N.E.D. (Nutrient Extraction Device)

Winter 2007

Submitted for Metropolis Magazine’s Next Generation Competition

Team: Me, Kelly Murphy

The Nutrient Extraction Device (NED) is a speculative project intended to address non-point nutrient pollution in freshwater lakes, rivers, and streams. It is designed to be portable, easily produced, adaptable, and affordable.

Current physical systems for handling water pollution, like waste water treatment plants and constructed wetlands, deal with water at one monumental station within the system – cleaning water as it exits or enters or circulates through the system at that point. These cleansing methods work well for point source pollutants (PS) such as those coming from factories, power plants, and municipal sewer systems, which evacuate wastes at a known point. However, these systems are poor at combating non-point sources of pollution (NPS) – pollution that comes from a wide variety of sources and may enter the water system at almost any point. Non-point source pollution is primarily the result of urban and agricultural storm water runoff which may carry a host of pollutants such as Nitrogen and Phosphorous based fertilizers, pesticides, and heavy metals. Existing approaches to preventing NPS pollution utilize land management strategies. Federal programs currently address NPS pollution from regulatory, policy, non-regulatory management, incentive and educational program positions. While such programs are necessary, they are far from universal. They are only effective over an extended period of time, they require large amounts of political will, and often, they impose reforms within a single political boundary while a water system may stretch between multiple municipalities, states, and even between nations.

NEDs are an attempt at providing a small, cheap, and effective solution to the most common and destructive form of NPS pollution — nutrient pollution. Nutrient pollution is the result of an overabundance of dissolved nitrogen and phosphorous in water bodies. Though Nitrogen and Phosphorous are naturally occurring elements, an over abundance of either leads to the uncontrolled growth of certain organisms. These organisms, in turn, use up available oxygen and destroy other forms of life — a process called eutrophication. Essentially, NEDs mimic a natural wetland’s nutrient uptake process on a small but mechanically and biologically enhanced scale. A NED uses a river or stream’s natural current to pull water through a series of biological capsules. Light and heat are provided for these capsules by a small turbine that also harnesses power from the river’s current. Because the NED is small, inexpensive, and able to be mass produced many individual units can be strategically deployed in order to address NPS in a dispersed manner. Their passive design allows them to operate over long periods with no energy inputs, and with only periodic maintenance. Because NEDs are able to reside in-stream, essentially within a public right-of-way, they involve minimal political complexity, and no public or private land commitments.