Produce fuel from our sewage?
This seemingly crazy idea can come true. In southern Spain, a technology that uses microalgae is being tested, allowing biofuels to be made from wastewater - wastewater treatment that is very expensive to municipalities. It is a promising sector, but still complex and costly. Called All-Gas (pronounced "algae"), the project, launched in 2011, has just completed its first algae harvest, from the pilot unit located in the purification station of the seaside resort of Chiclana de la Frontera, near Of Cádiz. The plant, which for the time being extends over 200 square meters, aims to treat in 2016 phytoplankton grown on ten hectares and supply 200 cars and 20 trucks to biogas. The responsible for this € 12 million project, which is 60% funded by the European Union, is a consortium of six companies led by Spain's Aqualia, the world's number three water management company.
Industrial scale
"It's the first time in the world that it turns wastewater into biofuel into an industrial-scale, out-of-laboratory demonstrator," said Frank Rogalla, program coordinator and chief innovation officer at Aqualia. "We want to show that this technology is technically and economically viable." At the heart of this experiment is an old, updated water purification technique: the lagoon. In basins of 32 square meters of surface and 30 centimeters deep, microalgae develop naturally through photosynthesis, only revolved by wheels at dawn.
Almost all the ingredients required for efflorescence are present at the site: light, water and nutrients - the nitrogen and phosphorus found in pretreated wastewater. It remains to inject carbon dioxide (CO2), originating from the combustion of green waste. "Algae turns CO2 into oxygen, which allows the development of bacteria, which break down organic matter," says Frank Rogalla. "The whole of this natural ecosystem purifies the water."
High energy consumption
Once the paper is finished, microalgae, as well as part of the remaining organic matter, are harnessed energetically: collected and then placed in digesters, they produce a biogas composed essentially of methane. "I think we're going to fuel our first cars with biogas later this year," hopes Frank Rogalla. For now, with 6 kilos of algae per day, the crops are small. But those responsible for the project want to quickly install new basins. Over time, the planned production of 100 tonnes of algae per hectare per year should allow the annual production of 450 tonnes of methane on site and treat half of the wastewater in the city of Chiclana de la Frontera. This equation could solve the two main weaknesses of biofuels from algae: their energy balance and their cost. For two years now, algae has been promoted by the European Commission to replace agrofuels from rapeseed, soybeans, maize or palm trees, which have been neglected because of a not so favorable balance of carbon and competition with uncultivated land of food. In any case, algae-based fuels, which are not yet produced on an industrial scale, are criticized for their very high energy consumption. "There is still too much energy to be expended for the growth, harvesting and reuse of algae," says Olivier Bernard, a specialist in microalgae at the National Institute of Information and Automation Research (INIA).
Technique feasible until 2020
"In the All-Gas project, energy consumption is limited, because for now we only produce methane, not bioethanol or biodiesel, whose extraction is more complex," says Frank Rogalla. "In addition, the association of algae and bacteria in the lagoons allows a gain in energy compared to the procedures of the purification plants." In the latter, the so-called "activated sludge" purification mode requires an oxygen injection to allow the development Of bacteria, which consumes energy. Already the use of waste water lowers the cost of production of biofuels. "The treatment of the waters of the municipalities provides us with a source of income that amortizes the facilities," says Frank Rogalla. Thanks to this, he expects to sell methane at market price, that is, 40 cents per cubic meter. Another obstacle to be overcome is productivity. "The microalgae that develop naturally in these contaminated environments are not necessarily those that will give more biofuel," concludes Olivier Bernard. "There are still barriers to breaking down before we can produce large-scale fuels from algae. But the promising technique should be viable by 2020. "
This seemingly crazy idea can come true. In southern Spain, a technology that uses microalgae is being tested, allowing biofuels to be made from wastewater - wastewater treatment that is very expensive to municipalities. It is a promising sector, but still complex and costly. Called All-Gas (pronounced "algae"), the project, launched in 2011, has just completed its first algae harvest, from the pilot unit located in the purification station of the seaside resort of Chiclana de la Frontera, near Of Cádiz. The plant, which for the time being extends over 200 square meters, aims to treat in 2016 phytoplankton grown on ten hectares and supply 200 cars and 20 trucks to biogas. The responsible for this € 12 million project, which is 60% funded by the European Union, is a consortium of six companies led by Spain's Aqualia, the world's number three water management company.
Industrial scale
"It's the first time in the world that it turns wastewater into biofuel into an industrial-scale, out-of-laboratory demonstrator," said Frank Rogalla, program coordinator and chief innovation officer at Aqualia. "We want to show that this technology is technically and economically viable." At the heart of this experiment is an old, updated water purification technique: the lagoon. In basins of 32 square meters of surface and 30 centimeters deep, microalgae develop naturally through photosynthesis, only revolved by wheels at dawn.
Almost all the ingredients required for efflorescence are present at the site: light, water and nutrients - the nitrogen and phosphorus found in pretreated wastewater. It remains to inject carbon dioxide (CO2), originating from the combustion of green waste. "Algae turns CO2 into oxygen, which allows the development of bacteria, which break down organic matter," says Frank Rogalla. "The whole of this natural ecosystem purifies the water."
High energy consumption
Once the paper is finished, microalgae, as well as part of the remaining organic matter, are harnessed energetically: collected and then placed in digesters, they produce a biogas composed essentially of methane. "I think we're going to fuel our first cars with biogas later this year," hopes Frank Rogalla. For now, with 6 kilos of algae per day, the crops are small. But those responsible for the project want to quickly install new basins. Over time, the planned production of 100 tonnes of algae per hectare per year should allow the annual production of 450 tonnes of methane on site and treat half of the wastewater in the city of Chiclana de la Frontera. This equation could solve the two main weaknesses of biofuels from algae: their energy balance and their cost. For two years now, algae has been promoted by the European Commission to replace agrofuels from rapeseed, soybeans, maize or palm trees, which have been neglected because of a not so favorable balance of carbon and competition with uncultivated land of food. In any case, algae-based fuels, which are not yet produced on an industrial scale, are criticized for their very high energy consumption. "There is still too much energy to be expended for the growth, harvesting and reuse of algae," says Olivier Bernard, a specialist in microalgae at the National Institute of Information and Automation Research (INIA).
Technique feasible until 2020
"In the All-Gas project, energy consumption is limited, because for now we only produce methane, not bioethanol or biodiesel, whose extraction is more complex," says Frank Rogalla. "In addition, the association of algae and bacteria in the lagoons allows a gain in energy compared to the procedures of the purification plants." In the latter, the so-called "activated sludge" purification mode requires an oxygen injection to allow the development Of bacteria, which consumes energy. Already the use of waste water lowers the cost of production of biofuels. "The treatment of the waters of the municipalities provides us with a source of income that amortizes the facilities," says Frank Rogalla. Thanks to this, he expects to sell methane at market price, that is, 40 cents per cubic meter. Another obstacle to be overcome is productivity. "The microalgae that develop naturally in these contaminated environments are not necessarily those that will give more biofuel," concludes Olivier Bernard. "There are still barriers to breaking down before we can produce large-scale fuels from algae. But the promising technique should be viable by 2020. "
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