Effects of Riboflavin on the Biodegradation of Azo Dyes

The effects of riboflavin on Reactive Brilliant Red X-3B(RR2) dye(a reactive azo dye) removal from hypersaline dye wastewater and on the biologic phase of activated sludge was studied with a thermophilic up-flow anaerobic sludge blanket(UASB) reactor at(55±(1) ℃) and a mesophilic three-phase aerobic biological fluidized bed reactor combined process. Experimental results demonstrate that riboflavin can improve the dye removal in hypersaline wastewater.When the riboflavin dosage is about 5(mg/L),the removals of RR2 and COD_(Cr) are both more than 95%(the hydraulic retention time(HRT) is 18 hours;influent RR2 dye,COD_(Cr)and salt(NaCl) are 40-100(mg/L),800-(1,200)(mg/L),and(30,000)-(35,000)(mg/L),respectively).The organic loading rates of UASB and the three-phase aerobic biological fluidized bed reactor are 2-3(kg/(m~3·d)) and 0.3-0.4(kg/(kg·d)),respectively.The predominant activated sludge microbe in this system is bacillus sp.,and the addition of riboflavin causes smaller cell volume and less cell content.