|
Sewage treatment plants around the world are beginning to put value on waste, turning it into a marketable resource. Blue Plains Advanced Wastewater Treatment Plant in Washington is the largest facility of its kind in the world and is among the leaders in the effort. On an average day, 1.4 billion liters of raw sewage flow into the plant, delivered from around the city through 2,000 kilometers of underground sewer pipes and pumping stations, an amount that could fill the nearby sports stadium. The waste is loaded with nitrogen and other nutrients. General Manager George Hawkins makes sure the discharge doesn’t pollute the river on which two million people in the region depend for their drinking water. Limited discharge By law, Blue Plains can dump only a small percentage of those nutrients into the Potomac River. “We know that people buy nutrients all the time," Hawkins says. "So the question is how can we take things out of the water that we’re treating here and re-use it for the resource that it is?” A massive $4 billion environmental program is under way at Blue Plains. Among the three projects, two are mandated by the government, including one that will cut in half the amount of nitrogen and other waste nutrients discharged into the Potomac River. The other is an underground tunnel to prevent accidental sewage overflow from its network of ageing pipes. | 
