Turning Algae Blooms into Biofuels

Toxic blue-green algae blooms are ravaging through the delicate ecosystem of the Florida Everglades. As local, state, and federal officials are teaming together to address this issue (somewhat haphazardly), there is another possibility: turning the algae blooms into biofuels. Band-aid fixes on this issue will not offer long-term solutions. The answer would be an elimination of the fertilizer runoff that caused the problem. Point source conversion of algae biomass at the runoff site would provide another tool in the arsenal against this threat.

Lake Okeechobee, Florida’s largest lake is the epicenter of the latest outbreak. Governor Rick Scott has declared a state of emergency in seven counties. CityLab explores the severity of the threat to public health and the environment due to problems associated with cyanobacteria and how the algae blooms developed:

Pollution and warm water fuel the algae’s growth. Research from the U.S. EPA suggests that fertilizer runoff is introducing phosphorous and nitrogen to waterways, essentially fertilizing the algae.

Another factor is water flow. The Everglades, a wetland ecosystem, naturally flows from Lake Okeechobee south to Florida Bay. But since 1910, a series of more and more robust dikes have been built to contain that flow. The current dike system, called the Herbert Hoover Dike, is made up of about 143 miles of levees. Additional canals divert the flow to the east and west coasts.

With the natural flow of the Everglades staunched, water builds up when it rains. Then the algae blooms again, and like clockwork, the U.S. Army Corps of Engineers tries to relieve Lake Okeechobee’s water levels by discharging more water along the canals. This increases the concentration of fresh water in the estuary, giving the cyanobacteria even more opportunity to thrive.

Cyanobacteria. Image credit: Josef Reischig / CC BY-SA 3.0.
Josef Reischig / CC BY-SA 3.0

Postdoctoral fellow Zofia Taranu at the University of Ottawa published, “Acceleration of cyanobacterial dominance in north temperate‐subarctic lakes during the Anthropocene.” The piece looks at the impacts of algae blooms:

[C]yanobacteria can produce toxins that cause damage to the liver or nervous system. The most common symptoms of acute exposure to harmful algal blooms are skin rash or irritation, gastroenteritis and respiratory distress. Chronic, low dose exposures over a lifetime may also result in liver tumors or endocrine disruption.

Preliminary studies also suggest that a recently isolated cyanotoxin may become more concentrated across food chains and may be associated with the formation of progressive neurodegenerative diseases such as Alzheimer’s, Parkinson’s and ALS diseases.

Taranu shows how increase in cyanobacterial biomass is greatest under a combination of warmer water temperatures, increased intensity of thermal stratification, and elevated nutrient concentrations.

Picture
Zofia Taranu

How Floridians respond to government subsidies to Big Sugar will determine the race for the governor’s mansion in Tallahassee.

This morning Chad Gillis at the Fort Myers News-Press wrote about four main options to address Florida’s algae’s crisis.

  1. Caloosahatchee Reservoir

  2. Everglades Agriculture Area Reservoir
  3. Lake Okeechobee Regulation Schedule

  4. Deep Well Injection

But there is a fifth option: Small Scale Algae Biomass Conversion at Runoff Point Source.

Two years ago, IPWatch Dog considered the potential of algae biofuel from agricultural runoff, Toxic algal blooms of today could become the biofuels, fertilizers and antibiotics of tomorrow:

[In March 2016], researchers from Western Michigan University (WMU) made a presentation at that year’s national meeting of the American Chemical Society (ACS) on how algae could be transformed into biofuels and fertilizer. The WMU system was optimized for use near small farms, sources of much of the agricultural runoff which contribute to algal blooms in bodies of water. A 3D printed substrate developed by the research team grows algae in a controlled environment. The algae, which can be produced at a rate of two to eight times faster than ethanol feedstocks, can be collected for conversion into biofuels or fertilizer.

Additional study into the potential use of cyanobacteria algae as a feedstock for biofuel was being conducted as part of lake pollution research taking place at the University of Buffalo. In 2013, an environmental engineering team had constructed a vacuum system incorporating two 40-foot flumes to pump algae-laden water out of Lake Erie. Although the project was largely focused on water quality remediation, the team was also constructing a database of the physical properties of blue-green algae which could be used to determine the commercial properties of cyanobacteria.

Not far down the New York State Thruway, the Rochester Institute of Technology (RIT) recently engaged in a three-month pilot project focused on growing microalgae in controlled conditions as a renewable energy feedstock. Conducted in coordination with local renewable energy firm Synergy Biogas, RIT researchers worked with an anaerobic digester in Covington, NY, capable of treating up to 52,000 gallons of wastewater each day. The team is looking to see how effective the microalgae is at converting digested biomass from agricultural runoff. Lab results show that the technology was capable of reducing phosphorus pollution from runoff by 90 percent, down to 0.1 parts per million. The algae grown by the team planned to convert microalgae into ethanol and biodiesel feedstock by isolating the lipids. Further conversion techniques using the anaerobic digester would further extract lipids and carbohydrates for fertilizer.

Algae production could provide environmental benefits beyond scrubbing agricultural runoff of excess phosphorus and nitrogen. In late January, the ACS journal Industrial & Engineering Chemistry Research published a paper resulting from a joint research project between a pair of Mexican universities. The paper suggests the use of algae production to reduce carbon dioxide (CO2) emissions in flue gas from industrial facilities. The system, developed by researchers from both the Universidad Autónoma de Sinaloa and the Universidad Michoacana de San Nicolás de Hidalgo, is primarily focused at reducing CO2 emissions. The system also had the effect of reducing the costs of growing algae for biofuel feedstocks by 90 percent, although researchers still felt that an algae-based biorefinery was still economically unfeasible at that time.

Some of the economic challenges in developing biofuels from algal blooms are outlined within a 2011 paper sponsored by the National Institutes of Health (NIH). At that time, algae-based biofuel production costs using conventional technologies were anywhere from $300 USD to $2,600 USD per barrel, much higher than the production costs of petroleum, which have since dropped dramatically in recent years. The economic disincentive associated with algae exploration when compared to petroleum is very real, but not the only challenge. Challenges preventing increased biofuel production from algae resources include the need to find more efficient algae harvesting techniques, more cost-effective oil extraction and effective use of land and water. Conquering these challenges should reduce the cost per barrel, but much research is still to be done.

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