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Swine Wastewater Treatment for Small Farms by a New Anaerobic-Aerobic Biofiltration Technology
2019
Escalante-Estrada, V. E. | Garzón-Zúñiga, M. A. | Valle-Cervantes, S. | Páez-Lerma, J. B.
Effluents form the swine livestock industry contain a high concentration of pollutants and require complex treatment systems. The most recurrent form to treat Swine wastewater is by a conventional anaerobic–aerobic treatment. For example, an up-flow anaerobic blanket sludge reactor followed by an activated sludge reactor. However, in many countries, a high percentage of producers are small or medium-sized farms that can afford neither complex treatment systems nor specialized operations. The present study assessed the performance of a novel and different combinations of treatment processes, based on changing the anaerobic systems that require a specialized operation for one very simple to operate for farm owners. The assessed system is composed by a septic tank in combination with an up-flow anaerobic filter packed with volcanic rocks and an aerobic biofilter packed with waste wood chips. The effect of the hydraulic residence time and the volumetric organic loading in the septic tank and up-flow anaerobic filter and the effect of surface hydraulic loading in the aerobic biofilter were also evaluated. The system efficiently removed chemical oxygen demand (86–93%), total suspended solids (91–97%), volatile suspended solids (86–97%), and ammoniacal nitrogen (86–87%), showing a constant removal efficiency under a VOL of between 5 and 14.6 kg COD m⁻³ d⁻¹in the up-flow anaerobic filter. The advantages of this system are that the packing materials can be available in rural zones and are sustainable; the whole system is cost-effective and easy to handle; thus, farmers can operate and maintain it with their own means.
Afficher plus [+] Moins [-]Heavy metal distribution, translocation, and human health risk assessment in the soil-rice system around Dongting Lake area, China
2019
Tang, Lin | Deng, Sihan | Tan, Di | Long, Jiumei | Lei, Ming
Heavy metals including copper (Cu), zinc (Zn), cadmium (Cd), chromium (Cr), lead (Pb), and arsenic (As) were investigated in 89 pairs of rice plant and paddy soils around Dongting Lake area, China. Rice plants and soils were collected with GPS device, and heavy metal contents in different rice plant tissues and soils were measured. The aim of the present study was to assess the heavy metal pollution and translocation in the whole soil-rice system, including the consequent human health risk for residents. According to the indices of average geoaccumulation (Igₑₒ) of the studied elements, paddy soils in study area were moderately polluted by Cd, lowly polluted by Pb, and not polluted by Cu, Zn, Cr, and As. Considering the much higher concentrations of studied elements in roots than in other tissues of rice plants, a great mass of these elements was assumed to be confined in the roots. The low translocation factors from root to shoot (Tfᵣₒₒₜ₋ₛₕₒₒₜ) of all the studied heavy metals (0.04–0.74) underpinned this. The high translocation factors from soil to root (Tfₛₒᵢₗ₋ᵣₒₒₜ) of Cd (9.12), As (4.38), and Zn (2.05) indicated the high bioavailability of these heavy metals for rice plant. The health risk assessment using target hazard quotients (THQs) model indicated that Cd (5.17 for adults and 4.49 for children respectively) and As (3.61 for adults and 3.14 for children respectively) could cause human health risk both for adults and children. Further, given the rate of individual THQ values exceeding one, Cu might also be considered as a potential human health dangerous element in the study area. It was worth noting that as one of the main pollutants, Pb did not show human health risk through rice grain consumption due to its low Tf values in soil-rice system. However, the risk identification of As using comparisons of measured concentrations with risk screening value in Chinese paddy soil standard (GB15618-2018) was not consistent with the human health risk assessment result. This might indicate that site-specific risk screening values of As in China is in demand.
Afficher plus [+] Moins [-]Treatment of soil washing wastewater via adsorption of lead and zinc using graphene oxide
2019
Futalan, Cybelle M. | Phatai, Piaw | Kim, Jongsik | Maulana, Achmad Yanuar | Yee, Jurng-Jae
In the present work, graphene oxide (GO) was synthesized via the modified Hummers method and utilized in treating real soil washing wastewater via adsorptive removal of lead (Pb) and zinc (Zn). Characterization analysis of GO was performed using X-ray diffraction, Brunauer-Emmett-Teller method, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and zeta potential analysis. The Van’t Hoff, Eyring, and Arrhenius equations were applied to determine the activation and thermodynamic parameters namely activation energy (Eₐ), standard Gibbs energy change (ΔG°), standard enthalpy change (ΔH°), standard entropy change (ΔS°), change in activation Gibbs energy (ΔG#), change in activation enthalpy (ΔH#), and change in activation entropy (ΔS#). Based on the high coefficient of determination values (0.8882 ≥ R² ≥ 0.9094) and low values of SSE (0.0292 ≤ SSE ≤ 0.0511) and ARE (0.8014 ≤ ARE ≤ 0.8822), equilibrium data agreed well with the Freundlich isotherm. The maximum adsorption capacity for Pb(II) and Zn(II) was determined to be 11.57 and 4.65 mg/g, respectively. Kinetic studies revealed that pseudo-second-order equation fitted well with the experimental data, which indicates that chemisorption is the rate-determining step of the adsorption system. Results have shown the possibility of GO as a potential adsorbent material in the treatment of soil washing wastewater.
Afficher plus [+] Moins [-]Identifying the driving forces of CO2 emissions of China’s transport sector from temporal and spatial decomposition perspectives
2019
Zhang, Keyong | Liu, Xianmei | Yao, Jianming
The transport sector is the fourth largest industrial CO₂ emitter in China, next to power sector, iron and steel industries, and nonmetallic mineral product industry, and plays an important role in reducing China’s CO₂ emissions. In this study, a temporal decomposition analysis model, i.e., Logistic Mean Division Index (LMDI), is developed to analyze the influencing factors of CO₂ emissions in China’s transport sector during 2000–2015. Then, a multi-regional spatial decomposition model is employed to identify the key factors to induce the differences in CO₂ emissions of China’s 30 regional transport sectors in 2000, 2005, 2010, and 2015. Based on the empirical results, we find that both in the temporal and spatial perspectives, the main factors that affect CO₂ emissions in the transport sector are the same ones. From the temporal perspective, the income effect is the dominant factor increasing CO₂ emissions of transport sector, while energy intensity effect and transportation structure effect are the key influencing factors that curb the CO₂ emissions of China’s transport sector, during the whole study period. From the spatial perspective, the income effect, energy intensity effect, and transportation structure effect are the key influencing factors that enlarge the gap of CO₂ emissions of various transport sectors in the key study years. More importantly, the less-developed regions and high energy intensity regions (i.e., the lower energy efficiency regions) are identified to have the great potential to reduce CO₂ emissions of transport sector. Therefore, differentiated mitigation measures and interregional collaborations are encouraged to reduce transport sector’s CO₂ emissions in China.
Afficher plus [+] Moins [-]Mapping of Terrestrial Gamma Radiation in Soil Samples at Baghdad Governorate (Karakh Side), Using GIS Technology
2019
Ali Abid Abojassim and Leith Hani Rasheed
The radioactive field is one of the most important areas in human health. It must be studied to see the changes in the doses of human exposure. In this study, 46 soil samples were collected from different locations of Karakh side at Baghdad Governorate. The specific activity of natural radionuclides (terrestrial gamma radiation) 238U, 232Th and 40K for soil samples were measured using gamma-ray spectroscopy with NaI(Tl) ("3×3") detector in low-background. Moreover, ten radiological hazard parameters, which include radium equivalent activity (Raeq), absorbed gamma dose rate (Dγ), external hazard index (Hext), internal hazard index (Hint), representative gamma index (Iγr), annual effective dose equivalent (AEDE) that includes the indoor and outdoor effective dose rate, and ELCR were calculated. It has also used GIS technology for mapping specific activity and radiological radiation parameters for all the samples under study. The results show that, the average value of specific activity of terrestrial gamma radiation 238U, 232Th, 40K, 238U+232Th+40K and 235U were 16.47±0.94 Bq/ kg, 9.72±0.43 Bq/kg, 367.95±11.13 Bq/kg, 394.15±11.90 Bq/kg and 0.76±0.043 Bq/kg respectively. While, the average value of radiological radiation parameters such as Raeq, Hex, Hin, Iγr , Iα, Exposure, Dr, AGED, AEDEindoor, AEDEoutdoor, AEDEtotal, and ELCR in present study were 58.7183±2.017 Bq/kg, 0.1586±0.00546, 0.2032±0.00768, 0.4523±0.0151, 0.08237±0.0046, 3.367±0.113 μR/h, 28.8309±0.968 nGy/h, 207.1078±6.86 mSv/y, 0.1415±0.00475 mSv/y, 0.03541±0.00119 mSv/y, 0.177±0.00594 mSv/y and 0.6192 ±0.0208 respectively. The results indicate that the effective dose from terrestrial gamma radiation is everywhere across the area within the acceptable level, subject to the inherent spatial averaging of the measurements.
Afficher plus [+] Moins [-]Nano-porous Membrane Process for Brackish Groundwater Treatment: Efficiency Analysis Using Response Surface Methodology
2019
Yuzheng Lv, Jihao Zhou, Zhengjun Mai and Jie Liu
Excessively high concentration of inorganic salts in the groundwater is the main threat for residents to drink directly in the remote areas of northwestern China. In this paper, nano-porous membrane process was proposed to removal of diverse ions in such raw water. Through the response surface methodology (RSM), the effects of multiple factors on permeate flux and ion rejection rates were analysed, and the application scope of nanofiltration for various water resource was evaluated. It was found that the factors affecting permeate flux, chloride removal and nitrate removal (response value) followed some typical sequences, and the operating pressure was always the most influential factor. Besides, nanoporous membrane process showed predominant performance in the removal of sulphate, chloride and fluoride; the rejection rates were over 99%, 97% and 95%, respectively, and the produced water could completely satisfy the relevant national standards for drinking water. However, nitrate removal rate was seldom over 80%, and it reduced obviously with the increasing initial concentration of nitrate, thus the nitrate content of raw water should be controlled within 40 mg.L-1.
Afficher plus [+] Moins [-]Antibiotic Resistance of Pseudomonas aeruginosa in Well Waters in Irrigated Zone (Middle Atlas-Morocco)
2019
Fatima Zahra Hafiane, Latifa Tahri, Najia Ameur, Rajaa Rochdi, Karim Arifi and Mohammed Fekhaui
Pseudomonas aeruginosa is a bacteria which can live in freshwater, soil and plants. It is a commensal of the digestive tube, slightly abundant in human body. Its presence in wells water is a result of current anthropogenic activity and pollution loads. It is an important nosocomial pathogenic agent characterized by an intrinsic resistance to multiple antimicrobial agents which can develop high-level multidrug resistance. To assess the contamination of these well waters by this pathogenic germ, two hundred samples were collected for four seasonal campaigns between March 2017 and May 2018 with a rate of forty three (43) samples per season in an irrigated zone. The samples were analysed to identify P. aeruginosa, then the isolated serotypes were determined by slid agglutination test using four pools and 20 monovalent Antisera. The detected P. aeruginosa were tested for susceptibility to 18 antibiotics. A total of (n=85/139) isolated strains were identified as P. aeruginosa representing 61.15 % of prevalence among Pseudomonas spp. Antimicrobial resistance revealed that 68% of them are multidrug resistant, while15.09 % of strains resist at least to 7 antibiotics, 30.19% resist at least to 11 antibiotics, 13.21% resist at least to 12 antibiotics, 5.66% resist at least to 13 antibiotics, and 3.77% resist at least to 14 antibiotics. The high level resistance of P. aeruginosa is observed with piperacillin tazobactam (100/10μg) (84.91%), ciprofloxacin (5μg) (79.25%), imipenem (10μg) and ceftazidime (30μg) (37.58%). The resistance of phenotypes of P. aeruginosa strains allowed to identify (n=20/85) ESBL, (n=31/85) oxacillinase broad spectrum ES-OXA, (n=5/85) phenotype of impermeability to imipenem, (n=12/85) cephalosporinase AMPC, and (n=17/85) wild type. The results showed the high antibiotic resistance levels of P. aeruginosa strains from well water samples against antibiotics. Furthermore, based on the results, these well waters can be a source of P. aeruginosa and human and animal susceptibility to other opportunistic pathogens.
Afficher plus [+] Moins [-]Impact of Land Use Change on Hydrological Response of Krueng Aceh Watershed in Aceh Province, Indonesia
2019
Bos Ariadi Muis
Population growth and improvement in the people’s economy have caused the need for space to grow and have changed land use in the Krueng Aceh watershed. This study on the effect of changes in land use on the Krueng Aceh watershed hydrological response as a step to anticipate water shortage in the future using the geographical information analysis and the river regime coefficient (RRC) method approach. The results of this study revealed that the functional shifts from primary forests to production forests and from brushland to ricefield and settlements increased the RRC value from 14.59 to 56.74 in the last 20 years. The hydrological response showed that 18% of the water had the potential to not infiltrate and become runoff. The effect is a reduction in groundwater supply, flooding in the rainy season, drought in the dry season, and clean water scarcity in the future. The management of the future must be based on one river, one planning, and one management system principle.
Afficher plus [+] Moins [-]Structures and Anaerobic Metabolic Activity of Attached Microbial Communities During Biofilm Formation in Aquaculture Systems
2019
Jialei Li, Zhifei Li, Jun Xie, Guangjun Wang, Kai Zhang, Ermeng Yu, Wangbao Gong and Jingjing Tian
In this study, the structural characteristics of the attached microbial community during biofilm formation and the metabolic requirements under anaerobic conditions were evaluated. In particular, 16S rDNA sequencing technology was used to study the structural changes of the attached microbial community during biofilm formation (day 0, 10, 20, and 30) in an aquaculture system, and Biolog microplate technology was used to study metabolic characteristics under anaerobic conditions during biofilm formation. The AWCD (average well colour development), an indicator of carbon metabolism, of attached microorganisms during biofilm formation under anaerobic conditions differed significantly among time points (P < 0.05), and the carbon source utilization capacity was enhanced. Under anaerobic conditions during biofilm formation, the utilization of amines in six major carbon sources was the highest, followed by polymers, carbohydrates, amino acids, and carboxylic acids, and the utilization of phenols was the lowest. Under anaerobic conditions, the utilization rate by the attached microorganisms during biofilm formation was highest for Tween 40, followed by Tween 80, D-xylose, 4-hydroxybenzoic acid, α-D-glucose-1-phosphate, L-phenylalanine, and phenylethylamine. The 16s rDNA sequencing results showed that the dominant phyla of attached microorganisms during biofilm formation were mainly Proteobacteria, Bacteroidetes, Firmicutes, and Cyanobacteria. On the 10th and 20th days of biofilm formation, attached microorganisms were enriched for Rhodobacter of α-Proteobacteria and Janthinobacterium of β-Proteobacteria, which play important roles in biofilm denitrification. However, on the 30th day, enriched bacteria included the Burkholderiales of β-Proteobacteria, the Xanthomonadaceae and Thermomonas of γ- Proteobacteria, which function in cyanide decomposition.
Afficher plus [+] Moins [-]Environmental Pollution Caused by the Transportation Industry and Influencing Factors of Carbon Emission: A Case Study of Jiangxi Province, China
2019
Yating Huang
With the accelerating industrialization and urbanization in China, the energy consumption of the transportation industry in the country is increasing quickly, and its proportion to the total social energy consumption is significantly growing. The transportation industry is a main source of carbon emission in urban areas. The unreasonable structure of energy consumption, the low proportion of new-energy use, and low energy utilization influence the energy-saving and emission reduction in the transportation industry. Thus, in this work, the influencing factors of transportation-induced carbon emission were estimated to analyze the environmental pollution caused by the transportation industry further. Regression analysis was performed on the environmental pollution caused by the transportation industry and the influencing factors of carbon emission in Jiangxi Province, China. Subsequently, a random STIRPAT model was constructed, and the influencing factors of carbon emission from the transportation industry in Jiangxi Province from 2007 to 2017 were analyzed through the partial least squares (PLS) method. Regression results based on the PLS method were relatively ideal. Increases in gross domestic product per capita, population size, passenger person kilometers, rotation freight transport kilometers, and the number of car ownerships can intensify transportation-induced carbon emission. This emission is increased when transportation energy intensity declines, but can be significantly inhibited by increased energy prices. The conclusions of this study can provide references for the continuous optimization of the energy use structure in the transportation industry, saving of energy resources, reduction of greenhouse gas and pollutant emission, and acceleration of low carbonization in the transportation industry.
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