Análise da eficiência de uma ETA-piloto para a remoção de ferro e manganês.

Abstract

The present work dealt with the analysis and evaluation of the efficiency of a Water Treatment Station in a reduced model or ETA-Pilot for the removal of manganese iron ions from natural waters. The research was carried out in two stages that involved the operation of the ETA - Pilot without and with chemical dosage for the removal of these metallic ions. The first stage consisted in evaluating the efficiency of the ETA-Pilot without chemical dosing aid. In this stage, the ETA - Pilot operated with the following treatment processes: aeration, sedimentation, filtration and disinfection by chlorine compound. In Step 2 a chemical treatment was applied, represented by three (0 3) stages of chemical dosing. Calcium, CaO or calcium hydroxide, Ca (OH) 2 was used in Stage 1 to raise the pH of fear to facilitate the precipitation and removal of ferric ions. Stages 2 and 3 were applied to raise the pH to values of pH> 9.0 in order to promote the precipitation of manganic ions Stage 3 was applied to oxidize the remaining manganous ions to manganic ions using sodium hypochlorite NaCl All the substances used in the research are low-cost and easily of the different treatment processes, ie: raw, aerated, dosed (2nd Stage), decanted, filtered and disinfected. For each type of the sample in the two stages of the research, samples were collected showing the quality of the water. In all determinations, the water is of low ionic strength (I <-0.10) and the temperature was kept constant at 25 ° C. The results of the first Step showed that the treatment without chemical dosage only reduces the concentration of iron and manganese ions. However, for a prolonged settling time of about 8 hours a complete removal of iron is observed. The experimental results of the 2nd, Step showed the efficiency of the chemical treatment used in the Pilot - ETA.