[Chinese Mainland] GB 47946—2026 "Discharge Control Standard for Major Water Pollutants (Total Antimony, Total Molybdenum, etc.) in the Danjiangkou Reservoir Area and Upstream (Trial)" took effect on September 1: China's first watershed-based national dis

The Emission Control Standards for Major Water Pollutants (Total Antimony, Total Molybdenum, etc.) in the Danjiangkou Reservoir Area and Upstream (Trial) (GB 47946—2026), jointly issued by the Ministry of Ecology and Environment and the State Administration for Market Regulation, has been implemented for new pollutant discharge entities since 2026 年 9 月 1 日, was released on 2026 年 6 月 11 日, and existing entities will follow suit on 2028 年 1 月 1 日. This is China's first watershed-type emission standard issued in the form of a national standard—covering 3 provinces and 10 cities in Henan, Hubei, and Shaanxi, as well as parts of townships in Chengkou of Chongqing, Wanyuan of Sichuan, and Liangdang of Gansu, with a total watershed area of 9.5 万 square kilometers, and for the first time incorporating non-point source emissions into the scope of national water pollutant emission standard control.

Why a "Cross-Provincial Unified" Standard Is Needed

The Danjiangkou Reservoir is the water source for the Middle Route of the South-to-North Water Diversion Project, tasked with supplying water to cities in the Beijing-Tianjin and North China regions while also accommodating agricultural and ecological water use. The water quality in the reservoir area is generally good and maintains a mesotrophic state year-round, but some conventional pollutants in the watershed cannot consistently meet standards, and total molybdenum and total antimony concentrations are elevated during certain periods; according to estimates, pollutant emissions mainly come from non-point sources.

More challenging is the lack of uniformity in governance scale: major emission sources within the watershed are subject to different standards, control of total molybdenum and total antimony is insufficient, non-point source emissions account for a high proportion but lack targeted requirements, and differences in provincial standards make it difficult to form a coordinated governance effort. The positioning of the Danjiangkou Standard is thus clear—a watershed standard system featuring "upstream-downstream coordination, joint governance across both banks, and a unified approach for the entire region," using a unified yardstick to break through administrative divisions.

Five Main Lines of Point Source Control

• Tightening limits for small-scale urban sewage facilities—individual urban sewage centralized treatment facilities in the watershed with a scale of ≥500 cubic meters/day were previously subject to relatively lenient limits; the standard explicitly requires such facilities to implement the GB 18918 Grade 1A standard starting from 2028 年 1 月 1 日;
• Improving emission requirements for the molybdenum industry and antimony industry—reasonably determining total molybdenum and total antimony emission limits based on economic and technical feasibility, while strengthening control of mining wastewater (mine tunnel inflow), requiring pollutant discharge entities with mining units to collect and treat mine tunnel inflow to meet standard limits;
• Optimizing indirect discharge provisions—for industries with good biodegradability such as alcoholic beverage manufacturing, indirect discharge limits may be negotiated and agreed upon when conditions are met; other industries are subject to control requirements specified separately according to three discharge destinations: discharge into urban, single-industry-type, and comprehensive-type industrial wastewater centralized treatment facilities;
• Characteristic pollutants intercepted at the workshop outlet—pollutants such as formaldehyde, acrylonitrile, benzene, toluene, phenol, and aniline compounds are explicitly required to be monitored at the workshop or production facility wastewater discharge outlet and subject to direct discharge control requirements, reducing emissions at the source and preventing environmental cumulative risks;
• Adding comprehensive toxicity indicators—zebrafish embryo acute toxicity control requirements are proposed for comprehensive-type industrial wastewater centralized treatment facilities, the molybdenum industry, the antimony industry, and other non-ferrous metal industry pollutant discharge entities.

Non-Point Sources Entering the Standard: From "Point Source Only" to "Full Coverage of Point and Non-Point Sources"

This is the most innovative step of the Danjiangkou Standard. The standard comprehensively covers various non-point sources including polluted rainwater, aquaculture, livestock and poultry farming, and rural domestic sewage, and also incorporates new types of non-point sources such as rapid treatment facilities for combined sewer overflow and antimony-containing non-point source wastewater treatment facilities, achieving a dual expansion "from point source only to full coverage of point and non-point sources, and from traditional non-point sources to new types of non-point sources."

For water sector practitioners, this means that non-point source projects that previously existed as "soft requirements for non-point source governance" now have a comparable and assessable constraint framework at the national emission standard level—tracks such as urban initial rainwater storage and rapid treatment, aquaculture tailwater treatment, and rural decentralized sewage treatment will shift from "advocacy-based investment" to "compliance-based investment."

The "Zoned Differentiation + Fallback Limits" Model for Antimony-Containing Non-Point Sources

For the treatment of antimony-containing non-point source wastewater, the standard pioneers a "zoned differentiation + fallback limits" mechanism: granting local authorities flexible space to independently determine emission limits based on factors such as the distance between mining areas and water source areas, and river water volume, combined with total antimony control targets at monitoring sections; where local authorities have not established limits, fallback limits are recommended for implementation.

This mechanism respects regional differences and controls governance costs while safeguarding the bottom line of water quality safety, and has been officially defined as "providing a replicable methodological paradigm for non-point source control in other similar regions across the country." Considering that characteristic pollutants such as total antimony and total molybdenum were previously mostly subject to local self-management, this model is very likely to become a template for subsequent watershed-type standards to follow.

What It Means for Enterprises: Three Practical Recommendations

• First, determine applicability — Confirm whether the pollutant discharge unit is located within the Danjiangkou Reservoir Area and its upstream as defined in Appendix A, and distinguish whether it is a new unit (implemented from 2026 年 9 月 1 日) or an existing unit (implemented from 2028 年 1 月 1 日); existing units that have negotiated agreed indirect discharge limits may implement them earlier starting from 2026 年 9 月 1 日.
• Re-examine pretreatment agreements — Enterprises discharging into centralized treatment facilities in industrial parks need to re-verify indirect discharge control requirements according to the three discharge destinations, especially for pollutants such as formaldehyde, benzene series, and aniline compounds that must meet direct discharge standards at the workshop discharge outlet. Whether the existing pretreatment process capacity has been underestimated needs to be re-examined.
• Pay attention to the possibility of early implementation in five provinces — The standard explicitly states that Henan, Hubei, Shaanxi, Chongqing, Sichuan, and Gansu may, based on local ecological and environmental protection needs and economic and technological conditions, be approved by the provincial people's government for early implementation. It is not advisable to simply work backward on rectification plans based on the 2028 年 deadline.

What It Means for Us: TIANYI TECH's Assessment

TIANYI TECH has long served municipal and industrial park wastewater treatment and reclaimed water reuse clients. We assess that the impact of the "Danjiangkou Standard" extends beyond the reservoir area itself: it takes "watershed" rather than "administrative region" as the boundary unit of the standard, takes "non-point sources" rather than "only point sources" as the control object, and takes "comprehensive toxicity" rather than "only conventional indicators" as the risk scale — these three shifts are likely to become a common paradigm for subsequent reconstruction of key watershed standards. We recommend that relevant clients carry out plant-wide water balance and source investigation for characteristic pollutants such as total antimony and total molybdenum as soon as possible, deploy online monitoring at workshop outlets in advance where conditions permit, and shift compliance costs from end-of-pipe treatment to source separation and diversion.

About TIANYI LIMITED: TIANYI TECH is deeply engaged in the field of wastewater treatment and reclaimed water reuse, committed to providing efficient, low-carbon, and sustainable water treatment solutions for municipal and industrial clients.