Effects of different pre-treatments of piggery wastewater onDesmodesmus sp cultivation and nutrient removal

摘要

Piggery wastewater after anaerobic digestion was successfully adopted as medium to cultivate Desmodesmus sp. The characteristics of algal growth, lipid content and nutrient removal efficiency were examined in this study. UV sterilized, autoclaved, untreated wastewater and NaCIO pretreated were tested to find an optimal pre-treatment. Autoclaved wastewater showed a lower concentration of ammonia nitrogen (39.007mg/L) and higher N:P ratio (64.61) due to high temperature and high pressure. The dry cellweight were 0.209 g/L, 0.414 g/L, 0.245 g/L and 0.267 g/L, respectively. Removal efficiency of TAN, TN, P-PO_4 and COD in autoclaved wastewater were 92.30%, 86.98%, 99.99% and 29.90%. There are no significance differences in biomass accumulation, nutrient removal efficiency among NaCIO pretreated, UV sterilized and untreated wastewater. The maximum lipid content was observed in untreated wastewater (17.63%) and autoclaved wastewater (17.39%).