A brief history of water treatment technology - Zero discharge

In 2009, the first phase of Heyuan Power Plant was completed and put into operation. It also became the first power plant in China to achieve zero waste water discharge. The zero discharge system adopts the process of double alkali softening and full water evaporation.

In 2011, the national 12th Five-Year Plan for environmental Protection further proposed to study policies and measures to encourage enterprises to zero waste water discharge.

In July 2012, a group incident occurred in Nantong, Jiangsu Province to boycott the wastewater discharge project of Prince Paper industry. In 2014, the world's third largest and Asia's first papermaking enterprise built China's first papermaking wastewater zero discharge project. This is also the earliest zero-emission project in China to adopt the electrodialysis secondary concentration process.

In 2015, Huaneng Changxing Power Plant also built the country's first zero-emission system using positive osmosis technology. However, due to the complexity of the regeneration process and the low flux of the positive permeation membrane, the positive permeation technology has not been applied in the zero-emission project on a large scale. In the same year, the state officially issued the "Water Ten" to comprehensively strengthen the prevention and control of water pollution. At the end of 2015, the Ministry of Environmental Protection issued the "Environmental Access Conditions for Modern Coal Chemical Construction Projects (Trial)". The document clearly requires that modern coal chemical construction projects should take effective disposal measures for high-salt wastewater in areas lacking sewage bodies, shall not pollute groundwater, atmosphere, and soil, and the salt mud generated by wastewater treatment that cannot be reused as a resource shall be temporarily managed as hazardous waste. This not only clearly puts forward the requirement of zero discharge of wastewater for new coal chemical enterprises, but also guides the development of zero discharge process gradually to the direction of salt crystallization.