Up Flow Anaerobic Sludge Blanket - Special Reference to Treatment of Wastewater from Solvent Black 46

Abstract: An anaerobic sludge blanket wastewater treatment system uses an anaerobic process by forming a blanket of granular sludge which suspends in the tank whereas wastewater flows upwards through the blanket and is degraded by the anaerobic microorganisms. The upward flow combined with the settling action of gravity suspends the blanket with the aid of flocculants while the blanket begins to reach maturity at around three months. Small sludge granules begin to form whose surface area is covered in aggregations of bacteria.The performance of Up flow anaerobic sludge blanket (UASB) treating real wastewater generated from manufacturing of Solvent Black 46 (SB46) was investigated. Specifically, it was determined whether UASB could be used as treatment system at an existing dyestuffs production plant. Accordingly, UASB was developed with a reactor volume 25 L was being operated in different phases. Consistent chemical oxygen demand (COD) removal efficiency of around 90% was achieved at an organic loading rate (OLR) of 2 kg COD/ m3 d at inlet COD of 20000 mg/L. Effect of varying OLR on COD removal efficiency and methane production was evaluated by feeding wastewater at COD of 10000 mg/L. The COD removal efficiency of >90% at OLR of 2 gradually decreased to ~80% at OLR of 5 kg COD/ m3 d. Methane production was 320-343 L/kg COD removed at OLR 2 kg COD/ m3 d decreased to 147-200 L/kg COD removed at OLR of 5 kg COD/ m3 d. . Decolonization of wastewater led to generation of aromatic amines indicated by formation of a new peak at 286 nm in UV-Vis spectrum. Inlet pH of feed was in the range 6-6.3 which increased to 8.5-8.6 indicating degradation of acetate in the wastewater. Results of this study suggest that anaerobic treatment can be employed advantageously for SB46 wastewater, resulting in excellent COD removal without any energy input and producing useful methane