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Clean Water And Clean Power Through Algae

It’s an entire cycle where you’re dealing with not only a water pollution problem.

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A biochemist shows different types of microalgae for the study and manufacture of a biofuel in high displacement diesel engines for reducing emissions of gases and particulate matter in Santiago, Chile. VOA
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“Nature sometimes isn’t pretty,” said University of Maryland environmental scientist Peter May, grabbing a clump of slimy green-brown gunk.

That gunk lines the bottom of what’s called an algal turf scrubber at the Port of Baltimore. The meter-wide, shallow channel runs the length of a football field alongside one of the port’s giant parking lots.

“Actually, it’s always pretty,” May corrected himself. Even the gunk. Because that gunk is removing pollution from the Chesapeake Bay. Plus, May’s colleagues are turning it into clean, renewable electricity.

The Chesapeake needs the help.

Algal feast

Like many waterways around the world, the bay is polluted with excess nutrients from farm fertilizer runoff, city wastewater and other sources. Algae feast on those nutrients, triggering massive growth that chokes out other aquatic life. Last summer, algal growth left an average of 4.6 cubic kilometers of the bay without oxygen.

A third of the pollution reaching the bay literally falls out of the sky.

Fossil fuels burned in power plants, cars and elsewhere create nitrogen oxide air pollution, which ultimately ends up in the bay, either attached to airborne particles or dissolved in rainwater.

Forests would soak up that pollution. But like many urban areas, the Port of Baltimore has a pavement problem. There’s not a tree to be found at the entire 230-hectare Dundalk Marine Terminal, where the algae scrubber is located.

So regulators require the port to remove as much pollution from the bay as its parking lots allow in. That’s where the algal turf scrubber comes in.

Algae
Algae is seen near the City of Toledo water intake crib, Aug. 3, 2014, in Lake Erie, about 2.5 miles off the shore of Curtice, Ohio. VOA

Putting algae to work

The scrubber is like “a controlled algal bloom on land,” May said, “which puts the algae to work pulling nutrients out of the water.”

The city of Durham, N.C., is planning to build another scrubber to clean up a local reservoir. A pilot study found it would cost about half as much as typical pollution control measures, such as constructed wetlands, and much less than retrofitting existing systems. Others are up and running in Florida.

The algal turf scrubber creates one big challenge, May said.

“What do we do with that algae? You have to have an end use or else you’re going to pile that algae up very quickly,” he said.

It’s high in protein and omega-3 fatty acids. It’s been turned into animal feed. It can be fermented into biofuels. Some of May’s colleagues have used it to launch a fertilizer business.

But here at the Port of Baltimore, they’re turning it into electricity.

Baltimore, Algae
Containers are unloaded from a ship at the Port of Baltimore, Oct. 24, 2016. The port uses an algae scrubber to remove pollution from the Chesapeake Bay. VOA

Digesting for power

May works with University of Maryland colleague Stephanie Lansing, an expert in a process called anaerobic digestion. It’s not much different from our own digestion.

“You have bacteria in your gut that break down food. We’re doing that same process in an anaerobic digester,” Lansing said. “We’re breaking down the material, and we’re producing energy in the process.”

In this case, the microbes digesting the algae produce methane biogas. The biogas runs a fuel cell.

“The fuel cell is actually a very efficient way to use the energy,” she said. This small, pilot system produces a modest amount of electricity.

Also Read: India’s Floating Solar Panel a Gateway To Clean Energy For Asia

“You can use it to charge batteries. You can use it for lights. You can use it for fans,” she added.

The Port of Baltimore plans to build a larger system that will cover about a third of a hectare, which could produce a few hundred kilowatts — still modest, but not bad, when you start with just polluted water and algae.

“It’s an entire cycle where you’re dealing with not only a water pollution problem, but an air pollution issue,” Lansing said. (VOA)

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Now Create Energy Even While You’re Walking

The researchers are working on adding a magnetic component to the current mechanical harvester to scavenge energy over a larger portion of the day.

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Representational Image

A wearable energy-harvesting device could generate energy from the swing of an arm while walking or jogging, say researchers.

The device, about the size of a wristwatch, produces enough power to run a personal health monitoring system, reported the team from Pennsylvania State University and the University of Utah.

“The devices we make using our optimised materials run somewhere between 5 and 50 times better than anything else that’s been reported,” said Susan Trolier-McKinstry, the Steward S. Flaschen Professor of Materials Science and Engineering and Electrical Engineering from Penn State.

Energy-harvesting devices are in high demand to power the millions of devices that make up the Internet of Things (IoT).

 

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Representational image

 

By providing continuous power to a rechargeable battery or supercapacitor, energy harvesters can reduce the labour cost of changing out batteries when they fail and keep dead batteries out of landfills.

Also Read: Facial Recognition Technology Catches A Person With Fake Passport At The US Airport

According to the researchers, they can double the power output using the cold sintering process – a low-temperature synthesis technology developed at Penn State.

In addition, the researchers are working on adding a magnetic component to the current mechanical harvester to scavenge energy over a larger portion of the day when there is no physical activity, said the study published in the journal Advanced Functional Materials. (IANS)