically, our hypothesis is that urbanized tributaries are potentially able to simplify the biological diversity of the rivers where they flow. The collections were sampled in six sites every 2 weeks from April 2013 to March 2014, using artificial substrates. In conjunction with the benthic macroinvertebrate collections, the temperature, pH, and dissolved oxygen were measured using portable devices, as well as ammonia, total nitrogen, total phosphorus, and biochemical oxygen demand (BOD) in the laboratory. Rainfall values were also obtained. We observed a marked fall in the number of taxa and the values of richness, diversity equitability at the point located below the tributary mouth, with predominance of Chironomidae and Annelida. The high capture rates of a few groups considered tolerant and the high concentrations of total nitrogen, total phosphorus, and BOD confirm the alteration of the quality of the water at the sampling point located below the tributary mouth, leading to a local process of ecological simplification.
Afficher plus [+] Moins [-]Citric Acid Functionalized Bougainvillea spectabilis: a Novel, Sustainable, and Cost-effective Biosorbent for Removal of Heavy Metal (Pb2+) from Waste Water Texte intégral
2019
Nazir, Huma | Salmān, Muḥammad | Athar, Makshoof | Farooq, Umar | Wahab, Abdul | Akram, Momal
With increasing concern related to sustainable chemistry, we investigated the biosorption of Pb²⁺ ions from aqueous medium using an environmental friendly and economic biosorbent Bougainvillea spectabilis (BS). The BS was modified effectively using citric acid by hydrothermal method. The biosorbent(s) was characterized by scanning electron microscope (SEM), energy dispersion X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), and point of zero charge (pHₚzc). Various process parameters including biosorbent dosage, time of contact, temperature, solution pH, and initial Pb²⁺ ions concentration were studied in batch mode. Kinetic modeling was performed to evaluate the kinetic data and results showed that the studied process followed the pseudo second order (PSO) kinetics. Equilibrium modeling was done using famous equilibrium models, i.e., Langmuir, Freundlich, Dubinin-Kaganer-Radushkevish, and Temkin in non-linear fashion to evaluate equilibrium data by varying initial Pb²⁺ ions concentration from 20 to 180 mg/L. Based on RMSE values, Langmuir model fits best. This paper also discusses thermodynamic parameters (i.e., enthalpy, entropy, and free energy) showing that the process was spontaneous and endothermic in nature. In comparison with BS (B. spectabilis), an appreciable increase in uptake capacity of CABS (citric acid modified B. spectabilis) was observed in sequestration of Pb²⁺ ions from aqueous medium showing advantage of citric acid modification making it industrially favorable and socially acceptable biosorbent for efficient removal of lead from water.
Afficher plus [+] Moins [-]Multiple lines of evidence of sediment quality in an urban Marine Protected Area (Xixová-Japuí State Park, SP, Brazil) Texte intégral
2019
Moreira, Lucas Buruaem | de Camargo, Júlia Beatriz Duarte Alves | Belletato Marques, Bruna | Martins, César C. | de Souza Abessa, Denis Moledo
Marine Protected Areas (MPAs) aim to protect habitats, biodiversity, and ecological processes as a conservation tool. These areas have been affected by contamination, which threats the biodiversity and ecological functioning. In this study, we evaluated the sediment quality of Xixová-Japuí State Park (XJSP), an MPA located in an urbanized Bay (Santos, Southeast Brazil) by integrating multiple lines-of-evidence. Six sites were selected within the XJSP and analyzed for sediment chemistry, toxicity, and benthic community descriptors using Sediment Quality Triad approach (SQT). Whole-sediment Toxicity Identification Evaluation (TIE) was employed as a complementary line of evidence to confirm the presence of domestic effluent discharges as a potential stressor. The SQT showed that sediments collected within XJSP are impacted by contaminants, exhibiting chronic toxicity and changes in benthic community. TIE results indicated that trace metals, organic contaminants, and ammonia contributed to the observed effects. Our results also indicate a lack of effectiveness of MPA in protecting the biodiversity due to the contamination sources, which requires efforts to pollution control in order to ensure the environmental conservation and management plan goals.
Afficher plus [+] Moins [-]Photodegradation of 2,4-dichlorophenol and rhodamine B over n-type ZnO/p-type BiFeO3 heterojunctions: detailed reaction pathway and mechanism Texte intégral
2019
Humayun, Muhammad | Zheng, Zhiping | Fu, Qiuyun | Luo, Wei
The development of new technologies for efficient degradation of pollutant has been an increasing demand in the globe due to the serious environmental issues. Herein, we report n-type ZnO/p-type BiFeO₃ composites as highly efficient visible light nanophotocatalysts prepared via a wet chemical solution method. Based on the measurements of •OH-related fluorescence (FL) spectra, photoluminescence (PL) spectra, photoelectrochemical I–V curves, and electrochemical impedance spectra (EIS), it is demonstrated that the photo-induced charge carrier (electron-hole pairs) in the as-prepared n-type ZnO/p-type BiFeO₃ composites with proper amount of the coupled ZnO (10% by mass) exhibits high separation compared with the bare BiFeO₃ (BFO) nanoparticles. This is well responsible for the superior visible light photocatalytic performance of the composites for 2,4-dichlorophenol (2,4-DCP) and rhodamine B (RhB) degradation. It is confirmed by means of scavenger test and liquid chromatography-tandem mass spectrometry (LC/MS) analysis of the intermediate products that •OH is the pre-dominant oxidant involved in the degradation of 2,4-DCP. A detailed reaction pathway for 2,4-dichlorophenol degradation over the amount-optimized ZnO/BFO composite is proposed mainly based on the LC/MS product ions. This work will provide a feasible route to design and develop BFO-based highly efficient visible light–active photocatalysts for environmental purification and could be extended to other visible light–active semiconductor materials.
Afficher plus [+] Moins [-]Dietary exposure and risk assessment of organochlorine pesticide residues in rural communities living within catchment areas of iSimangaliso World Heritage Site, South Africa Texte intégral
2019
Buah-Kwofie, Archibold | Humphries, Marc S. | Pillay, Letitia
Dietary intake of contaminated food is a major route of human exposure to organochlorine pesticides (OCPs). Despite the prevalence of OCP usage in southern Africa for several decades, their impact on socioeconomically vulnerable communities remains largely overlooked. We investigated the accumulation of OCPs in crops commonly cultivated by rural communities surrounding iSimangaliso Wetland Park, South Africa. All samples analysed were found to be contaminated, with total OCP concentrations ranging between 190 and 240 ng g⁻¹ ww. Elevated levels of OCP residues were detected in all products, with the majority of samples exceeding European Commission’s maximum residue limits (MRLs). We combine these results with local OCP fish tissue estimates to assess potential dietary risks. Cumulative risk assessment indicated potential non-cancer risks associated with heptachlor epoxide, while a cancer risk as high as 1 in 10 was found to be associated with aldrin and dieldrin. This far exceeds USEPA guidelines and indicates that OCP residues in crops and fish from the study area pose a high risk to human health. The results of this study call for further attention to be given to the health implications of continued OCP use not only within the study area but also in Southern Africa in general.
Afficher plus [+] Moins [-]An assessment of energy efficiency based on environmental constraints and its influencing factors in China Texte intégral
2019
Chen, Yao | Xu, Jing-ting
The super-efficiency directional distance function (DDF) with data envelopment analysis (DEA) model (SEDDF-DEA) is more facilitative than to increase traditional method as a rise of energy efficiency in China, which is currently important energy development from Asia-pacific region countries. SEDDF-DEA is promoted as sustained total-factor energy efficiency (TFEE), value added outputs, and Malmquist-Luenberger productivity index (MLPI) to otherwise thorny environmental energy productivity problems with environmental constraint to concrete the means of regression model. This paper assesses the energy efficiency under environmental constraints using panel data covering the years of 2000–2015 in China. Considering the environmental constraints, the results showed that the average TFEE of the whole country followed an upward trend after 2006. The average MLPI score for the whole country increased by 10.57% during 2005–2010, which was mainly due to the progress made in developing and applying environmental technologies. The TFEE of the whole nation was promoted by the accumulation of capital stock, while it was suppressed by excessive production in secondary industries and foreign investment. The primary challenge for the northeast of China is to strengthen industrial transformation and upgrade traditional industries, as well as adjusting the economy and energy structure. The eastern and central regions of the country need to exploit clean- or low-energy industry to improve inefficiencies due to excessive consumption. The western region of China needs to implement renewable energy strategies to promote regional development.
Afficher plus [+] Moins [-]Analysis of Changes of Particle Size Distribution and Biological Composition of Flocs in Wastewater During the Growth of Algae Texte intégral
2019
Garbowski, Tomasz | Richter, Dorota | Pietryka, Mirosława
The process of growth of algae can be described using the images from microscopic analysis. The new approach to assessment of the growth dynamics of algae used the data of granulometric composition of liquid medium and the modified Avrami equation relating to the crystallisation process. This paper presents a comparison of both methods (granulometric and microscopic) for the analysis of the dynamics of changes in the growth of algae in wastewater. The experimental set-up consisted of four glass tanks filled with biologically treated sewage, in which algae grew. The cultivation of algae was carried out for 8 weeks. During this period, the granulometric analysis and microscopic observations of sewage were conducted. The study demonstrated that with increase in the size of flocs in treated sewage, biomass of algae was also increased. Therefore, the results obtained with the method of laser diffraction are in agreement with microscopic observation of flocs. Granulometric analysis could be, next to microscopic analysis, a method for the estimation of the dynamics of changes in the growth of algae in sewage. This knowledge will allow to selection of a suitable method of wastewater treatment and algal separation.
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