Water management in a concrete plant: Moringa oleifera employment analysis without wastewater treatment and reuse proposal after treatment

The civil construction acivities, great consumers of raw material and water resources, ha demonstrated signs to achieve a sustainable production. In this sector, the management and reuse of residual waters in concrete batchers would contribute in the decrease of negative impacts with relation to environment. However, to make the residual water reuse, viable, it is needed to make its threat, aimming the adequacy of such indicators as, alkalinity, residual free chlorine, hardness, ph and turbidity with the current regulations. Therefore, this article avaluated the possible applications for residual water threated with the use of "moringa oleifera" aqueous extract, obtained by two ways, as: only in distilled water (EAMO) and other in water distilled with calcium nitrate (EAMO/Ca2+) and with aluminium sulfate (Al-2(SO4)(3)) as the chemical coagulant. The analized threats made the decrease of alkalinity to 22% with EAMO/Ca2+ and 16% with the Al-2 (SO4)(3) extract, decrease of hardness to 11,4% with EAMO/Ca2+ and 4,7% with Al-2(SO4)(3) and an efficient remove of turbidity, higher than 85% to all the avaluated coagulants. The ph and free residual chlorine, kept theirselves constant. So, the consideraded best threat, extracted from EAMO/Ca2+, makes the reuse of residual water to non potable ways and concrete kneading.