Adequação de parâmetros físicos e químicos de efluente industrial e relação com a toxicidade

Abstract

The identification of possible determinants of toxicity parameters in industrial effluent aiming the reduction of the pollutant load helps in minimizing the toxic effects of the dump of industrial effluents in a receiving body in order to preserver the aquatic biota. The aim of this study was to adapt the physicochemical parameters and the toxicity factor to the environmental legislation. The study was divided into three steps performed between October 2010 and February 2015. Step 1 included physical, chemical and toxicological samples collected between October 2010 and November 2012, before the changes performed in the plating process. The step 2, performed after the changes in the finishing treatment process, shows the physical, chemical and toxicological result of the analyses made between July and September 2013. Step 3 shows the physical, chemical and toxicological characterization of the effluent between January 2014 and February 2015, after performed adjustments in the effluent treatment. Among fourteen analysed samples of treated effluent, seven belonged to Step 1 (Samples 1 to 7); two to Step 2 (Samples 8 and 9) e five to Step 3 (Samples 10 to 14). The physical, chemical and toxicological analysis were made in laboratories accredited by the environmental agency. Considering the complex nature of industrial effluents, the analysis of the result shows the improvement in the quality of the treated effluent with the adequacy to the current legislation in relation to physicochemical parameters. The reduction of zinc, iron and nickel had success with the installation of the filter press. The use of powder coal was responsible for the adequacy of the effluent to CONSEMA 129/2006. The check of pH by measurement equipments, from Step 3, does not allow the adjustment of this parameter, but it allowed the better control of the pH on the treated effluent. The modifications performed allowed the adequacy of the effluent to the launch default in relation to the physicochemical parameters. However, it has been observed an increasing of toxicity in the effluent probably due to the mechanism for reducing the surfactants that it was used. Based in this information, other strategies should be defined in an attempt to comply with the legislation about the toxicity before the dump in the receiving body.