Otimização do tratamento de água de manancial com baixa turbidez e cor elevada utilizando filtração direta e dupla filtração

Abstract

Studies and research carried out in Rio Grande do Norte show an increasing and continuous increase in the eutrophication of surface water sources by residues from anthropic activities that entail several risksto human health. Forsuch a situation, it is essential that the studies be carried out in the choice of a configuration of water treatment technologies capable of guaranteeing the quality of the water offered to the local population. With this, it is important to obtain more conditions,such asthose that are not major changes during the treatment process, with an ability to cover changes in the water quality of management. In this way, the present work is reproduced, on a pilot scale, as treatment techniques for double filtration and direct filtration, with pre-oxidation and coagulation for the treatment of reservoir water with a high density of cyanobacteria, low turbulence and color seeking to obtain the most robust, that is, more stable in the process. The control factors studied were the filtration rate and particle size of the descending and rising filters that had the filtering time considered as a noise factor in the process. In order to carry out and analyze the experiments, two experimental plans were used, being a split plot design for direct filtering and a split plot design for double filtration. In response to the treatment, the parameters of turbidity, apparent color, true color, pH, temperature, absorbance at 254 nm, natural organic matter and filter leakage were applied. For configurations such as studied configurations there were no turbidity values in accordance with Annex XX of Consolidation Ordinance No. 5 of 2017, while the pH showed the alkaline level value without being statistically influenced by the studied control factors and the temperature is influenced by climatic conditions during the tests. For direct filtration, the most robust and longest condition of the filtration row corresponds to a rate of 280 m3 / m2.day, with the FDA 3 filter being the most indicated for longer filtration rows. While for double filtration, the most robust condition along the filtration row corresponds to a filtration index of 340 m3 / m2.day with the FAP filter 3, with the FDA filter 2 or more being the FDA filter 2 or more indicated by test results in accordance with legislation. Therefore, the subdivided plot design is an important tool for determining the conditions of the most stable control factors over the filtering time.