Recycling of Multiple Waste Streams for Transportation Fuel Production via Algae Cultivation at Wastewater Treatment Plants

Increasing oil prices have led to recent initiatives to find domestic and renewable sources of transportation fuels. The cultivation of algae for biofuels production offers a uniquely sustainable option to utilize both greenhouse gases and wastewater as a valuable commodity. Algal cells contain lipids which can be converted to biodiesel by the same processes already used for other feedstocks. The most striking advantage over other feedstocks is the potential of algae; with theoretical production per area much higher than the currently favored feedstocks. Also as a non-food crop it will not have an effect on global food prices. Furthermore; the non-oil components of the algae cell also have value, such as cellulose which has the potential to be used for ethanol or methane production. With these advantages in mind, the steady flow of water and nutrients from a wastewater treatment plant presents an opportunity for effluent to be used in algae cultivation. The necessary carbon source could be supplied through a synergistic relationship with coal fired power plants needing to sequester greenhouse gases or as carbon from onsite anaerobic digesters. In any case, the coupling of a wastewater treatment plant with an algae cultivation system offers many exciting opportunities, such as low energy nutrient removal, valuable commodity production, and abatement of greenhouse gases. This paper reviews the current technologies and methods in algae for biofuels production, and suggests the feasibility of their future application to wastewater treatment plants.