Algal turf scrubbers clean water with sunlight

An article published in the June issue of BioScience describes the early scale-up stage of a new biotechnology with environmental benefits and possible commercial potential. Algal turf scrubbers are field-sized, water-treatment systems that can extract excess nutrients from streams, canals, and lakes polluted by agricultural, domestic, and some industrial runoff.

They use sunlight as their principal source of energy and simultaneously restore oxygen levels. The devices work by pulsing contaminated water across algae that are allowed to grow on screens. Algal turf scrubbers produce waste suitable for use as a nitrogen- and phosphorus-rich fertilizer and for conversion to biofuel or high-value nutraceuticals. Some algal turf scrubbers can even operate in open water, thus minimizing loss of agricultural land to the systems.

The BioScience article, by Walter H. Adey of the Smithsonian Institution, Patrick C. Kangas of the University of Maryland, and Walter Mulbry of the US Department of Agriculture, notes that the need to clean wastewater and various types of runoff contaminated with nitrogen and phosphorus is immediate in many places where natural waters are polluted. Furthermore, some ecologists are worried about global supplies of phosphorus for use in fertilizer, so the byproduct could become more valuable over time.

The article stresses that algal turf scrubbing is not likely to ever be profitable just as a way of making fuel. Although more productive than terrestrial crops, algae, like other potential sources of biofuel, are expensive to cultivate, harvest, process, and convert into useful amounts of energy. But algal turf scrubbing could become common if the economic value of nutrient removal can be applied to the cost of building and running the units. That might depend on public policy that imposes a predictable cost on pollution of natural waters. But the fuel, fertilizer, and nutraceutical byproducts from algal turf scrubbing can only help.

After noon EDT on 1 June and for the remainder of the month, the full text of the article will be available for free download through the copy of this Press Release available at www.aibs.org/bioscience-press-releases/.

BioScience, published monthly, is the journal of the American Institute of Biological Sciences (AIBS). BioScience publishes commentary and peer-reviewed articles covering a wide range of biological fields, with a focus on “Organisms from Molecules to the Environment.” The journal has been published since 1964. AIBS is an umbrella organization for professional scientific societies and organizations that are involved with biology. It represents some 200 member societies and organizations with a combined membership of about 250,000.

The complete list of peer-reviewed articles in the June 2011 issue of BioScience is as follows:

Algal Turf Scrubbing: Cleaning Surface Waters with Solar Energy while Producing a Biofuel.

Walter H. Adey, Patrick C. Kangas, and Walter Mulbry

Intervention Ecology: Applying Ecological Science in the Twenty-first Century.
Richard J. Hobbs, Lauren M. Hallett, Paul R. Ehrlich, and Harold A. Mooney
Forecasting Environmental Hazards and the Application of Risk Maps to Predator Attacks on Livestock.

Adrian Treves, Kerry A. Martin, Adrian P. Wydeven, and Jane E. Wiedenhoeft

Creating a Successful Citizen Science Model to Detect and Report Invasive Species.

Travis Gallo and Damon Waitt

Training the Next Generation of Renaissance Scientists: The GK-12 Ecologists, Educators, and Schools Program at The University of Montana.

Brooke Baldauf McBride, Carol A. Brewer, Mary Bricker, and Michael Machura

Linking Indigenous and Scientific Knowledge of Climate Change.
Clarence Alexander, Nora Bynum, Elizabeth Johnson, Ursula King, Tero Mustonen, Peter Neofotis, Noel Oettlé, Cynthia Rosenzweig, Chie Sakakibara, Vyacheslav Shadrin, Marta Vicarelli, Jon Waterhouse, and Brian Weeks