Recently, the Ministry of Ecology and Environment issued HJ 945.4—2026 Technical Guideline for Formulating Water Pollutant Discharge Standards for Centralized Industrial Park Wastewater Treatment Facilities, which will officially take effect on September 1, 2026. As a national-level technical guideline for mixed industrial parks, it breaks away from the past management model of "emphasizing the end-of-pipe while neglecting the source", and — with sub-sector management, full coverage of emerging contaminants, specialized zone-based treatment, and wastewater recycling as its core directions — draws a new yardstick for water environment management in industrial parks and points out the upgrade path for industrial wastewater treatment and water reuse enterprises.

1. Understanding the Four Core Directions of the New Guideline

The guideline imposes more refined constraints on integrated industrial parks that include chemical industry sectors. Its core requirements can be summarized in four points.

First, zone- and category-based management: chemical wastewater is strictly prohibited from mixed discharge. Highly toxic, high-salinity, high-concentration mother liquor produced by chemical enterprises such as pharmaceutical intermediates and coating additives must be equipped with separate pretreatment facilities, is prohibited from being directly connected to the comprehensive wastewater network, and must meet dedicated acceptance limits for the chemical sector, preventing toxic wastewater from shocking the plant-wide biological treatment system.

Second, expand the pollutant monitoring list and focus on characteristic chemical toxicants. On top of conventional indicators such as COD and ammonia nitrogen, routine monitoring of salinity, comprehensive toxicity and persistent organic pollutants is added, filling the emerging-contaminant risk-control gap for characteristic toxic factors such as benzene series compounds, phenols and halogenated hydrocarbons.

Third, clear responsibilities across three treatment levels, consolidating the primary responsibility of enterprises for pretreatment. The guideline establishes a three-tier defense of "enterprise on-site pretreatment — zone-based specialized wastewater station treatment — advanced treatment at the integrated wastewater plant", changing the previous management misconception that all wastewater exceeding standards should be handled by the end-of-pipe plant. Discharging enterprises must assume the primary responsibility for wastewater source separation and pretreatment compliance.

Fourth, vigorously promote wastewater resource recovery to reduce the dual pressure of discharge and water intake. The guideline encourages industrial parks to build water reuse systems, so that chemical and manufacturing enterprises recycle treated tailwater, reduce total fresh water intake and direct wastewater discharge, and cut watershed pollution load from the source.

2. Real Shortcomings Facing Industrial Park Water Treatment

Based on the practice of development zones in multiple regions, many parks — although already equipped with dedicated pretreatment stations for chemical enterprises, specialized PCB wastewater stations and integrated wastewater treatment plants — still have weak points compared with the new guideline: front-end source separation retrofits at chemical enterprises are incomplete, with highly toxic distillation residues occasionally mixed into integrated wastewater; online monitoring capacity for emerging contaminants is insufficient, making source tracing of characteristic factors difficult; and the coverage of water reuse systems is still low, with tailwater resource recovery not yet at scale. These issues are precisely the "must-answer questions" for implementing the new guideline, and also the points where environmental enterprises can create the most value.

3. From "Meeting Discharge Standards" to "Systematic Treatment"

The essence of the new guideline is to push the logic of industrial water treatment from a single "end-of-pipe compliance" toward the systematic treatment of "source reduction + segregated treatment + resource recovery circulation". For enterprises, this means proactive action on three levels: at the front end, implement source separation and pretreatment compliance to keep risks out of the comprehensive network; in the middle, build zone-based specialized treatment units so that different water qualities follow the most economical process routes; and at the end, couple advanced treatment with water reuse to form a closed water loop. Whoever completes this layout first can turn "water treatment pressure" into "water efficiency dividends".

4. TIANYI TECH's Interpretation and Response

As a technology enterprise focused on wastewater treatment and water reuse, TIANYI TECH believes the new guideline is both a compliance threshold and a market opportunity. The company can provide integrated solutions from water quality surveys and process package design to operation and custody: for highly difficult wastewater from chemical, PCB, electroplating and printing and dyeing industries, it tailors source separation and pretreatment processes; for industrial park water reuse needs, it provides membrane separation, advanced oxidation and intelligent chemical dosing systems, helping park enterprises meet the new requirements at lower compliance cost. Turning "water treatment" into a "water efficiency project" is precisely TIANYI TECH's core answer to the new guideline.

Conclusion

September 1 is not merely a date, but a watershed for the shift in industrial water treatment logic. The more detailed the standards and the higher the threshold, the less room there is for "campaign-style treatment", and the larger the stage for "systematic capability". For TIANYI TECH and the broad base of industrial enterprises, completing source separation and resource recovery arrangements in line with the trend means gaining the first-mover advantage in the new round of environmental compliance and green manufacturing competition.