Remoção de ferro em água de irrigação através de filtragem em areia e zeólita

Abstract

Drip irrigation has proven to be an excellent system to reduce water use and energy consumption at agriculture. Water with high iron contents has been, however, a problem, due to emitter clogging. Efficient water treatment systems are needed for good irrigation because traditional systems used to remove iron from water have not been totally efficient, leaving the irrigation system vulnerable to clogging in general. This work proposes to evaluate effects of using zeolites as adsorbent in media filters, to remove iron from irrigation water. Different combinations of sand-zeolite proportions in the mixture were tested, as well as contact time between the mixture and the irrigation water. When the mixture sand-zeolite in proportion of 3:1 in volume was used, a reduction of 95% in iron concentration of water was observed, pointing the possibility to use zeolites in media filters to remove iron from the irrigation water. Bivalent iron adsorption on mixture of sand and zeolite was evaluated, using isotherms, verifying that iron adsorption can be well described through a linear isotherm with high adsorption of iron by the mixture of sand and zeolite. Bivalent iron kinetics in sand-zeolite mixture was also evaluated through the use of dispersive-convective model, confirming that mixture of sand and zeolite presents high iron adsorption. Finally, all results obtained allowed to conclude that zeolite addition in media filters present satisfactory efficiency in the removal of iron from irrigation waters.