Tratamento de resíduo sólido de laboratório por estabilização por solidificação e balanço de massa dos metais pesados cádmio e níquel.

Abstract

Higher Education Institutions represent a problem related to the treatment and final disposal of waste generated in their laboratories. The objective of this research was to perform the Solid of Laboratory Waste (SLW) treatment through the Solidification Stabilization (S/S) process and to apply the mass balance to the Cadmium and Nickel metals, in order to determine if there was attenuation of contaminants presents. The first stage of the research consisted in the characterization and classification of SLW, cement, sand and gravel. Afterwards, a one-way experimental planning was performed using the percentage of SLW as a factor and the response variables were: Compression Resistance (CR), Water Absorption Capacity (WAC), Humidification / Drying (H/D) and Lixiviation. Then the samples were prepared for 10%, 30% and 45% of SLW, where the integrity, durability and immobilization of contaminants tests were carried out. Finally, the statistical analysis of the data, the mass balance and the calculation of the retention efficiency of the metals Cadmium and Nickel in the cementitious matrix were carried out. All treatments were approved in the tests of Compressive Strength, Water Absorption Capacity and Humidification / Drying. From the leaching tests after the S/S it was observed that the residue remained in Class I (Hazardous), despite the significant reduction in the concentrations of the evaluated metals. In view of this, the material should be sent to the disposal in specific landfills for Hazardous Waste, according to the recommendation of ABNT NBR 10.157 (1987).Statistical analysis of the data showed that the percentage of SLW influenced significantly of the CR, WAC, H/D and Lixiviation tests. All treatments performed had a retention efficiency above 98%, indicating that S/S was an effective method for the treatment of laboratory solid waste. Through the mass balance it can be observed that there was significant reduction in the leaching of Cadmium and Nickel after the S/S, when compared to the crude of laboratory solid residue, without treatment. With this, it was concluded that, although SLW remained in Class I (Hazardous), there was significant reduction in the Cadmium and Nickel masses, noting that S/S was an efficient process to attenuate the contaminants present.