An integrated anaerobic - physico-chemical treatment concept for wool scouring wastewater

The strong flow wastewater from a wool scouring industry is treated by a co mbination of anaerobic digestion and physico-chemical postreatment. Based o n previous laboratory results (Gutierrez et al., 1999), three anaerobic baf fled reactors (ABR) of 300 m(3) each were built, processing 60% of the stro ng flow of a wool scouring mill for about two years. COD and grease removal in the anaerobic reactors were 47-50% and 50-55% respectively, with an org anic load between 8.9 and 8.7 kg COD/m(3) d. The effluent of the anaerobic reactors was assayed with additives in an industrial decanter centrifuge. A s results of these assays, all the effluent of the three reactors was sent to the decanter centrifuge after dosing additives. Overall COD and grease r emoval of the integrated system were 87% and 93% respectively. Dosage of co agulation-flocculation additives was optimized in a continuous flocculation device. The proposed treatment is cheaper and easier to control than other s alternatives with COD removal higher than 93%.