The paper presents the results of the analysis of the effluents of a pulp mill that uses as raw material hardwood (mainly beech and poplar) in terms of extractibles in oil ether, correlated with other quality indicators: pH, suspended solids, fix residue, COD(Mn), COD(Cr), BOD. The total charge of the effluent is driven by the charge of wastewater from pulping and washing stages: 105.85 mg/L in pulping effluent and 86.16 mg/L in washing effluent. It has been observed a proportionality between the extractibles content and the values of COD(Cr) and filterable dry residue. The reduction of extractibles may be achieved with a supplemental effluent treatment with aluminum sulfate in the presence of polyacrylamide (PAA) as flocculent. For an effluent with 118 mg/L extractibles in oil ether, a treatment with 400 mg/L aluminum sulfate and 5 mg/L PAA, a 47% reduction of extractibles has been reached, simultaneously with important reductions of COD(Mn), COD(Cr) and fix residue.
