Biological sulfate removal from acrylic fiber manufacturing wastewater using a two-stage UASB reactor.
A two-stage UASB reactor was employed to remove sulfate from acrylic fiber manufacturing wastewater. Mesophilic operation (35 +/- 0.5 degree C) was performed with hydraulic retention time (HRT) varied between 28 and 40 hr. Mixed liquor suspended solids (MLSS) in the reactor was maintained about 8000 mg/L. The results indicated that sulfate removal was enhanced with increasing the ratio of COD/SO4(2-). At low COD/SO4(2-), the growth of the sulfate-reducing bacteria (SRB) was carbon-limited. The optimal sulfate removal efficiencies were 75% when the HRT was no less than 38 hr. Sulfidogenesis mainly happened in the sulfate-reducing stage, while methanogenesis in the methane-producing stage. Microbes in sulfate-reducing stage performed granulation better than that in methane-producing stage. Higher extracellular polymeric substances (EPS) content in sulfate-reducing stage helped to adhere and connect the flocculent sludge particles together. SRB accounted for about 31% both in sulfate-reducing stage and methane-producing stage at COD/SO4(2-) ratio of 0.5, while it dropped dramatically from 34% in sulfate-reducing stage to 10% in methane-producing stage corresponding to the COD/SO4(2-) ratio of 4.7. SRB and MPA were predominant in sulfate-reducing stage and methane-producing stage respectively.
State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. ljin0532@126.com
Jin
J
Li
Jun
J
Wang
Zhaokun
Z
Luan
Zhongguang
Z
Ji
Lian
L
Yu
D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors / Q000382:microbiology; D017404:In Situ Hybridization, Fluorescence; D059013:Microbial Consortia; D013431:Sulfates / Q000302:isolation & purification*; D013783:Textile Industry; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*
D013431:Sulfates; D014874:Water Pollutants, Chemical