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- Chemical oxidation of fish canning wastewater by Fenton’s reagentPublication . Cristovão, Raquel; Gonçalves, Cristiana; Botelho, Cidália; Martins, Ramiro; Boaventura, RuiThe fish canning industry generates large volume of wastewater for which the treatment is particularly difficult due to the high content of organic matter and salts and to the significant amount of oil and grease they present. In this work, a closed jacketed batch reactor was used to study the feasibility of applying a Fenton reaction step after an activated sludge biological treatment. For this purpose and in order to find optimal conditions, a 33 Box-Behnken full factorial design was used. The predicted optimum value (64% DOC degradation) was found for hydrogen peroxide concentration of 1520 mg/L, iron concentration of 338 mg/L and pH 3.2.
- Uptake and release of divalent zinc ions from aqueous solutions by aquatic moss Fontinalis antipyretica.Publication . Martins, Ramiro; Boaventura, RuiAquatic mosses are able to accumulate zinc and some other heavy metal ions from aqueous solutions and partially release them when exposed to metal-free water. They play an important role in the assessment of toxic elements in water. The advantage of mosses over direct water sampling is that the use of the former lessens spatial and temporal variations, enhances the level of contaminant identification by concentrating toxic elements, and provides information relative to the bioavailable species. However, to make the concentration of metals that can be measured in mosses a reliable indicator of the concentration of toxic elements in the water, we need to model the bioaccumulation phenomenon. Laboratory experiments were conducted to determine zinc uptake and release kinetics by the aquatic moss Fontinalis antipyretica, as this species is widely spread in Portuguese rivers and the majority of the European countries. Zinc was chosen for this study because (i) it acts as micro-nutrient for plant growth in low concentration values; (ii) it is toxic when in excess inhibiting the growth and (iii) it is present in many industrial wastewaters and mine drainage waters discharged into rivers and lakes.
- Treatment of wastewater containing mineral oil by sorption onto granulated corkPublication . Ferreira, Catarina Isabel de Almeida; Pereira, J.; Pintor, Ariana; Correia, P.; Silva, J.; Vilar, Vítor J.P.; Botelho, Cidália; Martins, Ramiro; Orfão, J.; Boaventura, RuiThe aim of this work is the development of a new method to remove oils from wastewaters, namely hydrocarbons. These contaminants, when present in high concentrations, are efficiently removed by physical and chemical processes, such as gravity separators, flocculation and flotation processes; however for low concentrations, these methods are not applicable [1]. Moreover, advanced separation processes such as membrane separation [2] and activated carbon adsorption [3] are expensive options for the treatment of oil-containing wastewaters. This new technique is based on oil and hydrocarbons’ sorption on cork granules.