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Yang K.,University of Jinan | Yan L.-G.,University of Jinan | Yan L.-G.,Groundwater Technology | Yang Y.-M.,China Institute of Technology | And 6 more authors.
Separation and Purification Technology | Year: 2014

Phosphate removal is important for the natural water or wastewater treatment, and adsorption is an efficient treatment process. In this study, Mg-Al and Zn-Al layered double hydroxides (LDHs) were synthesized by co-precipitation method at a constant pH of 9-10. The prepared LDHs were characterized by X-ray diffraction (XRD) and BET surface area determination. The XRD patterns showed the characteristic basal reflections of hydrotalcite-like LDH materials. BET surface area of Zn-Al LDH was larger than that of Mg-Al LDH. Adsorption experiments were carried out as a function of LDHs dosage, contact time and initial pH of phosphate solution. The adsorption of phosphate reached equilibrium quickly at about 40 min. The experimental data showed a good compliance with the pseudo-second-order kinetic model. The Freundlich and Langmuir models both described the adsorption isotherm data well (R2 > 0.98). Zeta potential and fourier transform infrared spectroscopy (FTIR) analyses were used to elucidate adsorption mechanisms. The results indicated that phosphate species were adsorbed via electrostatic attraction, ligand exchange and ion exchange. The removal ratio of phosphate onto Zn-Al LDH was higher than Mg-Al LDH and reached 95% respectively, suggesting that Mg-Al and Zn-Al LDHs were excellent adsorbents for phosphorus removal from aqueous solution. © 2014 Elsevier B.V. All rights reserved.

Pang G.,University of Jinan | Pang G.,Groundwater Technology | Xu Z.,University of Jinan | Xu Z.,Shandong Provincial Engineering Technology Research Center for Ecological Carbon Sink and Capture Utilization | And 2 more authors.
Nongye Jixie Xuebao/Transactions of the Chinese Society for Agricultural Machinery | Year: 2017

In order to investigate the impact factors and mechanism of high water use efficiency under water-saving irrigation technology, experiment with two irrigation treatments was carried out in rice field, including flooding irrigation (FI) and non-flooding controlled irrigation (NFI). In the FI rice fields, a depth of 3~5 cm standing water was always maintained after transplantation, except during the drainage period in later tillering and yellow maturity stages. In the NFI rice fields, the pond water was kept between 5 mm and 25 mm during the first 7~8 d after transplantation at the regreening stage. At other stages, irrigation was applied only to keep the soil moist and flooding was avoided; standing water up to 5 cm depth in NFI fields was maintained for less than 5 d just to meet the requirements for the pesticide or fertilizer application. The relationships between stomatal regulation, environmental factors and leaf water use efficiency were studied, meanwhile, the regression equations of leaf water use efficiency were established, and the path analysis method was applied to analyze the impact factors. The results showed that there was a quadratic regression equation between stomatal conductance (Gs) and transpiration rate (Tr), photosynthetic rate (Pn), leaf water use efficiency (LWUE) under NFI treatment, to maintain high LWUE, optimal stomatal conductance was 0.54 mol/(m2·s), and the peak value was appeared earlier than that of FI treatment. There was also a quadratic regression equation between LWUE and environmental factors, including air temperature (Ta), leaf temperature (Tl), leaf-air temperature difference (ΔT), air CO2 concentration (Ca) and photosynthesis available radiation (Par). While LWUE was negatively related to intercellular CO2 concentration (Ci) and positively correlated with soil moisture (θ), the relationship between LWUE and relative humidity (Rh) was exponential. The temperature factors composed of Ta, Tl and ΔT contributed 39.19% to LWUE, while the CO2 concentration factors composed of Ca and Ci contributed 17.81%, the vapor factor composed of Rh and θ contributed 17.81%, and the light factor composed of Par contributed 9.01%. Furthermore, the regression equation of LWUE was established, and the path analysis method was applied to analyze the impact factors, as for the NFI treatment, it was found that Par, Gs and θ may not be the main influence factors, the sensitive indicators affecting the LWUE were Ci, Tl and Rh. © 2017, Chinese Society of Agricultural Machinery. All right reserved.

Wang Y.S.,University of Jinan | Wang Y.S.,Groundwater Technology | Xu Z.H.,University of Jinan
Applied Mechanics and Materials | Year: 2014

The stable isotope compositions of soil water from the profiles at Jinan southern mountain reveal information about the mechanism of soil movement. The stable isotopes in soil water have a wide range from -8.92‰ to -5.95‰ forδ 18O and -50.01‰ to -79.44‰ forδD. The mean isotope values is -7.75‰ forδ 18O and 65.84‰ forδD. The low-δD of shallow (<5cm) soil water is due to the precipitation infiltration. And deep soil water (>5cm) is enrichment, which indicates the soil water is evaporated before recharging. The stable oxygen and hydrogen isotope are plotted near the meteoric water line. The trend line for the relationship between δ18O and δD of soil water is given. © (2014) Trans Tech Publications, Switzerland.

Hao Y.-F.,University of Jinan | Yan L.-G.,University of Jinan | Yan L.-G.,Groundwater Technology | Yu H.-Q.,University of Jinan | And 4 more authors.
Journal of Molecular Liquids | Year: 2014

Hydroxy-aluminum pillared bentonite (Al-Bent) was prepared and characterized in this work, and its dye adsorption capacity was comparatively studied in batch experiments. Results of characterization revealed that because of the intercalation of hydroxy-aluminum polyoxycations, a significant increase of interlayer basal spacing, BET surface area and total pore volume was beneficial to dyes' adsorption. The sodium bentonite had a higher adsorption affinity for Basic Fuchsin (BF) and Basic Green (BG) than Acid Turquoise Blue A (ATBA). After pillaring, the adsorption capacity of the three dyes increased and the rise of pH changed insignificantly with solution from 2 to 8. The pseudo-second-order kinetic model provided the best correlation of the experimental data (R2> 0.99). Henry and Freundlich models both described the adsorption isotherm data well. The adsorption capacity of Al-Bent for the three dyes, especially the basic dyes BF and BG, was high over a wide range of aqueous concentrations and followed the order of BG > BF > ATBA. © 2014 Published by Elsevier B.V.

Oliveira V.,Rua Bage | Makeschin F.,Groundwater Technology | Sano E.,Embrapa Cerrados | Lorz C.,Weihenstephan-Triesdorf University of Applied Sciences
Environmental Earth Sciences | Year: 2014

The extent of degraded areas in Brazil, mostly caused by human activities, is increasing. Degradation leads frequently to bare soils, which, due to lack of vegetation cover, are liable to erosion and, therefore, might be the main source of sediments. The objective of this study is to analyze the physical and chemical soil properties of a degraded site (bare soil) in the Federal District of Brazil, which is located in the Cerrado biome, one of the global frontiers for agricultural expansion and urbanization as well as a major global biodiversity ‘hotspot’. Soil samples from degraded and reference sites were collected in this area and analyzed. The results of this study confirm that several soil physical and chemical factors are altered by compaction and topsoil removal. In particular, our study shows that degraded soils are rather low in nutrients and have unfavorable physical soil properties compared to reference soils under native vegetation of Cerrado with dynamic nutrient cycling and low bulk densities. © 2014, Springer-Verlag Berlin Heidelberg.

Eschenbach W.,Johann Heinrich Von Thunen Institute | Well R.,Johann Heinrich Von Thunen Institute | Walther W.,Groundwater Technology
Biogeosciences | Year: 2015

Knowledge about the spatial variability of in situ denitrification rates (Dr(in situ)) and their relation to the denitrification capacity in nitrate-contaminated aquifers is crucial to predict the development of groundwater quality. Therefore, 28 push-pull 15N tracer tests for the measurement of in situ denitrification rates were conducted in two sandy Pleistocene aquifers in northern Germany.

The 15N analysis of denitrification-derived 15N-labelled N2 and N2O dissolved in water samples collected during the push-pull 15N tracer tests was performed using isotope ratio mass spectrometry (IRMS) in the lab and additionally for some tracer tests online in the field with a quadrupole membrane inlet mass spectrometer (MIMS) in order to test the feasibility of on-site real-time 15N analysis. Aquifer material from the same locations and depths as the push-pull injection points was incubated, and the initial and cumulative denitrification after 1 year of incubation (Dcum(365)) as well as the stock of reduced compounds (SRC) was compared with in situ measurements of denitrification. This was done to derive transfer functions suitable to predict Dcum(365) and SRC from Dr(in situ).

Dr(in situ) ranged from 0 to 51.5 Î1/4g N kgg'1 dg'1. Denitrification rates derived from on-site isotope analysis using MIMS satisfactorily coincided with laboratory analysis by conventional IRMS, thus proving the feasibility of in situ analysis. Dr(in situ) was significantly higher in the sulfidic zone of both aquifers compared to the zone of non-sulfidic aquifer material. Overall, regressions between the Dcum(365) and SRC of the tested aquifer material with Dr(in situ) exhibited only a modest linear correlation for the full data set. However, the predictability of Dcum(365) and SRC from Dr(in situ) data clearly increased for aquifer samples from the zone of NO3g'-bearing groundwater.

In the NO3g'-free aquifer zone, a lag phase of denitrification after NO3g' injections was observed, which confounded the relationship between reactive compounds and in situ denitrification activity. This finding was attributed to adaptation processes in the microbial community after NO3g' injections. It was also demonstrated that the microbial community in the NO3g'-free zone just below the NO3g'-bearing zone can be adapted to denitrification by NO3g injections into wells for an extended period. In situ denitrification rates were 30 to 65 times higher after pre-conditioning with NO3g. Results from this study suggest that such pre-conditioning is crucial for the measurement of Dr(in situ) in deeper aquifer material from the NO3g'-free groundwater zone and thus for the prediction of Dcum(365) and SRC from Dr(in situ). © Author(s) 2015.

Woltersdorf L.,Institute for Social Ecological Research ISOE | Jokisch A.,Groundwater Technology | Kluge T.,Institute for Social Ecological Research ISOE
Water Policy | Year: 2014

Rainwater harvesting to irrigate small-scale gardens enhances food self-sufficiency to overcome rural poverty. So far rainwater harvesting is not encouraged by the Namibian National Water Supply and Sanitation Policy nor supported financially by the Namibian government. This study proposes two rainwater harvesting facilities to irrigate gardens; one collects rain from household roofs with tank storage, the second collects rain on a pond roof with pond storage. The aim of this paper is to assess the benefits of rainwater harvesting-based gardening and to propose policy and financing implications for the Namibian government. We investigate the benefits of rainwater harvesting through a literature review, a cost-benefit analysis, monitoring of project pilot plants and a comparison with the existing irrigation and drinking water infrastructure. The results indicate that rainwater harvesting offers numerous benefits in technological, economic, environmental and social terms. The facilities have a positive net present value under favourable circumstances. However, material investment costs pose a financing problem. We recommend that government fund the rainwater harvesting infrastructure and finance privately garden and operation and maintenance costs. Integrating these aspects into a national rainwater harvesting policy would create the conditions to achieve the benefits of an up-scale of rainwater harvesting based gardening in Namibia. © IWA Publishing 2014.

Salcedo-Sanchez E.R.,Mexico State University | Salcedo-Sanchez E.R.,Groundwater Technology | Esteller M.V.,Mexico State University | Esteller M.V.,Groundwater Technology | And 4 more authors.
Environmental Earth Sciences | Year: 2013

The Valley of Puebla aquifer (VPA), at the central region of Mexico, is subject to intensive exploitation to satisfy the urban and industrial demand in the region. As a result of this increased exploitation, a number of state and federal agencies in charge of water management are concerned about the problems associated with the aquifer (decline of groundwater table, deterioration in water quality, poor well productivity and increased pumping and water treatment costs). This study presents a groundwater management model that combines "MODFLOW" simulation with optimization tools "MODRSP". This simulation-optimization model for groundwater evaluates a complex range of management options to identify the strategies that best fit the objectives for allocating resources in the VPA. Four hypothetical scenarios were defined to analyze the response of the hydrogeological system for future pumping schemes. Based on the simulation of flow with the MODFLOW program, promising results for the implementation of the optimization of water quantity were found in scenarios 3 and 4. However, upon comparison and analysis of the feasibility of recovery of the piezometric level (considering the policy of gradual reductions of pumping), scenario 4 was selected for optimization purposes. The response functions of scenario 4 were then obtained and optimized, establishing an extraction rate of 204.92 millions of m3/year (Mm3/year). The reduction in groundwater extraction will be possible by substituting the volume removed by 35 wells (that should be discontinued) by the same volume of water from another source. © 2013 Springer-Verlag Berlin Heidelberg.

PubMed | Groundwater Technology and University of South Florida
Type: Journal Article | Journal: Journal of the Air & Waste Management Association (1995) | Year: 2017

Rotary screens, or trommels, are an important unit operation in material and fuel processing. A computer model has been developed based upon fundamental mechanics. The coefficients and variables employed in the model thus have real physical meaning; adjusting them based upon laboratory data allows the model user to draw conclusions about the behavior of the trommel that can be applied to design and operational changes. The laboratory testing program was specifically designed to test the model described in this paper. The model proved able to track the laboratory data. Important phenomena that were validated or revealed included the significance of particle layering, changes in bed sliding with rotational velocity, and the pre-eminence of residence time.

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