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RESUMO Este trabalho procurou avaliar a eficiência de tratamento floculante com sulfato de alumínio ou cloreto férrico para o efluente bruto neutralizado de uma indústria de celulose e papel. A filtração do efluente, removendo fibras, finos, macromoléculas e flocos naturais, permitiu expressivas reduções da cor aparente, cor real e DQO do mesmo. Enquanto o sulfato de alumínio mostrou excelentes resultados, o cloreto férrico não teve bom desempenho. Deve-se otimizar as concentrações, as formas de agitação e a decantação dos flocos. Para as amostras testadas, na primeira seqüência de testes, concentrações com cerca de 2500 ppm de sulfato de alumínio (com 14 moléculas de água de hidratação) mostraram ótimos resultados para redução de cor aparente, cor real, DQO e cloretos. Conforme o previsto, na segunda seqüência de testes as concentrações de [Al2 (SO4)3, 14 H2O] diminuíram para todos os índices físico-químicos testados. A melhor concentração para pH, cor aparente e cor real foi de 1000 ppm filtrado, enquanto que para cloretos foi de 2000 ppm não filtrado, com o tempo de agitação de 1 minuto com alta velocidade e 15 minutos à baixa velocidade, com exceção da cor real que foi de 10 minutos à baixa velocidade. Como recomendação, sugere-se avaliar uma etapa seqüencial de filtração após clarifloculação/decantação. Com isso, o desempenho de um tratamento físico-químico de efluentes desse tipo será eficiente, apesar do custo envolvido na aquisição do insumo sulfato de alumínio. ABSTRACT This paper tried to evaluate the efficiency of the flakelet treatment with aluminum sulphate or ferric chloride for the neutralized brute effluent of a pulp and paper industry. The effluent filtration, removing fibers, fines macromolecules and natural flakes, permited expressive reductions of the apparent color, real color and COD of the same. While the aluminum sulphate showed excellent results, the ferric chloride didn’t have good performance. It should optimize the concentrations the stirring forms and the flakes decantation. To the samples tested in the first sequence of tests, concentrations around 2,500 ppm of aluminum sulphate (with 14 water molecules of hydration) they showed excelent results to the reduction of the apparent and real color, COD and clorides. As it was foreseen, in the second sequence of tests, the concentrations of [Al2 (SO4)3, 14 H2O] decresead to all the physicochemical index testad. The best concentration to pH, apparent color and real color was of 1,000 ppm filtrated, while the chorides it was 2000 ppm not filtrated, with one minute [1] in high- speed and fifteen [15] minutes in low speed, stirring time except the real color that was ten [10] minutes in low speed. A recommendation, is suggested to evaluate a sequencial phase of filtration after (clarifloculation/decantation). With this, the performance of a physicochemical treatment of the effluents of this type will be efficient, in spite of the cost involved in the acquisition of aluminum sulphate supply.

Three technologies were tested (TiO2/UV, H2O2/UV, and TiO2/H2O2/UV) for the degradation and color removal of a 25 mg L-1 mixture of three acid dyes: Blue 9, Red 18, and Yellow 23. A low speed rotating disc reactor (20 rpm) and a H2O2 concentration of 2.5 mmol L-1 were used. The dyes did not significantly undergo photolysis, although they were all degraded by the studied advanced oxidation processes. With the TiO2/H2O2/UV process, a strong synergism was observed (color removal reached 100%). Pseudo first order kinetic constants were estimated for all processes, as well as the respective apparent photonic efficiencies.