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 Cy perus papyrus and Phragmites mauritianus plants for the purification of pie -settled municipal wastewater in tropical environments was investigated in concrete lined constructed wetlands for a period of 11 months. BOD and tota l suspended solids concentrations in the effluents from both systems were b elow 20 mg/l and 25 mg/l, respectively. In the C. papyrus systems, the remo val rates for COD, NH4+ and o-PO4- averaged to 3.75, 1.01 and 0.05 (g/m(2), day), respectively. In P. mauritianus units, the rates were 1.52, 0.97 and 0.068 (g/m(2).day), respectively. A high degree of faecal coliform removal was attained at longer retention limes in the two systems. (C) 1999 IAWQ P ublished by Elsevier Science Ltd. All rights reserved.