In which year and month did the six-water therapy begin?

Six kinds of sewage treatment refers to the unified treatment of six kinds of sewage in the city to promote the resource utilization and environmental protection of urban sewage. The sixth water control project has no definite start time, but it is carried out in different cities in stages. Take Beijing as an example. The "six waters" in Beijing include domestic sewage, commercial sewage, medical sewage, catering sewage, industrial sewage and rainwater. In 2007, the Beijing municipal government began to implement the urban black and odorous water treatment project, including the six-water treatment. Since then, Beijing has successively carried out a number of related projects, including the construction of sewage treatment plants, the transformation of pipe networks, and the promotion of decentralized sewage treatment. , promote the six waters together.