| Oily wastewater, which constitute a large part of industrial wastewaters, can contain emulsified oil and surfactants, a wide variety of hydrocarbons and related contaminants, inorganic salts and organic matter. Conventional treatment techniques include dissolved air flotation, gravity separation, chemical breaking of emulsions, coagulation and flocculation. However, these techniques have several drawbacks, such as complex operational procedures, low efficiency in the case of small-diameter oil droplets and a large amount of sludge produced, which, in itself, represents an environmental and economic problem. Flocculation of oily wastewaters employ often polymers designed for other applications and used at dosages tenfold higher than for those used in sludge dewatering. Hence, it is not surprising that companies with such oily wastes, including dairies, food-processing or edible oil producers, are often reluctant to try to recover assets from their water resource while they are still recoverable (i.e. in the plant). The main purpose of this work is twofold: the development of novel flocculants to treat oily wastewaters, especially from food industry, and to use more health-friendly formulations in their synthesis. In this way, it is possible to produce a specific product to treat a defined wastewater, avoiding the problems of having to overdose polymers designed for other types of waters. Besides this, it is also possible to do this development using processes that are safer for health, replacing the hazardous compounds used in their synthesis, especially the aromatic compounds.;As results of the studies conducted, a wide range of flocculants was prepared, apparently with suitable characteristics for application in the treatment of oily wastewaters from organic nature. The developed flocculants and application procedures on oily wastewaters treatment show to be very promising, suggesting to be worthy of pursuing in research with the view to achieve a possible future practice at an industrial scale. The same applies to the monitoring methodology developed, which was applied for the first time in this work, to follow the flocculation process in a real effluent. This work is inserted in a European Project of European Industrial Doctorates (FP7 Marie Curie-EID), involving the collaboration of a company with large experience in polyelectrolytes production, especially tuned polymers, which is also partner of the Project. (Abstract shortened by ProQuest.). |
