Fig. 3 shows the comparison of NH4-N effluent concentrations
between batch and continuous modes for the test series with 4-day
retention time. In planted beds, statistical analysis showed that
there was significant enhancement (p < 0.001) of NH4-N removal in
batch flow mode (95.2%) as compared to continuous flow operation
(80.4%); while in unplanted beds, there was no significant difference
(p > 0.05) for batch flow (49.3%) as compared to the continuous
flow mode (47%). A similar conclusion was drawn for batch
and continuous flow operation at 2-day HRT. In addition, in both
batch and continuous operational modes, NH4-N removal was
significantly enhanced (p < 0.001) in the planted beds as compared
to the unplanted beds.