The IVCW plots did not perform well in nitrogen removal
at the high loading rate. NH4
+ N concentrations were higher
in the effluent than those in the influent in most cases due to
the ammonification of organic-N in urea and flour to NH4
+ N.
NH4
+ N was the predominant nitrogen form in the effluent TN
(Fig. 3b and c), indicating that nitrification was the limited step for
TN removal. It was regarded that ammonification was presented
under both aerobic/anaerobic conditions and proceeded kinetically
more rapidly than nitrification (Kadlec and Knight, 1996;
Vymazal, 2007).