Algae grown on wastewater media are a potential source of low-cost lipids for production of liquid biofuels. This study investigated lipid productivity and nutrient removal by green algae grown during treatment of dairy farm and municipal wastewaters supplemented with CO 2 .Dairy wastewater was treated outdoors in bench-scale batch cultures. The lipid content of the volatile solids peaked at Day 6, during exponential growth, and declined thereafter. Peak lipid content ranged from 14-29%, depending on wastewater concentration. Maximum lipid productivity also peaked at Day 6 of batch growth, with a volumetric productivity of 17 mg/day/L of reactor and an areal productivity of 2.8 g/m 2 /day, which would be equivalent to 11,000 L/ha/yr (1,200 gallons/acre/year) if sustained year-round. After 12 days, ammonium and orthophosphate removals were 96% and >99%, respectively. Municipal wastewater was treated in semi-continuous indoor cultures with 2-4 day hydraulic residence times (HRTs).Maximum lipid productivity for the municipal wastewater was 24 mg/day/L, observed in the 3-day HRT cultures. Over 99% removal of ammonium and orthophosphate was achieved.The results from both types of wastewater suggest that CO 2 -supplemented algae cultures can simultaneously remove dissolved nitrogen and phosphorus to low levels while generating a feedstock potentially useful for liquid biofuels production.1

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A life cycle assessment (LCA) focused on greenhouse gas (GHG) emissions from the production of microalgal biodiesel was carried out based on a detailed engineering and economic analysis. This LCA applies the methodology of the California Low Carbon Fuel Standard (CA LCFS) and uses life cycle inventory (LCI) data for process inputs, based on the California-Modified Greenhouse Gases, Regulated Emissions, and Energy use in Transportation (CA GREET) model. Based on detailed mass and energy balances, calculated GHG emissions from this algal biodiesel system are 70% lower than those of conventional diesel fuel, meeting the minimum 50% GHG reduction requirements under the EPA RFS2 and 60% for the European Union Renewable Energy Directive. This LCA study provides a guide to the research and development objectives that must be achieved to meet both economic and environmental goals for microalgae biodiesel production.