Application of Anaerobic Granular Sludge to Treatment of Fishmeal Industry Wastewaters under Highly Saline Conditions

An up-flow anaerobic sludge beds (UASB) reactor was fed with fishmeal industry wastewaters at different salinity levels in order to assess the effects on anaerobic granular sludge properties. When the wastewaters sodium concentration varied from 0.52 to 7.6 g/L, no activity inhibitions were observed according to the analysis of granular sludge performance. At sodium concentrations over 9.0 g/L the negative influence of salinity on microorganisms was observed in reactor, which resulted in decreased COD removal rate and reduced granule strength. The results show that fishmeal industry wastewater consists of abundant nutriment which are beneficial to the formation and activity of anaerobic granular sludge, and that the inhibition of granular sludge will occur when the wastewater sodium concentrations increase in steps.