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Performance evaluation of intrinsic bioremediation on the treatment of petroleum-hydrocarbon contaminated groundwaterLee, Ya-Chuan 30 June 2011 (has links)
Accidental spills of hydrocarbons from underground storage tanks or pipelines are a common cause of subsurface contamination. Anthropogenic hydrocarbon contamination of soil is a global issue throughout the industrialised world. In England and Wales alone, 12% of all serious contamination incidents in 2007 were hydrocarbon related. Biodegradation could be in situ process leading to a decrease of benzene concentrations in groundwater. Recently, monitored natural attenuation has become an effective alternative to the more active remediation methods for the in situ treatment of contaminated subsurface environments. The main objective of this study was to examine the possibility of adopting monitored natural attenuation as a remediation technique for the contaminated groundwater aquifer. In this natural attenuation study, the following tasks were conducted bioremediation investigation, biological first-order decay rates, Mann-Kendall Test model and BIOSCREEN model for the contaminated groundwater aquifer. In this study, a full-scale natural bioremediation investigation was conducted at a petroleum hydrocarbon spill site. In this study, The calculated biodegradation capacity (8.261 mg/L) at this site is much higher than the detected concentrations of petroleum-hydrocarbons (3-4 mg/L) within the most contaminated area inside the plume. Thus, natural biodegradation should be able to remove the contaminants effectively. The calculated biological first-order decay rates for benzene were between 1.7¡Ñ10-3-9.0¡Ñ10-4 day-1 respectively. Mann-Kendall test was applied to analyze the trend of contaminant variations. Results show that the S-value of monitor wells SW-1W, SW-4W, SW-42W, SW-23W, SW-30W, SW-67W and SW-70W were -2.23607, -1.16276, -1.52053, -1.34164, -1.26323, 0 and -1.34164, respectively. The negative S values reveal that the all contaminants tended to decrease. This indicates that the hydrocarbon plume at this site is not expanding, and has been contained effectively by the natural attenuation mechanisms. BIOSCREEN model from the groundwater analyses indicate, a first-order decay model reached the downgradient monitor well located 220 m from the spill location. that approximately 89% of the contaminate removal was due to biodegradation processes. The study of petroleum-hydrocarbons bacterial consortium were include Aquincola tertiaricarbonis L10¡BBosea sp. GR060219¡BBrachymonas petroleovorans strain CHX¡BHydrogenophaga sp. p3(2011)¡BHydrogenophaga sp.¡BMethylibium sp. YIM 61602¡BMycobacterium sp.¡BRhodoferax sp. IMCC1723¡BRhodoferax sp.¡BUncultured Rhodocyclaceae bacterium clone Elev_16S_975¡BUncultured Rhodocyclaceae bacterium clone eub62B1¤ÎUncultured Beggiatoa sp. clone GE7GXPU01BJTWR. Thus, the in situ bioremediation technology has the potential to be developed into an environmentally, economically and naturally acceptable remediation technology. Evidences for the occurrence of natural attenuation include the following: (1) depletion of dissolved oxygen, nitrate, and sulfate; (2) production of dissolved ferrous iron, sulfide, and CO2; (3) decreased BTEX concentrations and BTEX as carbon to TOC ratio along the transport path; (4) increased alkalinity and microbial species; (5) limited spreading of the BTEX plume; and (6) preferential removal of certain BTEX components along the transport path. Results indicate that natural attenuation can effectively contain the plume, and biodegradation processes played an important role on contaminant removal.
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Application of monitored natural attenuation to remediate petroleum-hydrocarbon contaminated groundwaterKuo, Ya-lin 29 August 2006 (has links)
Contamination of groundwater by petroleum-hydrocarbons is a serious environmental problem. Monitored natural attenuation (MNA) is a passive remedial approach to degrade and dissipate contaminants in groundwater. In this study, a full-scale natural bioremediation investigation was conducted at a gasoline spill site. Results show that the concentrations of major contaminants [benzene, toluene, ethylbenzene, and xylenes (BTEX)] dropped to below detection limit before they reached the downgradient monitor well. This indicates that natural biodegradation process was the major cause of the contaminant reduction.
In this study, 1,2,4-trimethylbenzene (1,2,4-TMB) was used as tracer to calculate the biological decay rates of BTEX. The calculated biological first-order decay rates for ethylbenzene, m+p-xylene, toluene, benzene, and o-xylene were 1.5¡Ñ10-3, 1.2¡Ñ10-3, 7.0¡Ñ10-4, 6.7¡Ñ10-4, and 1.2¡Ñ10-4, respectively. Mann-Kendall test was applied to analyze the trend of contaminant variations. Results show that the S-value of four monitor wells (CT-4, CT-41, CT-42, and CT-7) were -0.52, -1.57, -0.52, and -1.22, respectively. The negative S values reveal that the all contaminants tended to decrease. This indicates that the hydrocarbon plume at this site is not expanding, and has been contained effectively by the natural attenuation mechanisms.
Evidences for the occurrence of natural attenuation include the following: (1) depletion of dissolved oxygen, nitrate, and sulfate; (2) production of dissolved ferrous iron, sulfide, and CO2; (3) decreased BTEX concentrations and BTEX as carbon to TOC ratio along the transport path; (4) increased alkalinity and microbial species; (5) limited spreading of the BTEX plume; and (6) preferential removal of certain BTEX components along the transport path. Results also show that the biodegradation capacity (46.02 mg/L) for BTEX and 1,2,4-TMB was much higher than the detected contaminants within the plume. Results indicate that natural attenuation can effectively contain the plume, and biodegradation processes played an important role on contaminant removal.
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Žemių sausinimo įtaka Mūšos upės hidrologimiam režimui / Impact of Land Drainage on Musa River Hydrological RegimeNorvydaitė, Laura 16 June 2010 (has links)
Šlapių žemių sausinimo įtaka nuotėkiui Lietuvoje vertinama nevienareikšmiškai. Darbe analizuojama Mūšos upės ties Ustukiais hidrologinės charakteristikos ir žemių sausinimo šioje baseino dalyje įtaka upės nuotėkiui. Darbui atlikti panaudoti 1960 – 2006 metų paros nuotėkio, metinio kritulių kiekio, vidutinės paros oro temperatūros duomenys ir nusausintų plotų apimtys. Sudarytas kritulių įtakos debitui grafikas, kuris parodo, kad šie rodikliai glaudžiai susiję. Nagrinėjami du laikotarpiai 1960-1981 metai iki patvenkiant Mūšos upę, ir 1983-2006 metai po Dvariukų tvenkinio įrengimo. Naudojant DHRAM programinę įrangą, išskirtos ir analizuotos 33 debito charakteristikos. Naudojant Mano–Kendalio testą nustatyti 33-jų hidrologinių charakteristikų kaitos trendai. Tyrimas parodė, kad žemių sausinimas didelės įtakos Mūšos upės nuotėkio pokyčiams nepadarė. Sausinimo poveikis pasireiškia maksimalių debitų sumažėjimu ir paros debitų pokyčiais. / Wet soil drainage on the runoff Lithuania controversial. The paper analyzes the beating of the river at Ustukiai hydrological characteristics and soil drainage in the basin of the river runoff influence. Used to carry out the 1960 - 2006 years of daily runoff, rainfall, average daily air temperature data and the volume of drained areas. Made in rainfall affect the flow graph, which shows that these indicators are closely related. Study of two periods of 1960-1981 years before damming Mūša river, and the 1983-2006 year Dvariukų pond construction. Using DHRAM software identified and analyzed the 33 characteristics of flow. Using Mann-Kendall test to determine their 33-hydrological characteristics of the change in trend. The study showed that the draining of lands affected by high river runoff beating did not change. The drainage effect of maximal decrease in discharges and daily discharges change.
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Analýza koncentrací živin ve vodách a jejich odnosů z vybraného povodí / Analysis of nutrients concentrations in waters and their transport from selected catchmentJIRKOVSKÁ, Veronika January 2014 (has links)
The aim of this study was to analyze the presence of the trend of long-term time series of concentrations and losses of nutrients and their descriptions. The concentrations of nitrogen and phosphorus compounds were evaluated. The analysis was performed on selected catchment of large, medium and small areas. All observed catchment are located in the basin of dam Švihov. Trends were tested using non parametric methods - Mann-Kendall test, Seasonal Mann-Kendall test and Kendall's correlation coefficient . In this study there are generally described monitored cycles of nutrients, nitrogen and phosphorous. There are also characterized the factors, which effect leaching of these nutrients to water (from the catchment). The paper also outlines the progression of water quality in the Czech Republic, which was influenced by political and economic changes in Europe in the second half of the 20th century.
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Avaliação da disponibilidade de água em aquíferos por meio de análises espaço-temporaisBrito Neto, Romildo Toscano de 21 December 2012 (has links)
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Previous issue date: 2012-12-21 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Increasing groundwater extraction for domestic, agricultural, and industrial supply frequently
makes exploitation exceed the natural recharge rate. This results in decreasing volumes,
deteriorating water quality, and soil degradation. The goal of this study is to assess water
availability in the Texas State (USA) portion of the Ogallala aquifer, where extraction has
reached levels that are above the recharge values. Fifty three years of water level data from
wells between 1960 and 2012 were used. Fifty three surfaces each were created using both
(kriging and spline techniques) of spatial interpolation, and cross-validation methods (leaveone-
out, and holdout) were used to compare the predicted water level surfaces with the well
data. The predictions were similar and the results were satisfactory, however we found spline
technique simpler, and easier for automatic processing of multiple surfaces, and we
recommend it. However, kriging technique presents higher accuracy. After processing the
water level surfaces; the saturated thickness and volume (pixel by pixel), for the whole time
series were estimated. This allowed temporal analysis to be performed from the results. A set
of 492 water level variation time series (to analyze trends using the Mann-Kendall test) were
selected and grouped by cluster analysis (using both hierarchical and k-means methods). From
the temporal analyses, the spatial distribution of the results was verified, and it was observed
that the clusters most likely to decrease converge with the critical areas identified.
Furthermore, the influence of agricultural activities on water level variance was established,
showing a strong relationship between the two. Finally, the results showed that over 53 years,
the total water volume had been reduced by 33.9%. A full 74.39% of the time series analyzed
also showed a decreasing trend in water levels, and it was observed that the saturated
thickness is gradually being reduced as well / O crescimento da exploração de águas subterrâneas para suprir demandas de abastecimento,
agricultura e indústria faz com que a extração frequentemente exceda a recarga natural,
resultando num declínio de seu volume, deterioração do solo e qualidade da água. O objetivo
geral deste trabalho é avaliar a disponibilidade de água na porção do aquífero Ogallala
contido no Estado do Texas (EUA), onde a explotação tem alcançado níveis acima dos
valores de recarga. Para isto, inicialmente, foram utilizados dados de nível da água de poços
com uma série de 53 anos (1960 a 2012), criando-se 53 superfícies por cada método de
interpolação espacial (krigagem e spline). Em seguida, foi realizada uma comparação entre as
técnicas de interpolação pelos métodos leave-one-out e holdout de validação cruzada, além de
verificar as diferenças nas estimativas do volume total do aquífero. Os dois métodos de
interpolação produziram resultados semelhantes e desempenhos satisfatórios; entretanto,
recomenda-se o spline para processar múltiplas superfícies de nível da água de modo
automatizado e a krigagem para quando se demandar maior acurácia dos resultados. De posse
das superfícies de nível da água, foi estimada a camada saturada do aquífero e o volume pixel
a pixel, para toda a série histórica, o que permitiu a partir dos resultados espaciais, realizar
análises temporais. Em paralelo, foi selecionado um conjunto de 492 séries temporais de
variação do nível da água para se analisar tendências (teste de Mann-Kendall) e agrupá-las
por meio de análise de cluster (método hierárquico e k-means). A partir destas análises
temporais, foi verificada a distribuição espacial dos resultados, constatando que o grupo de
clusters com a maior tendência de decrescimento converge com áreas críticas identificadas.
Além disso, foi verificada a influência de áreas cultivadas na variação do nível da água,
mostrando que existe uma forte relação entre os dois fenômenos. Por fim, os resultados
mostram que houve uma redução de 33,9% do volume total em 53 anos, 74,39% das séries
analisadas indicaram tendência decrescente e observou-se que o nível da camada saturada
vem reduzindo gradativamente
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Změny srážko-odtokového režimu v oblasti Šumavy / Changes of rainfall-runoff regime in the Šumava /Bohemian Forest regionFiala, Ondřej January 2015 (has links)
CHANGES OF RAINFALL-RUNOFF REGIME IN THE ŠUMAVA / BOHEMIAN FOREST REGION Abstract: The goal of this thesis is the evaluation of changes in rainfall-runoff regime in the Šumava region from time and spacial point of view. The thesis includes research and applied part. The research part is dedicated to the methods of evaluation of runoff changes and their possible causes in the Šumava region. In the applied part there is an analysis of precipitaion - runoff regime for long-term time series of average annual and monthly discharges and also annual and monthly precipitations for selected gauging stations in Czech, German and Austrian part of Šumava using absolute and relative homogenity tests and Mann - Kendall test for long-term trend. One of the main aims of this thesis is the identification of possible orographical effect or the difference between windward and leeward part of Šumava. In conclusion the achieved results are evaluated, discussed and compared with subject publications. Key words: absolute homogenity, Mann - Kendall test, runoff, discharge, relative homogenity, precipitation, trend, Šumava, changes
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Změny podílu pevných a kapalných srážek v chladném půlroce a jejich vliv na jarní odtok z vybraných horských povodí / Changes in snowfall fraction in cold season and their impact on spring runoff in selected mountain catchmentsBlšťák, Adam January 2018 (has links)
The precipitation falling as rain or snow has different impact on regional water resources and their annual distribution. Shift from solid to liquid form of precipitation following the increase of the surface air temperatures could be important because such change could influence the timing of spring runoff and cause water scarcity in summer. In this study, the spatial and temporal variations of ratio of snowfall to total precipitation (Sf), mean air temperature, day of year of melt-out and winter and spring runoff is analysed. Data were examined for 11 meteorological and 6 hydrological stations in the mountains catchment in Czechia for November-April 1965-2014. Data were analyzed using the Mann-Kendall trend test. Major results show that Sf has been decreasing strongly throughout the whole examined area, with the strongest decrease in the foothill area of the northern mountains of Czechia. Stronger decrease is observed in lower elevations, at the stations with meant air temperature close to melt temperature. Strongest decrease was observed in March and the weakest decrease was observed in December and April, The significant decreases in Sf are associated with large increase in mean winter air temperatures. Due to the increasing mean air temperature in the cold season, the total rainfall is...
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Variabilidade espaço-temporal da precipitação e vazão e suas consequências para a gestão dos recursos hídricos regionais / Spatial-temporal variability of precipitation and flow and its consequences for the management of regional water resourcesSilva, Danilo José Brandão Vitor [UNESP] 19 January 2017 (has links)
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Previous issue date: 2017-01-19 / Este trabalho analisou os parâmetros hidroclimatológicos, buscando encontrar o padrão de precipitação em uma abordagem espaço-temporal para a porção paulista da bacia do rio Paraíba do Sul, empregando o interpolador geoestatístico krigagem. Além disso, verificou a existência de tendência de precipitação e de vazão em séries históricas nesta mesma bacia, utilizando o teste estatístico de Mann-Kendall. Com relação a espacialização da precipitação, foi constatada uma significativa variação espacial para os períodos analisados (verão, outono, inverno e primavera). No verão, período de recarga dos reservatórios, foram registrados os menores índices de precipitação na área de contribuição das sub-bacias que abastecem os reservatórios do Paraibuna e do Jaguari, implicando em uma possível redução na vazão afluente. Não se constatou tendência de precipitação estatisticamente significativa em escala de tempo interanual para os postos pluviométricos, entretanto, foi identificada tendência de diminuição para o outono. Para os postos fluviométricos das sub-bacias do rio Paraibuna, do rio Paraitinga e do rio Jaguari-Buquira, em um período interanual, houve tendência de aumento de vazão para séries históricas de 1930 a 1970 e de diminuição para séries de 1930 a 2015. As estações de medição de vazão utilizadas foram aquelas localizadas a montante dos reservatórios, não estando submetidas assim ao efeito de regularização de vazão. A tendência de diminuição de vazão encontrada para a região pode levar a uma alteração na disponibilidade hídrica e a um possível impacto no abastecimento e na geração de energia. / This research analyzed the hydroclimatological parameters, seeking to find the precipitation pattern in a space-time approach for the São Paulo portion of the Paraíba do Sul river basin, using the geostatistical interpolator kriging. In addition, it verified the existence of precipitation and streamflow trends in historical series for the same basin, using the statistical test of Mann-Kendall. Regarding the precipitation pattern, a significant spatial variability was observed for the periods analyzed (summer, autumn, winter and spring). In the summer, reservoir recharge period, the lowest precipitation rates were recorded in the sub-basin contribution area that supply the Paraibuna and Jaguari reservoirs, implying a possible reduction in the inflow. There was no statistically significant precipitation trend in the interannual time scale for the pluviometric stations, however, a decrease trend was identified for the autumn. For fluviometric stations in the sub-basins of the Paraibuna, Paraitinga and Jaguari-Buquira rivers, in the interannual time scale, there was a trend towards an increase in streamflow for historical series from 1930 to 1970 and decrease for series from 1930 to 2015. The streamflow stations used were those located upstream of the reservoirs and were not subject to the effect of flow regulation. The downward trend in streamflow found in the region can lead to a change in water availability and a possible impact on the supply and energy generation.
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Iterative interpolation of daily precipitation data over AlbertaDai, Qingfang 06 1900 (has links)
This thesis develops an optimal interpolation method that takes daily precipitation values collected from weather stations and produces precipitation estimates on a grid. The method, called Hybrid 2.0, combines EOF-based linear interpolation with the nearest-station method. Gridded monthly precipitation is first obtained via EOF, then distributed among days via nearest station. Hybrid 2.0 builds on an earlier method, called Hybrid 1.0, that applies an inverse-distance weighting method to obtain gridded monthly values. Hybrid 2.0 uses these monthly Hybrid 1.0 values as inputs when constructing EOF functions.
The data used in this thesis were obtained from the Meteorological Service of Canada. Few weather stations were located in the northern and mountain regions of Alberta prior to 1950. As a result, the Hybrid 1.0 gridded results underestimate precipitation in these regions for that period. The main contribution of Hybrid 2.0 is a substantial reduction in this bias, obtained by implicitly taking topographic elevation into account. Bias reduction is achieved by extracting EOFs from Hybrid 1.0 output for 1951-2002, when many more stations were present in the northern and mountain regions. Hybrid 2.0 is shown to be more accurate in interpolating both monthly and daily precipitation in Alberta, when compared with Hybrid 1.0 and other methods. The thesis also provides detailed analyses of precipitation trends and droughts using the gridded Hybrid 2.0 daily values. Optimality of the selected EOF modes and sensitivity to data error in the EOF-based linear reconstruction are also discussed in this thesis.
Agricultural uses of historical climate data have become extremely important. Applications include: enabling prompt, optimal decisions on market prices and disaster aid, designing future agricultural practices such as adaptation to climate and technology changes, and managing risks for agricultural producers and governments in areas such as drought monitoring. Many applications require a reliable interpolation technique to accurately reconstruct daily climate estimates onto grids of various resolutions. The gridded Hybrid 2.0 daily precipitation values produced by this thesis satisfy this requirement and can be used as inputs for many agricultural applications. / Applied Mathematics
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Analysis of Stream Runoff Trends in the Blue Ridge and Piedmont of Southeastern United StatesKharel, Usha 20 April 2009 (has links)
The purpose of the study was to examine the temporal trends of three monthly variables: stream runoff, rainfall and air temperature and to find out if any correlation exists between rainfall and stream runoff in the Blue Ridge and Piedmont provinces of the southeast United States. Trend significance was determined using the non-parametric Mann-Kendall test on a monthly and annual basis. GIS analysis was used to find and integrate the urban and non-urban stream gauging, rainfall and temperature stations in the study area. The Mann-Kendall test showed a statistically insignificant temporal trend for all three variables. The correlation of 0.4 was observed for runoff and rainfall, which showed that these two parameters are moderately correlated.
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