Щоб переглянути інші типи публікацій з цієї теми, перейдіть за посиланням: TREATED SOIL.
Дисертації з теми "TREATED SOIL"
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся з топ-50 дисертацій для дослідження на тему "TREATED SOIL".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Переглядайте дисертації для різних дисциплін та оформлюйте правильно вашу бібліографію.
1
BELCHIOR, INGRID MILENA REYES MARTINEZ. "BEHAVIOR OF A LIME-TREATED EXPANSIVE SOIL." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2016. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=29430@1.
Повний текст джерелаАнотація:
PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
PROGRAMA DE EXCELENCIA ACADEMICA
Os principais objetivos desta pesquisa são investigar o efeito da cal hidratada (HL) no comportamento de um solo expansivo, Eagle Ford do Texas (USA), e medir a eficiência do tratamento com cal sobre a redução da expansão através de variações das condições de preparação das amostras. Este estudo envolveu ensaios edométricos e ensaios de centrífuga, que é uma nova técnica desenvolvida pela Universidade do Texas em Austin (EUA). Até o presente trabalho, nenhum estudo tem sido desenvolvido usando esta centrífuga para analisar a redução da expansão em solos expansivos estabilizados. Além disso, nenhum estudo tem medido o melhoramento da eficiência do tratamento com cal devido às variáveis controladas durante a preparação das misturas solo-cal (ou seja, umidade, densidade, período entre a mistura e a compactação e tempo de cura), como também da tensão aplicada. Este trabalho também incluiu investigações sobre modificações das propriedades geotécnicas, composição mineralógica e constituição microestrutural, devido à adição de cal. A partir da análise das curvas de expansão vs. tempo, três valores foram definidos para examinar o comportamento expansivo: o potencial expansivo (Sp) e as inclinações de expansão primária (PSS) e secundária (SSS). A avaliação da eficiência do tratamento com cal, quantificada através do parâmetro Razão da Redução do Potencial Expansivo (SPR), indica: (i) eliminação de 97 por cento de Sp com 4 por cento de HL; (ii) melhoramento do SPR pelo aumento do tempo de cura; (iii) efeito adverso na SPR de períodos longos entre mistura e a compactação; (iv) possibilidade de diminuir a dosagem de cal necessária para reduzir a expansão através do aumento da umidade de compactação e/ou redução da densidade seca de compactação; e (v) dependência da dosagem da cal para prevenir a expansão no nível-g.
The main objectives of this research are to investigate the effect of hydrated lime (HL) treatment on the swelling behavior of a natural expansive soil, Eagle Ford clay from Texas (USA), and to measure the efficiency of lime treatment on swelling reduction due to variations in the condition of specimen preparation. This study involved conventional free swell tests and centrifuge tests, which are a new technique developed by the University of Texas at Austin (USA). So far, no studies have been performed using this centrifuge to analyze the swelling reduction in expansive soils by stabilization treatments. Also, no studies have measured the improving of lime treatment efficiency due to variables controlled during preparation of lime-soil mixtures (i.e. compaction moisture content, compaction dry density, mellowing and curing time), as well as the applied effective stress. This work also involved investigations about modifications of geotechnical properties, mineralogical composition and microstructural constitution due to the addition of lime. From the analysis of the swelling vs. time curves, three values were defined to examine the swelling behavior: the swelling potential (Sp), the primary swelling slope (PSS) and the secondary swelling slope (SSS). Assessment of the lime treatment efficiency, as quantified by the Swelling Potential Reduction Ratio (SPR) indicates: (i) the elimination of 97 per cent of Sp with 4 per cent HL; (ii) SPR enhancement with increasing curing time; (iii) adverse effect of mellowing periods on the SPR; (iv) the possibility to decrease the necessary lime dosage by increasing the compaction moisture and/or reducing the compaction dry density; and (v) dependency of the hydrated lime dosage to prevent swelling on the applied g-level (i.e. applied stress).
2
Warren, Jason George. "Management of Alum-Treated Poultry Litter." Diss., Virginia Tech, 2005. http://hdl.handle.net/10919/30232.
Повний текст джерелаАнотація:
Previous research has shown that treatment of poultry litter with alum is an effective management strategy to reduce phosphorus (P) solubility in litter thereby reducing potential P losses to surface runoff after surface applications. However, limited data are available evaluating alum-treated poultry litter (ATPL) environmental impact in cultivated systems and how its application will affect crop production. In addition little is known as to how its application affects various P fractions or exchangeable Aluminum (Al) content in treated soils. Two, 3-yr field trials with corn (Zea mays L.) were used to show that, when applied at rates based on current litter management strategies, ATPL resulted in yields similar to those achieved through applications of non-treated poultry litter (NPL). These trials also showed that ATPL applications resulted in lower soil P status and decreased P losses in surface water runoff compared to application of NPL. A 4-yr field trial with fescue (Festuca arudinacea) also showed no significant differences in productivity when comparing ATPL and NPL. This trial was utilized to evaluate the distribution of P in soils receiving ATPL. Soil analysis data showed that ATPL applications result in decreased water-extractable P (H2O-P) and that this decrease was associated with an elevation in NaOH extractable organic soil P. A laboratory incubation was utilized to evaluate the short and long-term impact of ATPL application on soil pH, exchangeable soil Al and H2O-P. Data from this incubation confirmed that the relationship between soil pH and exchangeable Al is not adversely affected by ATPL applications. Also, variations in the H2O-P content of soils treated with two different ATPL sources could not be associated with differences in Al:P ratio or soluble P content of the two litters, providing evidence that additional characteristics also control P availability after incorporation in soil.Ph. D.
3
Sariosseiri, Farid. "Critical state framework for interpretation of geotechnical properties of cement treated soils." Online access for everyone, 2008. http://www.dissertations.wsu.edu/Dissertations/Summer2008/f_sariosseiri_070208.pdf.
Повний текст джерела
4
Flynn, Colleen P. "The fate of nitrate in soil treated with hog manure." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/mq23304.pdf.
Повний текст джерела
5
Bennett, Michael Dever. "Effect of Concentration of Sphagnum Peat Moss on Strength of Binder-Treated Soil." Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/93210.
Повний текст джерелаАнотація:
Organic soils are formed as deceased plant and animal wildlife is deposited and decomposed in wet environs. These soils have loose structures, low undrained strengths, and high natural water contents, and require improvement before they can be used as foundation materials. Previous researchers have found that the deep mixing method effectively improves organic soils. This study presents a quantitative and reliable method for predicting the strength of one organic soil treated with deep mixing.
For this thesis, organic soils were manufactured from commercially available components. Soil-binder mixture specimens with different values of organic matter content, OM, binder content, water-to-binder ratio, and curing time were tested for unconfined compressive strength (UCS). Least-squares regression was used to fit a predictive equation, modified from the findings of previous researchers, to this data. The equation estimates the UCS of a deep-mixed organic soil specimen using its total water-to-binder ratio and mixture dry unit weight. Soil OM is incorporated into the equation as a threshold binder content, aT, required to improve a soil with a given OM; the aT term is used to calculate an effective total water-to-binder ratio.
This thesis reached several important conclusions. The modified equation was successfully fitted to the data, meaning that the UCS of some organic soil-binder mixtures may be predicted in the same manner as that of inorganic soil-binder mixtures. The fitting coefficients from the predictive equations indicated that for the soils and binder tested, specimens of organic soil-binder mixtures have a greater relative gain of UCS immediately after mixing compared to specimens of inorganic soil-binder mixtures. However, the inorganic mixtures generally have a greater relative gain of UCS during the curing period. The influence of curing temperature was found to be similar for organic and inorganic mixtures. For the organic soils and binder tested in this research, aT may be expressed as a linear or power function of OM. For both functions, the value of aT was negligible at values of OM below 45%, which reflects the chemistry of the organic matter in the peat moss. For projects involving deep mixing of organic soils, the predictive equation will be used most effectively by fitting it to the results of bench-scale testing and then checking it against the results of field-scale testing.Master of Science
Organic soils are formed continuously as matter from deceased organisms – mainly plants – is deposited in wet environs and decomposes. Organic soils are most commonly found in swamps, marshes, and coastal areas. These soils make poor foundation materials due to their low strengths. Deep mixing, or soil mixing, involves introducing a binder like Portland cement or lime into soil and blending the soil and binder together to form columns or blocks. Upon mixing, cementitious reactions occur, and the soil-binder mixture gains strength as it cures. Deep mixing may be performed using either a dry binder, known as dry mixing, or a binder-water slurry, referred to as wet mixing. Deep mixing may be used to treat either inorganic or organic soils to depths of 30 meters or greater. Contractor experience has shown that deep mixing is one of the most effective methods of improving the strength of organic soils. Lab-scale studies (by previous researchers) of wet mixing of inorganic soils have found that the strength of soil-binder mixtures can be expressed as a function of mixture curing time and curing temperature, as well as the quantity of binder used, or binder factor, and the consistency of the binder slurry. No corresponding expression has been generated for wet mixing of organic soils, although many studies on the subject have been performed by previous researchers. The goal of this research was to generate such an expression for one organic soil. The soil used was made of sphagnum peat moss, an organic material commonly found in nature, and an inorganic clay used by previous researchers in studies of deep mixing in inorganic soils. The binder used in this research was a Portland cement. For this research, 43 unique soil-binder mixtures were manufactured. Each mixture involved a unique combination of soil organic matter content, binder factor, and binder slurry consistency. After a soil-binder mixture was made, it was divided, placed into cylindrical molds, and allowed to cure. The temperature of the curing environment of the mixture was monitored. Mixture compressive strength was assessed after 7, 14, and 28 days of curing using two cylindrically molded specimens of the mixture. Data on mixture strength was then evaluated to assess whether it could be expressed as a function of the variables tested. iv This research determined that the strength of at least some organic soils improved with wet mixing can be expressed as a function of soil organic matter content, binder factor, binder slurry consistency, and mixture curing time and curing temperature. The function will likely prove useful to deep mixing contractors, who routinely perform lab-scale deep mixing trials on samples of the soils to be improved in the field. Assuming wet mixing is used, the results of the trials are used to select values of binder factor and binder slurry consistency for the project. The function generated from this research will allow deep mixing contractors to select these values more reliably during the lab-scale phase of their work.
6
Faraj, Mustafa Ali. "The effect on soil and sugar beet plants of irrigating polyacrylamide treated soil with saline water." Thesis, University of Manchester, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329578.
Повний текст джерела
7
Herring, Ian James. "The effect of soil inhabiting micro-organisms on preservative treated wood." Thesis, Imperial College London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298364.
Повний текст джерела
8
Garnett, Kathryn. "Interactions of metals and nitrilotriacetic acid in sewage sludge-treated soil." Thesis, Imperial College London, 1987. http://hdl.handle.net/10044/1/38325.
Повний текст джерела
9
Spencer, Laura Marie. "Evaluation of sand treated with colloidal silica gel." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/37131.
Повний текст джерелаАнотація:
Liquefiable soils are common at ports due to the use of hydraulic fills for construction of waterfront facilities. Liquefaction-induced ground failure can result in permanent ground deformations that can cause loss of foundation support and structural damage. This can lead to substantial repair and/or replacement costs and business interruption losses that can have an adverse effect on the port and the surrounding community. Although numerous soil improvement methods exist for remediating a liquefaction-prone site, many of these methods are poorly suited for developed sites because they could damage existing infrastructure and disrupt port operations. An alternative is to use a passive remediation technique. Treating liquefiable soils with colloidal silica gel via permeation grouting has been shown to resist cyclic deformations and is a candidate to be used as a soil stabilizer in passive mitigation.
The small-strain dynamic properties are essential to determine the response to seismic loading. The small-to-intermediate strain shear modulus and damping ratio of loose sand treated with colloidal silica gel was investigated and the influence of colloidal silica concentration was determined. The effect of introducing colloidal silica gel into the pore space in the initial phase of treatment results in a 10% to 12% increase in the small-strain shear modulus, depending on colloidal silica concentration. The modulus reduction curve indicates that treatment does not affect the linear threshold shear strain, however the treated samples reduce at a greater rate than the untreated samples in the intermediate-strain range above 0.01% cyclic shear strain. It was observed that the treated sand has slightly higher damping ratio in the small-strain range; however, at cyclic shear strains around 0.003% the trend reverses and the untreated sand begins to have higher damping ratio.
Due to the nature of the colloidal silica gelation process, chemical bonds continue to form with time, thus the effect of aging on the dynamic properties is important. A parametric study was performed to investigate the influence of gel time on the increase in small-strain shear modulus. The effect of aging increases the small-strain shear modulus after gelling by 200 to 300% for the 40-minute-gel time samples with a distance from gelation (time after gelation normalized by gel time) of 1000 to 2000; 700% for the 2-hour-gel time sample with a distance from gelation of 1000; and 200 to 400% for the 20-hour-gel time samples with a distance from gelation of 40 to 100.
The treatment of all potentially liquefiable soil at port facilities with colloidal silica would be cost prohibitive. Identifying treatment zones that would reduce the lateral pressure and resulting pile bending moments and displacements caused by liquefaction-induced lateral spreading to prevent foundation damage is an economic alternative. Colloidal silica gel treatment zones of varying size and location were evaluated by subjecting a 3-by-3 pile group in gently sloping liquefiable ground to 1-g shaking table tests. The results are compared to an untreated sample. The use of a colloidal silica treatment zone upslope of the pile group results in reduced maximum bending moments and pile displacements in the downslope row of piles when compared to an untreated sample; the presence of the treatment zone had minimal effect on the other rows of piles within the group.
10
Cid, João Filipe Xavier. "Response of grapevine to irrigation with treated wastewater." Master's thesis, ISA, 2019. http://hdl.handle.net/10400.5/19445.
Повний текст джерелаАнотація:
Mestrado em Viticultura e Enologia - Instituto Superior de Agronomia / Faculdade de Ciências. Universidade do PortoClimate change, population growth, industry expansion and increasing water demand in agriculture are pressuring water resources in dry, warm-climate regions, such as Mediterranean Europe. The aim of this study was to evaluate the possibility of using treated wastewater (TWW) for vineyard irrigation, as a strategy to maintain grapevine's water status within acceptable levels, while contributing to decrease the pressure on natural water resources. To achieve this goal, the effects of TWW and conventional water (CW) on grapevine and soil were compared after two years of irrigation. TWW appears to have had a significant impact on soil salinity, with TWW irrigated soil having a 10% higher salinity (VIC) than the CW irrigated one. Concerning grapevine growth rate and ecophysiology, shoot length of TWW irrigated vines was significantly lower (15%), though there were generally no differences in phenology and reflectance indexes (PRI and NDVI) between treatments. In one measurement during summer peak, though, NDVI values were significantly lower for TWW irrigated vines. Also during summer peak, berries of TWW irrigated vines were significantly darker and greener, and had higher total acidity than CW irrigated vines. Canopy traits such as exposed leaf area, total leaf area and leaf layer number did not differ between treatments, and the same occurred for grape and wood yield, suggesting that TWW had no impact on vine balance and yield. It is crucial to continue exploring the use of TWW for irrigation as an answer to drought and water scarcity, while studying its effects on crops and soil within wider time periods, to scout for long-term impacts of this practice
N/A
11
Young, Tyler B. "Early Age Assessment of Cement Treated Materials." BYU ScholarsArchive, 2007. https://scholarsarchive.byu.edu/etd/885.
Повний текст джерелаАнотація:
In order to avoid the occurrence of early-age damage, cement-treated base (CTB) materials must be allowed to cure for a period of time before the pavement can be opened to traffic. The purpose of this research was to evaluate the utility of the soil stiffness gauge (SSG), heavy Clegg impact soil tester (CIST), portable falling-weight deflectometer (PFWD), dynamic cone penetrometer, and falling-weight deflectometer for assessing early-age strength gain of cement-stabilized materials. Experimentation was performed at four sites on a pavement reconstruction project along Interstate 84 near Morgan, Utah, and three sites along Highway 91 near Richmond, Utah; cement stabilization was used to construct CTB layers at both locations. Each site was stationed to facilitate repeated measurements at the same locations with different devices and at different curing times. Because of the considerable attention they have received in the pavement construction industry for routine quality control and quality assurance programs, the SSG, CIST, and PFWD were the primary focus of the research. Statistical techniques were utilized to evaluate the sensitivity to curing time, repeatability, and efficiency of these devices. In addition, the ruggedness and ease of use of each device were evaluated. The test results indicate that the CIST data were more sensitive to curing time than the SSG and PFWD data at the majority of the cement-treated sites during the first 72 hours after construction. Furthermore, the results indicate that the CIST is superior to the other instruments with respect to repeatability, efficiency, ruggedness, and ease of use. Because the CIST is less expensive than the SSG and PFWD, it is more likely to be purchased by pavement engineers and contractors involved with construction of CTBs. For these reasons, this research suggests that the CIST offers greater overall utility than the SSG or PFWD for monitoring early-age strength gain of CTB. Further research is needed to identify appropriate threshold CIST values at which CTB layers develop sufficient strength to resist permanent deformation or marring under different types of trafficking.
12
Moss, Steven Phillip. "Experimental study for asphalt emulsion treated base." To access this resource online via ProQuest Dissertations and Theses @ UTEP, 2008. http://0-proquest.umi.com.lib.utep.edu/login?COPT=REJTPTU0YmImSU5UPTAmVkVSPTI=&clientId=2515.
Повний текст джерела
13
Lewsley, Gregory. "On the strength of saturated cement-treated soil reconstituted by wet-mixing." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/4175.
Повний текст джерелаАнотація:
Cutter Soil Mixing (CSM) is a recently developed deep mixing technique that has grown
to include the treatment of sandy and silty soils. This study seeks to investigate the influence of
(i) sand-silt ratio, (ii) cement content, (iii) water content and (iv) time on the unconfined
compressive strength of saturated cement-treated soil specimens. A new test device and method
of specimen reconstitution were conceived in order to obtain a saturated mix of soil and cement.
A comparison of results show strength increases non-linearly to decreasing total water-cement
ratio, and that this trend is largely independent of sand-silt ratio. Furthermore, strength increases
non-linearly with time and is independent of sand-silt ratio. Lastly, it is recommended that the
strength be correlated with total water-cement ratio rather than cement content, in order to
improve data reporting and provide design guidance to engineering practice.
14
Green, C. "Studies of the interactions of CCA and ACA preservative treated wood with soil." Thesis, University of Abertay Dundee, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382207.
Повний текст джерелаАнотація:
Chemical and microbiological changes at the interface between soil, and wood treated with CCA or ACA wood preservatives were investigated using a series of leaching and soil burial studies. The softwoods Scots pine (Pinus sylvestris, L.), Sitka spruce (Picea sitchensis, Carr) and the hardwood lime (Tilia vulgaris, Hayne) were used exclusively. Copper losses from both types of preservative treated wood were negligible, though adjacent soil copper concentrations significantly increased. These copper accumulations were associated with a reduction in dehydrogenase activity around the preservative treated material compared with levels around the untreated blocks, though activity around the treated wood was rarely less than background levels. Relatively large arsenic concentrations accumulated around the most heavily ACA-treated blocks, and were associated with a further reduction in activity of the soil microflora. The wood species also affected the microbial activity in adjacent soil; activity around all lime blocks was generally greater than microbial activity around the softwoods. Treatment of wood with ammonia or ACA solutions increased the wood nitrogen contents. Some of this nitrogen was readily water soluble, though its rapid diffusion into adjacent soil had no effect on microbial activity in this area. Water insoluble nitrogen was also retained within these blocks; this was shown to increase the rate of microbial colonisation and decay of the wood and was also associated with an increased toxic value of copper. Microbial activity was measured in all decaying wood blocks. This activity was influenced by the wood species, and treatment, as were the microbial colonisation and decay rates. The experimental conditions employed were designed to promote soft rot, rather than other forms of wood decay. Activity was greater in the outer wood surface of the buried blocks than in the inner wood, reflecting the surface nature of soft rot decay. Pre-burial leaching reduced the subsequent moisture uptake and increased the durability of CCA-treated wood during soil burial, though untreated wood was unaffected. However, similar rates of microbial decay of untreated wood blocks occurred over a range of different wood moisture contents. The implications of the findings on the relative performances of untreated, ammonia, CCA and ACA-treated wood in soil contact are discussed.
15
Leuther, Frederic [Verfasser], Hans-Jörg Gutachter] Vogel, and Jörg [Gutachter] [Bachmann. "Impact of treated wastewater irrigation on soil structure and soil water dynamics / Frederic Leuther ; Gutachter: Hans-Jörg Vogel, Jörg Bachmann." Halle (Saale) : Universitäts- und Landesbibliothek Sachsen-Anhalt, 2019. http://nbn-resolving.de/urn:nbn:de:gbv:3:4-1981185920-140560.
Повний текст джерела
16
Leuther, Frederic [Verfasser], Hans-Jörg [Gutachter] Vogel, and Jörg [Gutachter] Bachmann. "Impact of treated wastewater irrigation on soil structure and soil water dynamics / Frederic Leuther ; Gutachter: Hans-Jörg Vogel, Jörg Bachmann." Halle (Saale) : Universitäts- und Landesbibliothek Sachsen-Anhalt, 2019. http://d-nb.info/1210727757/34.
Повний текст джерела
17
Pontoni, Ludovico. "Accumulation and colloidal mobilization of trace heavy metals in soil irrigated with treated wastewater." Thesis, Paris Est, 2016. http://www.theses.fr/2016PESC1144/document.
Повний текст джерелаАнотація:
La réutilisation des eaux usées traitées pour l’irrigation est globalement acceptée et pratiquée pour faire face à la pénurie d'eau et économiser les ressources de haute qualité. Bien que cette pratique présente des avantages indéniables et contribue à un usage plus durable de l'eau douce, elle n’est pas exempt de problèmes liés à l'impact potentiel sur la qualité des sols récepteurs et sur les cultures de micropolluants contenus dans l'eau réutilisée. Parmi ces polluants, les métaux lourds (ML) en concentrations traces jouent un rôle primordial en raison de leur présence systématique dans l'eau utilisée et de leur persistance une fois libéré dans l'environnement. Le devenir des ML dans les sols peut difficilement être prédit parce que les mécanismes de mobilité à travers les sols sont extrêmement variés et liés à des phénomènes simultanés et très complexes impliquant différents équilibres chimiques. Les ML, comme beaucoup d'autres contaminants, ne sont pas seulement partagé entre la phase immobile (le sol) et les phases mobiles présentes dans l'eau. En effet, les colloïdes et les nanoparticules agissent comme une troisième phase mobile, avec leurs propres propriétés rhéologiques et des vitesses de migrations qui leur sont propres. Ce dernier aspect a été l'un des principaux objectifs d’étude de la thèse. Plusieurs essais expérimentaux ont été menés en irriguant un sol standard selon l'Organisation de coopération et de développement économiques (OCDE) avec une eau usés traités réel et / ou synthétiques, contenant des ML en concentrations traces. Pour chaque test, un sol spécifique (avec différentes teneurs en matière organique) et des eaux usées traitées de composition différente (avec différentes concentrations en métaux traces, de salinité, de la teneur en matière organique pour les eaux usées synthétiques, ou des eaux usées traitées réelles) ont été choisi afin d'évaluer les effets des conditions différentes sur le devenir global des ML. L'augmentation de la matière organique du sol de 2,5 à 10% a linéairement amélioré la mobilité des Cd, Cu et Ni avec une augmentation de la mobilité maximum de 35,6, 43,7 et 49,19% pour le Cd, Cu et Ni, respectivement. Pour la plupart des expériences, les ML ont été capturés dans la couche superficielle du sol (0,5 à 1 cm). Néanmoins, des pics de contamination ont été détectés à des profondeurs différentes dans les couches plus profondes du sol. L’étude de la composition des lixiviats montre des variations de concentrations fonction du métal étudié et des caractéristiques du sol et des eaux usées. Des pics de métaux dans le lixiviat sont apparus en même temps que la libération de la matière et / ou la libération de silicates organiques, ce qui démontre l'implication significative des colloïdes dans le transport des métaux. La concentration en sodium (20 mM) a été démontrée un impact fort sur la réduction de la mobilisation colloïdale et que plus de 95% du métal apporté a été détecté dans la couche superficielle du sol en dépit de sa teneur en matière organique. La salinité affiche donc des effets significatifs. L'irrigation avec des eaux usées traitées présentant une très haute teneur en Ca et Mg (111 et 134 mg / L, respectivement) a abouti à la libération moyenne plus élevée de silicium à partir de la matrice inorganique du sol (8,2 mg / L) par rapport à la faible salinité des eaux usées artificielle (1,9 mg / L). Par conséquent, la mobilisation ultérieure de Cd, Cu, Ni et Zn a été observée lorsque le sol a été irrigué avec des eaux usées traitées réelles. Une caractérisation spectroscopique avancée des lixiviats a été réalisée pour identifier les agrégats colloïdaux libérés par le sol dans le but d’en déterminer leur nature, leurs propriétés chimiques et leur état d'agrégationReuse of treated wastewater for agricultural purposes is worldwide accepted and practiced to face water scarcity and save high quality resources. Although such practice has undoubtable advantages and is certainly more sustainable respect to the use of fresh water, it is not exempt from severe concerns related to the potential impact on the receiving soil and on the crops of potentially harmful pollutants contained in the reused water at trace levels. Among these pollutants, trace heavy metals (HMs) play a primary role due to their spread presence in the used water and to their persistence once released in the environment. The fate of HMs in the soils can be hardly predicted as mechanisms of mobility through soils are extremely diverse and related to highly complex simultaneous phenomena and chemical equilibria. HMs, in fact, as many other contaminants, are not only partitioned between the solid immobile and the water mobile phases. Indeed, colloids and nanoparticles act as a third mobile phase, with their own rheological properties and velocity. This latter aspect has been one of the main focus of the thesis. In details the thesis describes the results of several experiments conducted irrigating the OECD standard soil with real and/or synthetic wastewater, containing HMs in trace. For each test a specific soil (e.g. varying the organic matter content) and wastewater composition (e.g. varying the metals concentration, the salinity, the organic matter content, or testing real treated wastewaters) has been chosen in order to evaluate the effects of different conditions on the overall HMs fate. The increase of soil organic matter from 2,5 to 10% linearly enhanced the mobility of Cd, Cu and Ni up to a maximum mobility increase of 35.6, 43.7 and 49.19 % for Cd, Cu and Ni, respectively. In most experiments metals accumulated in the top soil layer (0.5 - 1 cm). Nevertheless peaks of contamination were detected at different depths in the soil deeper layers and at different leaching time in the leachates depending on the metal and on the soil and wastewater characteristics. Peaks of metals in the leachate appeared simultaneously with release of organic matter and/or release of silicates, demonstrating outstanding involvement of colloids in metals transport. Sodium concentration (20mM) decidedly reduced colloidal mobilization whereas more than 95 % of the influent metal was detected in the top layer despite the soil organic matter content. Salinity displayed different effects. The irrigation with real treated wastewater with quite high content of Ca and Mg (111 and 134 mg/L, respectively) resulted in higher average release of silicon from the soil inorganic matrix (8.2 mg/L) compared to the low salinity artificial wastewater (1.9 mg/L). Consequently higher mobilization of Cd, Cu, Ni and Zn was observed when the soil was irrigated with real treated wastewater. An advanced spectroscopical characterization of the leachates was performed to identify such colloidal aggregates. The observation of 3D excitation-emission matrix demonstrated in all the leachates samples the presence of fulvic (230-450 nm ex-em fluorescence area) and humic (330-445 nm ex-em) substances. In this context, a novel analytical method was developed to quantify phenolic substances in soil matrices allowing the monitoring of humic matter migration in soil profiles. The novel method was more accurate and more precise respect to the traditional one, allowing to obtain higher recovery of total phenols in peat soil (15.5 % increase) with a decrease of the coefficient of variation (30.1% decrease). Organic water soluble colloids were extracted from the peat used to prepare the OECD standard soil and characterized. Results of size exclusion chromatography highlighted the supramolecular structure of the extracted organic matter. Such structure was further confirmed through fluorescence and 1H-NMR spectroscopy
18
Thuangsit, Denpetkul. "Assessment and Control of Virological Risk in Reclaimed Water Treated by Soil Aquifer Treatment." 京都大学 (Kyoto University), 2016. http://hdl.handle.net/2433/217158.
Повний текст джерела
19
Vela, Arturo Castro. "POTENTIAL FOR USE OF EFFLUENT WASTEWATER TREATED BY SOIL AQUIFER TREATMENT IN BANNING, CALIFORNIA." CSUSB ScholarWorks, 2015. https://scholarworks.lib.csusb.edu/etd/210.
Повний текст джерелаАнотація:
With the ever increasing demand for potable water due to the continued increase in population coupled with the threat of California’s current drought, water will remain a limited resource that must be managed responsibly. In order to strategically plan and manage water use in the most beneficial manner, water providers must take into account all sources of water, including recycled water and their applications. Recycled water as a source for supplementing high quality potable water is a sustainable strategy that will prove to be an essential tactic in any water management plan.
The purpose of this project is to emphasize the importance of supplementing potable water in the City of Banning by discussing the characteristics of California’s current water drought; evaluating the City of Banning’s available water supplies and current water demand; discussing the Soil Aquifer Treatment process; summarizing California’s regulations related to recycled water; and discussing the quality of recycled water available at NP-1, an unequipped City owned water well, by examining water quality testing on water samples taken from NP-1.
Analysis of water available at NP-1 showed that with additional disinfection, the water pumped from NP-1 could meet the recycled water requirements in order to be used on a local golf course. The local golf course is currently being irrigated with potable water, which would be supplemented with the recycled water from NP-1.
20
Scussel, Vildes Maria. "The effects of processing on residues of the fungicide Imazalil on postharvest-treated cucurbits." Thesis, University of Reading, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336683.
Повний текст джерела
21
Black, Amanda. "Bioavailability of cadmium, copper, nickel and zinc in soils treated with biosolids and metal salts." Lincoln University, 2010. http://hdl.handle.net/10182/1561.
Повний текст джерелаАнотація:
It is widely accepted that bioavailability, rather than total soil concentration, is preferred when assessing the risk associated with metal contamination. Despite this, debate continues on what constitutes a bioavailable pool and how to best predict bioavailability, especially in relation to crop plants. The overall aim of this thesis was to assess and validate measures of cadmium (Cd), copper (Cu), nickel (Ni) and zinc (Zn) bioavailability in a range of soils amended with metal salts and biosolids. Six potential measures of bioavailability were investigated and compared: total metal; 0.04 M EDTA extraction; 0.05 M Ca(NO₃)₂ extraction; soil solution extracted using rhizon probes; effective solution concentration (CE) determined using diffusive gradients in thin films (DGT); and modelled free ion activities (WHAM 6.0). These were compared to shoot metal concentrations obtained from plants grown in three soils with contrasting properties treated with biosolids and metal salts. The first study involved a wheat seedling (Triticum aestivum) assay carried out under controlled environmental conditions on incubated soils treated with metal salts and biosolids. Results showed that the presence of biosolids resulted in increases of DOC, salinity, Ca and Mg in soil solution as well as total concentrations of Cu and Zn, dry matter was also adversely affected by increased levels of salinity. The addition of biosolids did not significantly alter the extractability or solubility of Cd, Cu, Ni and Zn although concentrations of Cd in shoots were significantly lower in plants grown in biosolids amended soils compared with unamended soils. The second study involved a field experiment that used 20 cm diameter by 30 cm deep soil monoliths of the same three soils treated with metals and biosolids, and perennial ryegrass (Lolium perenne) was grown for 24 months. Results revealed the addition of biosolids significantly increased the amount of DOC, salinity, Ca and Mg in solution. The presence of biosolids also significantly altered the bioavailability of Cd, Cu, Ni and Zn, as measured by soil solution, CE and free ion activity. However, this change had little effect on plant metal uptake. The length of time following treatment application had the greatest effect on soil chemistry and metal availability, resulting in pH decreases and increases in DOC, soil solution salinity, Ca and Mg. The free ion activities of each metal increased with time, as did soil solution Cd and Zn and CE-Cu, with results for Zn indicative of migration through the soil profile with time. Plant uptake of Ni and Zn also changed with time. Nickel concentrations in shoots decreased, while concentrations of Zn in shoots increased. The findings from the two studies demonstrated that biosolids increased the amount of DOC, salinity, Ca and Mg present in soil solution. In the lysimeter study measures of metal availability were affected in soils amended with biosolids, but this did not effect shoot concentrations. The overall predictive strengths of the six potential measures of bioavailability was investigated using results from the previously described experiments and related studies carried out by ESR and Lincoln University using nine different soils amended with combinations of biosolids and metal salts. Of the four metals Ni provided the strongest correlations between metal bioavailability and shoot concentrations, with 0.05 M Ca(NO₃)₂ extraction giving the strongest relationship for Ni concentrations in shoots (r² = 0.73). This suggests that the solubility of Ni is highly indicative of shoot concentrations and that Ca(NO₃)₂ is a robust measure of Ni bioavailability. In addition Ca(NO₃)₂ provided the best estimate of Zn bioavailability (r² = 0.65), and CE-Cd provided the best measure of Cd bioavailability, although it could only describe 47 % of shoot Cd concentration. Results for Cu were typical of previously described studies as assays of Cu availability are almost always poorly correlated with shoot concentrations, with total Cu having the strongest relationship (r² = 0.34). Methods based on the extractability and solubility of Cu in soils were poor indicators of Cu concentration in shoots. Overall, the addition of biosolids did not alter the outcome of these bioavailability assays, and results indicated that total metal concentrations present in the soils and biosolids matrix, plus length of time since soil treatment, had a greater affect on metal bioavailability.
22
Schacht, Karsten [Verfasser], Bernd [Akademischer Betreuer] Marschner, and Yona [Akademischer Betreuer] Chen. "Treated wastewater irrigation in the Middle East: Soil suitability and impact on physical soil properties / Karsten Schacht. Gutachter: Bernd Marschner ; Yona Chen." Bochum : Ruhr-Universität Bochum, 2016. http://d-nb.info/1095884263/34.
Повний текст джерела
23
Michener, John E. "Effects of Environmental Factors on Construction of Soil-Cement Pavement Layers." Diss., CLICK HERE for online access, 2008. http://contentdm.lib.byu.edu/ETD/image/etd2630.pdf.
Повний текст джерела
24
Hope, Charles A. "Evaluation of Portable Devices for Monitoring Microcracking of Cement-Treated Base Layers." BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/2965.
Повний текст джерелаАнотація:
A relatively new method used to reduce the amount of cement-treated base (CTB) shrinkage cracking is microcracking of the CTB shortly after construction. Three portable instruments used in this study for monitoring the microcracking process include the heavy Clegg impact soil tester (CIST), portable falling-weight deflectometer (PFWD), and soil stiffness gauge (SSG). The specific objectives of this research were 1) to evaluate the sensitivity of each of the three portable instruments to microcracking, and 2) to compare measurements of CTB stiffness reduction obtained using the three devices. The test locations included in this study were Redwood Drive and Dale Avenue in Salt Lake City, Utah; 300 South in Spanish Fork, Utah; and a private access road in Wyoming. Experimental testing in the field consisted of randomized stationing at each site; sampling the CTB immediately after the cement was mixed into the reclaimed base material; compacting specimens for laboratory testing; and testing the CTB immediately after construction, immediately before microcracking, immediately after each pass of the vibratory roller during the microcracking process, and, in some instances, three days after microcracking. Several linear regression analyses were performed after data were collected using the CIST, PFWD, and SSG during the microcracking process to meet the objectives of this research. Results from the statistical analyses designed to evaluate the sensitivity of each of the three portable instruments to microcracking indicate that the PFWD and SSG are sensitive to microcracking, while the CIST is insensitive to microcracking. Results from the statistical analyses designed to compare measurements of CTB stiffness reduction demonstrate that neither of the instrument correlations involving the CIST are statistically significant. Only the correlation between the PFWD and SSG was shown to be statistically significant. Given the results of this research, engineers and contractors should utilize the PFWD or SSG for monitoring microcracking of CTB layers. The heavy CIST is unsuitable for monitoring microcracking and should not be used. For deriving target CTB stiffness reductions measured using either the PFWD or SSG from specified targets measured using the other, engineers and contractors should utilize the correlation chart developed in this research.
25
Quick, Tyler James. "Temporal and Spatial Variability in Base Materials Treated with Asphalt Emulsion." BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/2715.
Повний текст джерелаАнотація:
The first objective of this research was to investigate temporal trends in the mechanical properties of base materials stabilized with asphalt emulsion and to assess the rate at which emulsion-treated base (ETB) design properties are achieved. The second objective of this research was to identify construction and environmental factors most correlated to specific mechanical properties of ETB layers and to determine which construction factors exhibit the greatest variability. Additional statistical analysis was performed to determine if significant differences existed between different test sections on a given project. In this research, three experimental sections were established along a pavement reconstruction project near Saratoga Springs, Utah. Field tests were performed to assess the structural properties of the ETB immediately following construction and at 2, 3, 7, and 14 days; 4 months; and 1 year. Measured values were plotted against time to determine trends in ETB strength development. Several statistical analyses were then performed on the collected data. Modulus values were consistently low in all three sections during the first two weeks of testing, increased dramatically by 4 months, and then decreased considerably by 1 year. During the first two weeks following construction, the average ETB structural coefficient was 0.04. Only two of the three sections reached the design structural coefficient of 0.25, which occurred after approximately 3 months; however, the average structural coefficient measured for all three sections after 1 year of curing, which included a winter, was only 47 percent of the design strength. The results of this research show that, while pavement capacity is sufficient at 4 months, it is severely reduced during the first two weeks and at 1 year. Trafficking under these reduced capacities is not recommended. Statistical analysis showed that gradation, binder change during emulsion treatment, and moisture content have the most significant impact on ETB structural properties. Gradation and binder change during emulsion treatment also exhibited significant variability; tighter specifications on material gradations and improved uniformity in emulsion distribution should therefore be considered. Because of the negative impacts of moisture on ETB strength development, construction should not be performed in conditions of excess moisture.
26
Altinoklar, Hatice. "A Mathematical Modeling Study On The Feasibility Of Disposing Partially Treated Domestic Wastewater Using Soil Pile Systems." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/12607944/index.pdf.
Повний текст джерелаАнотація:
The soil pile system (SPS) is a wastewater infiltration system used for secondary and tertiary treatment of wastewater. The purpose of this study is to perform a feasibility study to assess the applicability of SPS for treatment and safe disposal of domestic wastewaters, using a simplistic steady-state flow analytical modeling and a numerical transient unsaturated flow and transport modeling approaches. It is also aimed to develop guidelines for the design and operation of field scale SPS using the results of modeling studies.
The analytical modeling approach (AMA) was used to assess total coliform and chlorine attenuation efficiency in a SPS with clay loam soil. Analytical modeling results showed that SPS can treat wastewater in terms of total coliform and chlorine. Thus, in the light of findings of analytical modeling study, a pilot scale field study was conducted for the identifying the design and operational characteristics of a field scale system. Numerical modeling approach was used to evaluate the impact on contaminant removal of transient nature of wastewater infiltration and redistribution through clay loam soil pile. The results of numerical and analytical models were compared to assess the effect of flow regime on contaminant removal efficiencies. Results show that there is no significant difference between removal efficiencies achieved by numerical and analytical models. Whereupon, analytical model was used to assess behavior of SPS with different soil types, namely silt loam, loam, and sandy loam soils.
Model results indicated that SPS can be effective reducing chlorine and total coliform concentrations of wastewater below discharge standards. Results also indicated that SPS is highly sensitive to soil thickness, infiltration rate, soil bulk density and most importantly decay rate coefficients and the performance of SPS is dependent on the design, construction, operation characteristics and soil-environmental conditions of the system.
27
Lapointe, Emilie. "Cement-treated soil : a comparison of laboratory and field data from Fountain slide remediation deep mixing project." Thesis, University of British Columbia, 2012. http://hdl.handle.net/2429/42127.
Повний текст джерелаАнотація:
In order to better understand the influence of laboratory reconstitution methods on the strength of cement-treated soil, a laboratory program was undertaken to investigate the unconfined compressive strength of cement-treated specimens reconstituted from low plasticity soils. The laboratory program examines two soil types and two reconstitution methods. The soil samples were taken from a Cutter Soil Mixer [CSM] field improvement site in British Columbia. Two reconstitution methods were used: a saturated wet-mixing method and an unsaturated dry-mixing method. To assess the relevance of using laboratory results to guide design, a subsequent field component of this research compares the strength of test specimens cast from field-mixed cement-treated soil, with the strength obtained from laboratory-reconstituted specimens.
The strength of laboratory-reconstituted soil specimens is largely independent of the soil type and reconstitution method used. A standardized approach for determining cement content in uncured mixed soil-cement is evaluated. Results from the method allow for direct comparison between the strength of field-mixed versus laboratory-reconstituted specimens as a function of the cement content, and/or the water-cement ratio. Based on the simplicity of use and accuracy of results, it is recommended that the Heat of Neutralization method (ASTM 5982-07) be incorporated into the quality assurance program of deep mixing projects.
28
Nevarez, Garibaldi Roberto. "Influences of Test Conditions and Mixture Proportions on Property Values of Soil Treated with Cement to Represent the Wet Method of Deep Mixing." Thesis, Virginia Tech, 2017. http://hdl.handle.net/10919/88437.
Повний текст джерелаАнотація:
A laboratory testing program was conducted on cement-treated soil mixtures fabricated to represent materials produced by the wet method of deep mixing. The testing program focused on investigating the influences that variations in laboratory testing conditions and in the mix design have on measured property values. A base soil was fabricated from commercially available soil components to produce a very soft lean clay that is relatively easy to mix and can be replicated for future research. The mix designs included a range of water-to-cement ratios of the slurries and a range of cement factors to produce a range of mixture consistencies and a range of unconfined compressive strengths after curing. Unconfined compressive strength (UCS) tests and unconsolidated-undrained (UU) triaxial compression tests were conducted. Secant modulus of elasticity were determined from bottom platen displacements, deformations between bottom platen and cross bar, and from LVDT's placed directly on the cement-treated soil specimens. Five end-face treatment methods were used for the specimens: sawing-and-hand-trimming, machine grinding, sulfur capping, neoprene pads, and gypsum capping. Key findings of this research include the following: (1) The end-face treatment method does not have a significant effect on the unconfined compressive strength and secant modulus; (2) a relationship of UCS with curing time, total-water-to-cement ratio, and dry density of the mixture; (3) the secant modulus determined by bottom platen displacements is significantly affected by slack and deformations in the load frame; (4) the secant modulus determined by local strain measurements was about 630 time the UCS; (5) typical values of Poisson's ratio range from about 0.05 to 0.25 for stress levels equal to half the UCS and about 0.15 to 0.35 at the UCS; (6) Confinement increased the strength at high strains from less than 20% the UCS to about 60% the UCS. In addition to testing the cured mixtures, the consistency of the mixtures were measured right after mixing using a laboratory miniature vane. A combination of the UCS relationship along with the mixture consistency may provide useful information for deep mixing contractors.MS
29
Reese, Garth B. "Use of the Clegg Impact Soil Tester to Access Rutting Susceptiblity of Cement-Treated Base Material Under Early Trafficking." BYU ScholarsArchive, 2007. https://scholarsarchive.byu.edu/etd/894.
Повний текст джерелаАнотація:
In order to avoid the occurrence of early-age damage, cement-treated base (CTB) materials must be allowed to cure for a period of time before the pavement can be opened to traffic. Trafficking of a CTB before sufficient strength gain has occurred can lead to marring or rutting of the treated layer. The specific objectives of this research were to examine the correlation between Clegg impact values (CIVs) determined using a heavy Clegg impact soil tester and rut depths measured in newly constructed CTB and subsequently establish a threshold CIV at which rutting should not occur.The experimental work included field testing at several locations along United States Highway 91 near Smithfield, Utah, and laboratory testing at the Brigham Young University (BYU) Highway Materials Laboratory. In both the field and laboratory test programs, ruts were created in CTB layers using a specially manufactured heavy wheeled rutting device (HWRD). In the field, ruts caused by repeated passes of a standard pickup and a water truck were also evaluated. The collected data were analyzed using regression to identify a threshold CIV above which the CTB should not be susceptible to unacceptable rutting. From the collected data, one may conclude that successive wheel passes each cause less incremental rutting than previous passes and that CTB similar to the material tested in this research should experience only negligible rutting at CIVs greater than about 35. The maximum rut depth measured in either field or laboratory rutting tests was less than 0.35 in. in this research, probably due to the high quality limestone base material utilized to construct the CTB. In identifying a recommended threshold CIV at which CTB layers may be opened to early trafficking, researchers proposed a maximum tolerable rut depth of 0.10 in. for this project, which corresponds to a CIV of approximately 25. Because a CIV of 25 is associated with an acceptably minimal rut depth even after 100 passes of the HWRD, is achievable within a reasonable amount of time under normal curing conditions, and is consistent with earlier research, this threshold is recommended as the minimum average value that must be attained by a given CTB construction section before it can be opened to early trafficking. Use of the proposed threshold CIV should then ensure satisfactory performance of the CTB under even heavy construction traffic to the extent that the material properties do not differ greatly from those of the CTB evaluated in this research.
30
Schwer, Donald Roy III. "CHROMIUM, COPPER, AND ARSENIC CONCENTRATION AND SPECIATION IN SOIL ADJACENT TO CHROMATED COPPER ARSENATE (CCA) TREATED LUMBER ALONG A TOPOHYDROSEQUENCE." UKnowledge, 2010. http://uknowledge.uky.edu/gradschool_theses/68.
Повний текст джерелаАнотація:
Arsenic (As), Chromium (Cr), and Copper (Cu) are ubiquitous in soils as a result of anthropogenic and geogenic processes. The fate of As, Cr, and Cu in the environment is largely governed by their speciation, which is influenced by soil physiochemical properties. This study investigated the influence of soil physiochemical properties and landscape position on As, Cr, and Cu concentration and speciation in soils adjacent to Chromated Copper Arsenate (CCA) treated lumber fence posts. Concentration gradients showed elevated total As and Cu adjacent to the three fence posts, which decreased with increasing distance from the posts. In addition, As and Cu had higher concentrations in the surface soil samples than the subsoil samples possibly due to enhanced weathering of the CCA treated posts at the surface. Concentrations of As, Cr, and Cu were similar among the Maury and Donerail silt loam, however, they were closer to the background concentration in the Newark silt loam, a partially hydric soil, indicating mobility of the metals. Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy indicates As(V) is the predominate species which is principally coordinated with Fe and Al whereas, Cu(II) is coordinated with soil organic matter. Overall, the use of CCA treated lumber as a metal source can help determine how soil properties influence mobility and speciation of As, Cr, and Cu across the soil landscape.
31
Reese, G. Benjamin. "Use of the heavy Clegg impact soil tester to assess rutting susceptiblity of cement-treated base material under early trafficking /." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd1831.pdf.
Повний текст джерела
32
Das, Geetanjali. "Evaluation of kneading compaction method and the long-term performances of lime-treated soils." Thesis, Ecole centrale de Nantes, 2021. http://www.theses.fr/2021ECDN0043.
Повний текст джерелаАнотація:
L'étude du comportement des sols traités à la chaux est axée sur l'analyse de l'influence des conditions de mise en œuvre en laboratoire et in situ avec une attention particulière sur l'évolution de la microstructure. Les échantillons de sol prélevés dans un remblai constitué d’un sol traité à la chaux, soumis à l'exposition atmosphérique pendant 7 ans, montrent une évolution significative des performances du matériau, notamment sa résistance à la compression. Ces résultats mettent en évidence l'influence du traitement à la chaux sur le long terme. Le remblai étudié a été mis en oeuvre par "compactage par pétrissage", dont le mécanisme est moins étudié dans la littérature. Le pétrissage semble améliorer la dispersion de la chaux dans le sol,ainsi que sa structuration. Cette propriété est favorable à l'hydratation de composés cimentaires, particulièrement, en cas de présence d'eau disponible. L'effet du fluide interstitiel sur la performance hydraulique des sols traités à la chaux, et le mécanisme de lixiviation associé sont étudiés en fonction du volume des pores traversés par le fluide. Le nombre de volume de pore traversé s’avère être un paramètre clé pour l’étude de la durabilité des performances des sols traités. L'eau déminéralisée s'avère être plus agressive qu'une solution à faible force ionique. Cela démontre l'importance de prendre en compte le type de solution perméante. La performance à long terme du sol traité à la chaux soumis au cycle d’humidification séchage, sous différentes conditions d'essai et différents fluides, est évaluée. L'étude a révélé la contribution de la nature du fluide d'imbibition et des effets de la température sur l'évolution des propriétés physico-chimiques et microstructurales du sol traité à la chaux. Ainsi, la condition de compactage mise en œuvre, la nature du fluide d'essai et les conditions d'essai à l'échelle du laboratoire doivent se rapprocher de la situation sur le terrainInvestigation of the behavior of limetreated soil with emphasis on laboratory and field implementation technics and microstructural observations is made. Field investigation of a 7-year atmospherically cured embankment, thanks to measurement of sampled materials performances, shows a significant evolution in compressive strength, evidencing the long term benefits of lime treatment. This embankment was subjected to ‘kneading compaction’, which mechanism is less investigated. At laboratory scale, ‘kneading compaction’ is found to improve lime-dispersion and soil fabric. Such features, if accompanied by available water, favors the development of cementitious compounds. The effect of pore fluid on the hydraulic conductivity, k evolution, and leaching mechanism of kneaded lime-treated soil is studied. Using demineralized water as pore fluid is found to be comparatively aggressive than a low-ionic strength solution. Thus, demonstrating the importance of consideration of the type of permeant solution. Long-term performance of lime-treated soil by subjecting them to wetting-drying cycle using different testing conditions and different wetting fluids is evaluated. The evaluation revealed the importance of consideration of the nature of wetting fluid and temperature effects on the physicochemical and microstructure evolution of lime-treated soil. Thus, the reproduced compaction procedure, nature of the permeant solution, and testing conditions in the laboratory scale must be closer to the field situation
33
Ju, Hwanik. "Influence of Curing Temperature on Strength of Cement-treated Soil and Investigation of Optimum Mix Design for the Wet Method of Deep Mixing." Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/86723.
Повний текст джерелаАнотація:
The Deep Mixing Method (DMM) is a widely used, in-situ ground improvement technique that modifies and improves the engineering properties of soil by blending the soil with a cementitious binder. Laboratory specimens were prepared to represent soil improved by the wet method of deep mixing, in which the binder is delivered in the form of a cement-water slurry. To study the influence of curing temperature on the strength of the treated soil, specimens were cured in temperature-controlled water baths for the desired curing time. After curing, unconfined compressive strength (UCS) tests were conducted on the specimens. To investigate the optimum mix design for the wet method of deep mixing, UCS tests were performed to measure the strength of cured specimens, and laboratory miniature vane shear tests were conducted on uncured specimens to measure the undrained shear strength (su), which is used to represent the consistency of the mixture right after mixing. The consistency is important for field mixing because a softer mixture is easier to mix thoroughly. Based on the UCS test results, an equation that can provide a good fit to the strength data of the cured binder-treated soil is proposed. When the curing temperature was changed during curing, the UCS of the specimen cured at a low temperature and then cured at a high temperature was greater than the UCS of the specimen cured at a high temperature first. This seems to be due to different effects of elevated curing temperatures at early and late curing times on the cement reaction rates, such that elevating the curing temperature later produces a more constant reaction rate, which contributes to the reaction efficiency. An optimum mix design that minimizes the amount of binder while satisfying both a target strength of the cured mixture and a target consistency of the uncured mixture can be established by using the fitted equations for UCS and su. The amount of binder required for the optimum mix design increases as the plasticity of the base soil increases and the water content of the base soil (wbase soil) decreases.Master of Science
The Deep Mixing Method (DMM) is a ground improvement technique widely used to improve the strength and stiffness of loose sands, soft clays, and organic soils. The DMM is useful for both inland and coastal construction. There are two types of deep mixing. The dry method of deep mixing involves adding the binder in the form of dry powder, and the wet method of deep mixing involves mixing binder-water slurry with the soil. The strength of the cured mixture is significantly influenced by the amount of added cement and water, the curing time, and the curing temperature. This research evaluates the influence of curing temperature on the strength of cured cement-treated soil mixture. Mixture proportions and curing conditions also influence the consistency of the mixture right after mixing, which is important because it affects the amount of mixing energy necessary to thoroughly mix the binder slurry with the soil. This research developed and evaluated fitting equations that correlate the cured mixture strength and the uncured mixture consistency with mixture proportions and curing conditions. These fitting equations can then be used to select an economical and practical mix design method that minimizes the amount of binder needed to achieve both the desired cured strength and uncured consistency. The amount of binder required for the optimum mix design increases as the plasticity of the base soil increases and the water content of the base soil (wbase soil) decreases.
34
Murray, Matthew I. "Analysis of Aquifer and Operational Conditions for Successful Soil Aquifer Treatment of Treated Wastewater via Synthesis of Published Full-Scale and Laboratory-Scale Studies." DigitalCommons@CalPoly, 2020. https://digitalcommons.calpoly.edu/theses/2165.
Повний текст джерелаАнотація:
Soil aquifer treatment (SAT) of treated wastewater performance was evaluated across published full-scale and lab-scale studies developing insights on the aquifer and operational factors that affect SAT efficacy. The goal of this study was to develop a basis for predicting the contaminant removal capabilities of any given aquifer during managed recharge with treated wastewater.
Over 40 published SAT studies were reviewed and systematically compared to determine the influence of five major factors on contaminant removal performance: geologic composition, geochemical conditions, hydrogeological conditions, operational methods, and source water quality. Removal mechanisms for standard contaminants (dissolved and total organic carbon, nitrogen, and pathogens) were considered for each factor. By supplementing the theoretical understanding of contaminant removal in SAT systems with full scale and lab scale results, recommendations were developed for practical and effective SAT feasibility standards.
SAT of standard contaminants was found to be most effective in aquifers with a water table below 20-meters. SAT was also most favorable for source water with 10 to 20-mg/L of bulk organics and less than 10-mg/L of total nitrogen. Moreover, extended residence times in the saturated zone provide little additional bulk organic and nitrogen removal for aquifers with vadose zones that achieve more than 85% of total bulk organic removal. The results of this study should enhance feasibility studies for future soil aquifer treatment projects, thereby facilitating the use of sustainable indirect potable reuse.
35
Fogler, Kendall Wilson. "Effect of Soil Amendments from Antibiotic Treated Cows on Antibiotic Resistant Bacteria and Genes Recovered from the Surfaces of Lettuce and Radishes: Field Study." Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/92587.
Повний текст джерелаАнотація:
Cattle are commonly treated with antibiotics that may survive digestion and promote antibiotic resistance when manure or composted manure is used as a soil amendment for crop production. This study was conducted to determine the effects of antibiotic administration and soil amendment practices on microbial diversity and antibiotic resistance of bacteria recovered from the surfaces of lettuce and radishes grown using recommended application rates. Vegetables were planted in field plots amended with raw manure from antibiotic-treated dairy cows, composted-manure from cows with different histories of antibiotic administration, or a chemical fertilizer control (12 plots, n=3). Culture-based methods, 16SrDNA amplicon sequencing, qPCR and shot-gun metagenomics were utilized to profile bacteria and characterize the different gene markers for antibiotic resistance. Culture-based methodologies revealed that lettuce grown in soils amended with BSAs had significantly larger clindamycin resistant populations compared to control conditions. Growth in BSAs was associated with significant changes to the bacterial community composition of radish and lettuce. Total sul1 copies were 160X more abundant on lettuce grown in manure and total tet(W) copies were 30X more abundant on radishes grown in manure. Analysis of shotgun metagenomic data revealed that lettuce grown in manure-amended soils possessed resistance genes for three additional antibiotic classes compared to other treatments. This study demonstrates that raw, antibiotic-exposed manure may alter microbiota and the antibiotic resistance genes present on vegetables. Proper composting of BSAs as recommended by the U.S. Department of Agriculture and Environmental Protection Agency is recommended to mitigate the spread of resistance to vegetable surfaces.MSLFS
36
Villalba, Hugo Abelardo González. "Blending polymer-sulfur coated and NBPT-treated urea to improve nitrogen use efficiency and grain yield in corn production systems." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/11/11140/tde-14082018-100857/.
Повний текст джерелаАнотація:
Blends of controlled release and stabilized nitrogen (N) fertilizer represent an alternative to provide N at all corn growth stages, and is an option to reduce costs compared to the use of solely controlled release N. In this context, field experiments were conducted in Southeast Brazil with the use of a blend of polymer-sulfur coated urea (PSCU) and NBPT-treated urea (NBPTU) at a 70:30 ratio, applied at corn planting and incorporated into the soil. The objectives of the study were: i) to quantify and measure each fertilizer-derived N fate in the plants, and determine the nitrogen recovery efficiency of each N source in the blend; ii) to evaluate corn grain yield response to N rates (blend) in contrasting cropping systems, and to assess the posibility of reducing N rate when applying a blend of two enhanced efficiency N fertilizers compared to the application of regular urea; iii) understand and monitor changes in plant biomass and N uptake during the growing season. Fertilizer N contributed with less than 50% of the total plant N uptake at all evaluated corn growth stages (V4, V12, R2, and R6). At V4 growth stage, most of the N in the plant derived from fertilizer (NPDF) was provided by NBPTU, while later in the season, most of the NPDF was provided by PSCU. At harvest, most of the plant N was allocated in the grains (59%). Of the total plant N, 64% was supplied by the native soil N pool, 26% was provided by PSCU, and 10% by NBPTU. Therefore, NBPTU provided N to corn early in the season, while PSCU played a crucial role supplying N later in the season, as plants demand for N increased. Soil N was the main N source at all GS and this fraction decreased as N rate increased. At harvest, 64% of the total plant N was derived from the soil native N pool, 26% derived from PSCU, and 10% from urea. The measured fertilizer NRE of urea was in average 36%, and the estimated NUE from PSCU was 51%. In the second study, corn grain yield varied between sites, probably due to soil and climate characteristics of each site. Corn grain yield, N uptake, and biomass production were greatly impacted by fertilizer N. Grain yield and N uptake showed a quadratic response to N rates (blend). The blend of PSCU and NBPTU, applied at corn planting and incorporated into the soil proved to be a great strategy to attain yields at N rates below those needed when using regular urea. The third chapter focused on corn biomass and N uptake and partitioning throughout the growing season, and it was demonstrated that the amount of N uptake after flowering can reach up to 50% of the total plant N, thus, N availability must be guaranteed in late vegetative corn growth stages, and especially in the reproductive stages, which can be achieved by adopting enhanced efficiency N fertilizers such as the blend of PSCU and NBPTU used in this study.A mistura de fertilizantes nitrogenados de liberação controlada e estabilizados representa uma alternativa para fornecer nitrogênio (N) em todos os estádios da cultura do milho, além de ser uma opção válida para reduzir custos em comparação ao uso exclusivo de produtos de liberação controlada. Neste sentido, conduziram-se experimentos de campo na região Sudeste do Brasil com a aplicação de um blend de ureia revestida com enxofre e polímeros (UREP) e ureia tratada com NBPT (U-NBPT), na proporção 70:30, aplicada na semeadura do milho, de forma incorporada. Os objetivos do trabalho foram: i) avaliar o destino do N dentro das plantas de milho proveniente dos fertilizantes misturados e determinar a eficiência de recuperação de cada um; ii) avaliar a resposta do rendimento de grãos de milho a doses de N (blend) em sistemas de produção contrastantes e avaliar a possibilidade de reduzir as doses de N quando aplicado o blend em comparação à ureia convencional; iii) entender e monitorar as mudanças da biomassa e o nitrogênio dentro das plantas de milho ao longo do ciclo da cultura. No primeiro estudo, o N na planta proveniente da UREP, da U-NBPT, e do solo (N-Solo) variaram ao longo do ciclo do milho. Contudo os fertilizantes nitrogenados contribuiram com menos de 50% do N total da planta em todos os estadios avaliados (V4, V12, R2 e R6). No estádio V4, a maior parte do N na planta proveniente de fertilizante (NPPF) foi fornecido pela U-NBPT, enquanto que nos estadios seguintes, a maior parte do NPPF foi fornecido pela UREP. O N-Solo foi o maior fornecedor de N para a planta, mas a contribuição diminuiu com o aumento das doses de N. Na colheita, 59% do total do N da planta foi alocado nos grãos. Do total de N da planta, 64% foi proveniente do N-Solo, 26% foi fornecido pela UREP, e 10% pela U-NBPT. A eficiência de recuperação da UREP e U-NBPT foram, respectivamente, 51 e 36%. No segundo estudo, o rendimento de grãos de milho variou entre locais, provavelmente devido às condições edafo-climáticas de cada área experimental. A aplicação do fertilizante nitrogenado influenciou o rendimento de grãos de milho, a produção de biomassa e acúmulo de N em todos os locais. O rendimento de grãos e acúmulo de N mostraram uma resposta quadrática às doses de N (blend). A incorporação do blend de UREP e U-NBPT na semeadura do milho mostrou-se como uma ótima estratégia para evitar perdas massivas de N e mostrou que pode atingir produtividade similar a ureia convencional com doses de N menores. O terceiro capítulo, com foco no acúmulo e particionamento da biomassa e N nas plantas de milho ao longo do ciclo, desmonstrou que a quantidade de N absorvido após o florescimento pode chegar a 50% do total de N acumulado nas plantas, pelo que adequada disponibilidade de N deve ser garantida nos estádios vegetativos finais e nos estádios reprodutivos da cultura do milho, o que pode ser conseguido com o uso de misturas de UREP e U-NBPT.
37
Somireddy, Upender Reddy. "Effect of Herbicide-Organic Mulch Combinations on Weed Control and Herbicide Persistence." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1325255792.
Повний текст джерела
38
Dixon, Paul A. "Factors Affecting the Strength of Road Base Stabilized with Cement Slurry or Dry Cement in Conjunction with Full-Depth Reclamation." BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/2629.
Повний текст джерелаАнотація:
Full-depth reclamation (FDR) in conjunction with cement stabilization is an established practice for rehabilitating deteriorating asphalt roads. Conventionally, FDR uses dry cement powder applied with a pneumatic spreader, creating undesirable fugitive cement dust. The cement dust poses a nuisance and, when inhaled, a health threat. Consequently, FDR in conjunction with conventional cement stabilization cannot generally be used in urban areas. To solve the problem of fugitive cement dust, the use of cement slurry, prepared by combining cement powder and water, has been proposed to allow cement stabilization to be utilized in urban areas. However, using cement slurry introduces several factors not associated with using dry cement that may affect road base strength, dry density (DD), and moisture content (MC). The objectives of this research were to 1) identify construction-related factors that influence the strength of road base treated with cement slurry in conjunction with FDR and quantify the effects of these factors and 2) compare the strength of road base treated with cement slurry with that of road base treated with dry cement. To achieve the research objectives, road base taken from an FDR project was subjected to extensive full-factorial laboratory testing. The 7-day unconfined compressive strength (UCS), DD, and MC were measured as dependent variables, while independent variables included cement content; slurry water batching temperature; cement slurry aging temperature; cement slurry aging time; presence of a set-retarding, water-reducing admixture; and aggregate-slurry mixing time. This research suggests that, when road base is stabilized with cement slurry in conjunction with FDR, the slurry water batching temperature; haul time; environmental temperature; and presence of a set-retarding, water-reducing admixture will not significantly affect the strength of CTB, provided that those factors fall within the limits explored in this research and are applied to a road base with similar properties. Cement content and cement-aggregate mixing time are positively correlated with the strength of CTB regardless of cement form. Additionally, using cement slurry will result in slightly lower strength values than using dry cement.
39
Woods, William Eric. "Copper migration through petroleum-treated soils." Virtual Press, 1990. http://liblink.bsu.edu/uhtbin/catkey/722463.
Повний текст джерелаАнотація:
The purpose of the project was to determine the effect of various petroleum amendments on the migration rate of Cu. The petroleum amendments used in this research are frequently added to the soil surface in petroleum landfarming. Such petroleum wastes often contain significant amounts of Cu and other metals.Soil columns were amended with citric acid, used crankcase oil and Illinois crude oil. Each amendment was spiked (treated) with three different concentrations of Cu and each treatment was replicated three times. The columns were leached once per week, for ten weeks, with distilled water acidified to pH 4.5 to simulate acid rain. Leachate from the soil columns was analyzed weekly for total Cu. At the end of the ten week period, the soil was analyzed for Cu and TOC content at 7 cm intervals to determine the amount of migration by Cu and the organic amendments, resectively. The soil (a Glynwood silt loam) and the organic amendments were each analyzed for total Cu to determine background levels. The soil was analyzed for pH, TOC, electrical conductivity and soil texture.Analysis of the leachate and soil showed differential migration of Cu through the soil columns. Significant levels of Cu leached in the columns amended with citric acid (as high as 85.3 mg/L) in the first 3 weeks of the study. The Cu content of the leachate from columns amended with crude petroleum were at approximately background levels (5.5 mg/L) as was the leachate from columns amended with crankcase oil (0.2 mg/L). In the later weeks of the research, as the petroleum amendments were broken down by microorganisms, some Cu was chelated to small fragments of the petroleum and leached through the soil columns. Most of the Cu appeared to remain on the surface of the columns, bound to the petroleum amendments. Analysis of the soil, for total Cu content with depth, showed very little Cu accumulation at any depth in the soil column, beyond the soil surface. In most cases Cu levels remained near the background levels found in the control columns.Moderate correlation was found (r2 = .59 for crude oil; r2 = - .54 for crankcase oil; r2 = .85 for citric acid) between Cu levels and TOC levels in the soil columns with depth.From the results of the current study it can be inferred that practices such as petroleum landfarming and land disposal of some hazardous materials may allow for the migration of both the applied petroleum wastes and any metals which may be contained within.Department of Natural Resources
40
D’ávila, Rodrigo Souza. "APLICAÇÃO DE REGRESSÃO LINEAR MÚLTIPLA NA ANÁLISE DA DINÂMICA DE CÁTIONS TROCÁVEIS EM UM SISTEMA SOLO-PLANTA IRRIGADO COM ÁGUA RESIDUÁRIA." UNIVERSIDADE ESTADUAL DE PONTA GROSSA, 2013. http://tede2.uepg.br/jspui/handle/prefix/123.
Повний текст джерелаАнотація:
Made available in DSpace on 2017-07-21T14:19:22Z (GMT). No. of bitstreams: 1
Rodrigo Souza.pdf: 360141 bytes, checksum: 6bf9d8f9ce30fb6fa717ad9798736d1e (MD5)
Previous issue date: 2013-07-22Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
The competition of water in different regions of the world, between agriculture and the human needs, has led to restrictions in the increase of food production, resulting in search for alternative sources. The use of effluent from secondary treatment of sewage (ETSE) has been a common practice in several seasonal situations. The aims of this work were: (i) create regression models to assist in the understanding of the dynamics of acidity (current, exchangeable and total), the exchangeable bases and the exchangeable sodium percentage (ESP) in the soil, through the use of multiple linear regression (RLM), considering variables of soil, soil solution, plant, ETSE, weather and complementary variables, and (ii) compare the generated models with the standard method and the models generated from selecting variables. For the construction of the MLR models, the method of stepwise variable selection, forward and backward were used and compared with the standard method through the index adjusted determination coefficient (R2adj) and the variance inflation factor (VIF). The models developed from the method of variables selection were the most indicated. All the attributes in the scenarios and layers of the studied soils were not explained by the same group of variables. In general the results were consistent as far as the pH increased, the H + Al (total acidity) and Al (potential acidity) concentration decreased and Ca (calcium), Mg (magnesium) were increased. Because of the low-K (potassium) in the soil, the contribution of this nutrient by irrigation with ETSE cause little influence in the concentrations of this element. Due to the high sodium absorption ratio (SAR) in the effluent concentrations of this element, as well as PST were increased over time in soil. The accumulation and export of Na (sodium) by plants was not sufficient to prevent the increase in the concentrations of exchangeable Na and ESP in all studied scenarios and layers.
A concorrência de água entre o setor agrícola e as necessidades humanas em diversas regiões do mundo tem ocasionado restrições no incremento da produção de alimentos, implicando em buscas por fontes alternativas. A utilização de efluente de tratamento secundário de esgoto (ETSE) tem sido uma prática comum em várias situações sazonais. Objetivou-se neste trabalho:(i) criar modelos de regressão para auxiliar no entendimento da dinâmica da acidez (trocável e total), bases trocáveis e percentual de sódio trocável (PST) no solo, através do uso de regressão linear múltipla (RLM), considerando variáveis de solo, solução no solo, planta, ETSE, meteorológicas e variáveis complementares; e (ii) comparar os modelos gerados com método padrão e os modelos gerados com seleção de variáveis. Para construção dos modelos de RLM foram utilizados o método de seleção de variáveis stepwise, forward e backward e comparados com o método padrão, através dos índices de coeficiente de determinação ajustado (R2adj) e do fator de inflação de variância (FIV). Os modelos desenvolvidos a partir do método de seleção de variáveis foram os mais indicados. Todos os atributos nos cenários e camadas de solos estudados não foram explicadas por um mesmo grupo de variáveis. De modo geral, os resultados foram coerentes, pois na medida em que o pH aumentou, as concentrações H+Al e Al diminuíram e as de Ca e Mg foram incrementadas. O baixo teor de K no solo, evidenciou que o aporte desse nutriente pela irrigação com ETSE pouco influência as concentrações desse elemento. Devido à alta razão de adsorção de sódio (RAS) no ETSE as concentrações deste elemento, bem como PST foram aumentadas ao longo do tempo no solo. O acúmulo e a exportação de Na pelas plantas não foi suficiente para evitar o incremento nas concentrações de Na trocável e PST em todos os cenários e camadas estudados.
41
Kohut, Rafael. "Závlaha vyčištěnými odpadními vodami." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2017. http://www.nusl.cz/ntk/nusl-265532.
Повний текст джерелаАнотація:
The thesis deals with the issue of simulation of treated wastewater irrigation by the HYDRUS 2D software. The first part of the thesis is designed as a theoretical research of academic information and knowledge. It aims at introducing the issue of treated wastewater utilization for the purpose of the irrigation. Furthermore it provides basic theoretical information on numeric simulation of the dissolved materials motion and transport in the soil. The last chapter of the theoretical part describes the calibration of the simulation by the HYDRUS 2D software. The second part of the thesis is devoted to the formation of filtration columns placed in the chosen site of the root zone wastewater plant. Within the filtration columns the automatic irrigation was formed and set off. Measuring of humidity in filtration columns was taking place for 81 days as well as the water sampling after the flow through the soil horizons. On the grounds of the measuring results the calibration of numeric simulation was carried out by the HYDRUS 2D software. The last part of the thesis presents the applications through the extending and alternation of the modelled setting. The main aim of the thesis is to calibrate the model and propose a general solution to advancement at realization of irrigation details when using the treated wastewater for the purpose of irrigation.
42
Chevremont, Anne-Celine. "Optimisation multivariée d’un traitement des eaux usées par DEL-UV en vue d’une réutilisation pour l’irrigation Multivariate optimization of fecal bioindicator inactivation by coupling UV-A and UV-C LEDs Effect of coupled UV-A and UV-C LEDs on both microbiological and chemical pollution of urban wastewaters Impact of watering with UV-LED-treated wastewater on microbial and physico-chemical parameters of soil Fate of carbamazepine and anthracene in soils watered with UV-LED treated wastewaters." Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4735.
Повний текст джерелаАнотація:
Le développement de nouvelles technologies pour le recyclage des eaux usées est une priorité pour les régions arides et semi-arides tels que les pays du bassin méditerranéen. L'objectif de ce travail a été, dans un premier temps, de développer un système de traitement tertiaire des eaux usées en testant l'efficacité de diodes électroluminescentes émettant des UV-A et/ou des UV-C (DEL-UV) sur l'inactivation de souches bactériennes indicatrices de pollution fécale (Escherichia coli et Enterococcus faecalis) puis sur des effluents urbains, en étudiant la diminution des pollutions microbiennes et chimiques. Cette première étape a mis en évidence l'efficacité accrue du couplage UV-A et UV-C, permettant d'obtenir une eau de qualité répondant aux exigences législatives relatives à la réutilisation des eaux usées pour l'irrigation. La deuxième partie de ce travail était l'étude de l'impact de l'arrosage avec des eaux usées traitées par DEL-UV sur les paramètres du sol et sur le devenir de certain polluant aromatiques dans les sols (anthracène et carbamazépine). L'arrosage avec des eaux usées traitées par DEL-UV ne modifie pas la composition chimique de la matière organique de sol, l'activité catabolique globale des microorganismes, et le nombre et la diversité de bactéries indicatrices de pollution fécale par rapport au sol arrosé avec de l'eau d'irrigation. Certaines activités enzymatiques liées à la dégradation de la matière organique augmentent dans les sols arrosés avec des eaux usées traitées par DEL-UV, montrant que la matière organique apportée par l'effluent est activement dégradée par les microorganismesThe development of new technologies for wastewater reuse is a priority for arid and semi-arid areas such as Mediterranean countries. The objective of this work was, firstly, to develop a system for tertiary treatment of wastewaters testing LEDs emitting UV-A and / or UV-C (UV LEDs) on fecal indicator inactivation (Escherichia coli and Enterococcus faecalis) and then on urban effluents, by studying the decrease in both microbial and chemical pollution. This first step has highlighted a higher efficiency of this system when UV UV-A and UV-C are coupled. Wasterwaters with quality meeting the statutory requirements for the reuse of wastewater for irrigation were obtained and used in the second part of this work was to study the impact of watering with UV-LED- treated wastewaters on soil parameters and on the fate of pollutants (anthracene and carbamazepine) in soils. Watering with UV-LED treated wastewater does not change the chemical composition of soil organic matter, the global catabolic activity of soil microorganisms, and the number and diversity of fecal indicators compared to control (irrigation water). Certain enzymatic activities related to the degradation of organic matter increased in soil watered with UV-LED treated wastewater, showing that the organic matter added by the effluent is actively degraded by microorganisms. In addition, aromatic pollutants are oxidized two to three times faster in soils watered with UV-LED treated wastewater
43
Maxted, Andrew P. "Phytoextraction of cadmium from soils treated with sewage sludge." Thesis, University of Nottingham, 2003. http://eprints.nottingham.ac.uk/11887/.
Повний текст джерелаАнотація:
The efficacy of phytoextraction strategies were tested by pot and field trials on soil contaminated with heavy metals, including Cd, derived from long-term disposal of sewage sludge. The strategies investigated were: i) the use of hyperaccumulators; ii) chemically-enhanced uptake using arable species and iii) the use of short rotation coppice (SRC). Chemical interventions including EDTA, chloride salts, HCl and herbicide were used to enhance uptake by arable and SRC species. Tissue Cd concentrations in the Ganges population of Thlaspi caerulescens were lower than reported in other studies; the mean Cd concentration was 265 mg kg". It was deduced that Cd uptake was limited by a low Cd2+ concentration in soil and the rate at which solution Cd was replenished. High rates of plant mortality were observed, raising questions over the successful husbandry of T. caerulescens for phytoextraction. Chemical interventions produced significant increases in metal uptake by arable and SRC species. For example, Cd uptake by Z. mays following application of 10 mmol EDTA kg'' and by Salix caprea x cineria x viminalis following combined application of EDTA and HCI. However, concentrations were still well below those required for successful remediation. Furthermore downward migration of metal was observed through the soil profile following EDTA application. For example, the soil Cd concentration in the 0- 10 cm profile was reduced from 32.0 to 25.5 mg kg' seven months after application of 10 mmol EDTA kg'', yet only 1% of this reduction could be accounted for by Z. mays Cd off-take. Realistic estimates for phytoextraction timescales and costs were made in line with legislative thresholds. Overall the time required to reduce total soil Cd concentrations below 3 mg kg-1 was large and the costs were prohibitive. For example, although Cd off-take by Ganges was greater than for any of the other species tested, it was estimated that well over one century would be required to reach target metal concentrations.
44
Young, Tyler Blaine. "Early-age strength assessment of cement-treated materials /." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd1779.pdf.
Повний текст джерела
45
Antoniadis, Vasileios. "Heavy metal availability and mobility in sewage sludge-treated soils." Thesis, University of Reading, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298663.
Повний текст джерела
46
Shea, Michael Scott. "Hydraulic Conductivity of Cement-Treated Soils and Aggregates after Freezing." BYU ScholarsArchive, 2010. https://scholarsarchive.byu.edu/etd/2434.
Повний текст джерелаАнотація:
Improvements in the strength and durability of frost-susceptible soils and aggregates can be achieved through chemical stabilization using portland cement, where the efficacy of cement stabilization for improving durability depends on the degree to which hydraulic conductivity is reduced. Hydraulic conductivity is commonly estimated from basic soil properties using Moulton's empirical equation. However, the hydraulic conductivity estimation does not consider the detrimental effects of freezing or the benefits of cement stabilization. The purpose of this research was to derive new equations relating hydraulic conductivity after freezing to specific material properties of cement-treated soils and aggregates stabilized with different concentrations of cement. This research included material samples from two locations in Alaska and from single locations in Minnesota, Montana, Texas, and Utah, for a total of six material samples. Each soil or aggregate type was subjected to material characterization by the Unified Soil Classification System (USCS) and the American Association of State Highway and Transportation Officials (AASHTO) classification system. Moisture-density curves were developed, and unconfined compressive strength (UCS) testing was performed to determine cement concentrations generally corresponding to low, medium, and high 7-day UCS values of 200, 400, and 600 psi, respectively. After being cured for 28 days at 100 percent relative humidity, the prepared specimens were subjected to frost conditioning and hydraulic conductivity testing. The Alaska-Elliott, Minnesota, Montana, and Utah materials exhibit decreasing hydraulic conductivity with increasing UCS, the Texas material exhibits increasing hydraulic conductivity with increasing strength from the low to medium cement concentration levels but decreasing hydraulic conductivity from the medium to high cement concentration levels, and the Alaska-Dalton material exhibits increasing hydraulic conductivity with increasing strength. Multivariable regression analyses were performed to investigate relationships between hydraulic conductivity and several material properties, including soil gradation and classification, fineness modulus, specific gravity, cement content, porosity, compaction method, dry density, and 7-day UCS for each specimen. The R2 values computed for the six-parameter, four-parameter, USCS, and AASHTO-classification models are 0.795, 0.767, 0.930, and 0.782, respectively. Further research is recommended to investigate the effects of cement on hydraulic conductivity for USCS and AASHTO soil types not covered in this research.
47
Mitchell, Leslie Grant. "Solubility and phytoavailability of cadmium in soils treated with nitrogen fertilizers." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/mq23423.pdf.
Повний текст джерела
48
Robin, Victor Paul Michel. "Analytical and numerical modelling of artificially structured soils." Thesis, University of Exeter, 2014. http://hdl.handle.net/10871/16565.
Повний текст джерелаАнотація:
The effects of lime treatment on the mechanical properties of soils are usually not accounted for in the design of geotechnical structures. As a result the potential of lime treatment has not been fully exploited. In this thesis, a comprehensive experimental program has been carried out to identity the key features of the mechanical behaviour of structured materials. The chemical modifications arising from lime treatment were quantified using thermal analysis methods. From these results a non-linear chemo-mechanical coupling was established between the concentration of cementitious compounds and the yield stress. Using these results, a new formulation to model the degradation of the structure at yield has been developed and implemented in a constitutive model for structured materials. This new model, developed in the framework of the Modified Cam Clay model, requires a limited number of additional parameters that all have a physical meaning and can all be determined from a single isotropic compression test. The model has proven to be successful in reproducing the key features of structured materials and for the modelling of the mechanical behaviour of lime treated specimens under various stress paths. Due to similarities in behaviour, it is shown that the formulation is also suitable for naturally structured soils. To account for a structured material in the design of geotechnical structures, a fully functional finite element program for elasto-plastic problems was developed including the pre- and post-processing of the results. A thorough validation has confirmed the good implementation of the finite element method and its suitability for the modelling of complex geometries involving structured materials.
49
Paul, Craig M. "Microbial and Chemical Affects on Leachate from Calcareous Soils Treated with Wastewater Effluent." BYU ScholarsArchive, 2005. https://scholarsarchive.byu.edu/etd/462.
Повний текст джерелаАнотація:
Increasing human populations are placing greater strain on water resources, prompting the use of treated wastewater effluent for irrigation in some areas, including the desert regions of the Western United States. To determine the potential effects of using secondary effluent for irrigation, we applied wastewater effluent and irrigation waters to natural and artificially constructed calcareous soils in greenhouse and field lysimeters, and in soil columns. The leachate from one field lysimeter contained increased fecal coliform counts than the effluent. Leachate coliform counts were decreased or not significantly changed in two field lysimeters. Electrical conductivity (EC), sodium adsorption ratio (SAR), chloride and nitrate concentrations also increased significantly in the leachate of the three field lysimeters however. Samples collected from the greenhouse lysimeters showed a significant decrease in all categories except EC, was not significantly changed. Soil column drainage samples showed a decrease in coliform counts, and increase in EC and chloride levels while SAR and nitrate levels varied with clay content. Preferential flow of coliform bacteria and high EC and SAR values could indicate long term effects that may affect the sustainability of the practice.
50
McBroom, Mark David. "Kinetics and community profiling of sulfate-reducing bacteria in organic carbon treated mine tailings." Thesis, Montana State University, 2005. http://etd.lib.montana.edu/etd/2005/mcbroom/McBroomM0505.pdf.
Повний текст джерела