The potential use of an anaerobic sequencing batch biofilm reactor (ASBBR) in pilot-scale for the treatment of a sulfate-rich industrial wastewater was evaluated. The pilot 1.2 m³ ASBBR reactor was filled with mineral coal for biomass immobilization (fixed film). The sulfate loading rates applied were 0.15; 0.30; 0.65; 1.30 and 1.90 kg SO4-2/cycle (or batch). Each cycle lasted 48 h. The influent concentrations were, respectively, 0.25; 0.50; 1.0; 2.0 and 3.0 gSO4-2.l-1. Ethanol was used as electron donor for sulfate reduction. The reactor operated at ambient temperature (29±8ºC), and the mean efficiencies of sulfate removal were in the range 88 to 92% in the 92 run cycles. The total operating period comprised 275 days. Based on the results obtained in this research, it could be concluded that the ASBBR can be an efficient alternative for the removal of sulfate from other industrial wastewaters with similar characteristics.
Sulfate; anaerobic treatment; anaerobic sequencing batch biofilm reactor; mineral coal; ethanol
