Assessing the Feasibility of Wastewater Effluent as a Nutrient Source for Algae in the Context of Biofuel Production

Algae have the potential to support the production of biodiesel due to their ability to produce large volumes of oils in relatively small footprints. However, algae production for biodiesel is hampered by the expenses associated with water and nutrients required for sufficient growth. A possible source of inexpensive and nutrient-rich water is the effluent of traditional wastewater treatment facilities. If wastewater effluent can support algae growth, the added benefit of reducing high nutrient loads to natural water systems can be realized. The overarching goal of the current research was to explore the feasibility of growing algae (Scenedesmus) using wastewater effluent from a local treatment facility. The algae growth in wastewater was comparable to the nutrient-rich Bristol\u27s solution. Additionally, when a proposed limiting nutrient (bicarbonate) was raised, growth on wastewater effluent showed an increasing trend. However, this increase in growth rate was observed after the first week of growth. Similarly, when another typical limiting nutrient (iron) was added to the effluent, growth parameters were substantially increased compared to effluent alone. The fluorometry data also indicate that the effects of iron on algae growth are not realized until after the first week of growth. However, the normal turnover rate for wastewater in a sanitation plant is typically 1-3 days. The results of this experiment therefore suggest that carbonate and iron may not be beneficial supplements to algae grown using continuous-stream effluent from a wastewater facility. Yet, if the algae are grown in batch cultures for longer than one week, the addition of these limiting nutrients may result in elevated growth rates. Nevertheless, the data from the current research indicate that wastewater effluent may be an inexpensive and nutrient-rich medium for algae growth