Produção, caracterização e aplicação de carvão ativado de caroço de pêssego no tratamento de efluente têxtil / Production, characterization, and application of activated charcoal from peach kernel in textile effluent treatment

RESUMO O objetivo deste estudo foi caracterizar a produção de um carvão de caroço de pêssego e também avaliar a adsorção de corantes têxteis pelo carvão ativado de caroço de pêssego. A ativação do carvão foi realizada utilizando cloreto de zinco como agente oxidante. O carvão ativado foi então utilizado na adsorção de corantes, para posterior aplicação no tratamento de um efluente têxtil. Primeiramente, realizou-se a produção de carvão ativado com as temperaturas de 500, 700 e 900°C e tempo de carbonização de 10 15 e 20 minutos e verificou-se a remoção dos corantes preto reativo 5 e azul de metileno. De acordo com a metodologia de superfície de resposta, a melhor temperatura de produção apresentou-se acima de 700°C com tempo de exposição de 10 minutos para os dois corantes. Desse carvão ativado, avaliaram-se os dados de densidade, teor de umidade e cinzas, pH e rendimento. Também foram realizados ensaios cinéticos e de equilíbrio. Os dados foram ajustados a três modelos cinéticos. As medidas para determinação da eficiência na remoção de cor do efluente têxtil foram realizadas pelo método espectrofotométrico e demonstraram média de remoção superior a 62% da cor presente no efluente bruto. Desse modo, o caroço de pêssego demonstrou elevado potencial para a produção de carvão ativado visando o tratamento de efluentes contendo corantes, podendo servir como alternativa de baixo custo.

ABSTRACT The aim of this study was to characterize the production of activated charcoal from the peach kernel and assess the adsorption of textile dyes by this activated charcoal. The activation of the charcoal was performed using zinc chloride as the oxidizing agent. The activated charcoal was then used in the adsorption of dyes for later application in the treatment of a textile effluent. Firstly, the production of activated carbon was carried out at temperatures of 500, 700, and 900°C and carbonization time of 10, 15, and 20 minutes and the removal of the Reactive Black 5 and Methylene Blue dyes was verified. According to the methodology of response surface, the best production temperature was above 700°C with 10 min exposure for both dyes. From this activated carbon, data on density, moisture and ash content, pH, and yield were evaluated. Kinetic and equilibrium tests were also performed. The data were fitted to three kinetic models. The measures to determine the efficiency in the color removal of the textile effluent were carried out by the spectrophotometric method and demonstrated an average removal greater than 62% of the color present in the raw effluent. In this way, the peach kernel demonstrated a high potential for the production of activated carbon aiming at the treatment of effluents containing dyes and can serve as a low cost alternative.

Evaluation of a Combined System Based on an Upflow Anaerobic Sludge Blanket Reactor (UASB) and Shallow Polishing Pond (SPP) for Textile Effluent Treatment

Abstract Color removal from textile effluents was evaluated using a laboratory-combined process based on an upflow anaerobic sludge blanket (UASB) reactor followed by a shallow polishing pond (SPP). The anaerobic reactor was fed with a real textile effluent, diluted 10-times in a 350 mg/L solution of pre-treated residual yeast extract from a brewery industry as nutrient source. The parameters color, COD, N-NH3 and toxicity were monitored throughout 45 days of operation. According to the results, decolorization and COD removal were highest in the anaerobic step, whereas the effluent was polished in the SPP unit. The overall efficiency of the complete UASB-SPP system for COD and color were 88 and 62%, respectively. Moreover, the N-NH3 generated by the residual yeast extract ammonification was below 5 mg/L for the final effluent. Finally, no toxicity was detected after the treatment steps, as shown by the Vibrio fischeri microscale assay.

Delineamento Box-Behnken para remoção de DQO de efluente têxtil utilizando eletrocoagulação com corrente contínua pulsada / Box-Behnken design for COD removal of textile wastewater using electrocoagulation with pulsed DC

RESUMO A remoção de poluentes de efluentes industriais de forma efetiva e economicamente viável ainda é um desafio. Dessa forma, o presente trabalho propôs investigar a tecnologia de eletrocoagulação (EC) para o tratamento de efluente têxtil utilizando corrente contínua pulsada (CCP). A metodologia de superfície de resposta Box-Behnken foi utilizada para analisar e otimizar as condições operacionais, visando à máxima remoção de demanda química de oxigênio (DQO). Os experimentos foram realizados com um volume reacional de 2,6 L, em modo batelada. Diante dos resultados obtidos, a configuração ótima considerada foi: velocidade de agitação = 200 rpm, frequência dos pulsos = 1.000 Hz e espaçamento entre os eletrodos = 1 mm, em 50 minutos de EC. Nessas condições foi obtida uma remoção de DQO de 81,23% (valor remanescente de 152 mg O2.L-1). Em adição, verificou-se que o processo de EC também é eficaz para a redução de cor, turbidez, sólidos suspensos totais, sulfato e sulfeto. A concentração de íons cloreto não foi alterada durante a EC, apresentando-se como um aspecto favorável para a reutilização do efluente tratado no próprio processo produtivo têxtil, o qual demanda uma elevada concentração de NaCl.

ABSTRACT The effective and economically viable removal of industrial wastewater pollutants is still a challenge. Thus, this study proposed to investigate the electrocoagulation technology (EC) for the treatment of textile effluent using pulsed direct current (CCP). The methodology of Box-Behnken response surface was used to analyze and optimize the operating conditions, aimed at maximum chemical oxygen demand (COD) removal. The experiments were performed with a reaction volume of 2.6 L in batch mode. Based on these results, the optimal configuration was: agitation speed = 200 rpm, frequency of pulses = 1,000 Hz and spacing between electrodes = 1 mm, in 50 minutes of EC. Under these conditions it was obtained a COD removal of 81.23% (remainder value of 152 mg O2.L-1). In addition, it was found that the EC process is also effective for reduction of color, turbidity, total suspended solids, sulfate and sulfide. The concentration of chloride ions was not modified during the EC, presenting itself as a favorable aspect for the reuse of treated wastewater in the textile production process itself, which demands a high concentration of NaCl.

Influência do excesso de nitrogênio amoniacal no tratamento de efluente têxtil em reator de bateladas sequenciais com Aspergillus niger AN 400 / Influence of excess nitrogen in the treatment of the textile effluent in sequential batch reactors with Aspergillus nigerAN 400

RESUMO Água residuária têxtil foi tratada com Aspergillus niger AN 400 em reator de bateladas sequenciais, em ciclos de 48 h para avaliar o efeito de fonte adicional de nitrogênio sobre a eficiência do sistema alimentado com efluente diluído (10% v/v) e glicose (3 g.L-1). O afluente recebeu fonte adicional de nitrogênio (etapa I), acarretando em excesso de nitrogênio amoniacal (192 mg.L-1) no meio, resultando em remoção de matéria orgânica de 85%, porém em apenas 55% de remoção de corante. Ao se diminuir a concentração média de amônia para 98 mg.L-1 (etapa II), a remoção de corante (83%) passou a ser superior à de matéria orgânica, de 69%, mostrando o efeito negativo de concentrações elevadas de amônia sobre o sistema, favorecendo ainda o crescimento de bactérias, o que provavelmente inibiu a produção de enzimas fúngicas e contribuiu para a perda de eficiência na remoção de corante e formação de subprodutos.

ABSTRACT Textile wastewater was treated by Aspergillus niger AN 400 in sequential batch reactor, which was operated in cycles of 48 h in order to evaluate the effect of an additional source of nitrogen on the system's efficiency, which was fed with effluent diluted (10% v/v) and glucose (3 g.L-1). The influent received addition of an external source of nitrogen (phase I), in which there was excess ammonia (192 mg.L-1) in the medium, resulting in organic matter removal of 85%, but in only 55% removal of dye. In the phase II, when the average concentration of ammonia in the medium was lower (98 mg.L-1), removal of dye (83%) became higher than that of organic matter (69%), showing the negative effect of high concentrations of ammonia over the system and favoring the growth of bacteria, which probably inhibit the production of fungal enzymes and contributed to the loss of efficiency in the removal of dye and the formation of byproducts.

Decolourization of textile dye effluent by non-viable biomass of Aspergillus fumigatus

The aim of this work was to study the decolourization of textile dye effluent by non-viable biomass of Aspergillus fumigates. The dried non-viable fungal biomass exhibited maximum dye removal at pH 7.0 with temperature of 30ºC and 3 g/l (w/v) biomass concentration, after 24 h contact time. The results showed that the non-viable biomass possessed high efficiency for dye removal from textile effluent.

Assessment of the toxicity of waste water from a textile industry to Cyprinus carpio.

Static, short-term, acute toxicity tests were performed over a period of 96 hrs using different concentrations of influent and effluent of textile industry waste water with the objective of evaluating their acute toxicity on fresh water fish, Cyprinus carpio (common carp). The LC50 24, 48, 72 and 96 hr of influent and effluent were 25.9, 21.10, 15.66, 11.11% (v/v) and 63.18, 54.89, 48.62, 36.04% (v/v), respectively. The acute toxic unit TUa values for 24, 48, 72, 96 hr for influent and effluent are 3.85, 4.73, 6.38, 8.99 and 1.58, 1.82, 2.05, 2.77, respectively. Correspondingly, the TF was found to be 1, 1.22, 1.65 and 2.33 for influent, and for effluent 1, 1.15, 1.29 and 1.75. Total efficiency of the treatment was 69.16% and the safe concentration of effluent is set to be 3.60%. These data are highly useful in establishing limits of acceptability by the aquatic animals. The need to introduce toxicity evaluation assay for confirming the quality of effluent from the point view of effective environmental safe limits and to ensure integrity of aquatic environment, is stressed.

Emprego de bomba multifásica como unidade geradora de microbolhas de ar em sistema de flotação aplicado ao pré-tratamento de efluente têxtil / Multiphase pump as microbubble generator for flotation system applied to pre-treatment of textile wastewater

O artigo apresenta os resultados de uma pesquisa desenvolvida com o objetivo de avaliar o desempenho de bomba multifásica (mistura de ar e água) aplicada em substituição à câmara de saturação, em sistema de flotação localizado em uma indústria têxtil. Na unidade piloto (taxa de aplicação superficial de clarificação igual a 128,6 ± 10 m.d-1), foi verificado que os melhores resultados em termos de eficiência de remoção de turbidez e cor aparente (eficiência de remoção superior a 95 por cento) foram obtidos nos ensaios realizados com razão de recirculação em torno de 30 por cento associada à composição volumétrica de ar de 13 por cento.

This paper presents the results of a research carried out that aims to evaluate the performance of a multiphase pump (mixture of air and water) applied to replace the saturator chamber in a flotation system located in a textile industry. In the pilot unit (hydraulic surface loading equal to 128.6 ± 10 m.d-1), it was verified that the best results in terms of removal efficiency of turbidity and apparent color (efficiency removal over 95 percent) were obtained for the essays performed with recirculation ratio equal to 30 percent and air supply of 13 percent.