a b s t r a c tThe use of natural coagulants represents an important step for sustainable environmental technologies. Consequently, substantial research has been conducted to replace chemical coagulants with biodegradable and non-toxic coagulants based on natural compounds. In this study, the efficiency of a natural tannin-based coagulant (Tanfloc SG ® ) was tested as a replacer of ferric chloride, to remove organic matter from the polishing treatment step of swine slaughterhouse wastewater. Experimental designs defining the optimal treatment conditions of the wastewater were used to minimise the measured responses. The apparent colour and turbidity values were satisfactorily reduced (78% and 96%, respectively) by Tanfloc SG ® , with a chemical oxygen demand reduction of 50%. The ferric chloride presented a lower performance than Tanfloc SG ® in almost all analyses. The results showed that Tanfloc SG ® performed excellently in the role of the primary coagulant, favourably replacing ferric chloride in the treatment of coagulation, flocculation and sedimentation of the study effluent.
With increasing of world population food production has also increased to supply these needs. As a result of these factors have increased the use of natural resources, among them can be highlight that water after being used throughout the process eventually generates effluents with high pollutant load which if not properly treated can result in major environmental problems. To minimize this problem is used the treatment of these effluents and one of the mechanisms used is coagulation. The coagulants agents can be of chemical origin such as aluminum or iron, or natural origin, also called polyelectrolytes, such as moringa, chitosan and tannin. The advantages of using polyelectrolytes are numerous, they can be used in the effluents treatment from various industries, wastewater treatment and even drinking water treatment, in addition to their lower cost, higher efficiency, the lower volume of the sludge generated compared with the chemical coagulant, also its lower toxicity enables easier discharge and may even be used in agriculture as fertilizer.Additional keywords: chitosan; ferric chloride; moringa; polyelectrolyte; tannin. ResumoCom o aumento da população mundial, a produção de alimentos também tem aumentado para suprir essas necessidades. Como consequência desses fatores, tem-se o aumento da utilização dos recursos naturais, entre os quais se pode destacar o hídrico que, após ser utilizado durante todo o processo, acaba gerando efluentes com alta carga poluente que, se não forem devidamente tratados, podem acarretar grandes problemas ambientais. Para minimizar esse problema, faz-se o tratamento destes efluentes, e um dos mecanismos utilizados é a coagulação. Os agentes coagulantes podem ser de origem química, como alumínio ou ferro, ou de origem natural, também chamados de polieletrólitos, como moringa, quitosana e tanino. As vantagens da utilização dos polieletrólitos são inúmeras, pois podem ser utilizadas em tratamento de efluentes de vários segmentos da indústria, tratamento de esgotos domésticos e até mesmo para tratamento de água
This study purpose was to investigate the usage of two natural coagulants: Tanfloc SG® and chitosan, in order to replace the currently ferric chloride usage by the wastewater coagulation process from slaughterhouses subsequently initial treatment. Preliminary tests were accomplished to delimit the research groups of the operating parameters: pH and coagulant concentration, based on the wastewater COD diminution. Therefore, following these results, the tests were defined by a rotational central composite design (CCRD) with three central and four axial points, amounting eleven tests, demarcating the optimum operating parameters for each coagulant, which were, respectively, pH 7.0 and concentration of 200.0 mg.L -1 for Tanfloc SG®, pH 4.0 and concentration of 500.0 mg.L -1 for chitosan, and for ferric chloride, it was pH 4.5 and concentration of 100.0 mg.L -1 . Tests were managed under optimal conditions and the results suggested that the Tanfloc SG ® coagulant was expressively more efficient in the secondary wastewater treatment from slaughterhouse.
The aim of this work was to evaluate the decolorization of a textile effluent and of reactive dyes by the basidiomycete Pleurotus pulmonarius and by laccase. The fungus decolorized all dyes. The decolorization percent varied from 47% to 98%. The dyes did not inhibit the biomass growth and in all experiments, the COD reduction was verified. The fungus also decolorized the effluent. Evaluating the influence of the inoculum concentration and the medium agitation speed on the decolorization, the best result, around 62%, was obtained using 50rpm and 50% of inoculum concentration. For the experiments using laccase, the decolorization percent of the dyes blue-bf-r, turquoise blue, navy blue-ble, rbb-r, yellow-gle, black and grey was greater than 30%. For the dyes scarlet red, red-4b and yellow-3r, the decolorization results were bellow 20%. The effluent decolorization was about 35%. The fungus, as well as the enzyme, decolorized the textile effluent and dyes.
Cranberries and blueberries are small fruits known for their antioxidant properties. However, due to their high water content and short shelf life, they are generally marketed as dehydrated berries. The present work aimed to model the rehydration of dehydrated berries. Rehydration tests were conducted at 7 and 29°C using milk as a solvent and at 7, 29, and 45°C when the solvent was water. The mass gain was assessed at different intervals, and the experimental data were fitted to the Fick model considering the berries as spheres. Six empirical/semi-empirical models describing the diffusion of water during drying were used to predict the rehydration process. Fick's law satisfactorily represented the data, and the highest diffusion coefficients were found when the berries were rehydrated in water at 45°C. Rehydration of berries in milk resulted in nutrient gain as different diffusive flows occurred during the process. The use of empirical models to predict the operating time of the rehydration processes allows flexibility as such models are mathematically simpler than the Fick model. Diffusivity is essential for the design/construction of equipment, and/or process optimization and implementation.
RESUMOOs processos de oxidação avançada (POAs) têm surgido como métodos eficazes para o tratamento terciário de efluentes industriais porque eles são capazes de destruir os poluentes e não apenas transferí-los de uma fase para outra como ocorre nos processos terciários convencionais aplicados em indústrias frigoríficas. O processo biológico, tratamento principal utilizado para efluentes frigoríficos, é limitado à degradação de substâncias biodegradáveis e que não são tóxicas para a cultura biológica. A utilização de um processo integrado FentonCoagulação para o tratamento terciário desses efluentes aparece como uma alternativa promissora e, portanto, o objetivo do presente trabalho foi determinar as condições operacionais do processo proposto para o tratamento terciário de efluente frigorífico. As variáveis investigadas foram a razão [Fe +2 ]/[H 2 O 2 ] e pH COAGULAÇÃO . Os ensaios foram conduzidos em triplicata de acordo com um delineamento central composto rotacional (DCCR) 2 2 , com três pontos centrais e quatro pontos axiais, que totalizou 11 ensaios. A eficiência do processo proposto foi determinada em cada ensaio experimental em função da eficiência de remoção da demanda química de oxigênio (DQO). Na faixa investigada, as condições operacionais definidas foram razão [Fe +2 ]/[H 2 O 2 ] de 0,800 e o pH COAGULAÇÃO de 5,50. O estudo revelou que o processo integrado Fenton-Coagulação proposto conduzido nas condições definidas alcançou uma eficiência de remoção de DQO superior a 71%, e pode, portanto, ser usado para o tratamento terciário de efluente frigorífico com o objetivo de degradação de matéria orgânica recalcitrante (não biodegradável).Palavras-chave: degradação, matéria orgânica, processos de oxidação avançada. Determination of operational conditions for tertiary treatment of slaughterhouse wastewater by the integrated Fenton-Coagulation process ABSTRACTAdvanced oxidation processes (AOPs) appear to be effective methods for tertiary wastewater treatment because they are able to destroy pollutants and not only transfer them from one phase to another without destroying them as is the case with conventional tertiary processes applied in the slaughterhouse industries. Biological processes are the main
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