Standards Development

Scope

This document specifies the guidelines for wastewater treatment and reuse in thermal power plants, including the types and characteristics of wastewater from thermal power plants, and the technologies of wastewater treatment and reuse.

In this document, the drainage systems of thermal power plants are divided into fuel supply system, chemical water treatment system, boiler and auxiliary system, recirculating cooling system, flue gas processing system, gasification scrubber system and ash handling system. Wastewater from these systems is classified according to its system sources. In addition, according to the water requirements of systems in the plant, technical guidelines for wastewater treatment and reuse are provided.

It is applicable to thermal power plants that generate electricity from combustible fuels, including coalfired power plants, oil-fired power plants, gas-fired power plants, biomass-fired power plants, waste incineration power plants and integrated gasification combined cycle (IGCC).

Purpose

Studies have shown that electric power plants account for approximately half the global industrial water withdrawal [1], which means that the problem of water shortage will be aggravated with the expansion of electricity. Although the generation of electricity from renewable sources (wind, hydro and solar PV etc.) with almost zero water consumption is growing, the proportion of world gross electricity generated by combustible fuels still accounts for 66.8% in 2017, and this proportion will remain stable until 2040 [2]. In addition, the wastewater from thermal power plants (power plants that use combustible fuels to generate electricity) is diverse, with high volume and complex pollutant components [3], and its discharge poses a serious threat to the water ecological environment. Therefore, the realization of inplant reuse of wastewater in thermal power plants can not only reduce water withdrawal in plants, but also reduce wastewater discharge, which is of great significance to solve the environmental problems of the global water shortage and serious water pollution.

In addition, the United States [4], China [5], Japan [6], International Energy Agency (IEA) [7] and other countries and organizations have issued relevant policies or regulations to encourage the reuse or even zero emission of wastewater from thermal power plants. And the United States, China, South Korea, Australia and other countries have lots of engineering cases of wastewater reuse in thermal power plants. Therefore, the policy requirements of the government and the wastewater treatment needs of power industry are the market power to promote the standardization of wastewater treatment and reuse in thermal power plants.

At present, the traditional wastewater treatment and reuse in thermal power plants have some problems. Firstly, the wastewater treatment and reuse are not complete. The reuse of cooling tower drainage and other large flow wastewater is involving, but desulfurization wastewater, ash washing wastewater and other tail water are just treated to up-to-standard discharge. Secondly, the wastewater treatment and reuse are too extensive. All wastewater in the plant is treated in a cluster treatment system, ignoring the characteristics of wastewater in different processes, so the wastewater with high quality is wasted. In addition, there is no international standard about in-plant wastewater treatment and reuse for thermal power plants to refer. Therefore, this proposal will make up the gap, and provide more efficient wastewater treatment and reuse process through the analysis of wastewater classification and characteristics of different systems in thermal power plants, so as to realize the maximization of wastewater reuse in thermal power plants.

This proposal is formulated to achieve the following objectives: (1) providing feasible technical guidelines for the treatment and reuse of wastewater in thermal power plants, and optimizing the reuse of wastewater in plants, and normalizing the market. (2) strengthening the awareness of water conservation and environmental protection in industrial enterprises, and promoting green industrial development, and ultimately achieving the sustainable development goals.