Using Flue Gas and Wastewater to Make Algae

by Lisa Sheppard

A three-year, $2.5 million Illinois Sustainable Technology Center (ISTC) engineering-scale project will be one of the first and largest to combine carbon dioxide from a coal-fired power plant with nutrients from wastewater treatment plants to cultivate algae for animal feeds. The project will demonstrate that producing algae for commodity animal products can be cost-effective and has added environmental benefits.

Algae is an attractive alternative for use in taking up CO₂ from power plants because it requires less land, according to ISTC principal investigator Lance Schideman. Researchers will use Spirulina because it is already FDA approved for use as a food ingredient and has a high protein content, which commands higher prices.

The algae cultivation system will be integrated with the City Water, Light and Power plant in Springfield, Illinois. Dr. Schideman is collaborating with University of Illinois researchers Joshua McCann and Carl Parsons, who will conduct the animal feed studies. Global Algae Innovations will provide the algae biomass production system. The project is co-funded by the U.S. Department of Energy National Energy Technology Laboratory.

In the past, ISTC scientists have researched wastewater algae systems that are now used at 10 wastewater treatment plants. The scientists have also been leaders in recycling the byproducts of hydrothermal biofuel production to enhance algal biomass productivity. Global Algae Innovations is a leading designer and equipment supplier in the algae industry that has developed and demonstrated cost-effective, large-scale algae production systems.

Putting all the pieces together

“We’re putting all the pieces together in a coordinated fashion and lowering the net costs of growing algae using industrial and municipal by-products as inputs to improve the economic environmental sustainability of algal carbon capture,” Dr. Schideman said.
This approach reduces pollution and replaces the costly CO₂ and nutrient inputs used in most algae cultivation systems. In the current commercial technology, managers buy liquid CO₂ and various commercial fertilizers for the nutrient supply.

“Using wastewater is a cost savings in the production process and it helps to solve problems that wastewater treatment plants are experiencing in trying to minimize nutrient discharges into the environment,” Dr. Schideman said. “In Illinois, the treatment plants are under increasing scrutiny, and regulations that are now voluntary are expected to become more stringent and potentially mandatory within the next decade.”

Ultimately, the system will produce feed especially for cattle and chickens. The product will be dry, which helps reduce spoilage, and will have a high nutritional value compared with some other feeds.

The typical price range for most bulk animal feed ingredients is $150–350 per ton, and certain high-value products can have a market value of $1,000–$2,000 per ton. Algae has the potential to command prices near the top of the range since some species contain highly nutritional components such as antioxidants and poly-unsaturated fatty acids. However, algal animal feeds are not yet established in the market, and the value of these products must be demonstrated through research studies like this one.