Standards Development

Scope

This standard provides technical guidance on the reuse of reclaimed water in thermal power plants. It covers key control parameters for the application of reclaimed water in different water systems of thermal power plants, specifies typical units and operational considerations for various advanced treatment systems, and proposes corresponding process flows for utilizing different grades of reclaimed water in various water systems of power plants.

This standard is applicable to thermal power plants, including coal-fired power plants, oil-fired power plants, gas-fired power plants, biomass power plants, waste incineration power plants.

This standard aims to: 

a)Provide a decision-making basis for policymakers involved in the reuse of reclaimed water in thermal power plants.

b)Offer technical references for project developers and operators of reclaimed water reuse projects requiring advanced treatment in thermal power plants. 

c)Establish normative technical guidelines for reclaimed water reuse in thermal power plants, promoting the adoption and advancement of advanced treatment technologies for reclaimed water.

Purpose

Approximately 50% of global industrial water withdrawal is attributed to power generation . From a global perspective, predictions indicate that thermal power generation will remain dominant until 2040 . Against the escalating water scarcity in certain countries, water conservation and efficient utilization in thermal power plants have become increasingly critical.

"Reclaimed water" refers to treated water recovered from domestic sewage, industrial wastewater, rainwater, and other sources, which is treated for reuse. The reuse of reclaimed water serves dual purposes: it creates a secondary water source for urban supply, significantly reducing the consumption of "tap water" (potable water), while partially mitigating pollution of water sources caused by "sewage" (wastewater), thereby protecting water resources and reducing water withdrawal. Many countries and regions, including China, Australia, the United States, the European Union, have enacted laws, regulations, guidelines, and standards mandating the agricultural, industrial, and other applications of reclaimed water. These policies require the use of reclaimed water for landscaping, irrigation, auxiliary equipment cooling, and similar purposes. Driven by mandatory policies, declining availability of freshwater , and the enhanced accessibility of reclaimed water are driving the adoption of reclaimed water in thermal power plants as a trend. Currently, the majority of reclaimed water in thermal power plants is allocated to recirculating cooling water, with other primary applications encompassing boiler makeup water , ash handling water, landscaping irrigation, and auxiliary equipment cooling.

 Compared to freshwater, reclaimed water is characterized by higher salinity, higher organic matter, and higher microbial content, requiring advanced treatment when reused in thermal power plants. Different water requirements in various systems of thermal power plants impose varying quality standards on the water supply. For recirculating cooling water, critical parameters include organic compounds, microbial contamination, and hardness. These contaminants become concentrated during cooling cycles, substantially exacerbating corrosion, scaling, and microbial proliferation . Boiler makeup water demands stricter controls on ionic constituents, silica, and total organic carbon (TOC). Auxiliary cooling water prioritize water diversity and relatively lower quality standards, with treatment focusing primarily on suspended solids and microbial control rather than advanced desalination. Consequently, establishing standardized water quality parameters for reclaimed water utilized in thermal power plants and implementing proper advanced treatment to eliminate pollutants has become essential, as this effectively addresses challenges including corrosion, scaling, and microbial growth. Accordingly, this standard establishes key control parameters for the reuse of reclaimed water in water systems of thermal power plants, outlines typical process units and operational considerations for advanced treatment systems, and proposes corresponding process flows for applying different grades of reclaimed water to specific water system within plants.

The formulation of the Guidelines for Advanced Treatment of Reclaimed Water for Reuse in Thermal Power Plants can provide systematic technical support for reclaimed water recycling in the thermal power industry. By defining requirements and compatible processes for reclaimed water reuse in systems such as recirculating cooling water and boiler makeup water under varying water quality grades, and by standardizing the selection and operational criteria of advanced treatment technologies, this approach effectively mitigates risks including corrosion, scaling, and microbial proliferation caused by water quality fluctuations. It ensures safe and stable power generation, promotes standardized development of water-saving technologies in the industry, and advances the innovation of near-zero liquid discharge technologies for wastewater in thermal power industry.