CLARIFICAÇÃO DE ÁGUAS PLUVIAIS RICAS EM ÓXIDOS DE FERRO ACUMULADAS EM CAVA DE MINERAÇÃO ATRAVÉS DA UTILIZAÇÃO DE UM COAGULANTE NATURAL, A MORINGA OLEIFERA

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

The surface waters, which run off over the slopes of a trench of the Mina de Alegria Mariana (MG), carry solid particles of several dimensions, which settle in the bottom. These waters have high turbidity, red colour and high stability of the suspended particles, basically constituted by iron oxides (hematite e goethite). To allow the maintenance of the mining activity in the place it is necessary to pump out the water to stream nearby (João Manoel - tributary of the Piracicaba river), where coagulant (SK 800) and flocculant (BG 100) are added in order to eliminate the turbidity. The physical chemical characterization of the waters of the stream and of the river has been carried out. In the laboratory the addition of an alternative coagulant (Moringa oleifera seed extract) was tested. The purification of the active protein was carried out aiming to increase its stability and to minimize the increase of organic matter, which comes out from the water treatment. In the stream an increase in the turbidity of water was observed. Its chemical composition was determined by ICP-OES. An increase in the Na and Ca contents was observed, they are generated by products of the chemicals used in the treatment. Also the Fe and Mn contents increase due to the dissolution process acting on the suspended particles. The water of the river has also undergone alterations in its composition after receiving the stream, characterizing the influence of these procedures on the local hydrological system. With the clarification process, which uses the aqueous extracts of the seeds, a reduction of 99.0% of the initial turbidity was achieved. With the use of solution of NaCl 1.0 mol/L a reduction of 99.6% was observed. The efficiency of the saline extract is due essentially to the presence of the salt, which increases the ionic strength leading to the coagulation of the particles by the compression of the double layer. The increase of the sodium and chloride contents in the treated water deteriorates its quality. Detectable increase of COD of water was not detected. The use of purified protein in the clarification process of the trench lead to a reduction of 98.8% of the original turbidity.

ASSUNTO(S)

recursos hidricos Água purificação coagulação Óxidos de ferro recursos hídricos Águas residuais purificação floculação

ACESSO AO ARTIGO

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