Algae and in particular algal blooms have historically been considered a foe for the water industry. Yet a European funded project in Spain has set out to prove that algae can actually be a best friend for wastewater and its inherent nutrients.
In early December, the demo phase of the All-gas project was officially inaugurated as the largest site in the world for the production of biofuel from algae harvested using wastewater.
Green gold: an opportunity
It was in 2010 when the European Union (EU) Commission launched a call for a large scale demonstration of biofuel production from algae. This was largely in response to the hype generated in the US from what was being “green gold”.
“We saw an opportunity as algae grows well in wastewater,” says Frank Rogalla, director of innovation and technology at Aqualia. “It would avoid artificial fertilizers and provide treatment at the same time. Also, methane production from biomass has been a long tradition in wastewater treatment, and this biofuel would avoid the complications of lipid extraction from algae.”
The project has taken seven years to reach this stage, from laboratory, to pilot and the prototype. As Rogalla puts it, the team had to “start from scratch” as there was an absence of engineering capability to build a large scale demonstration bringing together the various elements. Only academic papers were available at the time.
As a result, with Aqualia as the coordinator, it brought in project participants including BDI-Bio Energy International (Austria), Fraunhofer-UMSICHT (Germany), HyGear (The Netherlands) and the University of Southampton (UK). The project is co-financed with €7.1 million by the EU Commission within the FP 7 programme: ENERGY.2010.3.4-1: Bio-fuels from algae.
Each partner is responsible for a key piece of the chain. For example, the University of Southampton is responsible for optimising the digestion; HyGear for optimising gas cleaning; BDI for trying to extract valuable substances out of the algae biomass and finally Fraunhofer is helping with analytics and undertaking the life-cycle assessment.
However, the project faced a major stumbling block when it came to regulation, as Rogalla explains: “One difficulty that costs us a lot of time is the permitting issue – as large scale algae cultivation with wastewater is new, there is no legal basis to authorize this activity. Is it aquaculture, is it water reuse, is it allowed in coastal areas?”
The principle is to recycle the nitrogen and phosphorus from wastewater into microalgae biomass, in turn making “wastewater treatment energy self-sufficient”, remarks Rogalla.
The prototype was built with two 500 m2 tanks, comprising a total capacity of 1000 m2. After testing the processes on a prototype scale with one vehicle being able to run 30,000 km on the algae biomethane, it was time to accelerate the project. It was then eventually scaled up to 20,000 m2 (four x 5000 m2) algae cultivation ponds with the aim to be able to fuel up to 40 vehicles.
Although the project was originally started with a Volkswagen, in December 2016 it was transferred to SEAT, the Spanish company in the VW group. SEAT is being used to validate the biomethane quality in the long-term tests.
Algae power
Data produced from the Chiclana site so far shows that the algae biofuel produced provides four times the distance of conventional biofuels, such as sugar ethanol or palm oil diesel. How is this possible?
“One of the reasons for the hype in the US is that the growth of algae is fast and they are rich in energy,” says Rogalla. “Indeed the most productive bioenergy crops, sugarcane to produce bioethanol, or palm to produce biodiesel, can yield 5000 litre per hectare, per year – enough to run five vehicles (with 20 000 km each and consuming 5 litres/100 km).”
Rogalla says that the same quantity of algae produced biofuel can instead power 20 vehicles, each running 20,000 km per year. “Instead of extracting lipids, a fraction of the biomass that is not all compatible with diesel, we can ferment all the biomass the biogas.”
The director of innovation says one of the main limitations in scaling up the All-gas project would be having enough low cost nutrients. He suggests that, in addition to municipal and industrial effluents, they could use animal waste. “There are nearly 40 million pigs in Spain and normally there is enough space in rural areas,” he adds.
Site inauguration and future expansion plans
The European Union commissioner for energy and climate change action, Miguel Arias Cañete, was present at the site inauguration. “We are aware that they are complex projects because they involve various companies but once the process has started, decarbonisation in the European Union is now unstoppable,” he said.
When WWi magazine first covered the All-gas project in 2010, Rogalla said at the time that the long-term plan is to roll the technology out along the company’s existing facilities along the Mediterranean belt. Is this still the case?
Aqualia serves 1000 communities, many in Southern Spain, including Andalucia, Extremadura and Castilla La Mancha. This is as well as operations in Portugal, Italy, North Africa and the Middle East – all with suitable climates to help algae growth and available wastewater.
“The obstacle here is the conservative nature of our industry,” adds Rogalla. “If it has not worked on large scale somewhere close for 10 years, people have difficulty to consider the solution. That is why this demo milestone is so important, we can now show on full scale for about 10,000 people (2000 m3/day) that the algae biofuel and water reuse synergy is a reality.”
Thinking long-term, he believes that using the results from Chiclana, they can convince “mayors and their engineers” to use their wastewater to fuel their school buses.
All-gas may have well proven that algae, together with wastewater, can be a friend rather than a foe. The next challenge remains rolling it out to other sites and convincing a sceptical audience on its merits.
