Browsing by Subject "sameus"

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  • Kahiluoto, Joonas; Hirvonen, Jukka; Näykki, Teemu (Springer, 2019)
    Environmental Monitoring and Assessment 191, 259 (2019)
    Continuous sensor measurements are becoming an important tool in environmental monitoring. However, the reliability of field measurements is still too often unknown, evaluated only through comparisons with laboratory methods or based on sometimes unrealistic information from the measuring device manufacturers. A water turbidity measurement system with automatic reference sample measurement and measurement uncertainty estimation was constructed and operated in laboratory conditions to test an approach that utilizes validation and quality control data for automatic measurement uncertainty estimation. Using validation and quality control data for measurement uncertainty estimation is a common practice in laboratories and, if applied to field measurements, could be a way to enhance the usability of field sensor measurements. The measurement system investigated performed replicate measurements of turbidity in river water and measured synthetic turbidity reference solutions at given intervals during the testing period. Measurement uncertainties were calculated for the results using AutoMUkit software and uncertainties were attached to appropriate results. The measurement results correlated well (R2 = 0.99) with laboratory results and the calculated measurement uncertainties were 0.8–2.1 formazin nephelometric units (FNU) (k = 2) for 1.2–5 FNU range and 11–27% (k = 2) for 5–40 FNU range. The measurement uncertainty estimation settings (such as measurement range selected and a number of replicates) provided by the user have a significant effect on the calculated measurement uncertainties. More research is needed especially on finding suitable measurement uncertainty estimation intervals for different field conditions. The approach presented is also applicable for other online measurements besides turbidity within limits set by available measurement devices and stable reference solutions. Potentially interesting areas of application could be the measurement of conductivity, pH, chemical oxygen demand (COD)/total organic carbon (TOC), or metals.
  • Spilling, Kristian; Asmala, Eero; Haavisto, Noora; Haraguchi, Lumi; Kraft, Kaisa; Lehto, Anne-Mari; Lewandowska, Aleksandra; Norkko, Joanna; Piiparinen, Jonna; Seppälä, Jukka; Vanharanta, Mari; Vehmaa, Anu; Ylöstalo, Pasi; Tamminen, Timo (Elsevier, 2022)
    Science of the Total Environment
    Highlights •Modest brownification did not affect primary production, but increased bacterial production. •Concentration of inorganic nitrogen was the primary driver for the phytoplankton development. •Brownification benefitted picophytoplankton. Abstract Climate change is projected to cause brownification of some coastal seas due to increased runoff of terrestrially derived organic matter. We carried out a mesocosm experiment (15 d) to test the effect of this on the planktonic ecosystem expecting reduced primary production and shifts in the phytoplankton community composition. The experiment was set up in 2.2 m3 mesocosm bags using four treatments, each with three replicates: control (Contr) without any manipulation, organic carbon additive HuminFeed (Hum; 2 mg L−1), inorganic nutrients (Nutr; 5.7 μM NH4 and 0.65 μM PO4), and combined Nutr and Hum (Nutr + Hum) additions. Measured variables included organic and inorganic nutrient pools, chlorophyll a (Chla), primary and bacterial production and particle counts by flow cytometry. The bags with added inorganic nutrients developed a phytoplankton bloom that depleted inorganic N at day 6, followed by a rapid decline in Chla. Brownification did not reduce primary production at the tested concentration. Bacterial production was lowest in the Contr, but similar in the three treatments receiving additions likely due to increased carbon available for heterotrophic bacteria. Picoeukaryotes clearly benefited by brownification after inorganic N depletion, which could be due to more effective nutrient recycling, nutrient affinity, light absorption, or alternatively lower grazing pressure. In conclusion, brownification shifted the phytoplankton community composition towards smaller species with potential effects on carbon fluxes, such as sinking rates and export to the sea floor.
  • Rotikko, Johanna (Helsingfors universitet, 2012)
    The literature review dealed with the production of, and factors affecting the optimal processing of, traditional sauce base. Aspects of manufacturing relating to recycling and energy, such as recycling of animal by-products, were also discussed. The aim of the experimental work was to find a solution for the problem related to the opacity of the meat stock caused by a pressure cooking method. The key aim was to find the causes of opacity when the bones were pressure cooked (up to 1.5 bar) and to identify a method to prevent the occurrence of turbidity. Different cooking times, pressures and proteolytic enzyme combinations were evaluated during experimental studies. The goal was to obtain a beef-flavoured demi-glace sauce base broth with a bright appearance and as high a dry matter content as possible. Dry matter, total protein and connective tissue protein concentrations, pH and turbidity values were evaluated when comparing the results of the manufacturing methods and conditions. In addition, potential methods to improve the heat recovery systems were investigated. The dry matter of the broth consisted mainly of proteins. There was slightly faster increase in dry matter concentration at higher pressure than lower pressure. Addition of the proteolytic enzyme had the same effect. Based on this study the broth manufacturer must choose between a high gelatin content and turbidity when pursuing high dry matter content. The dry matter hydrolysed from bones by pressure cooking was almost exclusively collagen. Collagen dissolved in water while the rest of the bone proteins precipitated when heated. The construction of the heat recovery system in a small food processing company may be unprofitable. Improving energy efficiency in a small food company is challenging but possible if professionals accurately evaluate the conditions.
  • Kasvio, Pinja; Ulvi, Teemu; Koskiaho, Jari; Jormola, Jukka (Suomen ympäristökeskus, 2016)
    Suomen ympäristökeskuksen raportteja 7/2016
    Hulevedet voivat olla merkittävä vesistöjen kuormituslähde. Nykyisen lainsäädännön mukaan hulevesiä ei tulisi johtaa suoraan viemäriverkon kautta vesistöihin, vaan niitä pitää imeyttää, viivyttää ja käsitellä tulva- ja vedenlaatuhaittojen vähentämiseksi. Näiden toimenpiteiden kokonaisuutta kutsutaan hulevesien hallinnaksi. HULE-hankkeessa tutkittiin kahden käsittelymenetelmän toimivuutta hulevesien laadun hallinnassa. Tutkimuksessa oli mukana kolme kosteikkokohdetta ja yksi biosuodatusalue, joiden avulla on mahdollista sekä viivyttää hulevesiä ennen niiden johtamista vesistöön että puhdistaa niistä erilaisia haitta-aineita ja osittain myös imeyttää vesiä maaperään. Espoon kosteikkoon johdettiin liikenne- ja teollisuusalueen hulevesiä, kun taas Järvenpään ja Kuopion kosteikoilla käsiteltiin pientaloalueilta tulevia vesiä. Tampereen biosuodatusalueella puhdistettiin Lielahden lumenkaatopaikan sulamisvesiä. Rakenteiden toimintaa seurattiin kaikilla kohteilla vesinäytteiden avulla. Espoossa ja Tampereella tehtiin myös jatkuvatoimisia mittauksia automaattilaitteistoilla. Tutkimuksissa sameuden, kiintoaineen, kokonais- ja fosfaattifosforin ja metallien osalta parhaat puhdistustulokset saavutti Tampereen biosuodatusalue. Typpeä biosuodatuksessa ei kuitenkaan poistunut, vaan sitä huuhtoutui lisää. Kosteikkojen toimivuudessa oli vaihtelua kohteiden välillä. Tulokset osoittavat, että myös kosteikoilla on mahdollista vähentää veden sameutta ja poistaa kiintoainetta ja fosforia, mutta reduktiot olivat biosuodatusaluetta alhaisempia. Osasyynä heikkoihin tuloksiin olivat pientaloalueilta tulevien vesien erittäin matalat pitoisuudet. Kaksi tutkimuskosteikkoa pystyi poistamaan jonkin verran myös typpeä. Hulevesissä usein esiintyviä, tiesuolasta peräisin olevia klorideja kumpikaan menetelmä ei pystynyt pidättämään. Kosteikkoja on Suomessa käytetty ja tutkittu erityisesti maa- ja metsätalouden sekä turvetuotannon valumavesien käsittelyssä. Myös hulevesikosteikkoja on rakennettu jonkin verran. Kokemukset ja tutkimukset osoittavat, että ne voivat olla hyvin käyttökelpoisia valumavesien puhdistuksessa. Biosuodatus on sen sijaan Suomessa vielä harvinainen menetelmä, jonka toimivuudesta ei ole toistaiseksi tarpeeksi tietoa. Tässä hankkeessa saadut tulokset sen käytöstä ovat rohkaisevia, mutta Suomesta on myös tuoreita esimerkkejä, joissa väärin valituista rakennemateriaaleista liukeni ravinteita ja metalleja käsiteltäviin vesiin. Biosuodatus on osoittautunut useissa ulkomaisissa tutkimuksissa parhaimmillaan erinomaiseksi hulevesien käsittelymenetelmäksi. Suomessa tarvitaan vielä jatkotutkimuksia, että opitaan suunnittelemaan, toteuttamaan ja käyttämään menetelmää parhaiden puhdistustulosten saavuttamiseksi.
  • Lempinen, Pasi (Uudenmaan ympäristökeskus, 2009)
    UUDra 4 /2009
    Uudenmaan ympäristökeskus kunnosti viisi koskea Koskenkylänjoella vuosina 2006 ja 2007. Kunnostuksissa koskia kivettiin ja soraistettiin kalojen elinja lisääntymismahdollisuuksien parantamiseksi. Tavoitteena on saada jokeen vahvat, luontaisesti lisääntyvät lohikalakannat. Kunnostusten vaikutusta veden sameuteen seurattiin, kun Sävträsketin Kvarnfors kunnostettiin syksyllä 2006. Kosken alasuvannossa oli kaksi automaattista sameusmittaria koko kunnostusjakson ajan. Sameusmittausten perusteella kunnostus lisäsi veden sameutta vain vähän. Sen sijaan veden sameus nousi korkealle, kun joen virtaama kasvoi runsaiden sateiden takia. Vaikuttaa siltä, että runsaiden sateiden johdosta jokeen valui paljon kiintoainetta valumaalueelta. Mahdollisesti myös joen pohjalle kertynyt aines irtosi kasvaneen virtaaman seurauksena.
  • Brando, Vittorio E.; Sammartino, Michela; Colella, Simone; Bracaglia, Marco; Di Cicco, Annalisa; D’Alimonte, Davide; Kajiyama, Tamito; Kaitala, Seppo; Attila, Jenni (MDPI, 2021)
    Remote Sensing 2021, 13(16), 3071
    A relevant indicator for the eutrophication status in the Baltic Sea is the Chlorophyll-a concentration (Chl-a). Alas, ocean color remote sensing applications to estimate Chl-a in this brackish basin, characterized by large gradients in salinity and dissolved organic matter, are hampered by its optical complexity and atmospheric correction limits. This study presents Chl-a retrieval improvements for a fully reprocessed multi-sensor time series of remote-sensing reflectances (Rrs) at ~1 km spatial resolution for the Baltic Sea. A new ensemble scheme based on multilayer perceptron neural net (MLP) bio-optical algorithms has been implemented to this end. The study documents that this approach outperforms band-ratio algorithms when compared to in situ datasets, reducing the gross overestimates of Chl-a observed in the literature for this basin. The Rrs and Chl-a time series were then exploited for eutrophication monitoring, providing a quantitative description of spring and summer phytoplankton blooms in the Baltic Sea over 1998–2019. The analysis of the phytoplankton dynamics enabled the identification of the latitudinal variations in the spring bloom phenology across the basin, the early blooming in spring in the last two decades, and the description of the spatiotemporal coverage of summer cyanobacterial blooms in the central and southern Baltic Sea.
  • Kämäri, Maria; Alho, Petteri; Veijalainen, Noora; Aaltonen, Juha; Huokuna, Mikko; Lotsari, Eliisa (2015)
    Hydrological Processes 29(22): 4738–4755
    A large number of rivers are frozen annually and the river ice cover has an influence on the geomorphological processes. These processes in cohesive sediment rivers are not fully understood. Therefore, this paper demonstrates the impact of river ice cover on sediment transport, i.e. turbidity, suspended sediment loads and erosion potential, compared with a river with ice-free flow conditions. The present sediment transportation conditions during the annual cycle are analysed, and the implications of climate change on wintertime geomorphological processes are estimated. A one-dimensional hydrodynamic model has been applied to the Kokemäenjoki River in SW Finland. The shear stress forces directed to the river bed are simulated with present and projected hydro-climatic conditions. The results of shear stress simulations indicate that a thermally formed smooth ice cover diminishes river bed erosion, compared with an ice-free river with similar discharges. Based on long-term field data, the river ice cover reduces turbidity statistically significantly. Furthermore, suspended sediment concentrations measured in ice-free and ice-covered river water reveal a diminishing effect of ice cover on riverine sediment load. The hydrodynamic simulations suggest that the influence of rippled ice cover on shear stress is varying. Climate change is projected to increase the winter discharges by 27–77 % on average by 2070–2099. Thus, the increasing winter discharges and possible diminishing ice cover periods both increase the erosion potential of the river bed. Hence, the wintertime sediment load of the river is expected to become larger in the future.
  • Ahola-Iivarinen, Elina (Helsingfors universitet, 2016)
    In the literature review of this study, the focus was on biofilms that certain microbes produce, and their potential use in food industry. Biofilms consist of microbial cells and extracellular products, e.g., polysaccharides. Pullulan as an exopolysaccharide has many industrial applications and the aim of this study was to explore a new potential alpha-glucan, dextran, and especially its ability to form a stand-alone film. Pullulan and dextran were separately mixed in de-ionized water. The dynamic viscosities of dextran and pullulan solutions were determined. Film formation of dextran was not successful, not even with sorbitol as a plasticizer. The optical properties, water vapor and oxygen permeabilities and tensile strengths of pullulan films were studied. Additionally, Whatman42-filter material was coated with or immersed in dextran solution. Hence the changes in tensile strength and permeability values between a well-known material and dextran treated material could be detected. Pullulan films had low haze values (2.1–3.9%) and they were transparent to UVA-, UVB- and visible light. The tensile strength values of pullulan films were 47–53 MPa. For filter paper, the corresponding values were 10 MPa and application of dextran coating increased it to 15–19 MPa. All polysaccharide solutions exhibited Newtonian behavior and their relative viscosities were <10 mPa, 5% pullulan with viscosity around 20 mPa as an exception. Pullulan solutions had higher viscosities than dextran solutions. The air permeabilities were 10–50 ml/min for pullulan films, 10 ml/min for dextran-sorbitol film, 200 ml/min for dextran film and 200–500 ml/min for Whatman42 material. The oxygen permeability values for pullulan films were <0,1 cm3·μm m-2·d-1·kPa-1. Based on results in this study, pullulan films are impermeable to oxygen. As the films tolerated water vapor poorly, pullulan might be a potential component in packages made of composite materials, as individual packaging material in dry environment or possibly chemically modified to obtain better resistance to water vapor. Our results show that without additional modifications dextran does not form a continuous self-supporting films in these conditions.
  • Taipalinen, Irmeli (Vesihallitus. National Board of Waters, 1980)
    Vesientutkimuslaitoksen julkaisuja 39, 37-45
    Ruoppaustöiden vaikutuksista veden laatuun Kallavedessä
  • Jaakkola, Sauli (Helsingfors universitet, 2013)
    Assessing and avoiding environmental impact of agriculture and forestry has become more and more important during recent years. In Finland, half of the phosphorus load and nearly 40 % of the nitrogen load in the water system is caused by agriculture and forestry. Traditionally water quality monitoring has been carried out with manual water sampling and laboratory analyses. The problem with manual sampling is low amount of samples. Continuously working water quality sensors have been used for a relatively short time, which is why continuous water quality monitoring needs more research. The objective of the study is to clarify the feasibility of optical sensors in monitoring water quality and nutrient loading in an agricultural and forest management area. The study was carried out in three monitoring stations of the Savijoki catchment in Southwest Finland. Two of the stations were identically equipped and were located in forested subcatchments. A third station was located at the Savijoki catchment discharge point, making it possible to study how sensors work in different water qualities. According to the study, monitoring with continuously working sensors will result in more accurate nutrient loading estimates. With sensors used in the study it is also possible to draw conclusions about dynamics between run-off and nutrient concentrations in water. A prerequisite for successful monitoring is utilizing the appropriate sensors in the correct location. For example, low nitrate levels in water in forested areas have to be taken into consideration when choosing sensors. During the monitoring it is important to actively keep track of the quality of data and to check that sensors are working properly. Water quality sensors always need good calibration and control water samples from the entire concentration range. Sensors also have to be equipped with an automatic cleaning mechanism.