| dc.description.abstract | Leachate is one of the major problems in landfill since it contained high levels of
organic and inorganic matters. As it was highly contaminated, leachate could not be
discharged directly into the surface water bodies. Constructed wetlands are highly efficient
and low-cost alternative treatment systems for treating leachate. The main purpose of this
study was to compare the efficiency of horizontal subsurface flow system (HSSF) and
vertical subsurface flow system (VSSF) in the treatment of COD, nutrients (NH3-N and
PO4-P) and heavy metals (Fe and Mn) present in landfill leachate by the use of constructed
wetland systems. The amount of nutrient and heavy metals uptake by the plant
(Limnocharis flava), and the amount of heavy metals retained in the soil media was also
investigated. A laboratory-scale study was conducted on subsurface flow constructed
wetland systems operated in vertical and horizontal mode. Each system comprises of one
planted system and one control system. The planted systems namely HP and VP were
planted with Limnocharis flava, while the control systems namely HC and VC were left
unplanted. The systems operated identically at a flow rate of 0.029 m3/d and hydraulic
retention times of 24.1 hours and 19.7 hours in HSSF and VSSF systems, respectively.
Concentration based on overall removal efficiencies for VC, VP, HC and HP were COD >
93%, NH3–N > 98%, PO4–P, > 98%, Fe > 91%, and Mn > 94%, respectively. As a
conclusion, higher removal performance and accumulation was observed in the HSSF
system than that of VSSF system for all parameters observed. | en_US |
