Study On The Multiplication Of Anaerobic Granular Sludge In The Sulfate-containing Organic Wastewater

To overcome the deficiency of anaerobic granular sludge in the treatment of sulfateorganic wastewater, this paper investigated several mothods to improve multiplication rateof it in an up-flow anaerobic sludge bed without sealed cap at the top.In this paper, the simulate wastewater was prepared with a mixture of sodium sulfateand flour dissolved in water, the seed sludge was anaerobic granular sludge, thetemperature was35℃±1℃, and the hydraulic retention time was2.5³d. Under theseconditions, the effects of different concentrations of Ca²⁺and Al³⁺on the multiplication ofanaerobic granular sludge and sulfate removal efficiency were investigated, respectively.In addition, the effects on the multiplication of anaerobic granular sludge wereinvestigated by using globular aspergillus as carrier.The results show that:When the concentration of Ca²⁺was150mg/L, the multiplication rate of anaerobicgranular sludge was highest, and it was achieved29.76%; When the concentration of Ca²⁺was100mg/L, the multiplication rate of anaerobic granular sludge was25.00%, besides,the removal efficiencies of COD and the residue of SO42-were better than those in theconcentration of Ca²⁺was150mg/L. Thereby, the optimal concentration of Ca²⁺whichwas suitable for multiplication of anaerobic granular sludge was100mg/L. While theconcentration of Ca²⁺was100mg/L, the concentration of SO42-was3000mg/L, its residuewas determined as1300mg/L after running a cycle of the up-flow anaerobic reactor, theremoval of SO42-is20%higher than the reported work. When the concentration of Al³⁺was200mg/L, the maximium of sludge multiplication rate was55.78%. However, thesludge was appeared as dark white floccules, and the amount of sludge was depositedobviously after a period of time, thereby it should be Al（OH）3floccules. The particle sizeand settling velocity of globular aspergillus which was cultivated in the condition of26℃,160r/min and3days was similar to anaerobic granular sludg, but it was unstable anddecomposed completely during the running cycle in the reactor.