3.3.1. Removal of NO3
−–N
The raceways planted with C. esculenta have performed
with better removal of NO3
−–N in all experiments than the
unplanted system. Further, two key observations were made
from the results of experiments I and II vis-a-vis ` the NO3
−–N
removal patterns exhibited by the planted raceways (Table 3).
First, when the overall removal of NO3
−–N is considered, it was
the second half of the experimental period (during 11–20th
day) which has exhibited better removal of NO3
−–N (Fig. 4).
However, the peak removal of NO3
−–N was attained within
the 5th day of each run was the second observation. The second
observation, therefore, made us to reduce the duration of
each run from 10 to 5 days in the subsequent experiments III
and IV