Study of a combined heterotrophic and sulfur autotrophic denitrification technology for removal of nitrate in water.
A combined two-step process of heterotrophic denitrification in a fluidized reactor and sulfur autotrophic denitrification processes (CHSAD) was developed for the removal of nitrate in drinking water. In this process, the advantage of high efficiency of heterotrophic denitrification with non-excessive methanol and the advantage of non-pollution of sulfur autotriphic denitrification were integrated in this CHSAD process. And, this CHSAD process had the capacity of pH balance and could control the concentration of SO(4)(2-) in effluent by adjusting the operation condition. When the influent nitrate was 30 mg NO(3)(-)-N/L, the reactor could be operated efficiently at the hydraulic retention time (HRT) ranging from 20 to 40 min with C:N ratio (mg CH(3)OH:mg NO(3)(-)-N) of 2.0 (methanol as carbon source). The nitrate removal was nearly 100% and there was no accumulated nitrite or residual methanol in the effluent. The effluent pH was about 7.5 and the sulfate concentration was lower than 130 mg/L. The maximum volume-loading rate of the reactor was 2.16 kg NO(3)(-)-N/(m(3)d). The biomass and scanning electron microscopy graphs of biofilm were also analyzed.
Liu
Huijuan
H
State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Science, Chinese Academy of Science, Beijing 100085, China. hjliu@rcees.ac.cn
Jiang
Wei
W
Wan
Dongjin
D
Qu
Jiuhui
J
D052818:Autotrophic Processes; D001673:Biodegradation, Environmental; D018533:Biomass; D052836:Heterotrophic Processes; D006863:Hydrogen-Ion Concentration; D000432:Methanol / Q000737:chemistry; D009566:Nitrates / Q000302:isolation & purification*; D013431:Sulfates; D013455:Sulfur / Q000378:metabolism*; D014873:Water Pollutants / Q000378:metabolism*; D018508:Water Purification / Q000379:methods*; D014881:Water Supply
D009566:Nitrates; D013431:Sulfates; D014873:Water Pollutants; D013455:Sulfur; D000432:Methanol