城市的污水处理一直是个大难题。美国纽约市环保局另辟蹊径,变废为宝,把污水变成新能源,减少城市的环境污染,减轻了政府的负担。他们把污水里的污泥做成肥料,卖给各大农场; Urban sewage treatment has always been a big problem. New York City Environmental Protection Agency another way, turning waste into treasure, the sewage into a new energy source, reducing the city’s environmental pollution and reduce the burden on the government. They make the sewage sludge into fertilizer, sold to major farms;