Water scarcity for agriculture is one of the most important challenges to improve food security worldwide. In this thesis we study the potential to develop a low-cost controller for a small scale brackish desalination plant that consists of proven water treatment technologies, reverse osmosis, cation exchange, and nanofiltration to treat groundwater into two final products: drinking water and irrigation water. The plant is powered by a combination of wind and solar power systems. The low-cost controller uses Arduino Mega, and Arduino DUE, which consist of ATmega2560 and Atmel SAM3X8E ARM Cortex-M3 CPU microcontrollers. These are widely used systems characterized for good performance and low cost. However, Arduino also requires drivers and interfaces to allow the control and monitoring of sensors and actuators. The thesis explains the process, as well as the hardware and software implemented.

Mixed Matrix Membranes (MMMs) have received worldwide attention during the last decades. This is due to the fact that the resulting materials can combine the good processability and low cost of polymer membranes with the diverse functionality, high performance and thermal properties of the fillers. This work explores the fabrication and application of MMMs. We focused on the design and fabrication of nanofillers to impart target functionality to the membrane for water treatment, protective coating and gas separation. This thesis is divided into three sections according to the application including: I- Water Treatment: This part is divided into three chapters, two related to the membrane distillation (MD) and one related to the oil spill. Three different nanofillers have been used: Periodic mesoporous organosilica (PMO), graphene and carbon nanotube (CNT). Those nanofillers were homogeneously incorporated into polyetherimide (PEI) electrospun nanofiber membranes. The doped nanoparticle not only improved the mechanical properties and thermal stability of the pristine fiber but also enhanced the MD and oil spill performance due to the functionality of those nanofillers. II- Protective coating: This part includes two chapters describing the design and the fabrication of a smart antibacterial and anti-corrosion coating. In the first project, we fabricated colloidal lysozyme-templated gold nanoclusters gating antimicrobial-loaded silica nanoparticles (MSN-AuNCs@lys) as nano-fillers in poly(ethylene oxide)/poly(butylene terephthalate) polymer matrix. MSN-AuNCs@lys dispersed homogeneously within the polymer matrix with zero NPs leaching. The system was coated on a common radiographic dental imaging device that is prone to oral bacteria contamination. This coating can successfully sense and inhibit bacterial contamination via a controlled release mechanism that is only triggered by bacteria. In the second project, the coaxial electrospinning approach has been applied to fabricate smart core-shell nanofiber for controlled release of anti-corrosion material. Acetal-dextran was used as a pH controlled shell of the fibers and polyvinyl alcohol (PVA) as a hydrophilic core. Caffeine, as an anti-corrosion inhibitor was encapsulated in the fiber core to test its potential application as an anticorrosion coating. The almost negligible release was noticed at neutral pH. In acidic pH due to corrosion, the fibers quickly respond by releasing caffeine cargo. III- Gas separation: We describe the synthesis and application of novel ethylene-diamine-based PMO. The novel nanoparticles were homogeneously incorporated into polydimethylsiloxane to fabricate a MMMs thin layer on a porous polyacrylonitrile support. Our results prove that our PMOs can be used as nanofillers to enhance the CO2 selectivity of the PDMS polymer.

In this project the adsorption ability of mesoporous magnesium carbonate (MMC) for copper (Cu), cobalt (Co), chromium (Cr) and arsenic (As) was evaluated. This was done by mixing MMC and dissolved metal (of different concentrations) and measuring the concentration of the solution before and after addition of MMC with Inductively coupled plasma optical emission spectroscopy. Besides MMC, “ordinary” magnesium carbonate (MgCO_3) was evaluated for comparison. Furthermore, the MMC was characterised with various instruments before and after adsorption of the metals. The adsorption experiments established that MMC was able to adsorb large amounts of Cu, Co and As while MgCO_3 was not. Moreover, it was discovered that both materials adsorbed equally large amounts of Cr. At higher concentrations of Cu and Co the uptake capacity of MMC suddenly dropped. However, for As, it was determined that MMC reached saturation at a concentration of ~22 mg/L. An adsorption experiment of a mixture of metals of 20 mg/L of each metal could not conclude anything about the selectivity of MMC, but the experiment revealed that MMC was able to adsorb all of Cu, Co and As rapidly at this concentration. The characterisation of MMC before adsorption revealed an amorphous structure and a high porosity. The structure of MMC after adsorption of Cu went from amorphous to crystalline and after adsorption of Co and As the structure also became crystalline, but of a lower degree than after adsorption of Cu. Furthermore, it was discovered that ion exchange also occurred along with adsorption.

Plastproduktionen och användningen av plast ökar varje år i hela världen och detta är ett av världens största problem. Plaster är ett svårnedbrytbart ämne och processen kan ta hundratals år. Detta leder i sin tur till att plastackumuleringen orsakar skadlig påverkan på klimat, miljö och människor. Ett av alternativen som har stor potential för hanteringen av detta problem är att minska användningen av plast och i stället öka produktionen och användningen av bioplastereller biopolymerer som är nedbrytbar. Bioplaster har kortare nedbrytningstid än vanliga plaster och därför är bioplast ett bra alternativ istället för att använda vanliga plaster. Det finns tre olika grupper av bioplaster, nämligen dem som är biobaserade, bionedbrytbara och de som är både biobaserade och bionedbrytbara. Entyp av bioplast som är biologiskt nedbrytbar och biobaserad är polyhydroxialkanoater (PHA)som används i olika branscher då PHA är en av de biopolymerer som visar störst potential attersätta plast i framtiden. Forskning pågår på Högskolan i Borås med målet av att bilda en ny process för produktion och återvinning av PHA. Processen baseras på produktion av PHA från flyktiga fettsyror som produceras från acidogen jäsning. Acidogen jäsning är en modifierad process av anaerobmatsmältning som används idag för produktion av biogas från avfall. Den kan vara den rättaprocessen för återvinningen av PHA-baserade avfall och för att producera ett billigt substrat, nämligen flyktiga fettsyror för PHA produktion. Det här projektet handlar om en del av processen, nämligen produktion av PHA med bakterier. Forskningsgruppen på Högskolan iBorås har en bakteriestam som inte har undersökts för produktion av PHA. Innan bakterien kan studeras för produktion av PHA från flyktiga syror behövs medelinnehållet optimeras för bakterietillväxt. Syftet med detta arbete är att undersöka effekten av olika glukoskoncentrationer som kollkälla och olika mängder av ammoniumsulfat som används vid tillväxt av den bakterien Bacillusmegaterium för produktion av PHA. En jämförelse mellan det definierade mediet som användsi detta arbete och dess ersättning med nutrient broth, ett komplext medium som normalt används för bakterietillväxt genomfördes också för att utvärdera lämpligheten hos mediet underutveckling för att framgångsrikt stödja bakterietillväxt. Under detta arbete användes flera olika analytiska tekniker såsom pH mättning, Högupplösande vätskekromatografi (HPLC),Spektrometer (OD mättning), och Fourier-transform infraröd spektroskopi (FTIR) för att utvärdera bakterietillväxt och produktion av PHA samt analysera sammansättningen av PHAs. Mängden av ammoniumsulfat påverkade glukosförbrukningen, där koncentrationer av 3 g/Loch 7 g/L visades att leda till en snabbare glukosförbrukning jämfört med 5 g/L. Därför valdes3 g/L ammoniumsulfat då det innehåller mindre kemikalier användning och påverkar inte celltillväxten på ett negativ sätt. Under experimentet med användning av 3 g/Lammoniumsulfat med 10 g/L glukos, konsumerades glukosen fullständigt vid 72 timmar av bakterietillväxt och den maximala PHA-produktionen var på 13–14% baserad på torr cell vikt. Tillväxtmedelet som utvecklades i det här projektet visade att vara lämplig för bakterietillväxt eftersom användning av nutrient broth som används normalt för bakterietillväxt ledde till långsammare glukosförbrukning. Initial glukoskoncentration (5, 10 och 20 g/L) påverkade inte glukosförbrukningen och får studerats vidare för att öka cellkoncentrationen och följaktligen produktionen av PHA. En av det mest studerade i PHA-familjen är polyhydroxibutyrat (PHB). Under detta arbete visade det sig att genom användning av FTIR att PHB framställdes. / Plastic production and use of plastic are increasing every year throughout the world and this is one of the world's biggest problems. Plastic is a persistent substance, and its biodegradation process can take hundreds of years. This in turn leads to the accumulation of plastic causing harmful effects on the climate, the environment, and people. One of the alternatives that has great potential when it comes to dealing with this problem is to reduce the use of plastics and instead increase the production and use of bioplastics or biopolymers that are biodegradable. Bioplastics have a shorter biodegradation time than plastics and therefore bioplastics are a good alternative instead of using ordinary plastic. There are three different groups of bioplastics, namely those that are bio-based, those that are biodegradable and those that are both bio-based and biodegradable. One type of bioplastic that is biodegradable and bio-based is Polyhydroxyalkanoates (PHA) which are used in various industries as PHA is one of the biopolymers that shows the greatest potential to replace plastic in the future. Research is underway at the University of Borås with the goal of developing a new process for the production and recycling of PHAs. The process is based on the production of PHAs from volatile fatty acids produced from acidogenic fermentation. Acid fermentation is a modified process of anaerobic digestion; the latter is used nowadays to produce biogas from waste and can be the right process for recycling PHA-based waste and for producing a cheap substrate, namely volatile fatty acids for PHA's production. This project is about a part of the process, namely the production of PHAs with bacteria. The research group at the University of Borås has a bacterial strain that has not been yet investigated for the production of PHAs. Before this bacterium can be studied for the production of PHAs from volatile fatty acids the compositionoptimization of the cultivation medium for bacterial growth is needed. The purpose of this work is to investigate the effect of different glucose concentrations as a source of carbon and different amounts of ammonium sulphate in the growth of the bacterium Bacillus megaterium and the production of polyhydroxyalkanoates. A comparison between the defined medium under development in this project with nutrient broth, a complex medium normally used to grow bacteria, was also carried out in order to evaluate the suitability of the defined medium to support bacterial growth. During this work several different analytical techniques have been used such as pH measurement, High-Performance Liquid Chromatography (HPLC), Spectrometer (for optical density (OD) measurement), and Fourier-Transform Infrared Spectroscopy (FTIR) to evaluate bacterial growth and production of PHA as well as PHAs composition. The amount of ammonium sulphate affected glucose consumption rate, where concentrations of 3 g/L and 7 g/L were shown to lead to a faster glucose consumption compared to that at 5 g/L. Therefore, 3 g/L ammonium sulphate was chosen as it represents less chemical consumption while not affecting cell growth negatively. During bacterial cultivation in a medium containing 3 g/L ammonium sulphate, 10 g/L glucose, among other compounds, glucose was completely consumed after 72 hours of bacterial growth and the maximum PHA production was 13-14% based on cell dry weight. The cultivation medium developed in this project was shown to be suitable for bacterial growth since the use of nutrient broth, normally used for bacterial growth, led to slower glucose consumption. Initial glucose concentration (5, 10 and 20 g/L) did not affect glucose consumption rate and should be further studied to increase cell concentration and consequently the production of PHA. One of the most studied polymers in the PHA family is polyhydroxybutyrate (PHB). During this work, it was found, through the use of FTIR, that PHB was produced.

Thesis (M.Sc.(Agricultural Management )) -- University of Limpopo, 2020 / Avocado fruit ‘Hass’ harvested during early-season and exposed to temperature at 5.5°C for 28 d are susceptible to chilling injury (CI); and therefore, develop poor skin colour during ripening. In ‘Hass’ avocado fruit, skin colour change during ripening is used by European market to indicate fruit ripeness and softness. Therefore, the aim of this study was to evaluate the use of hot water (HW) and methyl jasmonate (MJ) as postharvest treatment dips to mitigate CI; and thereby, enhance ‘Hass’ avocado fruit peel colour during ripening. Fruit were harvested randomly from 5 selected trees treated alike during early season (April 2018); and thereafter, transported to the laboratory. At the laboratory, experiments of this study were divided into 2: experiment (1) fruit were dipped into HW (38, 42 and 46°C for 30, 25 and 20 min, respectively); and experiment (2) fruit were dipped into MJ (10 and 100 µmol/L for 2 min) treatments. In both experiments after these treatments, fruit were allowed to dry for 60 minutes at ambient (±25°C) temperature and untreated fruit were used as control. Thereafter, fruit were stored at commercial shipping temperature (5.5°C) for up to 28 d. After removal from cold storage, fruit were ripened at ambient temperature (±25°C) and evaluated every after 2 d for weight loss, firmness loss, objective colour parameters (lightness-L*, chroma-C* and hue angle-h*), subjective colour (eye colour) and ripening percentage. However, chilling injury (CI) and electrolyte leakage (EL) were evaluated immediately after removal from cold storage. The results showed that HW significantly (P< 0.05) increased weight and firmness loss during ripening. Furthermore, HW reduced EL and external chilling injury (ECI) of ‘Hass’ avocado fruit during cold storage. In addition, the results showed that HW had significant effect (P< 0.05) on colour parameter L* and eye colour rating, but did not affect (P> 0.05) C* and h*. Avocado ‘Hass’ fruit subjected to HW at 42°C/25 and 46°C/20 min developed purple colour (eye colour rating 4.47 and 4.36, respectively) during ripening when compared with HW at 38°C/30 min and control fruit. Moreover, results showed that dipping fruit in 10 µmol/L had a significant effect (P< 0.05) on reducing weight loss during ripening. Methyl jasmonate (10 and 100 µmol/L) treatment reduced EL and alleviated external chilling injury (ECI) of ‘Hass’ fruit during cold storage. The results showed that MJ (10 and 100 µmol/L) treatments had significant effect (P< 0.05) on colour parameter L*, h* and eye colour rating, but did not affect (P> 0.05) C*. Furthermore, ‘Hass’ fruit treated with 10 and 100 µmol/L MJ reached the purple skin colour (eye rating 5.39 and 5.19, respectively) during ripening. Fruit dipped in MJ (10 µmol/L) had low weight loss when compared with fruit treated with MJ (100 µmol/L). In conclusion, the results of this study indicated that HW (42°C/25 minutes) and MJ (10 µmol/L) effectively alleviated external chilling injury; and therefore, improved ‘Hass’ skin colour development during ripening / Agricultural Research Council-Institute (Agriseta) and University of Limpopo

The aim of the master thesis was to propose the reconstruction of the water treatment plant. I chose the water treatment plant in Čebín, which I have already describe with in the bachelor thesis. The water treatment plant has problems with increased iron, manganese and ammonium salts. In the first part I devoted myself to the current condition of the water treatment plant and the possibilities of removing the elements from the water. In the next chapter I compiled the equipment of the technological line. To remove iron and manganese, I suggested aeration using an injector, and for the removal of ammonium salts, potassium permanganate is used, which is used to regenerate the filters. A pair of pressure filters helps remove iron and manganese. In the last part of the thesis I described and evaluated the original condition of the water treatment plant. To evaluate the technical condition, I used the TEA Water web application.

V této práci byl popsán princip fotokatalýzy. Práce se soustřeďuje na kovové oxidy, které mají široké využití ve fotokatalytických aplikacích. Bylo také popsáno různé použití fotokatalytických materiálů. Tato práce se zaměřuje zejména na využití fotokatalytických materiálů pro rozklad organických vodu znečisťujících látek. Popsaný fotokatalyzátor je oxid měďný, který má velmi dobré vlastnosti pro rozklad organických látek pomocí fotokatalýzy. Schopnost rozkladu organických látek oxidu měďného byla popsána na rozkladu organického barviva methylová oranž.

No description available.

Submitted master's thesis is dealing with the problem of occurrence of residues of specific anthropogenic pollution of drinking water sources, with accent on possibilities of elimination of these compounds during drinking water treatment. There was pay attention to two estrogenic hormones – estradiol and ethinylestradiol. In laboratory scale there was tested efficiency of coagulation, activated carbon adsorption and ozonation in elimination of studied compounds from artificially contaminated water.

Karst rivers are special type of rivers because of their hydrography conditions. They usually flow from non-karst area and as soon as they reach in to the karst area they disappear underground. There, they flow through cavities until they reach the surface again. The aim of this thesis is to assess the impact of water outflow from wastewater treatment plant on karst rivers. The study was done in the central area of CHKO Moravský kras where the impact of two WWTP on a cave system Rudické propadání – Býčí skála is evaluated. As a part of this study a half-year monitoring was carried out, which consisted of water sampling once every two weeks. In total, 13 water samples were taken from 8 sampling points. Also 4 additional one-time samples were taken from the cave system. Moreover, flow rate, temperature, conductivity, oxygen concentration and pH were measured at the sampling point. Afterwards, the content of undissolved solids, CODCr, BOD, N-NH4+, N-NO2-, N-NO3-, P-PO43- and total phosphorus were determined in the samples. The change of parameters in time and during the flow in the river was observed from the measured values. The balance of pollutants in particular parts of the river was calculated. The outflow values from waste water treatment plants were compared to the emission limits for surface waters and the parameters of rivers were compared to the environmental quality standards. According to the results, it can be observed that the water quality improves after passing through the cavities. It was proven that the outflows from the observed waste water treatment plants are negatively influencing the water streams. The most serious problem is the wash up of sludge from WWTP Rudice and its consequent sedimentation in the river and/or outflow to the Rudické propadání.