Biological denitrification using corncobs as a carbon source and biofilm carrier.
In this research, agricultural waste--in particular, comcobs--was investigated for use as the sole carbon source and biofilm carrier to remove nitrate from wastewater in up-flow laboratory reactors. An artificial wastewater with a temperature range of 27 to 33 degrees C was used. Fast startup of the reactor and a high nitrate removal efficiency were observed. The highest denitrification rate of 0.203kg/(m3 x d) was achieved when flow rate and nitrate concentration were 153 L/d and 25.3 mgN/L, respectively. The accumulation of nitrite was not observed in this process. Moreover, flow rate and nitrate concentration of the influent were observed to have a significant effect on nitrate removal efficiency. A sharp decline of nitrate removal efficiency was observed when the flow rate was greater than 50 L/d. The reactor had the ability to accommodate a wide range of pH levels (6.5 to 8.5) and dissolved oxygen (1.5 mg/L to 4 mg/L). A time-dependent decrease in nitrate removal efficiency was observed after 67 days of operation. The addition of fresh corncobs brought about a rapid increase of nitrate removal efficiency. Results showed that corncobs could be used as an economical and effective carbon source for denitrification.
Xu
Zu-Xin
ZX
State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, China.
Shao
Liu
L
Yin
Hai-Long
HL
Chu
Hua-Qiang
HQ
Yao
Yi-Jun
YJ
D018441:Biofilms; D002244:Carbon / Q000378:metabolism*; D009573:Nitrites / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism; D003313:Zea mays
D009573:Nitrites; D002244:Carbon; D010100:Oxygen