Viability of water weeds and microalga in pulp and paper mill wastewater

Water weeds Azolla pinnata and Lemna minor and the chlorophycean alga Scendesmus bijugatus were grown in a paper mill wastewater. The objective of the study was to assess the viability of these species upon exposure to such effluents and to assess their potential in the improvement of effluent quality. The wastewater was analysed before and after the treatment with these species. The growth of the alga and the hydrophytes was also measured. The algal assay revealed that the clear effluent will promote algal growth on addition of fertilizer while water weeds did not require fertilizer input. Both the algae and macrophytes could reduce the BOD and COD of the effluent.