dc.description.abstract |
Among the vast number of methods that can be applied for the
treatment of contaminated water, one of the best methods of treating of abandoned
mine water was identified as the subsurface flow constructed wetlands through
pytoextraction. Therefore further research was carried out to the applicability of
constructed wetland to treat polluted water at abandoned quarry in Ragama (Prison
Quarry). The main objective of the study was to measure the removal efficiencies of
BOD, COD, NH3, NO3', PO.*3- using Thypha Latifolia (Cattail). The hydraulic retention
time was 8 days. The concentration of Nitrate, Orthophosphate and Ammonia was
monitored twice a week and BOD and COD were monitored once a week in order to
determine their removal rates. While monitoring the removal efficiencies, the
mechanisms of N, P and COD removals were identified. The mechanisms are based on
the principle of mass conservation. The main nitrogen removal mechanisms identified
were plant uptake and denitrification. It is assumed that ammonia and nitrate removal
from wetlands by macropytes depended on the biomass of the roots. Average Nitrate
and Ammonia removal from the planted cell was 42.9% and 27.8%, respectively,
whereas the removal efficiency of Ortho Phosphate was 17.5% in the planted tank.
Typha latifolia was identified as a suitable wetland plant which can remove nitrogen
compounds in contaminated water. |
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