Element speciation and behaviour in metal-rich Boreal river and estuarine systems using ultrafiltration and chemical modelling

The bioavailability of metals and their potential for environmental pollution depends not simply on total concentrations, but is to a great extent determined by their chemical form. Consequently, knowledge of aqueous metal species is essential in investigating potential metal toxicity and mobility. The overall aim of this thesis is, thus, to determine the species of major and trace elements and the size distribution among the different forms (e.g. ions, molecules and mineral particles) in selected metal-enriched Boreal river and estuarine systems by utilising filtration techniques and geochemical modelling. On the basis of the spatial physicochemical patterns found, the fractionation and complexation processes of elements (mainly related to input of humic matter and pH-change) were examined. Dissolved (<1 kDa), colloidal (1 kDa-0.45 μm) and particulate (>0.45 μm) size fractions of sulfate, organic carbon (OC) and 44 metals/metalloids were investigated in the extremely acidic Vörå River system and its estuary in W Finland, and in four river systems in SW Finland (Sirppujoki, Laajoki, Mynäjoki and Paimionjoki), largely affected by soil erosion and acid sulfate (AS) soils. In addition, geochemical modelling was used to predict the formation of free ions and complexes in these investigated waters. One of the most important findings of this study is that the very large amounts of metals known to be released from AS soils (including Al, Ca, Cd, Co, Cu, Mg, Mn, Na, Ni, Si, U and the lanthanoids) occur and can prevail mainly in toxic forms throughout acidic river systems; as free ions and/or sulfate-complexes. This has serious effects on the biota and especially dissolved Al is expected to have acute effects on fish and other organisms, but also other potentially toxic dissolved elements (e.g. Cd, Cu, Mn and Ni) can have fatal effects on the biota in these environments. In upstream areas that are generally relatively forested (higher pH and contents of OC) fewer bioavailable elements (including Al, Cu, Ni and U) may be found due to complexation with the more abundantly occurring colloidal OC. In the rivers in SW Finland total metal concentrations were relatively high, but most of the elements occurred largely in a colloidal or particulate form and even elements expected to be very soluble (Ca, K, Mg, Na and Sr) occurred to a large extent in colloidal form. According to geochemical modelling, these patterns may only to a limited extent be explained by in-stream metal complexation/adsorption. Instead there were strong indications that the high metal concentrations and dominant solid fractions were largely caused by erosion of metal bearing phyllosilicates. A strong influence of AS soils, known to exist in the catchment, could be clearly distinguished in the Sirppujoki River as it had very high concentrations of a metal sequence typical of AS soils in a dissolved form (Ba, Br, Ca, Cd, Co, K, Mg, Mn, Na, Ni, Rb and Sr). In the Paimionjoki River, metal concentrations (including Ba, Cs, Fe, Hf, Pb, Rb, Si, Th, Ti, Tl and V; not typical of AS soils in the area) were high, but it was found that the main cause of this was erosion of metal bearing phyllosilicates and thus these metals occurred dominantly in less toxic colloidal and particulate fractions. In the two nearby rivers (Laajoki and Mynäjoki) there was influence of AS soils, but it was largely masked by eroded phyllosilicates. Consequently, rivers draining clay plains sensitive to erosion, like those in SW Finland, have generally high background metal concentrations due to erosion. Thus, relying on only semi-dissolved (<0.45 μm) concentrations obtained in routine monitoring, or geochemical modelling based on such data, can lead to a great overestimation of the water toxicity in this environment. The potentially toxic elements that are of concern in AS soil areas will ultimately be precipitated in the recipient estuary or sea, where the acidic metalrich river water will gradually be diluted/neutralised with brackish seawater. Along such a rising pH gradient Al, Cu and U will precipitate first together with organic matter closest to the river mouth. Manganese is relatively persistent in solution and, thus, precipitates further down the estuary as Mn oxides together with elements such as Ba, Cd, Co, Cu and Ni. Iron oxides, on the contrary, are not important scavengers of metals in the estuary, they are predicted to be associated only with As and PO4.

Ohkolanjoen valuma-alueen suojavyöhykkeiden yleissuunnitelma

Vantaanjoen vesistöalueella sijaitsevan Ohkolanjoen valuma-alueella laadittiin maatalousalueiden suojavyöhykkeiden yleissuunnitelma syksyllä 2010. Kartoituksessa löytyneet kohteet sisällytettiin yleissuunnitelmaan karttojen muodossa. Suojavyöhykkeet pidättävät tehokkaasti maatalousmaalta vesistöön kulkeutuvia ravinteita ja kiintoainesta. Maisemallisesti suojavyöhykkeet elävöittävät ympäristöä ja edistävät luonnon monimuotoisuutta maatalousalueilla. Suojavyöhykkeitä voidaan perustaa vesistöön tai valtaojaan rajoittuville tai tulvaherkille pelloille, sekä pohjavesialueille. Suojavyöhyke perustetaan ympäristötukikelpoiselle lohkolle ja tukea hakevan viljelijän täytyy olla sitoutunut ympäristötukeen. Yleissuunnittelun tavoitteena on löytää ne kohteet, joissa suojavyöhykkeistä olisi eniten hyötyä vesiensuojelun kannalta. Huomioon on otettu myös maisemalliset arvot ja luonnon monimuotoisuus. Suojavyöhykkeiden perustamiseen voi hakea maatalouden ympäristötuen erityistukea. Yleissuunnitelmassa esitetyt kohteet ovat suosituksia, maatalouden erityistukien hakeminen on aina vapaaehtoista. Ohkolanjoen valuma-alueen yleissuunnitelmassa esitetään suojavyöhykesuositusta yhteensä 25,7 kilometrin matkalle. Tästä erittäin tarpeellisia on 11,4 km ja tarpeellisia 14,3 km. Pohjavesialueella peltoa on vain vähän.

Model-based estimation of liquid flows in the blast furnace hearth and taphole

This thesis presents a set of methods and models for estimation of iron and slag flows in the blast furnace hearth and taphole. The main focus was put on predicting taphole flow patterns and estimating the effects of various taphole conditions on the drainage behavior of the blast furnace hearth. All models were based on a general understanding of the typical tap cycle of an industrial blast furnace. Some of the models were evaluated on short-term process data from the reference furnace. A computational fluid dynamics (CFD) model was built and applied to simulate the complicated hearth flows and thus to predict the regions of the hearth exerted to erosion under various operating conditions. Key boundary variables of the CFD model were provided by a simplified drainage model based on the first principles. By examining the evolutions of liquid outflow rates measured from the furnace studied, the drainage model was improved to include the effects of taphole diameter and length. The estimated slag delays showed good agreement with the observed ones. The liquid flows in the taphole were further studied using two different models and the results of both models indicated that it is more likely that separated flow of iron and slag occurs in the taphole when the liquid outflow rates are comparable during tapping. The drainage process was simulated with an integrated model based on an overall balance analysis: The high in-furnace overpressure can compensate for the resistances induced by the liquid flows in the hearth and through the taphole. Finally, a recently developed multiphase CFD model including interfacial forces between immiscible liquids was developed and both the actual iron-slag system and a water-oil system in laboratory scale were simulated. The model was demonstrated to be a useful tool for simulating hearth flows for gaining understanding of the complex phenomena in the drainage of the blast furnace.

Lithostratigraphy and age of pre-Late Weichselian sediments in the Suupohja area, western Finland

Different types of laterally extensive sand- and gravel-dominated deposits, up to several tens of metres thick, were investigated in the Suupohja area of western Finland. The studied sediments were deposited in glacial, ice-marginal, glaciofluvial, sea or lake, littoral and terrestrial environments during several glacial-non-glacial cycles. Seventeen pre-Late Weichselian and three Late Weichselian/Holocene sedimentary units were identified. These were divided into ten formally and two informally defined formations that were together termed the Suupohja Group. Every unit are nevertheless not detectable throughout the study area. The informally defined “Karhukangas lower deposits” represent the lowest units in the Suupohja Group. The Karhukangas lower deposits with 5 till units, 3 glaciolacustrine/-marine units and 2 sand units, were interpreted as having been deposited during possibly four glacial-non-glacial cycles before the Late Pleistocene Subepoch (MIS 6 or earlier). The Kankalo Sand above the Karhukangas lower deposits comprises glaciofluvial and aeolian sands of Late Saalian, Eemian or Early Weichselian origin (MIS 6–MIS 5c). The Kariluoma Till above the Kankalo Sand was possibly deposited during the Late Saalian glacial advance, although an Early Weichselian origin is also possible. The Harrinkangas Formation, with glaciofluvial and quiet-water sediments, is interpreted as having been deposited during the Late Saalian and Eemian Stages (MIS 6–MIS 5e). The uppermost units in the deposits studied, the Kodesjärvi Formation (shore deposit), Isojoki Sand (aeolian), Rävåsen Formation (glaciofluvial), Vanhakylä Formation (shore line deposit), Dagsmark Till and Kauhajoki Till, were deposited during the Weichselian Stage (MIS 5d–MIS 2). In addition, Early Holocene (MIS 1) eskers without till cover were informally termed the “Holocene esker deposits”. The Lumikangas Formation represents gravelly shore deposits formed in the Holocene Epoch, when these areas last emerged from the sea. The first Weichselian ice expansion possibly reached the western part of Suupohja in the Early Weichselian Substage (MIS 5d?), but it did not expand further to the east. The second Weichselian glaciation of relatively short duration occupied the southern part of Finland in the later part of Middle Weichselian (MIS 3). Thus, the southern half of the country remained ice-free for the majority (~65–75%) of the Weichselian Stage. Instead, both humid temperate and periglacial conditions alternated. In the initial part of Middle Weichselian, this area was partly submerged, which indicates eastward expansion of the Scandinavian ice sheet(s), depressing the lithosphere. The exceptionally thick sediment cover, multiple lithofacies, relict landscape and preserved preglacially weathered bedrock are evidence of weak glacial erosion in the Suupohja area during the latest as well as earlier glaciations, making this area one of the key areas in Quaternary research.

Modeling of Liquid-Solid Flow in Industrial Scale

In the present work, liquid-solid flow in industrial scale is modeled using the commercial software of Computational Fluid Dynamics (CFD) ANSYS Fluent 14.5. In literature, there are few studies on liquid-solid flow in industrial scale, but any information about the particular case with modified geometry cannot be found. The aim of this thesis is to describe the strengths and weaknesses of the multiphase models, when a large-scale application is studied within liquid-solid flow, including the boundary-layer characteristics. The results indicate that the selection of the most appropriate multiphase model depends on the flow regime. Thus, careful estimations of the flow regime are recommended to be done before modeling. The computational tool is developed for this purpose during this thesis. The homogeneous multiphase model is valid only for homogeneous suspension, the discrete phase model (DPM) is recommended for homogeneous and heterogeneous suspension where pipe Froude number is greater than 1.0, while the mixture and Eulerian models are able to predict also flow regimes, where pipe Froude number is smaller than 1.0 and particles tend to settle. With increasing material density ratio and decreasing pipe Froude number, the Eulerian model gives the most accurate results, because it does not include simplifications in Navier-Stokes equations like the other models. In addition, the results indicate that the potential location of erosion in the pipe depends on material density ratio. Possible sedimentation of particles can cause erosion and increase pressure drop as well. In the pipe bend, especially secondary flows, perpendicular to the main flow, affect the location of erosion.

KERÄÄJÄKASVIT - hyötyä viljelijälle ja ympäristölle

Tässä julkaisussa käsitellään kerääjäkasvien toimivuutta typen huuhtoutumisen vähentäjänä ja soveltuvuutta käytännön viljelyyn. Ensimmäisessä osassa käsitellään kerääjäkasvien mahdollisuuksia vähentää typen huuhtoutumista tieteelliseltä tutkimuspohjalta ja toisessa osassa paneudutaan viljelijöiden tilakohtaisiin kerääjäkasvikokemuksiin. Tutkimusten ja tilakohtaisten kokeilujen pohjalta kerääjäkasvit estävät typen huuhtoutumista. Kerääjäkasveilla on myös suotuisa vaikutus maan rakenteeseen ja se vähentää eroosiota ja rikkakasvien määrää kasvustoissa. Julkaisu on suunniteltu auttamaan viljelijöitä, jotka harkitsevat aloittavansa kerääjäkasvien viljelyä. Tämä opas on osa TEHO Plus -hankkeen tuottamaa materiaalia viljelijöiden ja neuvojien käyttöön, mikä täydentää hankkeen laatimaa Maatilan ympäristökäsikirjaa.

FÅNGGRÖDOR – nytta för odlaren och miljön

Den här publikationen går in på hur fånggrödorna minskar kväveurlakningen och hur de lämpar sig för odling i praktiken. I första delen behandlar vi fånggrödornas möjligheter att minska urlakningen av kväve på en vetenskaplig forskningsgrund och i andra delen går vi in på jordbrukarnas erfarenheter av fånggrödor gårdsvis. Forskningen och de gårdsvisa försöken visar att fånggrödorna hindrar kväveurlakningen. Fånggrödorna har också en gynnsam verkan på markstrukturen och den minskar erosionen och mängden ogräs i växtligheten. Publikationen är avsedd att vara till hjälp för de jordbrukare som planerar att börja odla fånggrödor. Denna guide ingår i det material som producerats inom TEHO Plus-projektet för jordbrukare och rådgivare. Den kompletterar Gårdens miljöhandbok, som också sammanställts inom projektet.

Fluvio-morphological processes of meander bends - Combining conventional field measurements, close-range remote sensing and computational modelling

Meandering rivers have been perceived to evolve rather similarly around the world independently of the location or size of the river. Despite the many consistent processes and characteristics they have also been noted to show complex and unique sets of fluviomorphological processes in which local factors play important role. These complex interactions of flow and morphology affect notably the development of the river. Comprehensive and fundamental field, flume and theoretically based studies of fluviomorphological processes in meandering rivers have been carried out especially during the latter part of the 20th century. However, as these studies have been carried out with traditional field measurements techniques their spatial and temporal resolution is not competitive to the level achievable today. The hypothesis of this study is that, by exploiting e increased spatial and temporal resolution of the data, achieved by combining conventional field measurements with a range of modern technologies, will provide new insights to the spatial patterns of the flow-sediment interaction in meandering streams, which have perceived to show notable variation in space and time. This thesis shows how the modern technologies can be combined to derive very high spatial and temporal resolution data on fluvio-morphological processes over meander bends. The flow structure over the bends is recorded in situ using acoustic Doppler current profiler (ADCP) and the spatial and temporal resolution of the flow data is enhanced using 2D and 3D CFD over various meander bends. The CFD are also exploited to simulate sediment transport. Multi-temporal terrestrial laser scanning (TLS), mobile laser scanning (MLS) and echo sounding data are used to measure the flow-based changes and formations over meander bends and to build the computational models. The spatial patterns of erosion and deposition over meander bends are analysed relative to the measured and modelled flow field and sediment transport. The results are compared with the classic theories of the processes in meander bends. Mainly, the results of this study follow well the existing theories and results of previous studies. However, some new insights regarding to the spatial and temporal patterns of the flow-sediment interaction in a natural sand-bed meander bend are provided. The results of this study show the advantages of the rapid and detailed measurements techniques and the achieved spatial and temporal resolution provided by CFD, unachievable with field measurements. The thesis also discusses the limitations which remain in the measurement and modelling methods and in understanding of fluvial geomorphology of meander bends. Further, the hydro- and morphodynamic models’ sensitivity to user-defined parameters is tested, and the modelling results are assessed against detailed field measurement. The study is implemented in the meandering sub-Arctic Pulmanki River in Finland. The river is unregulated and sand-bed and major morphological changes occur annually on the meander point bars, which are inundated only during the snow-melt-induced spring floods. The outcome of this study applies to sandbed meandering rivers in regions where normally one significant flood event occurs annually, such as Arctic areas with snow-melt induced spring floods, and where the point bars of the meander bends are inundated only during the flood events.

Siirtohinnoittelun kehitys ja tulevaisuus vuosien 1994–2014 ammattilehtikirjoitusten perusteella

Pro gradu-tutkimuksen tarkoituksena on selvittää, miten siirtohinnoittelun kehitys näkyy ammattikirjoituksissa 20 vuoden aikana sekä mihin suuntaan siirtohinnoittelu on kehittymässä tulevaisuudessa. Mitkä ovat siirtohinnoittelun riskit ja edut tutkimusaineiston perusteella ja minkälaisista näkökulmista siirtohinnoittelusta on 20 vuoden aikana kirjoitettu. Artikkeleista pyritään löytämään, minkälaisia eroja on suomalaisen ja kansainvälisen kirjoittelun väliltä. Tämä on laadullinen tutkimus, jossa käytetään tutkimusmenetelmänä sisällönanalyysia. Tutkimuksessa on sisällönanalyysin mukaisesti luokittelua, teemoittelua sekä vertailua. Tutkimusaineisto koostuu kolmesta lehdestä Verotus, Tilintarkastus-lehti, nykyään Balanssi ja The Accounting Review. Lehdistä on kerätty siirtohinnoittelua käsittelevät artikkelit 20 vuoden ajalta. Tutkimustulosten perusteella näkyy siirtohinnoittelun kehitys sekä kuinka aiheesta on tullut entistä keskeisempi. Siirtohinnoittelu on nyt merkittävässä roolissa kansainvälisessä verotuksessa. Haasteena nähdään markkinaehtoisen hinnan asettaminen oikeaan arvoon. Tärkeänä luokkana nousi siirtohinnoittelun kehittäminen. Myös valtioiden uhka siitä, että siirtohinnoittelun kautta verovaroja siirtyy toisiin valtioihin, oli yksi esiin noussut teema. Johtopäätöksenä voidaan todeta, että siirtohinnoittelu on problemaattinen verotuksen aihe, koska selkeää suoraa siirtohintaa ei aina pystytä antamaan tuotteelle, palvelulle tai rahoitukselle, vaan hinta on veteen piirretty viiva. Siirtohinnoittelua pidetään uhkana valtioiden veropohjan rappeutumiselle, jos sen avulla siirretään varoja alemman verotuksen valtioihin. Konsernit toimivat entistä laajemmin eri valtioissa, joten niiden tavoitteena on suunnitella eri konsernin osien tulosta. Tulevaisuudessa on paljon kehityskohtia ja tarpeita siirtohinnoittelun alueella. Kehitykseen vaikuttavat valtioiden yhteisöveropoliittiset päätökset sekä valtioiden omat lainsäädännöt sekä valtioiden sitoutuminen OECD:n säännöksiin, joiden avulla pyritään yhtenäisiin toimintamalleihin. Jatkossa tutkimusta voisi laajentaa kansainvälisemmäksi sekä vielä syvemmin voisi miettiä myös kehityksen suuntia ja niiden vaikutuksia.

Droplet Deposition in the Last Stage of Steam Turbine

During the expansion of steam in turbine, the steam crosses the saturation line and hence subsequent turbine stages run under wet condition. The stages under wet condition run with low efficiency as compared to stages running with supersaturated steam and the life of the last stage cascade is reduced due to erosion. After the steam crosses the saturation line it does not condense immediately but instead it becomes supersaturated which is a meta-stable state and reversion of equilibrium results in the formation of large number of small droplets in the range of 0.05 - 1 μm. Although these droplets are small enough to follow the stream lines of vapor however some of the fog droplets are deposited on the blade surface. After deposition they coagulate into films and rivulets which are then drawn towards the trailing edge of the blade due to viscous drag of the steam. These large droplets in the range of radius 100 μm are accelerated by steam until they impact on the next blade row causing erosion. The two phenomenon responsible for deposition are inertial impaction and turbulent-diffusion. This work shall discuss the deposition mechanism in steam turbine in detail and numerically model and validate with practical data.