Okeechobee: From Blooms to Biocrude
by Mary Ann Showalter (Pacific Northwest National Laboratory) PNNL’s hydrothermal liquefaction shows promise for turning harmful algal blooms into biocrude — … Algal blooms can also raise treatment costs for drinking water suppliers, according to the U.S. Environmental Protection Agency.
The U.S. Army Corps of Engineers Research and Development Center (ERDC) is leading a three-year project intended to mitigate growth of harmful algae blooms that can span hundreds of square miles.
And Pacific Northwest National Laboratory (PNNL) has helped the ERDC take their research one step further—by investigating these blooms as a viable source of biocrude fuel and fertilizer.
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The project is called Harmful Algal Bloom Interception, Treatment and Transformation System, or HABITATS. The goal is to remove blue-green algae from large bodies of water while simultaneously recovering energy and nutrients like nitrogen and phosphorus—an approach that mitigates near-term impacts from harmful algal blooms and helps reduce future blooms over time.
To achieve this goal, the HABITATS team has deployed a three-stage process: interception, treatment, and transformation.
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In the pilot, the research team discovered that the DAF consistently removed around 95 percent of the algae from the water and greatly concentrated the algae, reducing phosphorus, nitrogen, and organic carbon concentrations by greater than 95, 65, and 50 percent, respectively. In other words, with removal of the algae and associated nutrients such as phosphorus, the water was much cleaner when returned to the lake.
The resulting algae paste was then transported to PNNL for processing using HTL to determine if biocrude could be produced.
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PNNL will apply its expertise in catalytic upgrading to make diesel-range renewable fuel blendstocks from the HTL biocrude. READ MORE
