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Philosophiae Doctor - PhD / The disposal of brine effluent from inland wastewater desalination plants is a growing global problem with adverse economic and environmental implications because of the substantial cost associated with its disposal and the potential for polluting groundwater resources. Currently, the best and most economical option for brine disposal from inland desalination plants is the use of evaporation ponds, which concentrate the liquid until getting a solid waste that can be valued or directly managed by an authorized company. The effectiveness of these ponds is therefore dependent on the evaporation rate, which has previously been improved by the addition of dyes such as methylene blue. However, the addition of chemical dyes to the evaporation ponds poses a threat to the environment, wildlife, and humans.

Made available in DSpace on 2016-08-15T20:31:14Z (GMT). No. of bitstreams: 1 TeresaEPG_DISSERT.pdf: 731676 bytes, checksum: f024d9272492149e6edd0a0a8f38a28f (MD5) Previous issue date: 2010-12-22 / It evaluated the quality of carne-de-sol in the period from June to September of 2010 sold in five cities of Rio Grande do Norte - Mossoró, Apodi, Areia Branca, Baraúna and Grossos. It was collect 80 samples of carne-de-sol, of which 44 were from small establishments and 36 purchased in supermarkets and stores. The samples were subjected to microbiological testing - Salmonella, determining the most probable number of fecal coliform, halophilic bacteria and Staphylococcus aureus, the samples were positive for this bacteria were analyzed for resistance to antibiotics, and physical-chemical properties (pH, water activity, minerals and humidity). There was an interaction between intrinsic pH value (&#956; = 5.702) and Aa (&#956; = 0.868), , indicating a favorable environment for their multiplication, resulting in values that stood out significantly in what is expected legislation counting S. aureus (&#956; = 4.81 log UFC at 78.75%), Salmonella (25%) and fecal coliform (&#956; = 2.36 LogNMP / g, 63.75%). A significant correlation (p <0.05) between the number of halophilic bacteria (&#956; = 4.87 log UFC) and S. aureus, such conditions may be used as an indicator of contamination in the sun-dried meat. To the antibiotics, 22.5% of strains were resistant to gentamicin, whereas for penicillin G, chloramphenicol, tetraciclina were 100%, 67.5% and 46.26% respectively. It was found that the meat produced and marketed in the sun studied region is improper (96.25%) for consumption in accordance with Brazilian law / Foram avaliadas a qualidade da carne-de-sol no período de junho a setembro de 2010 comercializada em cinco cidades do Rio Grande do Norte Mossoró, Apodi, Areia Branca, Baraúna e Grossos. Sendo coletadas 80 amostras de carne-de-sol, as quais 44 foram provenientes de estabelecimentos de pequeno porte e 36 adquiridas em supermercados e frigoríficos. As amostras foram submetidas à análises microbiológicas Salmonella, determinação do número mais provável de coliformes termotolerantes, bactérias halofílicas e Staphylococcus aureus, as amostras positivas para esta bactéria foram submetidas à análise de resistência à antibióticos; e físico-químicas (pH, atividade de água, cinzas e umidade). Verificou-se interação dos fatores intrínsecos, pH (µ=5,702) e Aa (µ=0,868), do produto com a contagem bacteriana, indicando ambiente favorável para a sua multiplicação, resultando assim em valores que sobressaíram de maneira significativa o que está previsto na legislação para contagem de S. aureus (µ=4,81LogUFC, em 78,75%), Salmonella (presença em 25%) e coliformes termotolerantes (µ=2,36LogNMP/g, em 63,75%). Houve correlação significativa (p<0,05) entre a contagem de bactérias halofílicas (µ=4,87LogUFC) e a de S. aureus, podendo aquelas serem utilizadas como indicador de contaminação na carne-de-sol. Quanto à sensibilidade das cepas S. aureus aos antibióticos, 22,5% das cepas apresentaram resistência à gentamicina, enquanto para penicilina G, tetraciclina e cloranfenicol foram 100%, 67,5% e 46,26% respectivamente. Ficou constatado que a carne de sol produzida e comercializada na região estudada apresenta-se imprópria (96,25%) para o consumo de acordo com a legislação brasileira

Freshwater shortages causes challenges in mineral processing in Chile, especially in arid regions. As a result, froth flotation; a mineral process, is shifting usage of freshwater to seawater. This has consequences in the consumption of flotation reagents and decreasing the flotation efficiency. Biotechnological developments allow conceptualising the use of bacterial cells and their metabolites as bioreagents in flotation; classified as bioflotation. In this thesis, 5 halophilic bacteria, namely, Halomonas boliviensis, Marinobacter spp., Halobacillus litoralis Hol-1, Marinococcus halophilus KOR-3 and Halomonas eurihalina P6-1 have been screened for the potential use as pyrite biodepressants at micro- and batch-scale flotation. The effect of bioconditioning minerals with these bacteria was studied using zeta potential, fluorescence microscopy and contact angle. Experiments measuring zeta potential show the isoelectric point (IEP) of pyrite, chalcopyrite and molybdenite became more acidic post-bioconditioning. Fluorescence microscopy with Nile red; a hydrophobic stain, allowed for a method to visualize bacterial cells or collector potassium isopropyl xanthate (KIPX) on mineral particles of pyrite, chalcopyrite and molybdenite. Additionally contact angle experiments show that strains Halobacillus litoralis Hol-1, Marinococcus halophilus KOR-3 and Halomonas eurihalina P6-1 had an influence on the contact angle of pyrite and chalcopyrite, inducing changes in their hydrophobicity. Microflotation experiments showed a decreased recovery of pyrite in presence of all strains, but notably, Halobacillus litoralis Hol-1 and Marinococcus halophilus KOR-3, also showed an increased recovery of chalcopyrite, making them ideal candidates as pyrite biodepressants. Halomonas eurihalina P6-1 showed low recoveries of both minerals, but a higher selectivity depressing more pyrite than chalcopyrite. Usage of autoclaved biomass from the three aforementioned strains in batch-flotation experiments resulted in the recovery of chalcopyrite improving, with a small decrease in the recovery of pyrite, overall showing a positive potential but not improving the system. Halophilic bacteria such as the ones used in this study show an influence on the floatability of pyrite, which could be commercially exploited to substitute lime as a pyrite depressant. Furthermore, the work in this thesis focused on studying the effects of cells in artificial seawater, both at micro and batch-scales which brings the laboratory experiments a step closer to industrially relevant conditions.