Algae seen as cheapest, greenest bio-diesel source

WASHINGTON - Microalgae grown in wastewater has shown promise as a potential source of bio-diesel. It could be the cheapest and the greenest source ever.

The project is doubly “green” because algae consume nitrates and phosphates, and reduce bacteria and toxins in the water. The end result — clean wastewater and material for a promising bio-fuel.

The purified wastewater can be channelled back into receiving water bodies at treatment plants, while the bio-diesel can fuel buses, construction vehicles and farm equipment.

“Algae — as a renewable feedstock — grow a lot quicker than crops of corn or soybeans,” says Eric Lannan, who is working on his master’s degree in mechanical engineering at the Rochester Institute of Technology (RIT) in the US.

“We can start a new batch of algae about every seven days. It’s a more continuous source that could offset 50 percent of our total gas use for equipment that uses diesel,” he adds.

Algae could replace diesel’s telltale black puffs of exhaust with cleaner emissions low in sulphur and particulates that accompany fossil fuels, according to a Rochester Institute statement.

Algae have a lot of advantages. They are cheaper and faster to grow than corn, which requires nutrient-rich soil, fertilizer and insecticide. Factor in the fuel used to harvest and transport corn and ethanol starts to look complicated.

Conversely, algae are much simpler organisms. They use photosynthesis to convert sunlight into energy. They need only water - ponds or tanks to grow in - sunlight and carbon dioxide.