Efeito da concentração de fósforo na degradação aeróbia do glifosato em reator de leito fixo
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2017-09-21
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Universidade Federal de Goiás
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The present work had as objective to investigate the performance of a fixed bed aerobic
reactor with biomass adhered in the treatment of waters contaminated with glyphosate and
different concentrations of phosphorus. The effect of different phosphorus concentrations on
the adsorption kinetics of glyphosate in a support medium was evaluated by means of the
determination of the exhaust curve in a system composed of an adsorption column filled with
expanded clay. The glyphosate solution used was commercial product based on Glyphosate
Di-ammonium salt 445 g.L-1 (370 g.L-1 equivalent acid) and ultra purified water, with final
glyphosate concentration of 8 mg.L-1. Concentrations of 0.8 mg.L-1 were used in the
adsorbent assays; 8 mg.L-1; and 16 mg.L-1, and the pH values adopted were: 4; 7 and 10.
The results obtained demonstrate the influence of both pH and phosphate ions on the
adsorption of glyphosate in expanded clay, where the adsorption kinetics showed the
influence of both parameters, in general, on higher concentrations of phosphate ions. The
effect of different concentrations of phosphorus on glyphosate biodegradation kinetics was
evaluated by means of temporal profiles of the glyphosate and phosphorus concentration
decay in the same system used in the adsorption tests with aerobic sludge inoculation in the
expanded clay. The glyphosate solution was the same as that used in the 15 mg.L-1
adsorption assays, evaluating the degradation in the presence of concentrations of 2.15 mg.L-
1; 5.37 mg.L-1; 10.75 mg.L-1; 16.12 mg.L-1; 21.5 mg.L-1; 43 mg.L-1 phosphorus. The
results demonstrate the influence of phosphate ions on the degradation kinetics of glyphosate
in expanded clay. It is possible to observe that glyphosate treatment efficiency increased as
phosphorus concentrations increased, indicating that kinetics of degradation was directly
associated to kinetics adsorptive. The data were analyzed by means of multiple regression,
which was able to verify with 95% confidence the effect of the phosphorus (p <0.05) on the
degradation process.
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PAIVA, D. C. A. C. Efeito da concentração de fósforo na degradação aeróbia do glifosato em reator de leito fixo. 2017. 93 f. Dissertação (Mestrado em Engenharia Ambiental e Sanitária) - Universidade Federal de Goiás, Goiânia, 2017.