Abstract: In order to meet the increasingly strict environmental requirements，fossil-fired power plants are carrying out
large-scale wastewater treatments. According to the statistics including water intake quantity for unit power generation，
water discharge per unit power generation，total wastewater discharge and water discharge rate of four power plants which
are once-through cooling units in coastal and riverside areas，the water usage and discharge conditions of chemical
demineralised water systems，desulfurization systems，ash-slag disposal systems in power plants are analyzed. The common
problems existing in the main systems need water supply of once-through cooling power plants in coastal and riverside areas
were summarized，and a water pollution control technology was put forward combined with the actual situation of the power
plants. Firstly，the water flow should be optimized by adjusting the water-demand systems. Secondly，water-saving
technology is taken to reduce the amount of wastewater production. Thirdly，wastewater is reused after treatment to reduce
the terminal amount. Finally，the terminal wastewater is concentrated or solidification. After the optimization on the fossilfired power plant with once-through cooling system，the water intake quantity for unit power generation could be reduced to
0.160-0.240 m3（/ MW·h）

Key words: fossil-fired power plant with once-through cooling system, water usage and discharge, water saving, quantity