Nitrogen and phosphorous removal by small scale tropical constructed wetlands

Constructed wetlands are know as low cost ecotechological treatment system has good prospect for developed in developing coun­ tries. The objective of this study was to investigate the performance of constructed wetland in removal of nutrient; nitrogen and phosphorous compounds, from laboratories wastewater. Two series of small-scale constructed wetlands were set up at Center for Limnology, Cibinorg, Indonesia. One series is horizontal surface flow and the other is erti­ cal subsurface flow, The constructed wetlands are composed of sedi­ mentation tank followed b the first and second beds planted unith Thpa sp.; third bed contained Hydrlla sp. and Lemna sp. and a clari­ fier. Both surface and subsurface wetlands showed turbidity in the in­ fluent was 17 to SO NTU, however at the final effluent turbidity was l to 7. Both constructed wetlands series showed a high removal total­ phosphate, orthophosphate, and soluble phosphate of more than 94% over the whole period of investigation, The treatment efficiencies of ni­ trogen compounds was generally good with removal efficiencies of 97 to 99% for ammonium-nitrogen, removal of nitrite-nitrogen varied be­ tween 75 and 98 %, nitrate-nitrogen varied between 86 and 99%, while the total nitrogen removal between 64-96%. Although the subsurface flow is slightly good in performance for treatment than the surface flow, statistical analyses showed no significant difference between nu­ trient removal efficiencies in both subsurface and surface flow con­ structed wetlands.