Based on a report released in September, the U.S. Geological Survey is now planning to scale-up research on a technique that uses sludge from acid mine drainage to remove nutrients from agricultural and municipal wastewater in the Chesapeake Bay. Current phosphorus removal techniques, which typically rely on aluminum or iron salts, are expensive. However, acid mine drainage is treated by adding basic compounds, such as lime, and results in an iron-rich sludge. Rather than disposing of this sludge, it could be used for nutrient removal.