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Potential Alternative Reuse Pathways for Water Treatment Residuals: Remaining Barriers and Questions—a Review
2019
Turner, Tomi | Wheeler, Rebecca | Stone, Adam | Oliver, Ian
Water treatment residuals (WTRs) are by-products of the coagulation and flocculation phase of the drinking water treatment process that is employed in the vast majority of water treatment plants globally. Production of WTRs are liable to increase as clean drinking water becomes a standard resource. One of the largest disposal routes of these WTRs was via landfill, and the related disposal costs are a key driver behind the operational cost of the water treatment process. WTRs have many physical and chemical properties that lend them to potential positive reuse routes. Therefore, a large quantity of literature has been published on alternative reuse strategies. Existing or suggested alternative disposal routes for WTRs can be considered to fall within several categories: use as a pollutant and excess nutrient absorbent in soils and waters, bulk land application to agricultural soils, use in construction materials, and reuse through elemental recovery or as a wastewater coagulant. The main concerns and limitations restricting current and future beneficial uses of WTRs are discussed within. This includes those limitations linked to issues that have received much research attention such as perceived risks of undesirable phosphorous immobilisation and aluminium toxicity in soils, as well as areas that have received little coverage such as implications for terrestrial ecosystems following land application of WTRs.
Afficher plus [+] Moins [-]Photolysis of bis(2-ethylhexyl) phthalate in aqueous solutions at the presence of natural water photoreactive constituents under simulated sunlight irradiation
2019
Yu, Qian | Xiong, Xiyao | He, Jun | Zuo, Yuegang | Chen, Yong | Wang, Chengjun
The photolysis of bis(2-ethylhexyl) phthalate (DEHP) under simulated sunlight in the presence of the natural water photoreactive constituents was investigated. The presence of nitrate or ferric ions facilitated the photodegradation of DEHP via oxidation by generation of •OH. The fulvic acids (FAs), at low concentrations, promoted the photolysis of DEHP via energy transfer from the photoreaction-generated ³FA*. However, the DEHP photolysis was inhibited with high concentrations of FAs since the excess FAs at the surface of solution could act as light screening agents to keep FAs in bulk solution from the light irradiation, further reducing the ³FA* generation. When low concentrations of FAs and chloride ions coexist, the reactive chloride species Cl• and Cl₂•⁻ could generate via energy transfer from ³FA* to chloride ions and react with DEHP to enhance its degradation. Furthermore, the direct and •OH-initiated DEHP photodegraded intermediates and end products were identified by HPLC-MS² and its corresponding photolysis pathways were proposed.
Afficher plus [+] Moins [-]Simultaneous degradation of trichlorfon and removal of Cd(II) by Aspergillus sydowii strain PA F-2
2019
Zhang, Chao | Tao, Yue | Li, Shuangxi | Tian, Jiang | Ke-tan, | Wei, Sijie | Wang, Panpan | Chen, Lanzhou
Co-contamination with heavy metals and pesticides is a severe environmental problem, but little information is available regarding the simultaneous removal of these pollutants. In this study, we showed that Aspergillus sydowii strain PA F-2 isolated from soil contaminated with heavy metal and pesticides can simultaneously degrade trichlorfon (TCF) and adsorb Cd(II) from mineral salt medium. The maximum removal rates for TCF and Cd(II) were 55.52% and 57.90%, respectively, in the treatment containing 100 mg L⁻¹ TCF and 2 mg L⁻¹ Cd(II). As the initial Cd(II) concentration increased (2, 5, and 10 mg L⁻¹), the PA F-2 biomass, TCF degradation rate, and Cd(II) adsorption efficiency decreased, whereas the Cd(II) adsorption capacity by PA F-2 increased. The addition of exogenous glucose and sucrose significantly increased the PA F-2 biomass as well as the removal of TCF and Cd(II). Moreover, the TCF degradation pathway and Cd(II) adsorption mechanism were investigated by gas chromatography–mass spectrometry, scanning electron microscopy, and Fourier transform infrared spectroscopy. These results suggest that PA F-2 has potential applications in the bioremediation of TCF and Cd(II) co-contamination.
Afficher plus [+] Moins [-]Water Quality Assessment and Variation Trends Analysis of the Min River Sea-Entry Section, China
2019
Rao, Qinghua | Qiu, Yu | Li, Jiabing
In order to further understand the status of the water quality of Min River’s sea-entry section, the index systems for water environmental quality assessment was built based on twenty evaluation parameters including dissolved oxygen (DO), permanganate index (CODMₙ), chemical oxygen demand (CODCᵣ), biochemical oxygen demand (BOD₅), ammonia (NH₃-N), total phosphorus (TP), and total nitrogen (TN). Water environmental quality of Min River’s sea-entry section in 2015–2017 was evaluated by utilizing the entire-array-polygon synthesis illustration method, accompanied by the time-dependent trend analysis. The results demonstrated that the water environmental quality of Min River’s sea-entry section was between the levels I and II of the Environmental Quality Standards for Surface Water (EQSSW, GB3838-2002) in 2015–2017, indicating a generally good water quality. The water quality was affected by both natural factors (such as temperature, rainfall, and runoff) and human factors and had a tendency to deteriorate at the duration of 2015–2017. The research results are of great significance for further understanding of the discharge of pollutants from the Min River basin and will be a strong support for the scientific decision-making of marine management in Fujian Province.
Afficher plus [+] Moins [-]New Optical Tools for Water Quality Diagnostics
2019
Varotsos, Costas A. | Krapivin, Vladimir F. | Mkrtchyan, Ferdenant A.
New optical tools are proposed for the real-time diagnosis of water quality without traditional sampling and laboratory physico-chemical analysis. In particular, the optical decision-making system is developed as an operational tool for in-situ assessment of water quality in natural water areas. Specifically, three versions of this system are analyzed using 8-channel and 35-channel photometric devices and a 128-channel spectroelipsometric device. The spectral images obtained from these devices are the basis for the diagnosis of water quality by using new algorithms to detect these spectral images. In more detail, four algorithms are developed to identify optical spectral images of water objects. The effectiveness of these optical tools is demonstrated in experimental water quality control sites in water systems operating under different climatic conditions. Finally, the results for the determination of the various pollutants at the surface of these water bodies are presented.
Afficher plus [+] Moins [-]Concentrations of cadmium and lead, but not zinc, are higher in red fox tissues than in rodents—pollution gradient study in the Małopolska province (Poland)
2019
Ziętara, Joanna | Wierzbowska, Izabela A. | Gdula-Argasińska, Joanna | Gajda, Agnieszka | Laskowski, Ryszard
The main purpose of our research was to assess the chronic exposure of red foxes to Cd, Pb and Zn. We have determined concentrations of these metals in the kidney, liver and muscle of 36 red foxes hunted between December 2002 and March 2003 in differently polluted areas in southern Poland. Tissue concentrations of Pb and Cd in the red foxes significantly co-varied with concentrations of these elements in the soil, and differed between the tissues. We compared concentrations of Pb, Cd, and Zn in red foxes with two rodent species, Apodemus flavicollis and Myodes glareolus, trapped simultaneously in the same area. Concentrations of Pb and Cd appeared significantly higher in the red foxes than in the rodents, but the slopes of the relationship between metal concentrations in tissues and in soil were similar in all species. This indicates that extrapolation from results of monitoring studies conducted on rodents to mammalian carnivores is possible but requires applying an extrapolation factor.
Afficher plus [+] Moins [-]Bioleaching of Heavy Metals from Pig Manure Employing Indigenous Sulfur-Oxidizing Bacteria: Effects of Solid Content
2019
Wei, Xiaocheng | Huang, Wenli | Liu, Dongfang | Liao, Lirui | Wang, Zhendong | Li, Wenjiao
The effects of solid content (10–80 g/L) on the bioleaching of heavy metals (HMs) from pig manure (PM) were investigated using indigenous sulfur-oxidizing bacteria. The results showed that an increase in solid content increased the PM buffering capacity, which slowed the rates of pH reduction, ORP increase, and sulfur oxidation and decreased the solubilization efficiency of HMs from PM. Approximately 75–99% of Cu, 76–99% of Zn, and 55–88% of Mn were leached from PM with solid contents of 10–80 g/L after 28 days of bioleaching. However, the content of HMs in bioleached manure did not meet the requirement for agricultural application when the solid content was ≥ 60 g/L after 28 days of bioleaching. The solubilization of HMs from PM was well-described by a kinetic equation. Regression analysis showed that Cu solubilization was primarily controlled by ORP, and pH seemed to be the sole factor responsible for the solubilization of Zn and Mn. Additionally, nutrient (N, P, K, and organic matter) loss significantly increased when PM solid content decreased from 40 to 20 g/L. Therefore, the recommended solid content for the bioleaching of HMs from PM is 40 g/L.
Afficher plus [+] Moins [-]A web-based GIS system for wildlife species: a case study from Khouzestan Province, Iran
2019
Obeidavi, Zeinab | Rangzan, Kazem | Kabolizade, Mostafa | Mirzaei, Rouhollah
Recent efforts to aggregate, process, and use biodiversity information have appended novel opportunities and challenges for the field, and a rapid increase in studies that integrate and analyze data in the biological-ecological realm. We developed a web-based GIS system for the wildlife of Khouzestan Province that provides potential distribution maps and other spatial and nonspatial data on the wildlife of Khouzestan Province and its protected areas. We used MaxEnt and a fuzzy inference system to model distributions of species. Our application was structured using a client/server architecture, and the database design and construction was carried out using PostgreSQL/PostGIS, and GeoServer to serve maps. The mapping interface was developed using OpenLayers; ASP.NET was selected for designing the user interface. We used qualitative-quantitative methods to develop, design, refine, and finalize our system particularly as regards usability. The design approach resulted in a user-friendly interface that allows both specialists and non-specialists to quickly and efficiently run models to estimate potential distributions of species. Our application highlights what can be accomplished with a biodiversity-oriented web application.
Afficher plus [+] Moins [-]Performance evaluation of a photochemical model using different boundary conditions over the urban and industrialized metropolitan area of Vitória, Brazil
2019
Pedruzzi, Rizzieri | Baek, Bok H. | Henderson, Barron H. | Aravanis, Nikolle | Pinto, Janaina A. | Araujo, Igor B. | Nascimento, Erick G. S. | Reis Junior, Neyval C. | Moreira, Davidson M. | de Almeida Albuquerque, Taciana Toledo
Metropolitan areas may suffer with increase of air pollution due to the growth of urbanization, transportation, and industrial sectors. The Metropolitan Area of Vitória (MAV) in Brazil is facing air pollution problems, especially because of the urbanization of past years and of having many industries inside the metropolitan area. Developing air quality system is crucial to understand the air pollution mechanism over these areas. However, having a good input dataset for applying on photochemical models is hard and requires quite of research. One input file for air quality modeling which can play a key role on results is the lateral boundary conditions (LBC). This study aimed to investigate the influence of LBC over CMAQ simulation for particulate matter and ozone over MAV by applying four different methods as LBC during August 2010. The first scenario (M1) is based on a fixed, time-independent boundary conditions with zero concentrations for all pollutants; the second scenario (M2) used a fixed, time-independent concentration values, with average values from local monitoring stations; the third CMAQ nesting scenario (M3) used the nested boundary conditions varying with time from a previous simulation with CMAQ over a larger modeling domain, centered on MAV; and finally, the fourth GEOS-Chem scenario (M4) used the boundary conditions varying with time from simulations of global model GEOS-Chem. All scenarios runs are based on the same meteorology conditions and pollutant emissions. The air quality simulations were made over a domain 61 × 79 km centered on coordinates − 20.25° S, − 40.28° W with a resolution of 1 km. The results were evaluated with the measured data from the local monitoring stations. Overall, significant differences on concentrations and number of chemical species between the LBC scenarios are shown across all LBC scenarios. The M3 and M4 dynamic LBC scenarios showed the best performances over ozone estimates while M1 and M2 had poor performance. Although no LBC scenarios do not seem to have a great influence on total PM₁₀ and PM₂.₅ concentrations, individual PM₂.₅ species like Na, NO₃⁻, and NH₄⁺concentrations are influenced by the dynamic LBC approach, since those hourly individual PM₂.₅ species from CMAQ nesting approach (M3) and GEOS-Chem model (M4) were used as an input to LBC.
Afficher plus [+] Moins [-]Alterations in transcriptome and antioxidant activity of naturally aged mice exposed to selenium-rich rice
2019
Zeng, Rui | Liang, Yuanke | Farooq, Muhammad Umer | Zhang, Yujie | Ei, Hla Hla | Tang, Zhichen | Zheng, Tengda | Su, Yang | Ye, Xiaoying | Jia, Xiaomei | Zhu, Jianqing
Selenium (Se) is a vital element which leads to strong antioxidation in animals and humans. However, the mechanism underlying natural cereal Se–induced biological changes is not well understood. This study intended to explore the gene differential expression in naturally aged mice exposed to selenium by RNA-Seq technique. A total spectrum of 53 differentially expressed genes was quantified in mice heart tissues treated with Se-rich and general rice. The GO functional annotation of differentially expressed genes disclosed the enrichment of cellular process, ionic binding, biological regulation, and catalytic activity. One hundred twenty-three differential pathways (cardiovascular diseases, immune system, transport and catabolism, longevity regulating, and PI3K-AKT signaling) were identified according to KEGG metabolic terms. Afterwards, the effect of Se-rich rice on the antioxidant activity was assessed. The selenium-rich diet increased the total antioxidant capacity (T-AOC), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) in mice serum and livers while significantly reduces methane dicarboxylic aldehyde (MDA) contents. FOXO1 and FOXO3 genes, which acted as the regulators of apoptosis and the antioxidant enzyme, were significantly enhanced in mice when fed with Se-rich rice. In short, the present findings disclosed the alluring insights of organic and inorganic selenium sources on certain biological processes and antioxidant activity of living bodies. However, long-term trials are still required to draw a definitive conclusion, including risks and benefit analysis for various management strategies.
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