Effect of sulfide to nitrate ratios on the simultaneous anaerobic sulfide and nitrate removal.
Present investigation deals with the effect of sulfide to nitrate (S/N) molar ratio on the simultaneous anaerobic sulfide and nitrate removal on capacity, stability and selectivity of the process. The volumetric sulfide-sulfur and nitrate-nitrogen removal rates at molar S/N ratio of 5:2 were 4.86 kg(m(3)d)(-1) and 0.99 kg(m(3)d)(-1), respectively, which were higher than those at S/N molar ratios of 5:5 and 5:8. Moreover, the fluctuations in the effluent at S/N ratio of 5:2 were less than those at the other two tested ratios. During the operation, the ratio of converted sulfide to converted nitrate tended to approach 5:2. The selectivity for elemental sulfur and dinitrogen was improved when the S/N molar ratio was set at 5:2 rather than 5:5 or 5:8. The process became unstable if the influent sulfide surpassed its critical concentration. The electron balance between reactants was also analyzed for different S/N molar ratios.
Cai
Jing
J
Department of Environmental Engineering, Zhejiang University, Hangzhou, China.
Zheng
Ping
P
Mahmood
Qaisar
Q
D000693:Anaerobiosis; D019149:Bioreactors; D002681:China; D004583:Electrons; D004785:Environmental Pollutants / Q000302:isolation & purification; D019605:Euryarchaeota / Q000378:metabolism; D009566:Nitrates / Q000302:isolation & purification*; D009584:Nitrogen / Q000032:analysis; D013431:Sulfates; D013440:Sulfides / Q000302:isolation & purification*; D013455:Sulfur / Q000032:analysis; D014865:Waste Disposal, Fluid; D018508:Water Purification
D004785:Environmental Pollutants; D009566:Nitrates; D013431:Sulfates; D013440:Sulfides; D013455:Sulfur; D009584:Nitrogen