• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 8
  • 5
  • 4
  • 3
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 29
  • 29
  • 11
  • 11
  • 10
  • 7
  • 6
  • 6
  • 6
  • 5
  • 4
  • 4
  • 4
  • 4
  • 4
  • 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.
1

Future Strategy for Wastewater Treatment at Skärblacka Mill

Brusved Andersson, Linnea January 2014 (has links)
To replace nonrenewable materials, glass, plastics and metals, at the market the production of the environmental friendly material paper needs to increase numerously. An increased paper production leads to an enlarged wastewater flow at the paper mill and thereby higher surface load in the biologicalwastewater plant. Higher surface load in turn, leads to lower efficiency and higher emissions. To be able to increase the capacity of the paper production, the wastewater flow to the biological wastewater treatment needs to be decreased. In this thesis, the wastewater at Skärblacka mill has been studied to identify how to increase the production without increasing the flow of wastewater to the biological wastewater treatment. Different wastewater has been studied to identify sufficient clean wastewater flows that today are directed to the biological wastewater treatment. The outcome of this thesis is that up to 600 m3/h wastewater could be removed from the biological wastewater treatment due to sufficiently high purity. This outcome is primarily based on measurements of the emission parameters, Total Organic Carbon, Suspended Solids, Total Phosphorus and Total Nitrogen and the calculation of PEC/PNEC, environmental assessment, for the chemicals in the wastewater. The unload of up to 600 m3/h will contribute to an increased efficiency in the biological wastewater treatment and thereby lower emissions. Increased efficiency and lower levels of emissions will in turn contribute to a possibility to increase the paper production at Skärblacka mill without interfering withenvironmental demands.
2

Data-driven analysis of water and nutrient flows: Case of the Sava River Catchment and comparison with other regions

Levi, Lea January 2017 (has links)
A growing human population and demands for food, freshwater and energy are causing extensive changes in the water and biogeochemical cycles of river catchments around the world. Addressing and investigating such changes is particularly important for transboundary river catchments, where they impose additional risk to a region’s stability. This thesis investigates and develops data-driven methodologies for detecting hydro-climatic and nutrient load changes and their drivers with limited available data and on different catchment scales. As a specific case study, we analyze the Sava River Catchment (SRC) and compare its results with other world regions. A past–present to future evaluation of hydro-climatic data is done on the basis of a water balance approach including analysis of historic developments of land use and hydropower development data and projections of the Coupled Model Intercomparison Project, Phase 5 (CMIP5) output. Using observed water discharge and nutrient concentration data, we propose a novel conceptual model for estimating and spatially resolving total nitrogen (TN) and total phosphorus (TP) input and delivery-retention properties for a river catchment and its nested subcatchments, as well as detection of nutrient hotspots. The thesis identifies hydroclimatic change signals of hydropower-related drivers and finds consistency with other world regions. The proposed nutrient screening methodology provides a good distinction between human-related nutrient inputs and landscape-related transport influences on nutrient loading at subcatchment to catchment scale. A cross-regional comparison of the SRC data with the Baltic region shows similarity between nutrient-relevant indicators and driving socio-economic and hydro-climatic conditions. The study highlights a number of complexities with regard to CMIP5 model representation of water fluxes. The large intermodel range of CMIP5 future projections of fluxes calls for caution when using individual model results for assessing ongoing and future water and nutrient changes. / <p>QC 20170516</p> / VR 2009-3221 / FORMAS 2014-43
3

The Study of Treating Leachate in Landfill by Constructed Wetlands

Tsai, Kai-yuan 04 September 2004 (has links)
In this research, we dealt with the original landfill leachate, and put the flowing water by a traditional second one that has dealt with of sewage factory directly with the constructed wetland systems in lab-scale. The purpose the study is to compare the experimental results after dealing the leachate by different constructed wetland process systems which was judge at if the, can reach the water quality standard. The constructed wetland systems in the study were set up in a greenhouse on campus, which were operated between May 2004 and July 2003. Constructed wetland systematic attitude, include Free Water Surface System (FWS) and Subsurface Flow System (SSF) contact but two type constructed wetland system that become mainly. In the test use different waste water sources to feet the systems, and we planted different species of plants, and add extra carbon source. Thus, we can divide the experiment into two stages: (1) From July of 2003 to December of 2003. (2) From February of 2004 to May of 2004. In each stage, we tested three experiment group P1, P2 and total nitrogen of P3 except that the rate is 37¡Ó20%, 50¡Ó11% respectively and -6.1¡Ó37.8%. The removal efficiencies of ammonia nitrogen were estimated equal to 84¡Ó11%, 94¡Ó4% and 60¡Ó24% respectively. For total phosphorus and phosphate, P1 , P2 and P3 system were measured equal to 37¡Ó14%, 68¡Ó16% and 77¡Ó16%and 44¡Ó16%, 75¡Ó8% and 80¡Ó17% respectively . The ammonia nitrogen temperature correction coefficient (£c value) were calculated to be 0.921, 0.949, 0.926, 1.043 and 0.785 for P1, P2, P3, U1 and U2 system, respectively. The phosphate temperature correction coefficients (£c values ) were measured to be 1.006, 0.981, 1.070, 1.235 and 0.843 respectively for P1, P2, P3, U1 and U2 system. In order to increase the removal efficiencies of total nitrogen, it was always by adding carbon source. The experimental result showed, that it is add carbon source wait by system to SSF , its President nitrogen is it flow water pollution load leave 2g/m2/day nearly to put to have, and has not added water pollution load has flowed in the putting of the carbon source nearly has 6g/m2/day left, And nearly remain under 1g/m2/day in the putting and flowing water pollution load of TON, and not added the putting of the carbon source water pollution load has flowed nearly has 2-3g/m2/day left. This result showed that high total nitrogen removal efficiencies were by adding carbon source.
4

On-line measurement of some selected soil properties for controlled input crop management systems

Kuang, Boyan Y. January 2012 (has links)
The evaluation of the soil spatial variability using a fast, robust and cheap tool is one of the key steps towards the implementation of Precision Agriculture (PA) successfully. Soil organic carbon (OC), soil total nitrogen (TN) and soil moisture content (MC) are needed to be monitored for both agriculture and environmental applications. The literature has proven that visible and near infrared (vis-NIR) spectroscopy to be a quick, cheap and robust tool to acquire information about key soil properties simultaneously with relatively high accuracy. The on-line vis-NIR measurement accuracy depends largely on the quality of calibration models. In order to establish robust calibration models for OC, TN and MC valid for few selected European farms, several factors affecting model accuracy have been studied. Nonlinear calibration techniques, e.g. artificial neural network (ANN) combined with partial least squares regression (PLSR) has provided better calibration accuracy than the linear PLSR or principal component regression analysis (PCR) alone. It was also found that effects of sample concentration statistics, including the range or standard derivation and the number of samples used for model calibration are substantial, which should be taking into account carefully. Soil MC, texture and their interaction effects are other principle factors affecting the in situ and on-line vis-NIR measurement accuracy. This study confirmed that MC is the main negative effect, whereas soil clay content plays a positive role. The general calibration models developed for soil OC, TN and MC for farms in European were validated using a previously developed vis-NIR on-line measurement system equipped with a wider vis-NIR spectrophotometer (305 – 2200 nm) than the previous version. The validation results showed this wider range on-line vis-NIR system can acquire larger than 1500 data point per ha with a very good measurement accuracy for TN and OC and excellent accuracy for MC. The validation also showed that spiking few target field samples into the general calibration models is an effective and efficient approach for upgrading the implementation of the on-line vis-NIR sensor for measurement in new fields in the selected European farms.
5

Kėdainių ir Rokiškio miestų nuotekų valyklų efektyvumo tyrimai / Efficiency Evaluation of Wastewater Treatment Plants in Kėdainiai and Rokiškis Towns

Butkus, Paulius 30 May 2012 (has links)
Tyrimo objektas – Kėdainių ir Rokiškio miesto nuotekų valyklos. Tyrimo tikslas – nustatyti, įvertinti ir palyginti Kėdainių ir Rokiškio miestų nuotekų valyklų veikimo efektyvumą prieš ir po rekonstrukcijos. Darbo uždaviniai: 1. Surinkus esamus tyrimų duomenis nustatyti, įvertinti ir palyginti Kėdainių ir Rokiškio miestų nuotekų valyklų efektyvumą prieš ir po rekonstrukcijos; 2. Atlikti surinktų duomenų statistinę analizę; 3. Nustatyti priklausomybes tarp teršiančių medžiagų koncentracijų atitekančiose ir ištekančiose nuotekose; 4. Nustatyti teršiančių medžiagų koncentracijų po nuotekų valymo priklausomybes nuo temperatūros; 5. Nustatyti Pb ir Nb koncentracijų priklausomybes ištekančiose nuotekose nuo BDS7/Pb ir BDS7/Nb santykio atitekančiose nuotekose. Tyrimo metodai: Kėdainių ir Rokiškio miestų nuotekų valyklos efektyvumui nustatyti buvo atliekama nuotekų užterštumo analizė atsižvelgiant į biocheminio (BDS7) ir cheminio deguonies (ChDS), skendinčių medžiagų (SM), bendro azoto (Nb) ir bendro fosforo (Pb) koncentracijas prieš užterštų nuotekų valymą ir po valymo. UAB „Kėdainių vandenys“ ir UAB „Rokiškio vandenys” laboratorijose surinkti 2008–2011 metų tyrimų duomenys apdoroti naudojant Microsoft Excel 2007 ir STATISTICA programas. Tyrimo rezultatai: Pirmajame skyriuje aprašomas nuotekų tvarkymas Lietuvoje, nuotekų tvarkymo būdai ir jų efektyvumas, pagrindinės nuotekų užterštumo charakteristikos, reikalavimai išleidžiamoms nuotekoms ir nuotekų valymo metu susidariusio dumblo... [toliau žr. visą tekstą] / Object of the research: wastewater treatment plants in Kėdainiai and Rokiškis towns. Aim of the research work: to determine, evaluate and compare the efficiency of the wastewater treatment plants in Kėdainiai and Rokiškis towns before and after their reconstruction. Objectives: 1. Following the research data, to determine, evaluate and compare the efficiency of the wastewater treatment plants in Kėdainiai and Rokiškis towns before and after their reconstruction; (Why do you repeat the aim??) 2. To carry out the statistical analysis of the obtained research data; 3. To determine the proportion of pollutant concentrations in the incoming wastewater and in the effluent; 4. To determine how the pollutant concentrations that are found after the wastewater treatment are affected by temperature; 5. To determine how the Pt and Nt concentrations in the effluent depend on the proportion of BOD7/Pt and BOD7/Nt in the incoming wastewater. The research methods: to determine the efficiency of the wastewater treatment plants in Kėdainiai and Rokiškis towns, the analysis of the wastewater contaminants was performed considering the following data: concentrations of biochemical (BOD7) and chemical oxygen (COD), suspended solids (SS), total nitrogen (Nt) and total phosphorus (Pt) that were fixed before and after the contaminated wastewater treatment. The data of the research, which was carried out and stored in the laboratories of UAB Kėdainių vandenys and UAB Rokiškio vandenys in... [to full text]
6

Using satellite hyperspectral imagery to map soil organic matter, total nitrogen and total phosphorus

Zheng, Baojuan. January 2008 (has links)
Thesis (M.S.)--Indiana University, 2008. / Title from screen (viewed on June 3, 2009). Department of Earth Science, Indiana University-Purdue University Indianapolis (IUPUI). Advisor(s): Lin Li, Pierre Jacinthe, Gabriel M. Filippelli. Includes vita. Includes bibliographical references (leaves 78-81).
7

Valor nutritivo do feno de Cynodon - Vaquero aditivado com ureia e submetido a diferentes teores de umidade / Nutritional value of hay Cynodon Vaquero treated with urea and submitted to different levels of moisture

Mazzochin, Eliana Aparecida dos Reis 11 September 2013 (has links)
Made available in DSpace on 2017-07-10T17:47:56Z (GMT). No. of bitstreams: 1 Eliana_Aparecida_dos_Reis_Mazzochin.pdf: 747925 bytes, checksum: 5e3d8b4240f01cf2d39d2203ed469562 (MD5) Previous issue date: 2013-09-11 / The experiment was conducted to evaluate the bromatological composition, thein vitro digestibility, and the fractionation of Cynodon dactylon hay protein (Vaquero grass)treated with increasing doses of urea (0, 2.5 and 5%) based on the dry matter (DM), at different moisture contents (12, 18, 24 and 30%). The experiment was performed by a completely randomized design in a 4x3 factorial design with four replications. Urea was dissolved in sufficient water quantity to raise the moisture content of the hay to the desired values. The material was stored in plastic bags (11.39 kg/bag), which were sealed for 30 days. Afterwards, they were opened and samples were collected for laboratory analysis. It was found that the DM contente decreased with increasing doses of urea and moisture content. The total nitrogen (TN) increased with increasing doses of urea, and it was reduced to make the moisture content higher. The amounts of neutral detergent insoluble nitrogen (NDIN) and acid detergent insoluble nitrogen (ADIN) increased according to the moisture content and decreased as the dose of urea applied increased. NDIN values in relation to total nitrogen (NDIN/TN) decreased with increasing dose of urea, and the largest decreases were observed in treatments with lower moisture. The contents of ADIN in relation to the total nitrogen (ADIN/TN) were reduced with higher doses of urea, and higher levels of reduction occurred in 30% moisture. The ammoniated hay with different moisture contents increased levels of A fraction in relation to the total nitrogen, but did not affect B1. However, The B3 and C fractions decreased in response to ammoniation. The increase in the dose of urea promoted a reduction in the levels of neutral detergent fiber and acid detergent fiber. The contents of hemicellulose and cellulose decreased with increasing doses of urea, these reductions being more pronounced with increasing moisture content. There was no effect (P > 0.05) of urea doses, moisture content and interaction of the variables in the amount of lignin. The in vitro dry matter digestibility (IVDMD) was influenced by the dose of urea (P <0.05) and the moisture content (P<0.05). The higher IVDMD value was obtained for the level of 5% urea and 30% moisture. The in vitro digestibility of organic matter was not affected (p> 0.05) for any variable. The urea application with 12, 18, 24 or 30% moisture was favorable for increasing the nutritional value of the Vaquero grass / O experimento foi conduzido com o objetivo de avaliar a composição bromatológica, a digestibilidade in vitro e o fracionamento de proteínas do feno de Cynodon dactylon (capim Vaquero) tratado com doses crescentes de ureia (0, 2,5 e 5%) com base na matéria seca (MS) em diferentes teores de umidade (12, 18, 24 e 30%). O delineamento experimental utilizado foi o inteiramente casualizado em esquema fatorial 4x3, com quatro repetições. A ureia foi dissolvida em quantidade suficiente de água para elevar o teor de umidade do feno para os valores de umidade desejada. O feno tratado foi armazenado em sacos plásticos (11,39 kg/saco) vedados por 30 dias e, após abertura, foram coletadas amostras para as análises laboratoriais. Verificou-se que o teor de MS sofreu redução com as doses crescentes de ureia e o teor de umidade. Os teores de nitrogênio total (NT) aumentaram com as doses crescentes de ureia e foram decrescentes para a elevação do teor de umidade. As quantidades de nitrogênio insolúvel em detergente neutro (NIDN) e nitrogênio insolúvel em detergente ácido (NIDA) aumentaram em função dos teores de umidade e decresceram com o aumento da dose de ureia aplicada. Os valores de NIDN em relação ao nitrogênio total (NIDN/NT) apresentaram redução com o aumento da dose de ureia, e os maiores decréscimos foram observados para os tratamentos com menor umidade. Os teores de NIDA em relação ao nitrogênio total (NIDA/NT) foram reduzidos com maiores doses de ureia, e maior redução ocorreu para teores de 30% de umidade. A amonização dos fenos com diferentes conteúdos de umidade aumentou os teores da fração A em relação ao nitrogênio total, mas não afetou B1. Contudo, as frações B3 e C diminuíram em reposta à amonização. O aumento na dose de ureia promoveu redução nos teores de fibra em detergente neutro e fibra em detergente ácido. Os conteúdos de hemicelulose e celulose diminuíram com as doses crescentes de ureia, sendo essas reduções mais pronunciadas com a elevação dos teores de umidade. Não foi observado efeito (P > 0,05) das doses de ureia, teor de umidade e da interação das variáveis na quantidade de lignina. A digestibilidade in vitro da matéria seca (DIVMS) foi influenciada pela dose de ureia (P< 0,05) e pelos teores umidade (p<0,05). O maior valor de DIVMS foi obtido para o nível de 5% de ureia e 30% de umidade. A digestibilidade in vitro da matéria orgânica não foi influenciada (p>0,05) por nenhuma das variáveis. A aplicação de ureia associada a 12, 18, 24 ou 30% de umidade foi favorável para aumentar o valor nutritivo do feno de capim Vaquero
8

Nutrient Concentrations and Effects on Mill Run from Residential, Urban, and Industrial Stormwater Contamination

Carver, Melissa 02 May 2019 (has links)
Nutrients are introduced into the waters of the Commonwealth of Pennsylvania through various methods, mainly through point and non-point sources. Non-point sources would include agricultural means however, there are often other non-point sources that are often overlooked. Water runoff from stormwater is an important contributor to pollution entering various watersheds. Data was collected at 4 locations (the initial point of reference, residential, urban, and industrial) on Mill Run and 2 locations on Woodcock Creek, through surface water collection methods in dry and wet weather. Nitrate, Nitrite, Total Phosphorus, and Total Nitrogen were among the data collected. Total Phosphorus had an increasing trend in concentration as the study progressed. Nitrate, Nitrite and Total Nitrogen showed no increasing trends. Location 3 (Urban Zone) produced the largest increase in Total Phosphorus. Weather conditions played a role in higher Nitrate concentrations while warm water produced higher Nitrite concentrations
9

Landfill Leachate Sorption Potential of Kate Valley Soils

Chu, Kuang-Chi Kevin Yelias January 2014 (has links)
Kate Valley is a municipal waste landfill situated in Waipara, Northern Canterbury. It is a joint venture between the 6 local regional councils and Transwaste Canterbury Ltd to help dispose of waste quantities generated in the wider Canterbury region. Landfill waste disposal also generates waste streams. Major waste streams can include methane gas production and liquid leachate. One practice which can turn liquid leachate waste streams into a nutrient source for plants is land irrigation. It is important to have a thorough understanding of the interactions involved with leachate, soil structure, soil microbiology, flora. This thesis investigates the sorption mechanisms between Kate Valley soil and leachates, through batch and column experiments. Sorption mechanisms between leachate and soil were investigated through batch and column tests. Ex-situ soil samples were extracted from Kate Valley, along with raw leachate samples for batch tests at a soil to liquid ratio of 30 g vs. 70 ml respectively. Tested dilution leachate strengths ranged from raw to 50x raw leachate dilution; meanwhile soil samples were categorized into 3 groups based on soil depth: 0-20 cm, 20-40 cm, and 40-60 cm. Column tests were conducted on 3 extracted in-situ soil column monoliths. Column test irrigation conditions included: control case, 2x and 10x raw leachate dilution, and 200 mg/L KBr (bromide column), where the same soil column was used for bromine testing after control testing had ceased. Batch results suggest deeper soils are less effective at sorption of ammonia, where partitioning coefficient ranged from 9.5x*10-7 to 6.4*10-7 L/mg for 0-20 cm soil to 40-60 cm soil respectively. Column results generally showed lower partitioning capacity than batch results, at 4*10-8 and 5*10-8 L/mg for 10x and 2x dilution leachate irrigation respectively. Discrepancies in experimental data have been attributed to: different dilution leachates tested between batch and column tests, making it difficult for direct comparison; extreme soil to liquid ratios employed in experiments; direct data comparison between the “full-contact” experimental data (between leachate and soil), obtained from batch tests with column results, where not all soil may have been fully exposed for shrinkage of boundary layers of soil particles; and oxygen exposure of samples during testing and sampling, possibly encouraging nitrification.
10

Calcium Amelioration of Salinity (Sodicity) on Nitrogen Fixation, Stomatal Resistance, Potassium/Sodium Ratio and Total Nitrogen of Phaseolus vulgaris L.

Akhavan-Kharazian, Mahmood 01 May 1986 (has links)
Extreme salinity is one of the most common environmental constraints with which legume/rhizobia symbionts must deal in arid and semi-arid regions of the world. In some areas, with good management, it has been economically possible to ameliorate the saline soil with calcium. The objective of this study, therefore, was to investigate calcium amelioration of salinity (sodicity) on nitrogen fixation, stomatal resistance, potassium/sodium ratio, and total nitrogen of Phaseolus vulgaris L. Seeds of snapbeans were grown in pots under green house conditions and were irrigated with NaCl concentrations of 0, 0.4, 0.8 or 1.2 S m-1 combined with CaS04 . 2H20 or CaCl2. 2H20 , each at concentrations of 0, 4, and 8 mM . The results show that increasing NaCl concentration decreased leaf water potential, total leaf chlorophyll, shoot and root dry weight, and nitrogen fixation but increased stomatal diffusive resistance. At the highest level of NaCl, addition of CaS04to NaCl increased leaf water potential via increasing stomatal diffusive resistance. Such effects were not observed with the addition of CaCl2 to NaCl. Addition of CaS04 to all levels of NaCl increased total leaf chlorophyll. The shoot and root dry weight and nitrogen fixation was also increased when CaS04 was added to 0.4 and 0.8 S m-1 NaCl. Again, such effects were not observed with the addition of CaCl2 to NaCl. Furthermore, analysis of leaf mineral composition showed that leaf Ca2+ , Mg2+ and K+ were increased with each increase in NaCl concentration, whereas the K+/ Na+ ratio was decreased. Also, the total leaf nitrogen increased with 0.4 and 1.2 S m-1 NaCl as well as with all levels of CaS04. Neither CaS04 nor CaCl2 had any significant effect on leaf K+, Na+, or Mg2+ of the plant when they were added to different levels of NaCl. However, leaf Ca2+ increased with an increase in concentration of CaS04 or CaCl2, but only CaS04 exhibited an interaction when combined with NaCl. Speciation modeling showed that a considerable amount of S04 was complexed as the CaS04° and NaS04- species. In spite of this, CaS04 treatment had ameliorating effect on NaCl induced salinity symptoms in snapbeans.

Page generated in 0.0745 seconds