Dricksvattnet ombord på Sjöfartshögskolans fartyg Calmare Nyckel har vid tidigare provtagning visat på undermålig kvalitet. Orsaken till detta har inte undersökts innan. I detta arbete undersöks och identifieras orsaken och ett underlag för förbättring av vattenkvaliteten har tagits fram. Underlaget omfattas också av en arbetsbeskrivning för ombyggnation av färskvattensystemet och ett underlag för installation av en färskvattenproducerande anläggning. För att kontrollera vattenkvaliteten ombord genomfördes vattenprover och en undersökning av färskvattensystemet med endoskop. Resultaten analyserades sedan och ett åtgärdsprogram för förbättring av vattenkvaliteten har rekommenderats. Det nuvarande färskvattensystemet undersöktes och outnyttjade anläggningsdelar identifierades. En arbetsbeskrivning för demontering av ovan nämnda anläggningsdelar togs fram. Sjöfartshögskolan hade förvärvat en begagnad färskvattenanläggning vilken undersöktes för att avgöra om den gick att använda ombord på Calmare Nyckel. Undersökningen visade att anläggningen inte gick att använda och arbetet fortsatte med att utveckla en offert på en färskvattenproducerande anläggning som Sjöfartshögskolan beställde 2009. Ett underlag för installation av den färskvattenproducerande anläggningen togs fram och innehåller montageritningar, arbetsbeskrivningar, materialbehov, plan för monteringsarbetet och resursbehov. Metoden och åtgärdsprogrammet kan i framtida undersökningar fungera som hjälpmedel vid behov av att förbättra vattenkvaliteten ombord på liknande fartyg. / Drinking water onboard Kalmar Maritime Academy’s ship Calmare Nyckel has on previous sampling demonstrated insufficient quality. The reason for this has not been investigated before. This study examines and identifies the cause for the substandard water quality and support material for improvement has been developed. The material also contains a job description for rebuilding of the fresh water system and documents regarding installation of a freshwater generator. Water samples and examination of the fresh water system with endoscope was performed to verify the water quality onboard the ship. The results were analysed and a plan for improvement of water quality was recommended. The current fresh water system was investigated and unused components were identified. A description for removing the mentioned components was made. Kalmar Maritime Academy had acquired a used freshwater generator which was examined to determine whether it could be used onboard Calmare Nyckel. The examination revealed that it could not be used and the study proceeded to develop a quotation on a freshwater generator that Kalmar Maritime Academy had ordered in 2009. Material for the installation of the freshwater generator was created and includes assembly drawings, job descriptions, material requirements, plan for the assembly work and resource needs. The method and plan may in future investigations be used as aids to the improvement of water quality onboard similar vessels.

Thesis (MSc. (Geography)) --University of Limpopo, 2018 / Water hyacinth (Eichhornia crassipes) is recognised as the most notorious invasive species the world-over. Although its threats and effects are fully documented, its distribution is not yet understood, especially in complex environments, such as river systems. This has been associated with the lack of accurate (high spatial resolution) and robust techniques, together with the reliable data sources necessary for its quantification and monitoring. The advent of new generation sensors i.e. Landsat 8 Operational Land Imager (OLI) and Sentinel-2 MultiSpectral Instrument (MSI) data, with unique sensor design and improved sensing characteristics is therefore perceived to provide new opportunities for mapping the distribution of invasive water hyacinth in small waterbodies. This study aimed at mapping and understanding the spatio-temporal distribution of invasive water hyacinth in the Greater Letaba river system in Tzaneen, Limpopo Province of South Africa using Landsat 8 OLI and Sentinel-2 MSI data. Specifically, the study sought to identify multispectral remote sensing variables that can optimally detect and map invasive water hyacinth. Landsat 8 OLI and Sentinel-2 MSI were tested based on the spectral bands, vegetation indices, as well as the combined spectral bands plus vegetation indices, using discriminant analysis algorithm. From the findings, Sentinel-2 MSI outperformed Landsat 8 OLI in mapping water hyacinth, with an overall classification (OA) accuracy of 77.56% and 68.44%, respectively. This observation was further confirmed by a t-test statistical analysis which showed that there were significant differences (t=6.313, p<0.04) between the performance of the two sensors. Secondly, the study sought to map the spatial distribution of invasive water hyacinth in the river system over time (Seasonal). Multi-date 10 m Sentinel-2 MSI images were used to detect and monitor the seasonal distribution and variations of water hyacinth in the Greater Letaba River system. The study demonstrated that, about 63.82% of the river system was infested with water hyacinth during the wet season and 28.34% during the dry season. Sentinel-2 MSI managed to depict species spatio-temporal distribution with an OA of 80.79% during wet season and 79.04% in dry season, using integrated spectral bands and vegetation indices. New generation sensors provide new opportunities and potential for seasonal or long-term monitoring of aquatic invasive species like water hyacinth- a previously challenging task with broadband multispectral sensors. / Risk and Vulnerability Science Centre (RSVC)