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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Utilização de imagens de satélite para predição de clorofila-a e sólidos suspensos em corpos d\'água: estudo de caso da Represa do Lobo/SP / Use of satellite images to predict chlorophyll-a and suspended solids in water bodies: a study case of the Lobo Reservoir/SP

Guimarães, Tainá Thomassim 23 May 2019 (has links)
Medidas complementares ao monitoramento in situ da qualidade da água podem ser obtidas por meio de sensoriamento remoto, sendo clorofila-a e sólidos suspensos alguns dos parâmetros que podem ser estimados. Este trabalho teve como objetivo explorar técnicas de processamento de imagens, análises estatísticas e de inteligência artificial com o objetivo de predizer e modelar as concentrações de clorofila-a e sólidos suspensos totais na Represa do Lobo/SP. Metodologicamente, foram realizadas coletas em campo, em três diferentes datas, para amostragem de água e posterior análise laboratorial. Os resultados limnológicos foram analisados, modelados e comparados com imagens processadas do satélite Sentinel-2. Análises de regressão e redes neurais artificiais (RNA) foram exploradas para gerar modelos de predição para a área de estudo. Os resultados indicam que métodos de regressão podem não ser adequados para capturar as relações lineares e/ou não-lineares entre os compostos de interesse e as respostas espectrais da água recebidas pelo satélite, indicando a capacidade das redes neurais em modelar relações mais complexas. Através da integração da resposta que o sensor MSI do satélite Sentinel-2 coletou nas regiões do visível ao infravermelho médio e de RNAs foi possível modelar a concentração de clorofila-a, com valores de R² superiores a 0,65 e de RMSE inferiores a 2,5 μg/L, e gerar mapas que permitam seu monitoramento temporal e análise espacial na área de estudo. Os resultados para SST não foram satisfatórios devido à complexidade óptica do ambiente analisado, bem como as baixas concentrações de SST na represa. Portanto, a integração de dados de sensoriamento remoto no mapeamento de corpos d\'água com a aplicação de redes neurais na análise de dados é uma abordagem promissora para prever clorofila-a e sólidos suspensos, bem como suas variações temporais e espaciais. / Complementary measures to in situ monitoring of water quality can be obtained through remote sensing, with chlorophyll-a and suspended solids being some of the parameters that can be estimated. The objective of this work was to explore techniques for image processing, statistical analysis and artificial intelligence with the objective of predicting and modeling the concentrations of chlorophyll-a and total suspended solids in the Lobo Reservoir/SP. Methodologically, field samples were collected in three different dates for water sampling and laboratory analysis. The limnological results were analyzed, modeled and compared with processed images of the Sentinel-2 satellite. Regression analysis and artificial neural networks (ANNs) were explored to generate prediction models for the study area. The results indicate that regression methods may not be adequate to capture linear and/or nonlinear relationships between the compounds of interest and the spectral responses of water received by the satellite, indicating the ability of neural networks to model more complex relationships. Through of the integration of response wich the MSI sensor of Sentinel satellite collected in the visible and near-infrared regions and of the ANN analysis was possible modeling the chlorophyll-a concentration, wich R² values highers of 0.65 and RMSE less 2.5, and create predict maps wich allow your temporal monitoring and spatial analysis in the study area. The TSS results were unsatisfactory because of the optic complexity of analysed ambient, as well as your small TSS concentrations in the Lobo Reservoir. Therefore, the integration of remote sensing data in the mapping of water bodies with the application of neural networks in the data analysis is a promising approach to predict chlorophyll-a and suspended solids as well as their temporal and spatial variations.
12

Evaluation of compost specifications for stormwater management

Birt, Lindsay Nicole 15 May 2009 (has links)
Urban development will continue to increase in Texas because of population growth and urban sprawl. Despite the desire for urbanization and expansion of the economy, this growth increases the amount of construction, which, if not properly managed, can increase non-point source pollution and threaten surface water quality. Therefore, Texas Department of Transportation (TxDOT) has approved and promoted the use of compost as a stormwater best management practice (BMP) during highway construction. The objectives of this study were to construct and calibrate an indoor rainfall simulator and to determine the effectiveness of using compost rather than conventional hydroseeding or topsoil to reduce erosion from disturbed soils. Runoff rates, interrill erosion, and interrill erodibility were determined and compared across five compost treatments following TxDOT specifications for compost applied as an erosion control and two control treatments of topsoil (TS) and hydroseeding (HS) applied at 5 cm depth. The simulator produced 89% uniformity using ten Veejet 80100 nozzles at a target rate of 100 mm h-1. The surface runoff was collected after 5 minutes of rainfall (first flush) and during the last 30 minutes of rainfall (steady-state). The first flush mean runoff for GUC-5 treatment was significantly higher than all other treatments. All other treatments; 50% woodchips and 50% compost blend (ECC-1.3, ECC-5), and hydroseeding (HS) had significantly lower runoff and erosion rates compared to topsoil (TS) and compost manufactured topsoil (CMT) at first flush and steady-state. Furthermore, there were no performance differences between 1.3 cm and 5 cm compost applications at first flush or steady-state. The results of this project indicate that particle size, soil moisture capabilities, and time at which rainfall is applied affect surface runoff. TxDOT specification of using ECC at 5 cm depth on a max of 3:1 slope should be reconsidered. An ECC application depth of 1.3 cm was effective in reducing first flush runoff and interrill erosion rates.
13

Treatment conditions for the removal of contaminants from road runoff

Hallberg, Magnus January 2007 (has links)
The pollutant load in road runoff is related to traffic densities and road maintenance activities. Inurbanised areas treatment of road runoff is common and often considered necessary. The pollutantsare partitioned between the particulate and dissolved matter. However, the contaminantstend to have an affinity to the particulate material. Sedimentation, the predominant treatmentmethod for road runoff uses various types of ponds. Design tools used for stormwater treatmentsystems are based on extensive data from existing treatment systems. The variations in the empiricaldata make it difficult when attempting to evaluate precise conditions for pollutant removaland thereby minimising the land use for a treatment facility. This is a concern in highly urbanisedareas where land use often is restricted.In this work, field studies were conducted in three separate watersheds along the same motorwaywith an annual average daily traffic exceeding 120,000 vehicles. The aim was to assess treatmentconditions for the removal of contaminants from road runoff.The study of mass transport of total suspended solids used the EU Directive (1991/271/EEC)discharge requirement for urban wastewater treatment: 60 mg/l during winter and summer. Theresults showed that a capture of the total runoff volume was necessary during both seasons. Tenmetals (Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn), as dissolved and particulate bound, werestudied in the road runoff during a winter season and the following summer period. The dissolvedpart of Al, Cd, Co, Cr, Mn, and Ni was significantly higher in winter. The mass concentration(mg/kg) for all metals was significantly higher over the summer except for Al and Co, whichshowed a higher mass concentration during the winter. The total metal concentration showed agood correlation to total suspended solids (TSS) during winter with exception for Cd. Good correlationto TSS was also found for the summer period for Al, Cu, Fe, Mn, Ni, and Zn. A simplemodel could describe sedimentation by the initial concentration of TSS, albeit road salt (NaCl)had a significant impact on the sedimentation process during winter. Removal of dissolved metalswas studied by column experiments using water granulated blast furnace slag. The result showedgood removal for Cd, Cu, Ni, and Zn independent of NaCl concentrations. Sediment accumulation(mg sediment/mm precipitation) was relatively consistent for the studied summer seasons asopposed to winter. The sediment differed in metal mass concentrations (mg/kg) between theseasons. Concentrations of Cu and Zn were high in regard to the guidelines for sensitivity ofsediment dwelling organisms and Swedish guidelines for contaminated soils.The findings suggest that the entire runoff volume must be captured for treatment. The reductionof TSS concentration could be estimated for a specific surface load (m/h). This would alsoapply for majority of the studied metals that correlated well to the particulate material. Reactivefilter technology using water granulated blast furnace slag could be applied for treatment of runofffor the reduction of dissolved metals. However, long-term studies are necessary for its practicalimplementation. Furthermore; the work shows that on-line turbidity measurements could beused for expedient process control for treatment facilities in similar watersheds dominated byroads. The work could be used together with existing design methods and models to evaluate andoptimise road runoff treatment. / Föroreningsbelastningen i vägdagvatten är beroende av trafikbelastningen och vägunderhållet. Iurbaniserade områden är behandling av dagvatten vanlig och ofta bedömd nödvändig. Föroreningarnaär lösta och partikulära, men har vanligen en affinitet till det partikulära materialet. Denförhärskande behandlingsmetoden för dagvatten är sedimentering, vanligen i dammar. Designmodellernabygger på data från olika befintliga dagvattenanläggningar. Det varierande ursprungettill det empiriska underlaget medför svårighet att precist värdera designförutsättningarna och såledesminimera behandlingsanläggningens storlek. I förtätad stadsmiljö, där tillgång på mark ärbegränsad, kan detta vara ett problem.I detta arbete har fältförsök genomförts i tre avrinningsområden vilka domineras av en motorledmed en årlig dygnstrafik större än 120,000 fordon för att utvärdera behandlingsförutsättningar förvägdagvatten.Masstransporten av suspenderat material (SS) utvärderades utifrån EU Direktivet(1991/271/EEC) och gränsvärdet för avloppsvatten på 60 mg/l under vinter och sommar. Studienvisade att hela avrinningsvolymen bör behandlas oberoende av säsong. Fördelningen mellanpartikulärt och löst material studerades för tio metaller (Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn)under vinter och sommar. Den lösta delen av Al, Cd, Co, Cr, Mn och Ni var signifikant högreunder vintern. Den partikulära koncentrationen (mg/kg) för samtliga metaller var högre undersommaren med undantag för Al och Co vilka förekom i högre halter under vintern. Totalhalten(μg/l) av metallerna korrelerade väl med SS under vintern med undantag för Cd. Likaledes uppvisaderesultaten en god korrelation mellan SS och Al, Cu, Fe, Mn, Ni och Zn under sommaren.Sedimenteringsegenskaperna kunde beskrivas med en enkel modell utifrån koncentration av SS,men förhöjda halter av vägsalt (NaCl) befanns påverka sedimenteringen under vintern. Reduktionav lösta metaller studerades i pilotförsök med vattenkyld granulerad masugnsslagg. God avskiljningerhölls för Cd, Cu, Ni och Zn oberoende av förhöjda halter av vägsalt. Ackumulering avsediment (mg sediment/mm nederbörd) befanns vara konstant under sommaren i motsats tillstuderade vinterperioder. Sedimentkoncentrationerna av Cu och Zn var förhöjda med avseendepå riktlinjer för känslighet hos sedimentlevande organismer samt för återanvändning av slam.Resultaten visar att hela avrinningsvolymen måste behandlas. Reduktion av SS samt huvuddelenav metallerna, vilka visade god korrelation till det partikulära materialet, kan skattas utifrån enspecifik ytbelastning (m/h). Reduktion av lösta metaller kan ske med granulerad masugnsslagg,dock bör långtidsstudier genomföras. Vidare visar studien på möjligheten att nyttja kontinuerligturbiditetsmätning för en effektiv och praktisk processkontroll i reningsanläggningar för liknandeavrinningsområden med hög trafikbelastning. Resultaten av arbetet kan användas för bedömningoch optimering av vägdagvattenbehandling tillsammans med existerande designmetoder och modeller. / QC 20100709
14

To Analyze The Relationship between BOD, Nitrogen And Phosphorus Contents at Constant Dissolved Oxygen Concentration In Municipal Wastewater Treatment

Zaidi, Syed Faraz Ali, Sudthanom, Juthatip January 2011 (has links)
In this report, the application of Principle Component Analysis (PCA) and Partial Least Square (PLS)  regression analyzing methods used to understand the relationship of interdependent loads in municipal wastewater treatment plant. Two different wastewater treatment plants were chosen for analysis of  the relationship between interdependent loads. Firstly, the collected data of incoming wastewater and outgoing water from both Västerås and Eskilstuna wastewater treatment plants were analyzed to find some relationship or correlation between contents and compare the data of both the plants. Secondly, the correlated contents were used to generate the regression model for predicting the value in the future, in this report we have focussed only on ammonium nitrogen value for regression model. The PCA study shows the variation between incoming and outgoing wastewater’s characteristics  given by  Västerås and Eskilstuna plant. / BOD, ammonium nitrogen, nitrogen, phosphorus
15

Evaluation of compost specifications for stormwater management

Birt, Lindsay Nicole 15 May 2009 (has links)
Urban development will continue to increase in Texas because of population growth and urban sprawl. Despite the desire for urbanization and expansion of the economy, this growth increases the amount of construction, which, if not properly managed, can increase non-point source pollution and threaten surface water quality. Therefore, Texas Department of Transportation (TxDOT) has approved and promoted the use of compost as a stormwater best management practice (BMP) during highway construction. The objectives of this study were to construct and calibrate an indoor rainfall simulator and to determine the effectiveness of using compost rather than conventional hydroseeding or topsoil to reduce erosion from disturbed soils. Runoff rates, interrill erosion, and interrill erodibility were determined and compared across five compost treatments following TxDOT specifications for compost applied as an erosion control and two control treatments of topsoil (TS) and hydroseeding (HS) applied at 5 cm depth. The simulator produced 89% uniformity using ten Veejet 80100 nozzles at a target rate of 100 mm h-1. The surface runoff was collected after 5 minutes of rainfall (first flush) and during the last 30 minutes of rainfall (steady-state). The first flush mean runoff for GUC-5 treatment was significantly higher than all other treatments. All other treatments; 50% woodchips and 50% compost blend (ECC-1.3, ECC-5), and hydroseeding (HS) had significantly lower runoff and erosion rates compared to topsoil (TS) and compost manufactured topsoil (CMT) at first flush and steady-state. Furthermore, there were no performance differences between 1.3 cm and 5 cm compost applications at first flush or steady-state. The results of this project indicate that particle size, soil moisture capabilities, and time at which rainfall is applied affect surface runoff. TxDOT specification of using ECC at 5 cm depth on a max of 3:1 slope should be reconsidered. An ECC application depth of 1.3 cm was effective in reducing first flush runoff and interrill erosion rates.
16

Agricultural nonpoint source pollution management: Water quality impacts of Balm Road Treatment Marsh, Hillsborough County, Florida

Malone, Sarah J 01 June 2009 (has links)
Balm Road Treatment Marsh is a 12 ha constructed wetland treatment system in south-central Hillsborough County, Florida created to improve water quality in Bullfrog Creek and ultimately Tampa Bay. The treatment system was designed to treat runoff from approximately 741 ha of upstream agricultural land prior to discharging into the creek, with the primary goals of reducing sediment and nutrient loads. Water quality data from four sites on Bullfrog Creek were analyzed to determine impacts to ambient water quality and pollutant load reductions downstream. Results were compared to the performance of other wetlands to treat both nonpoint and point source pollution. Impacts to ambient water quality in the creek were found to be minimal, if any, and although significant load reductions were found downstream, they could not be attributed to wetland treatment affects with confidence. In general, nonpoint source pollution, particularly from agriculture, was found to be treated less effectively than point sources. The importance of monitoring the performance of stormwater projects while employing a strategic sample design and including receiving water impacts is highlighted.
17

The effects of effluent discharge and concentration on streambed infiltration in the Lower Santa Cruz River

Prietto, Jacob January 2014 (has links)
Wastewater generated in the Tucson metropolitan region is conveyed to and treated at the Roger Road Wastewater Reclamation Facility (WRF) and Ina Road WRF. From 2005 to 2012, approximately 15,000 acre-feet per year of effluent was returned to the City of Tucson for additional filtration and reuse in the reclaimed water system. The remaining 48,000+ acre-feet per year of treated effluent was discharged to the Santa Cruz River, where a variable portion of the effluent infiltrates the streambed. The effluent that infiltrates the streambed contributes to recharge credits for participants invested in the Managed Underground Storage Facilities. In the effluent-dependent river, physical, chemical, and biological processes work in combination to develop a clogging layer near the streambed surface, which reduces infiltration. Previous studies have shown that large storm events have the ability to scour away the clogging layer and are the most significant processes contributing to establishing infiltration rates. Without the occurrence of large storm events, other variables such as effluent discharge and effluent concentrations affect infiltration to a lesser degree. Effluent discharge, biochemical oxygen demand, and total suspended solids are monitored and recorded daily at the outfalls of the WRFs. The parameters were investigated individually and in combination using statistical analyses to determine their correlations with streambed infiltration in the Santa Cruz River. The dry spring-early summer seasons from 2005 to 2012 were analyzed. A water balance was constructed for non-stormflow days during each time period. Evapotranspiration was calculated using riparian vegetation surveys and detailed delineations of aerial photography of the surface water and streamside herbaceous vegetation. Infiltration was derived as the residual of the water balance. At the daily time scale, correlations among variables were unobtainable due to the extremely variable characteristics of infiltration. The seasonal time scale analyses demonstrated an inverse relationship between both the effluent concentrations of biochemical oxygen demand and total suspended solids with infiltration and a direct correlation between effluent discharge and infiltration under extreme conditions. Under normal conditions, the distribution of discharge between Roger Road WRF and Ina Road WRF had a critical effect on infiltration as a result of the different deposition and erosive regimes through the Santa Cruz River.
18

Assessment of the Physical and Biological Effects of Mine Related Total Suspended Solids in Arctic Lakes

VanEngen, Ryan 09 May 2012 (has links)
The objective of this thesis was to assess the physical (concentrations, durations, and sedimentation) and biological effects of total suspended solids (TSS) in Arctic lakes following in-lake construction of dikes. TSS concentration and duration estimates were applied in a Severity of Ill Effects model which predicted possible habitat degradation and a reduction of feeding of salmonids with no significant difference between stations (ANOVA, p=0.153). Benthic invertebrates collected inside suspended sediment containment curtains showed a decrease in richness and abundance (Tukey’s, p<0.05), with no effects elsewhere. Stable isotope analysis from lake trout and arctic char muscle tissue suggested no differences in isotopic signatures following TSS exposure, but stable isotope analysis of stomach contents in lake trout had a significant increase in δ15N compared to the reference basin (Tukey’s, p<0.05). These findings suggested that lake trout adapted their food sources under moderate TSS exposure and benthic invertebrates rapidly recovered to pre-disturbance values. / Agnico-Eagle Mines Limited: Meadowbank Division and the University of Guelph; Research approved by Department of Fisheries and Oceans & Nunavut Impact Review Board
19

Modelling Chemically Enhanced Primary Settlers Treating Wastewater using Particle Settling Velocity Distribution : Modellering av kemfällning i försedimentering för avloppsvatten, genom att använda distribuering av sedimentationshastigheter för suspenderadepartiklar.

Lundin, Emma January 2014 (has links)
The urban sprawl creates a gap between producers and consumers and the a sustainable circuitof nutrients and energy is difficult to maintain. Many times the waste that is created in urbanareas is not reused and the circuit is lost. In this project, wastewater treatment is looked atwith the view point that resource recovery is possible through energy production and reuse ofnutrients. In order to optimally run each process step at a wastewater treatment plant forimproved resource recovery, more knowledge is needed in order to not disregard the finaleffluent quality. The goal of this project was to develop a model in MATLAB/Simulink for achemically enhanced primary clarifier at a wastewater treatment plant. The potential ofproducing more biogas and reducing the aeration energy needed in the biological treatmentstep was looked at by focusing on describing the settling velocity of suspended solids.Experimental analysis on settling properties for solids was performed on sampled wastewaterentering the primary settler after changing the addition of chemicals prior in the process line.The wastewater samples were homogenized and then rapidly vacuum pumped up in a column.The solids in the column could thereafter settle and was retained in a cup at the bottom. Themass of total suspended solids (TSS) was classified in five different settling velocity classes,each class assigned a characteristic settling velocity. The experimental procedure followed theViCA's protocol (French acronym for Settling Velocity for Wastewater). A settler, much likethe secondary settler in the Benchmark Simulation Model No. 2 (BSM2), a 10 layer nonreactivetank was modeled. The mass balance in each layer of the settler was decided by thevertical solid flux in the tank and built on the characteristic settling velocity gained from theexperiments. Re-circulation of excess sludge from the subsequent steps at the plant showed toeffect the settling properties of the sludge in the primary settler. The components of TSSshowed to have the largest effect on the distribution of settling velocity. The variation in doseof both coagulant and cationic polymer prior the primary settling tank showed to effect theparticle settling distribution somewhat. A first simulation with an applicable dynamic influentscenario was run. Despite any proper calibration the model gave fairly good predictions ofmeasured TSS in the effluent and sludge outtake water. / När urbana områden växer uppstår svårigheter i att bibehålla ett hållbart kretslopp av energioch näringsämnen. Avståndet mellan producent och konsument ökar och många gångeråteranvänds inte det avfall som städerna producerar och det hållbara kretsloppet bryts. Dettaprojekt har fokuserat på resursåteranvändningen i avloppsvattenhanteringen genommöjligheterna som finns i energiproduktion i form av biogas samt återanvändning avnäringsämnen genom slamåterförsel. Mer kunskap behövs inom varje processteg för attoptimalt använda avloppsreningsverk för förbättrad resurs-återvinning så att inte utgåendevattenkvalitet blir lidande. Målet med projektet var att utveckla en modell iMATLAB/Simulink för primärsedimentering med kemisk fällning. Experimentelltanalyserades sedimentationsegenskaperna hos primärslam genom provtagning avavloppsvatten inkommande till försedimenteringen efter tillsatser av fällnings-kemikalier.Proverna homogeniserades och vakuumpumpades sedan snabbt upp i en kolonn. Detpartikulära materialet i kolonnen kunde därefter sedimentera och fångades upp i en kopp ibotten. Den sedimenterade massan av totalt suspenderat material (TSS) klassificerades i femolika sedimenteringshastighetsklasser och varje klass tilldelades en karakteristisksedimentationshastighet Det experimentella förfarandet följde ViCA’s protokoll (franskförkortning för sedimentationshastigheter för avloppsvatten). En modell av ensedimentationstank, ungefär som för sekundär-sedimenteringen i Benchmark SimulationModel No. 2 (BSM2), utvecklades som en 10 lager icke reaktiv tank. Massbalansen i varjelager bestämdes av det vertikala flödet av partiklar och beräknades med de experimentelltframtagna karakteristiska sedimentationshastigheterna. Återcirkulering av överskottsslam frånde efterföljande reningsstegen visade sig ha stor påverkan på slammetssedimentationsegenskaper i försedimenteringen. Typen av TSS-komponenter hade den störstainverkan på fördelningen av sedimentationshastigheter. Variationen i dos av bådefällningskemikalie och katjonspolymer före primär-sedimenteringstanken hade en visspåverkan på fördelningen. En första simulering med ett sannolikt dynamisk inflödesscenariokördes. Utan någon riktig kalibrering av modellen gav den ändå en relativt realistisk prognospå TSS i utgående vatten och i slamuttaget. / I samarbete med forskningsgruppen ModelEAU, Quebec, Kanada
20

Determining Soil Erosion with Varying Corn Stover Cover Factors

Koeninger, Nicole K 01 January 2015 (has links)
Since the Dust Bowl, conservation agriculture has become a common practice globally. Because of the rising interest in the use of corn biomass as a feedstock for biofuel production, the effects of corn stover removal on soil erosion were explored. It was hypothesized that selective harvesting strategies would impact soil erosion differently across a variety of slopes. Soil erosion boxes were constructed, and a rainfall simulator with an intensity of 30 mm hr-1 for 46 min was used to create runoff from slopes of 1, 5, and 10% and three cover factor treatments (no removal and two simulated corn stover removal strategies). Due to research time constraints, simulated corn roots were constructed to emulate actual corn roots in all experiments. The corn stover harvest strategies change the distribution of cobs, husks, leaves, and stalks in field; these changes were represented as the cover factor treatments. Changing the type of plant material on the soil surface impacted the predicted soil erosion from the Revised Universal Soil Loss Equation (RUSLE). Based on the results from this study, the effect of corn stover cover percentages had a significant impact on the predicted and observed soil loss.

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