Wastewater eating algae to biofuels could eliminate need for aeration
Just weeks after US President Barack Obama pledged $14 million to develop transportation fuel from algae, an EU backed project has been launched to promote algae harvesting at wastewater facilities...
LONDON, England, March 6, 2012 – Just weeks after US President Barack Obama pledged $14 million to develop transportation fuel from algae, an EU backed project has been launched to promote algae harvesting at wastewater facilities.
The €12 million, five-year project is starting at water management company aqualia’s wastewater treatment plant in Chiclana, Southern Spain and is backed by the European Union as part of its FP7 program with six partners.
Called All-Gas, which means algae in Spanish, the project will see “algal culture ponds” being used to grow micro-algae using nutrients contained in wastewater, such as phosphorous. A 10-hectare site will be needed for the project.
Taking advantage of a warm climate, the algae grows using natural sunlight, before being processed for the extraction of oils and other valuable by-products.
Frank Rogalla, head of R&D at aqualia, said that at existing algae farms, up to 30% of operation costs are normally the expense of buying and adding in nutrients to help with the algae growth. These nutrients are abundant in wastewater, he said, so it makes sense to incorporate the two industries.
Traditionally aeration processes at wastewater treatment plants are heavy energy users, accounting for up to 30% of a facility’s operating costs. In the US, according to the Environmental Protection Agency, drinking water and wastewater systems account for between 3% and 4% of national energy consumption.
However, Rogalla later told Water & Wastewater International magazine (WWi) that growing algae with wastewater can eliminate the need for aeration, thus reducing energy.
He said: “We have converted our treatment to anaeraobic pre-treatment, meaning we will generate biogas from the start instead of destroying organic matter, so no aeration will be needed. From the 0.5 kWh [kilowatt-hour] per m3 which you generally spend for aeration, that will be completely gone. We will have a net output of energy from algae conversion either to oils or to gas. So that’s why you get this positive output of 0.4 kWh per m3 of wastewater treated.”
Rogalla added: “It will not cost more than traditional wastewater treatment, which costs about 0.2 Euros per cubic metre. We think we will use the same operational costs but instead of consuming energy we will produce additional benefit, meaning we generate about 0.2 euros per cubic metre in additional profit from the fuel. Our aim is to be cost neutral.”
The project will be implemented in two stages, with a prototype facility being used to confirm the scale of the full-size plant during the first two years. Once the concept has been proven in full-scale ponds, a 10 hectare site will be developed and operated at commercial scale during the next three years.
Rogalla suggested the project could be rolled out among its existing facilities along the Mediterranean belt, including Italy, Portugal, Egypt and even South America, all of which have “favourable conditions, meaning the climate is advantageous and the land is available”.
It was only at end of February that US President Barack Obama announced that the Department of Energy would make $14 million available to support research and development into biofuels from algae. The Department has suggested that up to 17% of the US’ imported oil for transportation could be replaced with biofuels from algae.
- A full review of the All-Gas project including comments from all parties will be included in the April-May issue of Water & Wastewater International magazine. To sign up for a copy, please click here.