State Key Laboratory of Pollution Control and Resource Reuse,
College of Environmental Science and Engineering, Tongji University, Shanghai-200092, P. R. China
We investigated rice husk as the sole carbon source as well as biofilm carrier in the biological denitrification
of wastewater in up-flow laboratory reactors. Fast startup of the reactor and high nitrate removal efficiency
was observed. The highest denitrification rate (about 0.096kg/m3·d) was achieved when flow rate and
nitrate concentration were 41.4L/d and 25.0mg/L, respectively. Flow rate and nitrate concentration of the influent
were observed to have a significant effect on nitrate removal efficiency. The reactor had the ability to
accommodate a wide range of pH (6.5-8.5) and DO (1.5-4mg/L). A time-dependent decrease in nitrate removal
efficiency was observed after 72 days of operation. And the addition of new rice husk brought about a rapid
increase of nitrate removal efficiency. Results showed that rice husks can be an economical and effective carbon
source for the nitrate removal process.