1引言水是自然环境的重要组成部分,更是人类生产和生活不可缺少的自然资源,与土地、能源构成人类经济与社会发展的基本条件。近年来,我国经济发展迅速,城市化进程也不断加快,但与此同时,每年因供水不足而造成的工业产值损失达上千亿元。水资源问题已成为我国经济、社会进一步发展的主要障碍和制约因素。为了解决水资源紧张的问题,水的再生与回用,将中水开发为第二水源已越来越受到人们的重视。“中水”的定义有多种解释,在污水治理工程方面称为“再生水”。工厂方面称为“回用水”,一般以水质作为区分的标志。 1 Introduction Water is an important part of the natural environment, it is an indispensable natural resource for human production and life, and the basic conditions for human economic and social development with land and energy. In recent years, the economy of our country has been developing rapidly and the process of urbanization has also been accelerating. However, at the same time, the annual loss of industrial output caused by insufficient water supply has reached over 100 billion yuan. The issue of water resources has become a major obstacle and a constraint for further economic and social development in our country. In order to solve the problem of water shortage, water recycling and reuse, the development of water as the second source of water has been more and more people’s attention. There are various definitions of “Zhongshui” and are referred to as “reclaimed water” in terms of wastewater treatment works. Known as the factory “back to water”, the general water quality as a sign of distinction.