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Removal of heavy metals from CRUD and slime dam material using soil washing and bioremediationShumba, Trust 12 1900 (has links)
Thesis (MScEng (Process Engineering))--Stellenbosch University, 2008. / A substance called CRUD (Chalk River Unidentified Deposit) was deposited together
with gold tailings to the East Paydam tailings dam. Previous research conducted on
the material has shown that the crud leaches Mn and Ni at concentrations that are
above their acceptable risks limits as well as Zn which leaches at concentration
slightly below its acceptable limits thereby posing an environmental risk. The main
objective of the research was to test the hypothesis stating that soil washing in series
with bioremediation can be used to remove the heavy metals from the material from
the East Paydam tailings dam.
Various laboratory and pilot scale tests were conducted to investigate critical soil
washing and bioremediation parameters and their respective influence on the
treatment process. Laboratory work involved column tests and batch tests. These tests
were crucial in determining the critical parameters for the pilot scale tests such as the
selection of the suitable lixiviant from the four that were investigated. The optimal
concentration of the lixiviant was also determined together with the optimum soil:
liquid ratio. These parameters were employed in the pilot scale tests. Pilot scale tests
involved soil washing in series with bioremediation. The bacterial growth over the
bioremediation period was also determined. Precipitation of the heavy metals from
leachate was investigated by varying the pH and temperature.
Results showed that the soil from the East Paydam can effectively be treated by soil
washing in series with bioremediation. Oxalic acid was selected for soil washing of
the payable slimes at a concentration of 0.001M. However, material that contains high
amount of CRUD (deeper down the slime dam) required the relatively concentrated
0.1M oxalic acid and mechanical agitation. Bioremediation was determined to
increase the amount of heavy metals that was leached from the material from the East
Paydam slimes dam. Precipitation of the heavy metals at a pH of 12 achieved up to
98% removal of heavy metals from leachate.
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Potential of selected Karoo plant species for rehabilitation of old fieldsWitbooi, Bernadette M. (Bernadette Mary) 12 1900 (has links)
Thesis (MSc)--University of Stellenbosch, 2002. / ENGLISH ABSTRACT: The passive recovery of old fields in the Karoo is a slow process, hampered by low
and erratic rainfall, poor seed germination due to limited availability of suitable micro
sites for seedling establishment, competition from existing vegetation, altered soil
properties and the reduction of key soil biotic processes. The objectives of the study
were to investigate the role of seed banks in the recovery of old fields, and to identify
possible plant species and methods of establishing these species with the primary
aim of initiating the process of succession / recovery of old fields in the Little Karoo.
The investigation of the seed bank addressed the following issues: the resemblance
of the seed bank to the above-ground vegetation in an old field and the effect of
disturbance on the seed bank. Furthermore, the role of propaguie migration was
investigated to establish possible propaguie movement from undisturbed to disturbed
areas was investigated. The study indicated that the perennial seed bank had a 31 %
similarity to the above ground vegetation in the old field. The seed bank was
dominated by annual species. In the above-ground vegetation perennial canopy
cover was higher compared to annual cover. The perennials with the highest
densities in the soil seed bank were disturbance-adapted species with little
importance for grazing animals except perhaps in the short-term. Disturbance caused
annual densities to increase and perennial densities to decrease. The investigation of
propaguie migration compared adult canopy cover and seedling densities. The
results show that perennial distribution was patchy and that propaguie migration is
low to non-existent. This led to the conclusion that old fields require supplemental
seed additions.
A total of seven species were assessed for their restoration potential. The species
used in the investigation were Tripteris sinuata, Ruschia spinose, Drosanthemum
speciosum, Indigofera sessifolia, Pteronia incana, Ehrharfa calycina and
Chaetobromus dregeanus. Seed viability was examined using one of two techniques
ie. tetrazolium or a standard germination technique. The optimal temperature for
germination was determined using the following temperature regimes: 15°C day /
1DoC night, 20°C day /1 DoC night and 30°C day / 15°C night. The temperature range
with the best performance was 20°C day / 1DoC night indicating that species should
be sown in autumn or early winter. This timing coincides with the onset of rains in this
region. The field trial investigated the influence that various mechanical cultivation
techniques (ploughing, disking, tilling and clearing) and soil amendments (seed,
seed+aquasorb and seed+straw+branches) have on the establishment of the
selected species. Seed germination and seedling survival was monitored. The
influence of treatments on water infiltration and soil moisture was investigated. Only
four of the seven species germinated (Tripteris sinuata, Ehrharta calycina,
Chaetobromus dregeanus and Pteronia incana). As far as species performance was
concerned, T. sinuata performed best followed by E. calycina and C. dregeanus,
while P. incana failed to persist. The cultivation treatments that yielded the best
results were tilling, disking and ploughing. Emergence success in cleared and
untreated plots was relatively low. As far as seedling emergence was concerned the
most appropriate soil amendments were seed+aquasorb, seed and
seed+straw+branches. Although soil moisture was higher on-heuweltjies than offheuweltjies
there was no significant difference in seedling emergence and survival
between these localities. Even though soil moisture was higher in
seed+straw+branches treatment than in seed+aquasorb and seed treatments,
seedling emergence in this treatment were lower than in the two latter treatments.
This clearly indicates that soil moisture is not the only factor that influences the
establishment of species.
In the trial a mixture of late successional and pioneer species were sown, primarily
with the aim of initiating the process of succession! recovery of old fields. Contrary to
what was expected the late successional species germinated first. This has led to the
conclusion that these late successional species have no innate dormancy, further
proved by the inability of species to germinate after the second season. It could thus
be that these late successional species have a short live span, and that they
germinate when conditions are favourable. It must also be kept in mind that the seed
sown were freshly harvested, and it could be that the pioneer species needed an
after-ripening period before they germinated. / AFRIKAANSE OPSOMMING: Die passiewe herstel van oulande in die Karoo is 'n tydrowende proses, wat vertraag
word deur wisselvallige reënval, swak ontkieming as gevolg van 'n tekort aan
geskikte mikro-habitatte vir saailingvestiging, kompetisie van bestaande plantegroei,
veranderende grondeienskappe en die afname in sleutel biotiese prosesse. Die doel
van hierdie studie was, om die rol van saadbank in die herstel van oulande te bepaal,
sowel as om moontlike plantspesies te identifiseer en metodes van vestiging van
hierdie spesies te bepaal met die primêre doelom die proses van suksessie / herstel
van oulande in die Klein Karoo te inisieër.
Met die saadbankstudie is die volgende punte aangespreek: die ooreenkoms tussen
die meerjarige spesies in die saadbank en bogrondse plantegroei op ou lande, en die
effek van versteuring op die saadbank. Verder is gekyk na die rol van voortplantingsmeganisme
verspreiding om moontlike beweging vanaf onversteurde na versteurde
areas te ondersoek.
Die studie het aangedui dat daar 'n 31% ooreenkoms is tussen meerjarige spesies in
die saadbank en die bogrondse plantegroei op ou lande areas. In die bogrondse
plantegroei van die ou land was die kroonbedekking van meerjarige spesies hoër as
die van eenjarige spesies. Die dominante meerjarige spesies in die saadbank was
spesies wat aangepas is by versteurings, met min weidingswaarde, behalwe
moontlik oor die kort termyn. Versteuring het In verhoging in eenjarige en In afname
in meerjarige saailingdigthede veroorsaak. Resultate dui daarop dat meerjarige
verspreiding onreëlmatig is in die versteurde area en dat die teenwoordigheid van
voortplantingsmeganismes, baie laag is. Dit lei tot die gevolgtrekking dat oulande
addisionele saad benodig vir hervestiging.
'n Totaal van sewe spesies is ge-evalueer vir hulle moontlike restorasie potensiaal.
Die spesies wat in die ondersoek gebruik was, is Tripteris sinuata, Ruschia spinose,
Orosanthemum speciosum, Indigofera sessitolie. Pteronia incana, Ehrharta calycina
en Chaetobromus dregeanus. Die kiemkragtigheid van die spesies is bepaal deur
gebruik te maak van een van twee tegnieke nl. die tetrazolium of 'n standaard
ontkiemings tegniek. Die optimale temperature vir ontkieming is bepaal deur gebruik
te maak van die volgende temperatuurreekse: 15°e dag / 1Qoe nag, 200e dag /10oe
nag and 300e dag / 15°e nag. Die temperatuur reeks waarop spesies die beste presteer het, was 2DOC dag /1DOC nag. Dit dui daarop dat spesies tydens herfs en
vroeë winter gesaai moet word. Dit is dan ook die tydperk vir die aanvangs van die
reënseisoen in hierdie streek.
In die veldproef is gekyk na die invloed van verskeie meganiese bewerkings -
tegnieke (ploeg, dis, ghrop en plant verwydering) en grondverbeterings behandelings
(saad, saad+aquasorb en saad+strooi+takke), op die vestiging van geselekteerde
spesies. Saadontkieming en saailingoorlewing is gemonitor. Die invloed van die
behandelings op waterinfiltrasie en grondvog is ook ondersoek. Slegs vier van die
sewe spesies het ontkiem naamlik: Tripteris sinuata, Ehrharfa calycina,
Chaetobromus dregeanus en Pteronia incana. Spesies wat die beste presteer het,
was T. sinuata die gevolg deur E. calycina en C. dregeanus, terwyl P. incana nie
oorleef het nie. Die bewerkingsbehandelings wat die beste vestiging van plante
gegee het, was die ghrop en disbewerkings gevolg deur ploegbewerking.
Ontkiemings sukses in areas waar plante verwyder is en onbehandelde persele was
relatief laag. Die grondverbeterings behandeling wat die beste ontkieming gelewer
het was saad+aquasorb gevolg deur saad en saad+strooi+takke. Alhoewel grondvog
hoër was op heuweltjies as weg van heuweltjies, was daar geen betekenisvolle
verskil in ontkieming en oorlewing tussen hierdie lokaliteite nie. Alhoewel grondvog
hoër was in saad+strooi+takke behandelings as in saad+aquasorb en saad
behandelings was ontkieming laer in hierdie behandeling as in die saad+aquasorb en
saad behandelings. Dit dui dus daarop dat grondvog nie die enigste faktor is wat die
vestiging van spesies beinvloed nie.
In die veldproef is 'n mengsel van pionier en klimaks spesies gesaai, met die primêre
doelom die proses van suksessie/herstel van oulande te inisieër. In teenstelling met
wat verwag is het die meer klimaks spesies eerste ontkiem. Dit het gelei tot die
gevolgtrekking dat hierdie spesies geen dormansie het nie, en dit is verder bewys
deur 'n onvermoë om te ontkiem in die tweede seisoen. Dit mag wees dat die meer
klimaks spesies 'n kort lewensduur het, en dat hulle ontkiem wanneer toestande
gunstig is. Dit moet ingedagte gehou word dat die saad vars geoes was, en dit kon
dus wees dat die pionier spesies 'n na-rypwordings periode benodig voordat hulle
ontkiem.
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Physical and geochemical characterisation of canal sediments in the Black Country, West MidlandsAppasamy, Danen January 2011 (has links)
Potentially harmful elements (PHEs) have been researched in a wide variety of disciplines, including pedology, chemistry, pollution science and medicine. Within the scientific community, emphasis has usually been placed on the toxic elements, such as cadmium, chromium, lead and arsenic, but rarely has there been consideration of interactions between PHEs, the sediment matrix and processes occurring in the sediments. Dredging of canals is needed for navigability purposes and consequently testing of dredged sediments (to assess whether sediments are hazardous) and landfilling can be costly for British Waterways facing constantly changing regulations and reduction in government grants. PHE mobility and availability in canal sediments can be affected by oxygen availability, pH and Redox. Remediation is thus becoming a priority for British Waterways to limit their operational costs. Zeolites, a type of remediation tool, have been widely studied in the past 30 years due to their attractive properties, such as molecular-sieving, high cation exchange capacities and their affinity for PHEs. The pilot study to investigate the efficiency of the clinoptilolite showed that there was a concentration difference between PHEs adsorbed by the clinoptilolite and the PHE concentration lost from the sediments from three sites in the West Midlands. Thorough characterisation of the sediments was needed to understand the speciation of the PHEs and the secondary processes occurring in the sediments. The different components of the sediments were analysed using various analytical methods, such as X-Ray Fluorescence spectroscopy (XRF), particle size and X-ray Diffraction (XRD) for the solid-inorganic phase, Ion Chromatography (IC) and Inductively Coupled Plasma-Optical Emissions Spectroscopy (ICP-OES) for the liquid phase (pore water), Gas Chromatography-Mass Spectrometry (GC-MS) and organic loss on ignition for the organic phase, pH and Redox for the electrochemistry of the sediments and Scanning Electron Microscope with Energy Dispersive X-Ray analysis (SEM-EDX) for microscopy and imaging. The British Geological Survey (BGS) sequential extraction method was used to investigate the different phases in the sediments. pH remained near neutral for all three sites and Redox remained anoxic. Organic contents for all three sites were around 30% and contained most of the polycyclic aromatic hydrocarbons considered hazardous. Pore water showed only high concentrations of sulphates but low concentrations of PHEs, suggesting PHEs were not mobile. Sequential extraction confirmed the other results showing that PHEs were mainly associated with stable phases, such as iron and manganese oxides or sulphides. The results have been taken into consideration to design a new remediation strategy to maximise efficiency of the zeolite.
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Land contamination and its remediation methods: a case study in Hong KongChoi, Chung-ming., 蔡頌明. January 1995 (has links)
published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management
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Dioxin contamination in soil: remediation technology and environmental managementTsang, Jennifer Arr., 曾昭雅. January 2003 (has links)
published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management
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Student achievement in developmental mathematics and effective practices in developmental education: a study of an Urban Community College District in TexasAlcorta, Lisa Salinas 21 June 2010 (has links)
Success rates for students in developmental education are dismal. The greatest need for developmental education instruction occurs in mathematics, where high numbers of underprepared students generate great concern and the need for substantial changes in higher education institutions. With higher rates of students requiring remediation in the community colleges, the identification of effective policies and practices in developmental education is necessary to increase the achievement rates of developmental education students, and more specifically developmental mathematics students. This study explored the relationship between developmental mathematics student performance and developmental education programs of the Urban Community College District colleges. In addition, this study set out to identify institutional characteristics between colleges whose developmental mathematics students met state mandated academic outcomes at higher rates than their sister colleges. / text
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Recipientundersökning av Ensjön : Bedömning av sulfidmalmgruvan Enåsens eventuella påverkan på sjöns vattenkvalitetEnmark, Gustav January 2007 (has links)
<p>Ensåsengruvan is a mine situated within Ljusdals municipality in central Sweden. Themine was in use from 1984 to 1991 and has since been undergoing a remediation program. Mine tailings from sulfide rich ore is a potential environmental hazard due to its tendency to cause acid waters and heavy metal leakage. Lake Ensjön is situated one kilometer from the mine area. Due to the hydrological conditions it was not expected to receive inflowing water from the mining area. A study done in 2005 showed high amounts of heavy metals in the lake.</p><p>In this study water and sediments was analyzed to confirm the results from the 2005 study. Water was sampled two times during summer 2006 from the lake and adjoining streams. Sediment samples were collected with a core sampler at ten different locations within the lake. The water and sediment samples were analyzed for heavy metal content. Sub-samples from different depths in the sediment core were extracted so that conclusions on the contamination history could be drawn. The sediments were dated trough Cs-137 analyses. The depth in the profile with the highest Cs-137 content can be dated to the time of the Chernobyl fallout (1986). After dating, relevant samples were analyzed for metal content.</p><p>The results show that Ensjön is contaminated by a local source. The surface sediments are high in copper, zinc, nickel and cadmium content. The content is high both compared to the samples from deeper in the sediment core and the surface sediments analyzed in the reference study done in 1980. The amounts of heavy metals are also high relative to the standards set by the Swedish Environmental Protection Agency. The water from the stream adjoining the lake from the mining area is high in content of the previously mentioned metals. The methods used, including sediment dating and metal analyses together with water analyses, has proven to be useful in investigating a suspected contamination from a point source.</p><p>It can be concluded that Lake Ensjön is contaminated with water from the mine waste. No other sources in the catchment area can be the source of the enriched amounts of heavy metals. Focus should in further work be put upon finding the exact source of leakage from the mining area.</p> / <p>Från Enåsengruvan i Ljusdals kommun utvanns ur sulfidmalm guld, silver och koppar under åren 1984 till 1991. Avfall från sulfidmalmsgruvor medför miljöproblem genom försurning och läckage av tungmetaller. Vanligtvis täcks avfallet med jordmassor eller vatten för att förhindra påverkan på naturen. De studier som genomfördes under prospekteringen visade på att Ensjön, som är belägen inom en kilometers avstånd från gruvområdet, inte skulle påverkas av gruvan men en provtagning under 2005 visade på höga halter av tungmetaller i sjön.</p><p>I denna studie har Ensjöns vattenkvalitet undersökts genom vatten och sedimentanalyser. Vattenprover i sjön och dess inlopp togs två gånger under sommaren 2006 och sedimentprover togs vid ett tillfälle på tio olika lokaler i sjön. En djupprofil av sedimenten analyserades för att föroreningshistoriken från innan gruvan togs i bruk till nutid skulle kunna kartläggas. För att datera sedimenten analyserades de med avseende på Cs-137. De högsta halterna av Cs-137 kan härledas till nedfallet från Tjernobylolyckan 1986. Efter datering valdes lämpliga prover ut för metallanalys.</p><p>Resultaten visar på förhöjda halter av koppar, zink, nickel och kadmium. Halterna i ytsedimenten är höga både jämfört med de halter som återfinns på större djup i sedimentprofilen, motsvarande avsättning innan gruvdriften och vad som uppmättes i referensstudien från 1980. Halterna är även höga relativt de jämförvärden som Naturvårdsverket satt upp. Vattenanalyserna visar på att vattnet i inflödet från gruvområdet innehåller höga halter av de tidigare nämnda metallerna. Metoden med Cs-137-datering och analys med avseende på metaller av sediment har visat sig fungera väl för kartläggning av en nutida förorening från en punktkälla. Tillsammans med kompletterande vattenprover ger det en bra bild av den rådande situationen.</p><p>Då resultaten visar att Ensjöns vatten är påverkat av en punktkälla och alla andra källor kan uteslutas får det anses klarlagt att sjöns vatten är påverkat av dränagevatten från gruvområdet. Fortsatta studier bör fokusera på att klarlägga den exakta källan till läckaget från gruvområdet.</p>
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Föroreningsspridning via ledningsgravar : en fältstudie på Köpmanholmens industriområdeGardfors, Lars January 2005 (has links)
<p>Sewer trenches usually contain material with a higher hydraulic conductivity then the adjacent soil. Thus they can serve as paths of preferential flow in a polluted area. Wastewater from factories can also leak from wastewater pipes and pollute the soil in the sewer trenches.</p><p>The purpose of this project was to investigate pollutions in sewer trenches and in sewer pipes in the industrial area of Köpmanholmen, 20 km south of Örnsköldsvik in the north of Sweden. To make an estimation concerning the potential of transport of pollutions in sewer trenches, hydrological calculations were performed.</p><p>Leakage to any greater extent did not seem to be a problem in the area. This is the case both for the concrete and the wooden pipes that have served as factory wastewater pipes. A large transport in the lengthwise direction of the sewer trenches was not shown to exist. Instead the greatest risk of transport from a polluted area seems to come from infiltration into wastewater pipes, where the pollutants can flow readily to the recipient or wastewater treatment plant.</p> / <p>Rörgravar innehåller ofta grövre material med högre hydraulisk konduktivitet än omgivande jord och kan därför tjäna som spridningsvägar från förorenade områden. Avloppsvatten från fabriksområden kan också misstänkas ge upphov till föroreningar i rörgravar via läckage från avloppsrören.</p><p>Detta arbete har haft som mål att utreda föroreningssituationen i ledningsgravar och avloppsledningar på Köpmanholmens industriområde, ca 2 mil söder om Örnsköldsvik. För att bedöma ledningsgravarnas potential att sprida föroreningar har också hydrologiska beräkningar har gjorts.</p><p>Läckage i någon större omfattning från avloppsledningar har inte kunnat påvisas. Detta gäller både betongledningar och den trätub som har utgjort fabriksavlopp på området. Inte heller har någon föroreningsspridning kunnat påvisas i ledningsgravarnas längdriktning. Den största risken för spridning av föroreningar verkar istället vara via infiltration till avloppsledningarna. Detta ger en snabb transport från förorenade områden till recipient eller reningsverk.</p>
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Förorenade byggnader : Utvärdering av genomförda saneringarJohannesson, Sofia January 2008 (has links)
<p>Nowadays there are several contaminated buildings that receive a new field of application. These buildings used to have industrial activities which contaminated the buildings with both organic and inorganic pollutants that can cause serious health problems. Now these buildings get new functions like office work, school buildings or daycare centers. But before these buildings can be used as for instance schools some kind of remediation has to be carried out to remove the contamination. The aim with this report was to make an inventory of available methods for remediation of contaminated buildings and to evaluate the result of some performed remediations. The buildings that were investigated in this report were contaminated with organic pollutants. This report includes a summary of the legislation that concerns contaminated buildings, health problems that solvents and oils can cause and information of available methods for remediation of polluted buildings. A survey was made and property holders of remediated contaminated buildings answered it. According to the survey it emerged that air-regulated floors and new floor constructions were the most commonly used methods for remediation. The choice of method was often a balance between time and economy. After the remediation it’s important to do inspections to make sure that the remediation had removed the contamination. Inspection can be made by measuring the indoor air. Another way to inspect a remediation is to send out surveys to those people who stay in the building. The most important aspect during the remediation is to guarantee peoples health. Results from the survey showed that air-regulated floors are a good remediation method and often used with good results. To make the remediation work easier generic guideline values for different building materials should be developed to be used in the analysis of the degree of the remediation.</p>
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Regenerable Adsorbents for Removal of Arsenic from Contaminated Waters and Synthesis and Characterization of Multifunctional Magnetic Nanoparticles for Environmental and Biomedical ApplicationsVerdugo Gonzalez, Brenda January 2011 (has links)
The present work is divided into two sections. The first section deals with the synthesis of regenerable adsorbents for the removal of arsenic from contaminated waters. An adsorbent based on carboxymethylated polyethylenimine grafted agarose gels was synthesized and characterized as a regenerable synthetic ferric oxide adsorbent with high capacity for arsenate ions at pH 3.0. Similarly, four metal ion chelating adsorbents based on dipicolylamine were synthesized and characterized with respect to their Cu(II), Fe(III) and As(V) adsorption capacities. The most efficient adsorbents were Nov-PEI-DPA and Nov-TREN-DPA. Additionally, a commercial ion exchange resin was modified with permanganate to oxidize arsenite into arsenate. A complete oxidation-adsorption system was proposed in which a column packed with the oxidation resin was connected in series with an adsorbent column composed of the polyethylenimine grafted agarose gels.The second section involved work with magnetic nanoparticles. First, composite adsorbents consisting of magnetic particles encapsulated within agarose beads with and without grafted iminodiacetic acid (IDA) chelating groups were synthesized. The adsorption capacity of the adsorbents for Cu(II), Fe(III) and As(V) at different concentrations was investigated. Batch experiments were carried out to determine the Fe(III) and As(V) adsorption isotherms for the magnetic Novarose-IDA. Regenerability of the adsorbent was achieved with a pH change of the inlet solution, without affecting its magnetic or adsorption properties.Magnetic composite particles were synthesized for biomedical applications. First, magnetic nanoparticles were coated with silica and then used for gold nanoshell production. These nanoshells were functionalized with a Brij S10 derivative, containing carboxylic groups, using dodecanethiol as a bridging agent to incorporate a fluorescent biomolecule.Finally, magnetic and gold particles were encapsulated in PLGA nanoparticles. Docetaxel was loaded on these multifunctional nanoparticles and released studies were performed at 37°C. The presence of magnetite, colloidal gold and gold nanoshells in the PLGA nanoparticles was revealed by the coloration acquired by the polymeric nanoparticles. The release of drug from the polymeric nanoparticles showed a biphasic behavior with an initial burst followed by a prolonged slow release. There was no effect of the presence of magnetic or metallic particles on docetaxel release.
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