Abstract

Small and medium scale industries in Nigeria play a major role in polluting water bodies, and key among these pollutants are suspended solids, biological oxygen demand and heavy metals contamination. Conventional methods of treatment, such as chemical precipitation, do not provide sustainable solutions as the pollutants are merely transferred from the waste water to a sludge residue which is disposed of by land-filling. The pollutants eventually find their way to freshwater supplies thereby contaminating it.
Water hyacinth is a noxious weed that has a rapid growth rate and easily congests the water ways in Lagos, a coastal city in Nigeria, thereby creating serious problems in navigation, and irrigation. This can be harvested, and in line with the golden rules of sustainable development, used for the sustainable treatment of some industrial wastewaters.
This work investigates the effectiveness of water hyacinth in wastewater treatment. After a 5-week simple experiment, in which water hyacinths were planted in wastewater samples obtained from three different industries,  the average removal of pollutants were found to be 53.03%, 64.41%, 65.4%, 47.22%, 94.67% and 30.30% for Total Suspended Solids (TSS), Biochemical Oxygen Demand (BOD), Dissolved Oxygen (DO), nitrate-nitrogen, cadmium and iron respectively. Average Biocentration Factors (BCF) obtained for cadmium, copper and iron were 583.83, 734.41 and 2982.95 respectively.

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