Removing Phosphorous from Water

• Research conducted by Rutgers University in 2006 identified three methods of removing phosphorous from water.
  
  Phosphorous can be physically removed from the water by filtration or membrane technology. Filtration is accomplished using a sand filter. The Rutgers report indicates that membrane technology is a new and growing field of phosphorous removal technology. Their report indicates several technologies, including reverse osmosis. Membrane technology is useful for phosphorous levels of up to 0.04 mg per liter of water.
  
  Chemical treatment of water for phosphorous is accomplished by added chemical compounds containing iron, aluminum or calcium. A disadvantage to the chemical treatments for phosphorous is the sludge produced.
  
  Biological assimilation of phosphorous is usually accomplished in ponds. Algae, plankton or other water plants are allowed to grow and utilize the water-borne phosphorous. The plants are then mechanically removed from the water before it is discharged into a lake or river. Biological removal of phosphorous may not be an option in cold climates. Plants will not grow in a frozen pond.
  
  The Rutgers study said all these methods of phosphorous removal have been used by commercial and municipal waste and storm water treatment plants. This effectively combats the problem of phosphorous in water that originates at what are referred to as "point" sources such as a municipal sewer plant.
  
  According to the USGS, another problem is "nonpoint" sources. These sources of phosphorous in water include runoff crossing fertilized farm fields or even suburban lawns. Another nonpoint source of phosphorous in water is livestock manure. Runoff water that passes through a high concentration of manure can pick up phosphorous and carry it into nearby lakes and streams. The USGS indicates further regulation of nonpoint phosphorous sources would be beneficial to water quality.
  
  The USGS also says soil erosion contributes to phosphorous levels in lakes and rivers. Soil washed into the streams often contains phosphorous. The Department of Agriculture's Soil Conservation Service has operated erosion control programs since the 1930s.