Textile effluents are a result of the use of reactive dyes which present a strong environmental impact. These are substances of concern when conventional treatment processes are to be considered. This work refers to the study of post-treatment (purification) of the textile effluent originating from the use of reactive dyes (after biological treatment for activated sludge) through photocatalysis using TiO2 as semiconductor. The photocatalytic process was optimised according to the mass of the semiconductor (1.4 g l(-1)), flow of air (150 ml s(-1)), temperature (55 degrees C) and time of treatment (240 min). In the optimised conditions it was possible to verify high efficiency in the colour reduction (92%), COD (65%), BOD (40%) and TOC (29.3%). The study reached the conclusion that the photocatalytic process presents great potential as a method of post-treatment of effluents derived from the textile industry.

Final disposal of solid waste is still a cause for serious impacts on the environment. In sanitary landfills, waste undergoes physical, chemical, and biological decomposition, generating biogas and leachate. Leachate is a highly toxic liquid with a very high pollution potential. The purpose of this work is to evaluate toxicity of in natura leachate samples collected from Limeira Sanitary Landfill, in Limeira, SP. The ecotoxicological evaluation comprised acute toxicity assays using as test organisms Daphnia Similis, seeds of Eruca sativa (arugula), and Allium cepa roots (onion). Analyses of color, pH, turbidity, conductivity, hardness, nitrogen, total organic carbon (TOC), adsorbable organic halogen (AOX), and metals were also carried out. The main results for Eruca sativa (arugula) and Allium cepa (onion) indicated that the diluted leachate 50% presented similar toxicity to the phenol solution of 1000 mg.L -1 for arugula and 2000 mg.L -1 for onion. With the solution of Cr +6 concentrations of 3000 mg.L -1 for arugula and 2000 mg.L -1 for onion were found. For analyses with Daphnia Similis the EC50 was 9.3% on average. This way it was possible to observe that biological tests are necessary to evaluate the pollution in the effluents or water bodies. These tests serve to determine the toxic potential of a chemical agent or complex mixture.