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Результаты 2441-2450 из 2,511
A comparative study of abiological granular sludge (ABGS) formation in different processes for zinc removal from wastewater Полный текст
2014
Chai, Liyuan | Yan, Xu | Li, Qingzhu | Yang, Bentao | Wang, Qingwei
Abiological granular sludge (ABGS) formation is a potential and facile strategy for improving sludge settling performance during zinc removal from wastewater using chemical precipitation. In this study, the effect of pH, seed dosage, and flocculant dosage on ABGS formation and treated water quality was investigated. Results show that settling velocity of ABGS can reach up to 4.00 cm/s under optimal conditions, e.g., pH of 9.0, zinc oxide (ZnO) seeds dosage of 1.5 g/l, and polyacrylamide (PAM) dosage of 10 mg/l. More importantly, ABGS formation mechanism was investigated in NaOH precipitation process and compared with that in bio-polymer ferric sulfate (BPFS)–NaOH precipitation process regarding their sludge structure and composition. In the NaOH precipitation process, ABGS formation depends on some attractions between particles, such as van der Waals attraction and bridging attraction. However, during the BPFS–NaOH sludge formation process, steric repulsion becomes dominant due to the adsorption of BPFS on ZnO seeds. This repulsion further causes extremely loose structure and poor settling performance of BPFS–NaOH sludge.
Показать больше [+] Меньше [-]Coupling digestion in a pilot-scale UASB reactor and electrochemical oxidation over BDD anode to treat diluted cheese whey Полный текст
2014
Katsoni, Αthanasia | Mantzavinos, Dionissios | Diamadopoulos, Evan
The efficiency of the anaerobic treatment of cheese whey (CW) at mesophilic conditions was investigated. In addition, the applicability of electrochemical oxidation as an advanced post-treatment for the complete removal of chemical oxygen demand (COD) from the anaerobically treated cheese whey was evaluated. The diluted cheese whey, having a pH of 6.5 and a total COD of 6 g/L, was first treated in a 600-L, pilot-scale up-flow anaerobic sludge blanket (UASB) reactor. The UASB process, which was operated for 87 days at mesophilic conditions (32 ± 2 °C) at a hydraulic retention time (HRT) of 3 days, led to a COD removal efficiency between 66 and 97 %, while the particulate matter of the wastewater was effectively removed by entrapment in the sludge blanket of the reactor. When the anaerobic reactor effluent was post-treated over a boron-doped diamond (BDD) anode at 9 and 18 A and in the presence of NaCl as the supporting electrolyte, complete removal of COD was attained after 3–4 h of reaction. During electrochemical experiments, three groups of organochlorinated compounds, namely trihalomethanes (THMs), haloacetonitriles (HANs), and haloketons (HKs), as well as 1,2-dichloroethane (DCA) and chloropicrin were identified as by-products of the process; these, alongside free chlorine, are thought to increase the matrix ecotoxicity to Artemia salina.
Показать больше [+] Меньше [-]Enhancing phytoextraction of Cd by combining poplar (clone “I-214”) with Pseudomonas fluorescens and microbial consortia Полный текст
2014
Cocozza, Claudia | Vitullo, Domenico | Lima, Giuseppe | Maiuro, Lucia | Marchetti, Marco | Tognetti, R.
The plant–microorganism combinations may contribute to the success of phytoextraction of heavy metal-polluted soil. The purpose of this study was to investigate the effects of cadmium (Cd) soil concentration on selected physiological parameters of the poplar clone “I-214” inoculated at root level with a strain (BT4) of Pseudomonas fluorescens and a commercial product based on microbial consortia (Micosat F Fito®). Plants were subjected to Cd treatment of 40 mg kg⁻¹in greenhouse. The effects of plant–microbe interactions, plant growth, leaf physiology, and microbial activity were periodically monitored. Metal concentration and translocation factors in plant tissues proved enhanced Cd uptake in roots of plants inoculated with P. fluorescens and transfer to shoots in plants inoculated with Micosat F Fito®, suggesting a promising strategy for using microbes in support of Cd uptake. Plant–microbe integration increased total removal of Cd, without interfering with plant growth, while improving the photosynthetic capacity. Two major mechanisms of metal phytoextraction inducted by microbial inoculation may be suggested: improved Cd accumulation in roots inoculated with P. fluorescens, implying phytostabilization prospective and high Cd transfer to shoots of inoculated plants, outlining enhanced metal translocation.
Показать больше [+] Меньше [-]Air pollution control equipment selection guide Полный текст
2014
Schifftner, Kenneth C.
This book is a good discussion of various air pollution control equipment. It covers a wide range of equipment and gives a good overview of the principles and applications. Very valuable is the practical experiences that are not commonly available in a typical textbook. The language is easy to understand, especially for those who do not have formal training in air pollution control. It provides hybrid systems such as those applied to biomass gasification, odor control using biological technology, plasma arc waste reduction, and more.
Показать больше [+] Меньше [-]Fourteenth National Congress of the Environmental and Cultural Heritage Chemistry Division, “Chemistry in a Sustainable Society,” held in Rimini (Italy) in June 2013 Полный текст
2014
Bernardi, Elena | Passarini, Fabrizio | Morselli, Luciano
This report briefly presents the aims and the fields of interest of the Environmental and Cultural Heritage Division (Italian Chemical Society) and the issues addressed during its national congress, held in Rimini in June 2013. The broad range of topics raised by different speakers, the variety of affiliations and institutions participating at the conference, the scientific organisations and private companies co-sponsoring the different sessions give a clear picture of the interdisciplinarity which is a hallmark of this division.
Показать больше [+] Меньше [-]Occurrence and fate of four novel brominated flame retardants in wastewater treatment plants Полный текст
2014
Kim, M. P. (Maksim Pavlovich) | Guerra, P. | Alaee, M. | Smyth, S. A.
Four novel brominated flame retardants (NBFRs), i.e., decabromodiphenylethane (DBDPE), 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), pentabromoethylbenzene (PBEB), and hexabromobenzene (HBB) were studied in 377 liquid samples and 288 solid samples collected from 20 wastewater treatment plants. Lagoon, primary, secondary, and advanced treatment processes were included, in order to investigate NBFR occurrence and the effects of WWTP operational conditions on NBFR removal. Median influent and effluent levels were 14 to 3,700 and 1.0 to 180 pg/L respectively, with DBDPE being the highest in both. Overall median removal efficiencies for DBDPE, BTBPE, HBB, and PBEB across all process types were 81 to 93, 76 to 98, 61 to 97, and 54 to 97 %, respectively with advanced treatment processes obtaining the best removals. NBFRs removal was related to retention time, surface loading rate, and biomass concentration. Median NBFR levels in treated biosolids were 80 to 32,000 pg/g, influenced by solids treatment processes.
Показать больше [+] Меньше [-]Elicitors as alternative strategy to pesticides in grapevine? Current knowledge on their mode of action from controlled conditions to vineyard Полный текст
2014
Delaunois, Bertrand | Farace, Giovanni | Jeandet, Philippe | Clément, Christophe | Baillieul, Fabienne | Dorey, Stéphan | Cordelier, Sylvain
Development and optimisation of alternative strategies to reduce the use of classic chemical inputs for protection against diseases in vineyard is becoming a necessity. Among these strategies, one of the most promising consists in the stimulation and/or potentiation of the grapevine defence responses by the means of elicitors. Elicitors are highly diverse molecules both in nature and origins. This review aims at providing an overview of the current knowledge on these molecules and will highlight their potential efficacy from the laboratory in controlled conditions to vineyards. Recent findings and concepts (especially on plant innate immunity) and the new terminology (microbe-associated molecular patterns, effectors, etc.) are also discussed in this context. Other objectives of this review are to highlight the difficulty of transferring elicitors use and results from the controlled conditions to the vineyard, to determine their practical and effective use in viticulture and to propose ideas for improving their efficacy in non-controlled conditions.
Показать больше [+] Меньше [-]H2S photocatalytic oxidation over WO3/TiO 2 Hombikat UV100 Полный текст
2014
Alonso-Tellez, Angela | Robert, Didier | Keller, Valérie | Keller, Nicolas
Hydrogen sulfide (H₂S) is a toxic, corrosive and malodorous compound with damaging effects even when present at a low concentration in air. Consequently, the development of efficient and environmentally friendly remediation technologies as an alternative to conventional techniques is justified for environmental reasons and public concern over human health and well-being. In the context of indoor air quality control, the use of photocatalysis over semi-conductor oxides could be a valuable alternative purification technology due to its wide-ranging effect and its easy way of implementation. The superiority of the TiO₂Hombikat UV100 photocatalyst in comparison with the Aeroxide© TiO₂P25 standard was already apparent in the UV-A photocatalytic oxidation of H₂S. We report here on the first use of WO₃/TiO₂UV100 photocatalysts for this reaction. Associating WO₃to TiO₂UV100 was not beneficial in terms of semiconductor coupling and of charge transfer between both phases. Even if such coupled wide band-gap oxide semi-conductor photocatalysts suffered from on-flow deactivation due to the formation of poisoning sulfates as ultimate reaction products continuously stored at the surface, by contrast, their ability to strongly lower and delay the release of SO₂to the gas phase was very positive for maintaining a weak selectivity into the unwanted SO₂by-product.
Показать больше [+] Меньше [-]Biomass smoke in Burkina Faso: what is the relationship between particulate matter, carbon monoxide, and kitchen characteristics? Полный текст
2014
Yamamoto, S. S. | Louis, V. R. | Sié, A. | Sauerborn, R.
In Burkina Faso where cooking with biomass is very common, little information exists regarding kitchen characteristics and their impact on air pollutant levels. The measurement of air pollutants such as respirable particulate matter (PM₁₀), an important component of biomass smoke that has been linked to adverse health outcomes, can also pose challenges in terms of cost and the type of equipment needed. Carbon monoxide could potentially be a more economical and simpler measure of air pollution. The focus of this study was to first assess the association of kitchen characteristics with measured PM₁₀and CO levels and second, the relationship of PM₁₀with CO concentrations, across these different kitchen characteristics in households in Nouna, Burkina Faso. Twenty-four-hour concentrations of PM₁₀(area) were measured with portable monitors and CO (area and personal) estimated using color dosimeter tubes. Data on kitchen characteristics were collected through surveys. Most households used both wood and charcoal burned in three-stone and charcoal stoves. Mean outdoor kitchen PM₁₀levels were relatively high (774 μg/m³, 95 % CI 329–1,218 μg/m³), but lower than indoor concentrations (Satterthwaite t value, −6.14; p < 0.0001). In multivariable analyses, outdoor kitchens were negatively associated with PM₁₀(OR = 0.06, 95 % CI 0.02–0.16, p value <0.0001) and CO (OR = 0.03, 95 % CI 0.01–0.11, p value <0.0001) concentrations. Strong area PM₁₀and area CO correlations were found with indoor kitchens (Spearman’s r = 0.82, p < 0.0001), indoor stove use (Spearman’s r = 0.82, p < 0.0001), and the presence of a smoker in the household (Spearman’s r = 0.83, p < 0.0001). Weak correlations between area PM₁₀and personal CO levels were observed with three-stone (Spearman’s r = 0.23, p = 0.008) and improved stoves (Spearman’s r = 0.34, p = 0.003). This indicates that the extensive use of biomass fuels and multiple stove types for cooking still produce relatively high levels of exposure, even outdoors, suggesting that both fuel subsidies and stove improvement programs are likely necessary to address this problem. These findings also indicate that area CO color dosimeter tubes could be a useful measure of area PM₁₀concentrations when levels are influenced by strong emission sources or when used in indoors. The weaker correlation observed between area PM₁₀and personal CO levels suggests that area exposures are not as useful as proxies for personal exposures, which can vary widely from those recorded by stationary monitors.
Показать больше [+] Меньше [-]Oxidation of artificial sweetener sucralose by advanced oxidation processes: a review Полный текст
2014
Sharma, Virender K. | Oturan, Mehmet | Kim, Hyunook
Sucralose, a chlorinated carbohydrate, has shown its increased use as an artificial sweetener and persistently exists in wastewater treatment plant effluents and aquatic environment. This paper aims to review possible degradation of sucralose and related carbohydrates by biological, electrochemical, chemical, and advanced oxidation processes. Biodegradation of sucralose in waterworks did not occur significantly. Electrochemical oxidation of carbohydrates may be applied to seek degradation of sucralose. The kinetics of the oxidation of sucralose and the related carbohydrates by different oxidative species is compared. Free chlorine, ozone, and ferrate did not show any potential to degrade sucralose in water. Advanced oxidation processes, generating highly strong oxidizing agent hydroxyl radicals (•OH), have demonstrated effectiveness in transforming sucralose in water. The mechanism of oxidation of sucralose by•OH is briefly discussed.
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