Evaluation of Tannery Wastewater Treatment by Integrating Vesicular Basalt With Local Plant Species in a Constructed Wetland System

Tannery wastewater is composed of a complex mixture organic and inorganic components from various processes that can critically pollute the environment, especially water bodies if discharged without treatment. In this study, integrated vesicular basalt rock local plant species were used to establish horizontal subsurface flow constructed wetland system investigate treatment efficiency tannery wastewater. Four pilot units vegetated with P. purpureum , T. domingensis C. latifolius E. pyramidalis fifth unit was left unvegetated (control). The in systems effective removing total chromium (Cr), chemical oxygen demand (COD), 5-day biological (BOD 5 ) inflow removal reached up 99.38, 84.03, 80.32% for Cr, COD, BOD respectively, 6 days hydraulic retention time (HRT). suspended solid (TSS), phosphorus (TP), nitrate (NO 3 − maximum 70.59, 62.32, 71.23%, respectively. This treating wastewater, which below Ethiopian surface standard discharge limit set (200 mg L −1 ), COD (500 Cr (2 NO (20 TSS (50 TP (10 ).