Conclusions
The results of this study on batch versus continuous flow modes
of operation for a tropical SSF CW showed that while these loading
methods had no significant effect on COD removal, both ammonia
oxidation and TP removal were significantly enhanced in batch
versus continuous mode. At a 4-day HRT, the presence of plants
significantly enhanced both ammonia oxidation and TP removal in
both batch and continuous modes of operation as compared to that
for unplanted beds.
Estimation of the quantitative contribution of oxygen from batch
(drain and fill operation) as compared to plant rhizosphere aeration
from the differences in nitrification rates between batch versus
continuousandplantedversusunplantedbeds, leadstothe conclusion
that at the 4-day HRT used for this study, drain and fill cycling might
only account for less than half of the plant’s quantitative contribution
of oxygen. The findings of this study imply thatwheremaximalNand
P removal is desired, periodic draining and filling might be the
preferredoperational strategy for a full-scale SSF constructedwetland.