Avaliação da qualidade e processo de tratamento para redução do íon nitrato de águas subterrâneas da região de Maringá - PR

Abstract

The aim of this study was to evaluate the quality of groundwater in the region of Maringá - PR and reduction of nitrate ion with extract of seeds of Moringa oleifera Lam. For this, 38 groundwater sources samples, distributed in Maringá-PR were collected. These samples were sent to the laboratory management control and environmental preservation of the State University of Maringa, where they were subjected to physicochemical analysis. Once evaluated, it was possible to locate sources contaminated with nitrate at different concentrations, some of these (water samples containing 10, 25, 45 and 60 mg L-1 NO3-) were used to evaluate the removal of this ion in jar test equipment, treatment by coagulation / flocculation with the aid of the crude extract of Moringa oleifera Lam seeds (saline and aqueous solutions) (MO). These tests allowed to observe the behavior that the extract exerts MO in different concentrations of nitrate in groundwater. Finally, was evaluated the nitrate íon removal by coagulation / flocculation in jar test equipment combined with filtration tests (two slow domestic filters),it was compared with the filtration of groundwater in natura (without contact with coagulants). Results of the evaluation of groundwater quality in this region have shown risks to human health. The treatment of coagulation / flocculation with Moringa oleifera Lam removed nitrate up to 67% and 87% with the aqueous and saline extracts, respectively. The use of MO seeds extract was satisfactory to removal nitrate íon, however, it was observed that the higher the dosage of the seeds extract, increased the final turbidity (NTU over 30). Combined treatments with slow domestic filters were used to remove the residual turbidity after coagulation / flocculation, however, combined treatment did not meet the Ordinance of the Ministry of Health No. 2914, 2011 for the parameters studied. The best results were obtained in treatment of groundwater in natura with domestic filters, without coagulants, with residual of 40 mgL-NO3- and turbidity between 0 and 1 NTU. This study demonstrated that it is possible to remove nitrate using Moringa oleifera lam seeds extract, however, was observed increased turbidity in reaction becoming a not potable source water. Thus, more research is needed, evaluating different techniques in the active principle extraction present in these seeds to removal of nitrate íon in groundwater.