Assessing the efficacy of Azolla pinnata in four different wastewater treatment for agricultural re-use: a case history

摘要

Wastewaters from four different sources were treated using locally developed plant, while treatment components included Azolla pinnata fern and palm kernel shell charcoal. The four wastewater sources were: domestic, municipal, aquaculture and industrial. Twenty-five parameters considered included: temperature, turbidity, electrical conductivity, pH, total suspended solid, total dissolved solids, total solid, acidity, total hardness, total nitrogen, total phosphorus, ammonical nitrogen, dissolved oxygen, biological oxygen demand and chemical oxygen demand. Metals analyzed also included; sodium, potassium, calcium, magnesium, zinc, iron, lead, copper, cadmium and manganese. From the results, considerable reduction in pollutant parameters were obtained in the four wastewaters after treatment. Complete (100%) removal efficiencies were obtained in cadmium and manganese in all the wastewaters except for aquaculture wastewater, while complete removal was obtained in lead and copper in aquaculture wastewater only. Similarly, turbidity, phosphorus and nitrogen recorded complete removal in all the wastewaters except for 75.7% removal of phosphorus in municipal wastewater. Other parameters reduced appreciably with statistically significant results at P<0.05. This indicated high efficiency of the treatment plant, A. pinnata, in pollutants and metals' removal, thereby making the treated four wastewaters good enough to be recycled for irrigation purposes.