Guidelines for the Unconventional Water Recovery and Reuse in the Steel Industry

Background and Strategic Significance of GB/T 47106-2026 Standard Development

As China's steel industry accelerates its transformation towards green and low-carbon development, the efficient and sustainable utilization of water resources, as a fundamental strategic resource and a key production factor, has become a core issue for the industry's high-quality development. Traditionally, steel companies have been highly dependent on conventional freshwater, but against the backdrop of water scarcity and increasingly stringent ecological constraints, expanding water supply channels and improving water use efficiency are urgent tasks. The release of GB/T 47106-2026, "Guidelines for the Recycling and Utilization of Unconventional Water Resources in the Steel Industry," is an important standardization achievement in response to the national water management approach of "prioritizing water conservation, spatial balance, systematic governance, and dual-pronged approach," as well as the policy requirements of the "Industrial Water Efficiency Improvement Action Plan."

This standard, for the first time, systematically provides a comprehensive technical and management framework for the steel industry to utilize unconventional water resources such as seawater, rainwater, reclaimed water, mine water, and highly mineralized saline water. This marks a shift in my country's steel industry water resource management from a "demand-driven supply" model to a "diversified, complementary, and circular" model. The standard begins by clearly defining key terms, laying the foundation for a unified understanding of subsequent technical content. The definition clarifies the scope of resources, specifically stating that reclaimed water does not include wastewater reclaimed from the company's own wastewater treatment, emphasizing the development of external water resources. High-mineralized saline water is listed separately, reflecting attention to special water qualities such as brackish water. Reclaimed WaterWastewater that meets specific water quality requirements after treatment.The definition focuses on "availability," providing a conceptual basis for the graded utilization of reclaimed water of different qualities (such as miscellaneous water, industrial makeup water, and demineralized raw water). Mine WaterUnderground water, seepage water, and production wastewater collected during mine construction and mining.It covers the utilization of wastewater from related industries such as coal and metal mining, promoting cross-industry resource synergy. Specific radioactivity limits (total α < 0.5 Bq/L, total β < 1 Bq/L) are set for radioactive mine water. Initial Contaminated RainwaterRainfall within the first 15-30 minutes or with a thickness of 20-30 mm during the initial rainfall. This quantifies the key points for pollution control, guiding enterprises to set up initial rainwater diversion or dedicated treatment facilities, which is a prerequisite for achieving "clean use" of rainwater.

This document applies to all steel enterprises, regardless of whether they are located in coastal, inland, or water-rich/sparsely populated areas. All enterprises must consider incorporating unconventional water resources into their overall water system planning. The standard provides a set of "guidelines" rather than mandatory requirements, giving enterprises the flexibility to choose and adapt according to their own conditions (such as water source availability and techno-economic feasibility).

---

Four Basic Principles: Constructing the Top-Level Logic of Recycling

The three basic principles proposed in Chapter 4 of the standard constitute the decision-making framework for unconventional water resource utilization:

1. Compliance Priority Principle: All recycling activities must first comply with national and local laws, regulations, policies, and mandatory standards. This is the bottom line for the legal and compliant operation of the project.
2. Systematization and Efficiency Principle: Emphasizing "scientific allocation, economic efficiency, low carbon and environmental protection," and requiring that unconventional water resource systems be incorporated into the unified planning of the enterprise's water supply and drainage system. This means that treatment facilities cannot be built in isolation, but must be considered from the perspective of optimizing the entire plant's water network, taking into account the coupling and synergy with raw water, circulating water, wastewater treatment, and other systems.
3. Monitoring and Data-Driven Principle: Requires the installation of water quality and quantity monitoring devices to achieve source monitoring.
Understanding water supply capacity and water quality fluctuation patterns provides data support for stable process operation, precise chemical dosing, and risk early warning, forming the foundation for smart water management.

4. ---

   Five Major Technical Content Systems: A Complete Guide from Source to Reuse

   5.1 General Provisions: General Technical Requirements and Design Criteria

   This chapter is the general outline of the technical content, proposing universally applicable requirements:

   • Water Quality Entry Threshold: Clear requirements are set for the quality of raw water from different sources. For example, the quality of raw water for reverse osmosis seawater desalination should not be lower than Class III of GB 3097, and for multi-effect distillation, it should not be lower than Class IV; the total dissolved solids of reclaimed water, mine water, and brackish water should preferably not exceed 3000 mg/L. This provides a basis for enterprises to assess the feasibility of water sources and the difficulty of pretreatment.
   **Product Water Quality Benchmarking:** Strictly adhere to existing specific water quality standards (such as GB 50721, GB/T 50050, GB/T 18920) based on intended use (fresh water for production, demineralized water, circulating cooling makeup water, and miscellaneous water) to ensure safe reuse. **Process Selection and Evaluation Standardization:** Require that process technology selection be evaluated according to GB/T 32327 and GB/T 41017, and encourage comprehensive benefit evaluation based on GB/T 42247 and carbon footprint quantification based on GB/T 24067. This promotes a shift in water resource project decision-making from purely technical and economic comparisons to comprehensive evaluations encompassing environmental, low-carbon, and social benefits. **System Integration and Flexible Design:** **Facility Synergy:** Encourage prioritizing the use of existing water treatment facilities and adjusting them according to the characteristics of the raw water. Water Quality Consolidation and Differentiation: Water with similar quality is consolidated for treatment, while significantly different quality is pre-treated separately, balancing treatment efficiency and effectiveness. System Connectivity and Flexibility: Connecting pipes are required between different water sources and product water systems. Crossing and backflow measures are implemented between facilities, and an independent water distribution network is provided (especially for directly reused reclaimed water), greatly enhancing the plant's water system's **regulation flexibility and resistance to fluctuations**. Regulation Capacity Guarantee: The equalization tank must have at least two compartments and be mutually redundant with the comprehensive wastewater equalization tank, with an effective volume not less than 8 hours of design water volume, providing a crucial buffer against fluctuations in water quality and quantity.
   • Key Energy Efficiency Indicators: Lower limits were set for the water recovery rate of reverse osmosis seawater desalination units (≥45%), the water production ratio of multi-effect distillation (≥10), and the water recovery rate of other unconventional water deep treatment reverse osmosis systems (≥70%), directly driving technological progress and operational optimization, and reducing energy consumption per unit of produced water and concentrate discharge.

   ---

   5.2 Seawater Desalination: Adapting to Local Conditions and Energy Synergy

   For coastal steel enterprises, the standard provides two mainstream technical routes:

   High pretreatment requirements (resistance to fouling and scaling) necessitate strict membrane system design specifications. Water recovery rate is a core performance indicator. Multi-Effect Distillation (MED) Seawater Desalination GB/T 33463.1, GB/T 33542, GB/T 39222 Suitable for enterprises with suitable and stable waste heat steam resources at appropriate pressure and temperature, it is a model for achieving "heat-water" co-production. The product water quality can usually directly meet demineralized water standards. Integrated planning with the seawater cooling system of a self-owned power plant enables efficient utilization of both heat and cold sources. The "water production ratio" is a key indicator of its thermal energy utilization efficiency.

   Technical Route	Core Standard Basis	Applicable Conditions and Product Water Destination	Key Process Requirements
   Reverse Osmosis (RO) Seawater Desalination	GB/T 31327, GB/T 50619, HY/T 074	Highly versatile, especially suitable for enterprises with stable power supply or waste heat power generation. Primary RO permeate conforms to GB/T 43230 and can be used as fresh water for production or as feed water for secondary RO to produce demineralized water.

   The standard specifically points out that seawater desalination plants should be planned and constructed in a unified manner with the seawater cooling system of self-owned power plants. This reflects the design concept of reducing water intake and drainage costs and minimizing the impact of temperature discharge through system integration.

   ---

   5.3 Rainwater Harvesting and Utilization: Sponge City Plants and Smart Control

   For most inland steel enterprises, rainwater is an important supplementary water source. The standard requires:

   • Pollution Prevention First: Initial polluted rainwater must be collected and treated in designated areas, complying with GB 50721, to control non-point source pollution at its source.
   • Promotion Based on Local Conditions: Rainwater harvesting and utilization should be carried out in areas with an average annual rainfall of more than 400 mm. The use of sponge city technologies such as "infiltration, retention, storage, purification, utilization, and drainage" in plant construction is encouraged.
     Flexible Facility Configuration: Storage facilities should combine decentralized and centralized approaches, making full use of infiltration facilities and pipeline volume. Rainwater collection tanks can be installed at key nodes or ends of the rainwater pipe network, and the construction of rainwater storage projects with intelligent control systems is encouraged, even integrated with rainwater ecological parks. Differentiated Reuse Pathways: Collected rainwater can be transported to fresh water production systems, integrated wastewater treatment systems, or dedicated unconventional water treatment systems, depending on water quality. It can also be reused locally in circulating water systems with sedimentation and filtration facilities or for miscellaneous water uses. This diversified reuse path design reduces the cost and complexity of rainwater treatment.

   Application Case Study: A steel company in North China constructs sunken green spaces and infiltration ditches around the raw material yard and ironmaking area to intercept and purify initial rainwater; large rainwater storage tanks are built in low-lying areas of the plant and at the end of the main rainwater pipe network, equipped with online water quality monitoring and automatic control systems. During non-rainfall periods, the stored rainwater is pumped to a comprehensive wastewater treatment plant, where it undergoes coagulation-sedimentation-filtration-disinfection before being used to replenish the blast furnace circulating cooling water system, replacing approximately 10% of the conventional freshwater replenishment annually.

   ---

   5.4 Reclaimed Water Recycling and Utilization: Risk Management and Graded Utilization

   Using reclaimed water from urban wastewater treatment plants is an important way to solve the water shortage problem for steel companies, but safety risks must be given high priority.

   **Full-Process Risk Assessment:** The standard proactively proposes conducting health and ecological risk assessments throughout the entire process of reclaimed water recycling. This requires companies to not only focus on conventional water quality indicators but also on the potential risks of emerging pollutants such as persistent organic pollutants and endocrine disruptors, and to implement advanced removal and control measures. **Graded Utilization Guidance:** The standard requires compliance with the reclaimed water grading regulations of GB/T 41018, promoting "water use based on quality." Reclaimed water with better quality can be used as circulating cooling makeup water or miscellaneous water after simple pretreatment; companies with the necessary resources should further treat it (e.g., using an ultrafiltration-reverse osmosis dual-membrane method) to produce demineralized water for high-value reuse. **Priority Use and Differentiated Treatment:** The standard encourages water-scarce areas to prioritize the use of reclaimed water and recommends treating and reusing domestic sewage separately to avoid mixing with industrial wastewater and increasing treatment difficulty.

   ---

   5.5 Mine Water and Brine Recycling: Resource Utilization and Advanced Treatment

   For steel companies located near mining areas or possessing underground brine resources, this part of the standard provides specific guidance.

   • Technical Specification References: This standard references a series of mine water treatment standards, including GB/T 31392, GB/T 37758, and GB/T 37764, providing a complete technical toolbox for companies treating mine water with high mineralization, acidity, and other special water qualities.
   • Treatment Stages: After pretreatment, mine water can be used for production of fresh water, circulating cooling water, etc., depending on its quality. The standard specifically emphasizes that for mine water and brine, **further advanced treatment to produce demineralized water is recommended.** This is because their high salinity makes them more suitable for producing high-quality water through desalination processes such as reverse osmosis, while simple softening as makeup water may pose a scaling risk.

   ---

   Water Management and Safety & Environmental Protection: The Two Wings Ensuring Stable System Operation

   6. Water Management: Towards Smart Water Management

   The standard advocates the construction of a plant-wide water management platform. This is not only a regulatory requirement but also an inherent need for enterprises to improve water efficiency and reduce operating costs. The platform should have:

   • Centralized Monitoring and Visualization: Real-time monitoring of the operating status of the entire plant's water network, pumping stations, and treatment facilities.
   • Intelligent Analysis and Early Warning: Water efficiency analysis, raw water quality trend analysis, and the implementation of abnormal alarms and optimized water volume control.
   • System Integration: It can be expanded on the existing water supply and drainage management system, avoiding redundant investment.
     7. Safety and Environmental Protection Requirements: Strictly Adhering to Red Lines and Bottom Lines This section places unconventional water resource utilization under a more stringent environmental safety framework: Discharge Compliance: All wastewater, waste gas, waste residue, noise, etc., generated during unconventional water treatment processes must comply with national standards (such as GB 8978, GB 13456) and stricter local standards. Special Discharge Control: For concentrated brine from seawater desalination and cooling seawater discharge, the specific requirements of GB 18486 and HY/T 0187.2 must be met respectively to prevent impact on marine ecosystems. Sludge "Four-fold" Treatment: Sludge disposal must adhere to the principles of reduction, stabilization, harmlessness, and resource utilization, meeting clean production requirements. Monitoring Compliance: Self-monitoring must comply with technical guidelines such as HJ 878 and HJ 1083 to ensure data accuracy and validity. Standard Implementation Recommendations and Future Outlook Implementation Recommendations for Steel Enterprises: Water Resource Audits and Planning: First, conduct a detailed survey and assessment of the enterprise's current water usage and surrounding unconventional water resources. Based on this, formulate a medium- to long-term water resource substitution and optimization plan. Prioritize "Short-Term, Quick-Return" Projects: Such as rainwater harvesting for landscaping and toilet flushing, or upgrading existing wastewater treatment plants to reuse compliant effluent in the circulating cooling system. Prudent Decision-Making for Large Investment Projects: For large-scale investment projects such as seawater desalination and deep mine water treatment, a comprehensive technical, economic, environmental, and carbon footprint assessment must be conducted in strict accordance with the requirements of Standard 5.1.4. **Strengthening System Integration and Intelligent Management:** New or renovated projects must integrate the concepts of "system connectivity and flexible design" into their engineering design, and simultaneously plan, construct, or upgrade water management platforms. **Emphasis on Talent Cultivation and Standard Promotion:** Organize technical personnel to study this standard and the dozens of related standards referenced, cultivating a group of compound talents who understand both steelmaking processes and are proficient in water treatment technology. **Technical Evolution Trends of the Standard:** As a guiding standard, GB/T 47106-2026 may evolve into more refined sub-standards in the future, such as separately developing "Operation and Maintenance Specifications for Seawater Desalination in Steel Enterprises" and "Design Specifications for Rainwater Resource Utilization in Steel Enterprises." Meanwhile, with the deep integration of digital and intelligent technologies with water treatment technologies, future revisions to the standard may include content on smart water plant construction, such as digital twins, AI-optimized chemical dosing, and predictive maintenance. Furthermore, the requirements for "low carbon" and "zero liquid discharge" will become increasingly prominent, driving the standardization of advanced treatment technologies such as evaporation crystallization and salt resource recovery. In conclusion, the release and implementation of GB/T 47106-2026 provides a scientific "roadmap" and "blueprint" for the steel industry to overcome water resource constraints and build a modern water management system that coexists harmoniously with nature. Its full implementation will not only significantly improve the resource utilization efficiency and environmental performance of the steel industry but will also set a benchmark for the green transformation of my country's industrial sector.