Impact of coconut coir-pith as an alternative substrate material on water reclamation in submerged wetland systems

Abstract

Impacts of surplus organic carbon from coconut coir-pith as an alternative substrate material of submerged wetland systems was investigated in three similar Lysimeters (L1, L2, and L3), planted with Hydrilla verticillata. The substrate layer of L1 and L3 were amended with river sand and coconut coir-pith respectively, while the L2 was upgraded with a mixture of river sand and coir-pith (ratio = 1:1). The influent and effluent water quality parameters were examined to identify an elevated treatment activity. The total nitrogen (TN) removal efficiency was higher in L2 (52.3%) and L3 (62.1 %) compared to L1 (29.1 %). PO43-–P removal was marginally improved in L2 (74.2%) and L3 (74.4 %) than in L1 (68.7 %). The best results in terms of BOD5 (54.4 %) and TDS (40.5%) removal efficiencies were encountered in L2, whereas the maximum TSS (66.4 %) and conductivity (38.5 %) reductions were found in L3. The microbiological investigations have revealed that L2 and L3 were highly efficient in removing Escheria coli than L1. Statistical analyses by ANOVA showed that the water treatment efficiencies in L2 and L3 were substantially improved L1 (p<0.05).