Removal of COD, BOD and nutrients in swine manure wastewater using freshwater green microalgae

Aims: The aim of this study was to investigate the effectiveness of freshwater green microalgae in remediating swine manure wastewater. Two different species of freshwater green microalgae (Scenedesmus quadricauda and Stigeoclonium sp.) were used in this study. Methodology and results: Laboratory experiments were performed to compare the growth rate and nutrients (total phosphorus, ammonia nitrogen, nitrate nitrogen and nitrite nitrogen) uptake by these two species of microalgae in swine manure wastewater. Experimental work was carried out for 14 days at room temperature of 30 +/- 1 degrees C with about 1520 Lux of light intensity. The results showed that both microalgae grew well in swine manure wastewater. S. quadricauda performed better in remediating swine manure wastewater, by reducing 83.99% of COD, 80.39% of BOD5, 84.78% of total phosphorus (TP), 91.79% of ammonia nitrogen (NH3-N), 89.79% of nitrate nitrogen (NO3-N) and 87.14% of nitrite nitrogen (NO2-N) compared to Stigeoclonium sp. which was only able to remove 79.26% of COD, 76.27% of BOD5, 75.17% of TP, 86.42% of NH3-N, 84.38% of NO3-N and 82.38 NO2-N. Conclusion, significance and impact of study: The results of this study indicate that these two species of microalgae have potential to be used in the remediation of swine manure wastewater.