US-ENVIRONMENT-CLIMATE-ENERGY-COP21-ELECTRICITY

TO GO WITH AFP STORY BY KATHARYN GILLAM "US-ENVIRONMENT-CLIMATE-ENERGY-COP21-ELECTRICITY" A huge tank full of wastewater is seen at DC Water's Blue Plains plant in Washington, DC, on November 23, 2015. The plant treats 370 million gallons (1,400 million liters) of dirty water from more than two million households on a daily basis, purging it with the micro-organisms that first ingest carbon and then transform nitrates into nitrogen gas, making the water is clean enough to flow into the Potomac River or the Chesapeake Bay without disrupting their fragile ecosystems. As for the feces, they're either recycled as compost or, in a new step implemented six months ago, are used to produce 10 megawatts of electricity -- that's the amount of power used by some 8,000 households. The solid matter that slips to the bottom of the treatment pools is collected and subjected to a Norwegian hydrolysis technique that is being used in North America for the first time. AFP PHOTO/NICHOLAS KAMM / AFP / NICHOLAS KAMM (Photo credit should read NICHOLAS KAMM/AFP via Getty Images)