title: Using wastewater and high-rate algal ponds for nutrient removal and the production of bioenergy and biofuels.
abstract: This paper projects a positive outcome for large-scale algal biofuel and energy production when wastewater treatment is the primary goal. Such a view arises partly from a recent change in emphasis in wastewater treatment technology, from simply oxidising the organic matter in the waste (i.e. removing the biological oxygen demand) to removing the nutrients - specifically nitrogen and phosphorus - which are the root cause of eutrophication of inland waterways and coastal zones. A growing need for nutrient removal greatly improves the prospects for using new algal ponds in wastewater treatment, since microalgae are particularly efficient in capturing and removing such nutrients. Using a spreadsheet model, four scenarios combining algae biomass production with the making of biodiesel, biogas and other products were assessed for two of Australia's largest wastewater treatment plants. The results showed that super critical water reactors and anaerobic digesters could be attractive pathway options, the latter providing significant savings in greenhouse gas emissions. Combining anaerobic digestion with oil extraction and the internal economies derived from cheap land and recycling of water and nutrients on-site could allow algal oil to be produced for less than US$1 per litre.
authors.affiliation: CSIRO Energy Transformed Flagship, Aspendale, Australia. David.Batten@csiro.au
authors.forename: David
authors.initials: D
authors.lastname: Batten
authors.forename: Tom
authors.initials: T
authors.lastname: Beer
authors.forename: George
authors.initials: G
authors.lastname: Freischmidt
authors.forename: Tim
authors.initials: T
authors.lastname: Grant
authors.forename: Kurt
authors.initials: K
authors.lastname: Liffman
authors.forename: David
authors.initials: D
authors.lastname: Paterson
authors.forename: Tony
authors.initials: T
authors.lastname: Priestley
authors.forename: Lucas
authors.initials: L
authors.lastname: Rye
authors.forename: Greg
authors.initials: G
authors.lastname: Threlfall
mesh_terms: D000693:Anaerobiosis; D056804:Biofuels; D018533:Biomass; D058572:Carbon Footprint; D000460:Chlorophyta / Q000254:growth & development / Q000378:metabolism*; D009821:Oils / Q000302:isolation & purification; D018505:Waste Management / Q000379:methods*; D062065:Wastewater / Q000737:chemistry*
chemical_list: D056804:Biofuels; D009821:Oils; D062065:Wastewater