(752c) Using Wastewater for Microalgae Cultivation

The use of microalgae for food, feed and fuel has gained considerable interest in recent years, due to heightened oil prices, concerns of national energy security, and the realization of the human contribution to global warming environmental. However, if the concept is to become a reality, further optimization of culture conditions are needed. Algae grown on wastewater that contains high levels of nutrients like nitrogen, phosphorus and carbon, could potentially be a promising sustainable way to produce biofuels and biomass products. In addition, there is also potential for combining removing nutrients from wastewater with providing a useful algal biomass. This presentation shows the growth rate, lipid content, biomass production and fatty acid composition of microalgae (Chlorella sorokiniana) on wastewater from the various processes in wastewater treatment plants, such as centrate and tertiary wastewater, with and without modifications. Wastewater recycle strategies for cultivation are also investigated. To date we have determined that algae grow well on all types of wastewater studied without any loss of productivity. The algae remove all of the phosphate present in the water which is important for States that have zero phosphate emission requirements. A large portion of the nitrogen is removed as well, however, current studies involve determining which forms of nitrogen are not utilized by the algae and strategies for removing them. The lipid composition remains unchanged indicating that wastewater is a viable water source for algal cultivation.