A sewage-powered algae-to-energy plant that developers say is the world’s largest has grown its first crop of algae biomass at its site in Chiclana, Spain.
Spanish water company Aqualia, which is leading the All-gas project, calls the milestone a “major breakthrough” for the project that aims to obtain a low-cost biofuel from algae grown in wastewater.
By 2016, the biofuel produced by the All-gas project will be enough to power 200 vehicles annually “with a single toilet flush,” says project coordiantor Frank Rogalla, Aqualia’s director of innovation and technology. When the project reaches its demonstration phase, the biogas produced will be used to power public buses and garbage trucks in the region of Cadiz, Spain.
The biomass obtained shows a high energy potential relative to its digestibility level with a methane production capacity of around 200 to 300 liters of gas per kilogram of biomass processed by anaerobic digestion, Aqualia says. The microalgae also allows the purification of wastewater to a high standard.
Launched in May 2011, the five-year project has already completed its pilot phase (the first two years) in a 200-square-meter facility. Aqualia says plans for the construction of the biomass plant are on schedule, and a 1-hectare prototype is under construction. The project’s final phase will span 10 hectares.
This will be the first time a project of this scale — 10 hectares of cultivation — will be implemented in the world for the cultivation of algae into bioenergy using wastewater treatment, Aqualia says. Various other installations around 10 hectares exist but use food-based crops.
Project developers say the €12 million ($16 million) All-gas project, which has received European Union funding of €7.1 million ($9.5 million), will help the EU achieve its goal that 20 percent of the energy produced in Europe will come from renewable sources by 2020.
The raw material used to obtain the biofuel — sewage — is a waste product, whose treatment actively consumes energy and resources. The All-gas project proposes using this wastewater, as well as CO2, generated in biomass boilers from residuals such as garden waste or olive pits to feed the algae, which in turn are converted into biogas. A part of the biogas is CO2, which gets separated from the biomethane and recycled.
Also, the technology avoids using large-scale food crops to produce biofuels. Food-based biofuels have been criticized by some for raising food prices as well as having an adverse environmental effect.