Effluent treatment of metallurgical industries using free water surface wetlands

MAINE, M.A.; SANCHEZ, G.C.; HADAD H.R.; CAFFARATTI, S.E.; PEDRO, M.C.; DI LUCA, G.A.; MUFARREGE, M.M.

YORK

Simposio; 6th International Symposium on Wetland Pollutant Dynamics and Control. Constructed Wetland Association. WETPOL; 2015

The aim of this study was to evaluate the efficiency of two constructed wetlands (CW1 and CW2) for the treatment of effluents of metallurgical industries and determine if contaminants are retained by the sediment or the plants, key knowledge to perform a correct wetland management.Both systems are free water surface constructed wetlands. Wastewater (with high pH and salinity containing Fe, Cr, Ni and Zn and sewage were treated together. Effluents receive a primary treatment before reaching the wetlands. CW1 has been operating for 12 years. It is 2000 m2. CW2 is in operation for 5 years. It is 140 m2. Their efficiencies were determined from the influent and effluent contaminant concentrations. Samples were collected in triplicate. In both CWs, removal efficiencies were satisfactory. Since the conditions for metal removal (high pH, alkalinity, Fe, Ca and ionic concentrations) are largely provided by the effluents, the sediment would be expected to continue retaining metals as far as the composition of the influent remains the same. T. domingensis was tolerant to the effluents and efficient in the metal removal. T. domingensis detritus accumulated high metal concentrations. Metals are bound to sediment fractions that will not release them to the water while the chemical and environmental conditions of the system are maintained.