Sökresultat:
353 Uppsatser om Chemical precipitation - Sida 7 av 24
Utlakning av tungmetaller från Skörby deponi
The purpose of this thesis has been to assess whether leaching from one particular Swedishlandfill site, Skörbytippen, is contributing to elevated levels of heavy metals in a ditch runningfrom the landfill site to the lake Mälaren in the communal region of Håbo kommun. Since theditch is stretching approximately five km downstream from the landfill site, in situ observationsand maps with known points of inflow was utilized to determine appropriate test points for thecollection of samples.Soil, water and sediment samples were collected and analyzed for content of organic material, pHand conductivity. Data on plant-available elements and total amounts of heavy metals wasacquired through ICP-analysis.The results show that the Skörby landfill is currently in the methane-forming anaerobedevelopment phase, which indicates that the concentration of free and complex-bound metals inthe leachate water should be low due to chemical binding with other landfill compounds. The pHof the sediment samples was generally one unit higher than the soil samples and some of themeasured data, such as pH and conductivity, show that an environmentally disturbing dischargeof some kind of strongly alkaline chemical(s) has been made from Benders? takpanneindustri inclose proximity to the landfill.
El Niño Southern Oscillation och dess atmosfäriska fjärrpåverkan.
This paper is a literature study aiming to describe scientists newest theories andknowledge concerning the El Niño and Southern Oscillation. Firstly I have described the?normal? conditions with rising and sinking air in Hadley- and Walker-cells in theequatorial Pacific and from there moved on to explaining the reversed circulation patternsand higher sea surface temperatures (SST) leading to rising air and anomalousprecipitation in eastern Pacific constituting the El Niño phenomenon. My outermostinterest regarding El Niño has been the associated teleconnections, especially in nontropicalareas. I have described the El Niño effect on the Indian summer monsoon, ontropical cyclones and on storms and precipitation on higher latitudes.
Tillämpningar i kemiundervisningen : en studie av strategier för att presentera och synliggöra tillämpningar
The aim of this study is to investigate how and in which form students come in contact with practical applications in the upper secondary school course Chemistry B. The study is based upon the assumption that all learning is situated in a social environment. The theoretical framework is the design theory perspective, which entails an assumption that the pedagogical tools affect the knowledge content.The empiric materials in the study are collected through three methods: textbook analysis, classroom observations and questionnaires. Two groups of students and their teachers were observed during a section of the relevant course. The textbook analysis focuses upon the same course section in the textbooks of the two groups and compares these books with the relevant section in a third textbook.
Historiska emissioner av bly och arsenik till luft från Åfors Glasbruk och deras konsekvenser för miljön.
Åfors glasswork was a company which started in 1876 and closed in 2012 due to the bad economical situation in the company. After its closure, the glasswork left behind contaminated soil with different concentrations of heavy metals such as, arsenic from arsenic trioxide, a chemical used to remove bubbles during the melting of glass, and lead oxide, a chemical used in the production of crystal glass. Crystal glass?s production occurred under 1921-1971, but emissions of lead into the air from Åfors glasswork continued until 2011, because of the artist Bertil Valliens? artglas was made in Åfors glasswork from 1970?s and onwards.The aim of this study was to estimate how much lead (Pb) and arsenic (As) that were released by Åfors Glasswork into the atmosphere during the operational period of the glasswork in comparison with how much of lead and arsenic were purchased for the company. Added to the assistance of the data from National Archives the variations in the activities of Åfors glasswork could be shown.
Demand and perception of fertilizer : among small-holder farmers in Kenya
Hunger is a problem in some parts of the world (www, FAO 1, 2012). The lack of food is often a result of insufficient knowledge in soil fertility management (Röing de Nowina, 2012). Ongoing hunger and malnourishment are quite prevalent in Sub-Saharan Africa and are often combined with poverty (www, FAO 1, 2012). Farming is the most common occupation in this area and the farms are often small-scale farms with subsistence crops and a few cattle. The farmers who operate these small-scale farms are economically a weak group.
Lagafors CPU : Chemical Production Unit
This dissertation is performed at the request of Lagafors AB who develops and manufactures stationery and mobile hygiene solutions for companies in the food- processing industry. The objective of this dissertation is to develop and construct a new, cost efficient cleaning station based on an innovative technology.The technique is based on serially connected dosing pumps which allow the customer to work with concentrated detergents. This leads to serious reduction in the clients use expenses. Two units have been developed with this technique, one that is stationary and one that is mobile.The dissertation has led to good results which resulted in the sale of the first stationary unit of the Lagafors CPU before the end of this dissertation. .
Simulering av COD-fraktioner i en aktivslamanläggning vid en sulfatmassafabrik
This thesis work was made for Södra Cell Mörrums bruk in Blekinge. The purpose of the work was to develop a computer model in the simulation program Extend for the removal and balance of organic oxygen consuming substances, measured as COD (Chemical Oxygen Demand), in the new biological treatment plant in the mill. The plant produces two different pulp products, TCF- (Totally Chlorine Free) pulp and ECF- (Elementary Chlorine Free) pulp, for sale. The different bleaching procedures affect the characteristic of the wastewater and thus the effectiveness of the biological treatment plant.In the model that was developed the COD in the wastewater was divided into five different COD-fractions: soluble easily degradable (SS), soluble hardly degradable (SR), soluble inert (SI), particulate inert (XI) and particulate biomass (XB). To create the model FlowMac? was used as a base.
Patologiska förändringar och säsongsmässiga variationer i testiklar från svenska brunbjörnar (Ursus arctos) :
Functioning reproductive organs are essential for the survival of a species. The reproductive system is very sensitive to exposure of chemical substances of anthropogenic origin. Humans release great amounts of chemical substances to the environment by our means of life and these substances have been proved to have a negative effect on the reproductive ability of different vertebral classes. In the polar bear (Ursus maritimus) a declined reproductive ability as an effect of decreased testosterone levels and decreased testicular size has been connected to the presence of high levels of organohalogenic compounds like PCBs. Although the Swedish brown bear (Ursus arctos) is not as carnivorous as its close relative the polar bear it is still exposed to environmental.
Utveckling av en HBV/PULS-model med sammanfogade markfuktighets- och responsrutiner
Soil properties affect the chemical composition of soil water. When studying transport of chemical substances through a basin, it is therefore important to know from which soil layer the main part of the runoff is generated. The aim of this study is to develop an HBV/PULSE model with merged soil moisture and response routines, which generates good approximations of groundwater levels. It should be possible to extend the model to simulate transport of substances and take into account which soil layer the groundwater level is currently in. The hydrological version of HBV/PULSE is used since there is no need to account for pH or alcalinity at this stage.
Rotningsstimulerande effekt och kemisk analys av vattenbaserad extraktion av vedartade och örtartade skott av Salix smithiana Willd. :
Cuttings of Lonicera xylosteum L. were treated with willow extract to study the response in rooting capacity. The extracts were prepared by mixing chopped pieces of Salix x smithiana Willd. with water in a warring blender. The investigation comprised 2 types of salix extracts based on differences and dynamics between twigs in winter dormancy and twigs with new shoots.
To explore the rooting response, three tests were made.
Utredning av grundavlopp på broar
AbstractIn the fall of 2003 a project was started in the Swedish building sector that is called BASTA (the building sectors’ termination of especially harmful substances). The project is operated by the building companies NCC, Skanska, PEAB and JM, the Swedish Building Industry and the Swedish Environmental Institute IVL. The purpose of the project is to create a common environmental assessment system for the entire building industry and with the help of this system phase out the use of especially harmful properties from building products.In a large sense BASTA works like this; On the BASTA web site there is a database, to which a supplier can register the company and the company’s products. Only those products with a substance content that fulfil the demands of the BASTA system, is to be registered. As it is the supplier himself that carries out the registration of the company and the company’s products to the system, the BASTA-organisation annually controls that the companies that are registered in the database, fulfils BASTA’s demands.Since NCC is one of the companies that operates BASTA, BASTA is probably going to be the environmental assessment system that is recommended for the company in the future.
Utvärdering av byggsektorns miljöbedömningssystem BASTA
AbstractIn the fall of 2003 a project was started in the Swedish building sector that is called BASTA (the building sectors’ termination of especially harmful substances). The project is operated by the building companies NCC, Skanska, PEAB and JM, the Swedish Building Industry and the Swedish Environmental Institute IVL. The purpose of the project is to create a common environmental assessment system for the entire building industry and with the help of this system phase out the use of especially harmful properties from building products.In a large sense BASTA works like this; On the BASTA web site there is a database, to which a supplier can register the company and the company’s products. Only those products with a substance content that fulfil the demands of the BASTA system, is to be registered. As it is the supplier himself that carries out the registration of the company and the company’s products to the system, the BASTA-organisation annually controls that the companies that are registered in the database, fulfils BASTA’s demands.Since NCC is one of the companies that operates BASTA, BASTA is probably going to be the environmental assessment system that is recommended for the company in the future.
Sättningar vid övergång mellan bro och bank
AbstractIn the fall of 2003 a project was started in the Swedish building sector that is called BASTA (the building sectors’ termination of especially harmful substances). The project is operated by the building companies NCC, Skanska, PEAB and JM, the Swedish Building Industry and the Swedish Environmental Institute IVL. The purpose of the project is to create a common environmental assessment system for the entire building industry and with the help of this system phase out the use of especially harmful properties from building products.In a large sense BASTA works like this; On the BASTA web site there is a database, to which a supplier can register the company and the company’s products. Only those products with a substance content that fulfil the demands of the BASTA system, is to be registered. As it is the supplier himself that carries out the registration of the company and the company’s products to the system, the BASTA-organisation annually controls that the companies that are registered in the database, fulfils BASTA’s demands.Since NCC is one of the companies that operates BASTA, BASTA is probably going to be the environmental assessment system that is recommended for the company in the future.
Reglering av laborationsprocess med Matlab/Simulink
AbstractIn the fall of 2003 a project was started in the Swedish building sector that is called BASTA (the building sectors’ termination of especially harmful substances). The project is operated by the building companies NCC, Skanska, PEAB and JM, the Swedish Building Industry and the Swedish Environmental Institute IVL. The purpose of the project is to create a common environmental assessment system for the entire building industry and with the help of this system phase out the use of especially harmful properties from building products.In a large sense BASTA works like this; On the BASTA web site there is a database, to which a supplier can register the company and the company’s products. Only those products with a substance content that fulfil the demands of the BASTA system, is to be registered. As it is the supplier himself that carries out the registration of the company and the company’s products to the system, the BASTA-organisation annually controls that the companies that are registered in the database, fulfils BASTA’s demands.Since NCC is one of the companies that operates BASTA, BASTA is probably going to be the environmental assessment system that is recommended for the company in the future.
Optimering av glödgningsparametrar för kromstål
At Sandvik Materials Technology, Argon gas is used as furnace atmosphere when heattreating hot rolled wire. Upon heating chromium steel wire, a rich oxidelayer forms on the wire surface. The abstract of this masters thesis is to enhance the understanding of the constitution of the oxidelayers and the influence of the furnace atmosphere. This will be achieved by performing a number of annealing experiments on laboratory level. Also, the aim is to understand the chemical reactions and physical mecanisms controlling the pickling process.