Biodiesel production potential of wastewater treatment high rate algal pond biomass

This study investigates the year-round production potential and quality of biodiesel from wastewater treatment high rate algal pond (WWT HRAP) biomass and how it is affected by CO₂ addition to the culture. The mean monthly pond biomass and lipid productivities varied between 2.0±0.3 and 11.1±2.5gVSS/m²/d, and between 0.5±0.1 and 2.6±1.1g/m²/d, respectively. The biomass fatty acid methyl esters were highly complex which led to produce low-quality biodiesel so that it cannot be used directly as a transportation fuel. Overall, 0.9±0.1g/m²/d (3.2±0.5ton/ha/year) low-quality biodiesel could be produced from WWT HRAP biomass which could be further increased to 1.1±0.1g/m²/d (4.0ton/ha/year) by lowering culture pH to 6-7 during warm summer months. CO₂ addition, had little effect on both the biomass lipid content and profile and consequently did not change the quality of biodiesel.