A lab scale model of vertical flow constructed wetland(VFCW) was operated at varying hydraulic loading rates(HLRs) to find out the optimum HLR for treatment of domestic wastewater. The results from laboratory analysis indicated that the maximum removal efficiency for BOD, COD, P and TSS is achieved at a HLR of 0.18m3/m2/d. The removal efficiencies of VFCW with and without intermittent aeration were evaluated and results indicated that there was improvement in BOD and P removal efficiencies and lesser effect on COD and TSS removal efficiencies. Substrate alteration in VFCW by using cupola slag along with conventional materials like sand and gravel was also evaluated. There was significant increase in removal efficiencies for BOD, COD, P, TSS and the VFCW treated effluent met the disposal standards. Thus, Cupola slag can be regarded as a suitable filter media that can be used along with conventional filter materials like sand and gravel for the treatment of domestic wastewater.