Browsing by Author "Gorgich, M."
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- Application of domestic greywater for irrigating agricultural products: A brief studyPublication . Gorgich, M.; Mata, T.M.; Martins, A; Caetano, Nídia; Formigo, N.The decline in annual rainfall, coupled with the growing demand for water in agricultural fields, triggered a new crisis in today’s world. Thus, the focus is on finding solutions to new water resources. Taking a look at the normal daily life, most of the households’ effluents can be ranked into a less-polluted category, called greywater. Excluding human dejects, greywater comprises the outflow from washing machines, dishwashers and bathtubs. It is considered an effluent with a more economic treatment, because it contains less microbial pollution. Hence, this work revises the effects of greywater irrigation on the quality of crops, and provides a comprehensive study of the effects of greywater on the quality of soil. Furthermore, a comprehensive discussion is carried out to evaluate the energy consumption of facilities for both greywater and wastewater treatment to provide water used in irrigation. It also addresses current methodologies for treating greywater and evaluates the effects of crops irrigation with treated and untreated greywater, indicating the type of treatment chosen depending on the type of crop to be irrigated.
- Comparison of different lipid extraction procedures applied to three microalgal speciesPublication . Gorgich, M.; Mata, T.M.; Martins, A.A.; Branco-Vieira, M.; Caetano, NídiaThe increase in the world’s energy demand has contributed to the emergence of new sustainable energy sources, such as microalgae, with their great potential to provide biofuels and other high value co-products for the food and health’s markets. However, current biorefinery methodologies are either too complex to extract the targeted components such as high-value products, or require solvents with toxicity for humans and the environment. This work aims to evaluate different lipid extraction approaches applied to three microalgal species: Chlorella zofingiensis, Phaeodactylum tricornutum, and Arthrospira platensis, while employing less toxic and more economical solvents for the lipids extraction. Experimental results showed a promising outcome to tune current biorefinery methodologies, enhancing product yield as well as decreasing potential hazards.
- Flocculation of Arthrospira maxima for improved harvestingPublication . Caetano, Nídia; Martins, A.A.; Gorgich, M.; Gutiérrez, D.M.; Ribeiro, T.J.; Mata, T.M.The environmental impacts associated with the burning of fossil fuels coupled with growing concerns about security of energy supply, motivated the search for more sustainable forms of energy production, among which came microalgae for biofuels production. However, the commercial production of microalgae biofuels is still not competitive compared to fossil fuels, as it is necessary to solve some process bottlenecks, among which biomass harvesting, that is the focus of this work. Hence, this work intends to study the harvesting of microalga Arthrospira maxima through flocculation by pH variation and/or addition of CaCl2 as flocculant. Thus, it is described the effect of pH variation (in the range 6 to 12), followed by the addition of flocculant, on the harvesting efficiency. Results show that by pH increase over 10 using NaOH, or by flocculation using CaCl2 at a concentration of 0.2-2.0 g/L and at a 1:30 ratio (v/v) of CaCl2/microalgae culture, it is possible to effectively harvest this microalga.
- Influence of cultivation conditions on the bioenergy potential and bio-compounds of Chlorella vulgarisPublication . Caetano, Nídia; Melo, A.R.; Gorgich, M.; Branco-Vieira, M.; Martins, A.A.; Mata, T.M.This study aims to evaluate the influence of cultivation conditions on the bioenergy and high value biocompounds contents of Chlorella vulgaris. Results show that the use of nitrate rich media, from 170.7 mg/L, favors a faster biomass growth, reaching values above 800 mg/L biomass. In addition, it favors higher pigments concentrations with more emphasis for the cultures with a nitrate concentration of 569 mg/L, where chlorophyll-a and carotenoids reached maximum concentrations of 6 and 2 mg/L, respectively. As regards the lipid content, nitrate deprivation (<28.4 mg/L) favors the accumulation of lipid content by microalgae (around 42%). The use of media with lower iron concentrations (0.5 mg/L) was favorable for obtaining biomass with higher concentrations of chlorophyll-a, at an initial stage, with values varying from 0.2 to 0.6 mg/L. In the tests carried out under mixotrophic conditions (addition of glucose), it was observed that contamination occurred in all the cultures, possibly due to the high concentration of carbon source that had values between 0.5 and 1.5 g/L of glucose, and consequently, growth decreased.