After a $ 10 million project that took two years, NASA has now come up with a new system of growing algae in floating plastic bags. The system is designed with the aim of reducing the costs of biofuel production from algae, since the system can be coupled with wastewater treatment facilities.
In a prototype plant they used four nine-meter long plastic bags to cultivate algae at a wastewater treatment plant near San Francisco. The researchers hope that they can produce around 2000 gallons of oil per acre per year.
According to Jonathan Trent, the lead algae researcher in NASA, pumping wastewater from the sewage treatment plants and CO2 from the powerplants into the common polyethylene algae growth system will be economically viable methods of algae cultivation. He is of the opinion that San Francisco produces enough wastewater to feed a floating algae farm that covers 1,200 acres.
But the system has to face many implementation challenges, one of which is the huge requirement of plastic. According to one estimate, around 5 square kilometres of plastic may be required to produce 2.4 million gallons of oil, and the bags need to be replaced every year.
Trent feels that by recycling or reusing the plastic used in the cultivation system, the problems associated with plastic disposal could be addressed. This system doesn’t require the space that is needed for constructing artificial ponds in the wastewater treatment facilities.
Questions have also arisen about the ability of the plastic bags to withstand the corrosive salt water and storms. The researcers are not sure about the cost that would be required for replacing the damaged plastic bags and how expensive the system would be at a large scale.
They have they started a detailed economic analysis based on their results so far. The project also received $800,000 from the California Energy Commission.
If the associated challenges are addressed, the system would definitely be an alternative for the expensive algae growth systems and will dramatically reduce the costs associated with biofuel production form algae.
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