Tratamentos integrados em efluente metal-mecanico: precipita？？o química e biotratamento em reator do tipo air-lift

the objectives of this paper were: to perform the physical-chemical characterization of a metalworking effluent and to carry out the integrated treatment (chemical precipitation and biotreatment), using effluent autochthonous microorganisms (fi and fv) and a reference (a. niger). the characterization indicated ph of 1.7; color, 1,495 mg pt.l-1; chemical oxygen demand, 9,147 mgo2.l-1; oil and grease, 887 mg.l-1, and dissolved oxygen with 2.5 mgo2.l-1. with the chemical precipitation treatment, in ph = 7.5, the reduction of all the investigated metallic ions was obtained. the color was reduced 95% after the biotreatment using the fv microorganism. the chemical oxygen demand and oil and grease reductions were more significant when using fi, which reduced the same in 52 and 62%, respectively. these results indicated that the autochthonous microorganisms were more efficient in the effluent treatment than the reference organism a. niger.