Design and Performance of Experimental Constructed Wetlands in Uganda, Planted with Cyperus Papyrus and Phragmites Mauritianus

The viability of the use of constructed wetlands planted with indigenous Cyperus papyrus and Phragmites mauritianus plants for the purification of pre-settled municipal wastewater in tropical environments was investigated in concrete lined constructed wetlands for a period of 11 months. BOD and total suspended solids concentrations in the effluents from both systems were below 20 mg/l and 25 mg/l, respectively. In the C. papyrus systems, the removal rates for COD, NH₄⁺ and o-PO₄⁻ averaged to 3.75, 1.01 and 0.05 (g/m².day), respectively. In P. mauritianus units, the rates were 1.52, 0.97 and 0.068 (g/m².day), respectively. A high degree of faecal coliform removal was attained at longer retention times in the two systems.