Browsing by Author "Bergamasco, Rosangela"
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- Green technologies for cyanobacteria and natural organic matter water treatment using natural based productsPublication . Ribau Teixeira, Margarida; Camacho, Franciele Pereira; Serrão Sousa, Vânia; Bergamasco, RosangelaGreen technologies are environmentally friendly operations that limit the negative impacts of traditional industrial activities and can contribute to solving the challenge of sustainable water management. This work aims to develop a green water treatment sequence using a natural coagulant (Moringa oleifera) and a natural activated carbon (vegetable coconut palm) to remove Microcystis aeruginosa and natural organic matter in an integrated process. The proposed sequence, coagulation/flocculation/dissolved air flotation and activated carbon, is an eco-friendly and innovative option for water treatment managers, since it includes environmentally friendly products for the contaminant removal from water, replacing the traditional inorganic/synthetic coagulants and adsorbents. Results demonstrated that waters with concentrations as high as 150-200 mu g/I. of chlorophyll a and natural organic matter between 5 and 16 mg C/L presented removals higher than 80% for turbidity and chlorophyll a, 70-80% for dissolved organic matter and 80-90% for UV254nm. Moringa oleifera natural coagulant removed almost 80% of Microcystis aeruginosa cells in coagulation/flocculation/dissolved air flotation processes. The coconut palm activated carbon showed a high capacity to adsorb DOC from water with a maximum adsorbed capacity of 51.8 mg/g at equilibrium. The values obtained in treated water for the parameters measured are very encouraging, so this innovative integrated sequence may be used for improving water quality, benefiting human health and wellbeing. (C) 2017 Elsevier Ltd. All rights reserved.
- The use of Moringa oleifera as a natural coagulant in surface water treatmentPublication . Camacho, Franciele Pereira; Sousa, Vania Serrao; Bergamasco, Rosangela; Teixeira, Margarida RibauMoringa oleifera (MO) seed is a natural plant with active bio-coagulate compounds that can be used for water clarification since it reduces the use of chemical-based coagulants. This study aims to evaluate the impact of Moringa oleifera (MO) seeds and MO seeds with a reduced amount of oil as coagulants in conventional water treatment to remove cyanobacteria from different natural surface waters. Tests were performed for waters with low (5-10 NTU) and high (30-60 NTU) initial turbidity with and without Microcystis aeruginosa cells and for MO integral powder, MO oil-extracted with ethanol and with a pressurized technique, and MO extracted with NaCI. The results show that MO oil-extraction is not necessary when using MO seeds as a coagulant in coagulation/flocculation/sedimentation (CF/S). Chlorophyll a and turbidity removals were up to 85% for high-turbidity waters, with 50 mg.L-1 MO obtained, for MO integral powder and for all of the MO extraction methods used. Therefore, for these waters, integral powder (without any extraction) can be used. For low-turbidity waters and using a 1 M saline extraction of the active coagulant compound, chlorophyll a and turbidity removals were approximately 60%. It was also demonstrated that MO is capable of removing some of the organic matter present in water, namely, aromatic organic matter, between 40 and 50% when using MO extracted with NaCI. However, dissolved organic matter results showed an increase independent of the type of MO extraction used. (C) 2016 Elsevier B.V. All rights reserved.