| Natural occurring microalgae cultivation systems using 380 L raceway tanks were operated outdoors for 8 months and the effects of the culture substrate were investigated. The cultivation substrate was primary effluent with or without excess sludge. Results showed that when diluted excess sludge was added to the substrate, microalgae biomass increased more than when the substrate contained only primary effluent. In addition, the wastewater SS and water quality were removed to low levels. Microalgal culture systems that use excess sludge have higher organic acid content, higher biochemical methane potential, and higher efficiency to produce more microalgal biomass than wastewater treatment plant systems that do not use excess sludge. |
