Suymara Toledo Miranda

CARACTERIZAÇÃO DOS SÓLIDOS INTERSTICIAIS DE SISTEMAS ALAGADOS CONSTRUÍDOS DE ESCOAMENTO HORIZONTAL SUBSUPERFICIAL - DOI: 10.13083/1414-3984/reveng.v23n6p562-574

The objective of the present study was to evaluate the effect of reversing the direction of flow in constructed wetland of subsurface horizontal flow (CW-HSSF) in the qualitative and quantitative characteristics of the clogging material. For this, in the end of the experimental period, bed samples were collected from six CW-HSSF: two non-cultivated (CW-HSSF 1 and 4), two cultivated with tifton 85 grass (Cynodon spp.) (CW-HSSF 2 and 5) and two cultivated with alternathera (Alternanthera philoxeroides) (CW-HSSF 3 and 6). The interstitial solids were separated from the samples taken from the CW-HSSF porous media. In this material was quantified the mass of total solids (CST), total volatile solids (CSVT), and fixed total solids (CSFT) per volume (kg m-3) of CW-HSSF porous media. Each plant species influenced differently the distribution of CST, CSFT and CSVT in planted CW-HSSF. Even in conditions of CSVT/CST low relationship the organic fraction provided structure of the surface material support of CW-HSSF. On average, the reversal in the flow direction does not reduced the accumulation of organic matter in porous media. The high degree of clogging in CW-HSSF prevented or made less noticeable and prolonged the positive effects of reversing the direction of flow of wastewater on conditions of the porous media.

CARACTERIZAÇÃO E EXTRAÇÃO DE CRÔMIO DE RESÍDUOS SÓLIDOS DA INDÚSTRIA DO COURO - DOI: 10.13083/1414-3984/reveng.v23n4p326-335

The increase in leather exportation in recent years has increased the generation of solid waste from leather industries in Brazil. Classified as Class I Residue, hazardous and presenting high contamination potential, correct disposal of these wastes in the environment is mandatory. Given the high content of nitrogen present in leather, there is growing interest for its utilization in agriculture, however to make this possible it is necessary to reduce the chromium content in the residue. Therefore, this study sought to characterize waste from the leather industry and develop a method for chromium extraction from it. Based on waste characterization, it was observed that waste from Wet Blue leather differs physically and chemically from finished leather strips, and although it presents a high nitrogen content (14 dag kg-1), for agricultural use most of the chromium must be extracted. The extraction method using a phosphoric acid solution resulted in 91.1% efficiency of Cr removal, where sequential extraction is a viable option both economically and environmentally.