GB/T 46725-2025 Now Mandatory: "Collaborative Carbon Reduction" Becomes a Hard Constraint in Municipal Wastewater Treatment, Carbon Accounting Enters Daily Operations

Introduction

GB/T 46725-2025, Collaborative Carbon-Reduction Performance Evaluation — Municipal Wastewater Treatment, has been mandatory since February 1, 2026. The standard applies to municipal wastewater treatment plants with a capacity of ≥10,000 m³/d, rating them across five dimensions — pollution control, energy conservation, energy optimization, resource recycling and management coordination — with 19 indicators, and requires enterprises to establish a carbon accounting system. This means that "synergistic pollution and carbon reduction" has shifted from an advocacy to a hard constraint, and carbon accounting will become a core basis for future supervision, benchmark selection and project subsidies. For TIANYI TECH, whose core business is wastewater plant operations, this is a recalibration of operating standards.

Background: Why "Collaborative Carbon Reduction"

Municipal wastewater treatment is an energy-intensive industry. Industry estimates put the energy consumption of the entire treatment process at about 1%–3% of total social electricity use, with considerable indirect emissions from chemical dosing and sludge disposal. For a long time, plant assessment treated "compliance discharge" as the only hard indicator, leaving energy consumption and carbon emissions in a "soft constraint" state — save if you can, with no penalty if you don't.

As the "dual carbon" goals advance, regulators have realized that wastewater treatment is not only pollution control but also an energy-consuming, emission-producing unit; if only water quality is watched while carbon is ignored, pollution reduction and carbon reduction become disconnected. The introduction of GB/T 46725-2025 institutionalizes the word "collaborative" — requiring pollution reduction and carbon emissions to be accounted for simultaneously within the same operating system, using a unified performance yardstick to measure a plant's green credentials.

Core: A "Green Exam" of Five Dimensions and 19 Indicators

The core of the standard is a quantifiable performance table.

The pollution control dimension assesses stable compliance of effluent and pollutant removal efficiency — the fundamentals; the energy conservation dimension focuses on electricity and chemical consumption intensity, targeting the biggest share of operating costs; the energy optimization dimension encourages energy substitution through photovoltaics, biogas recovery and water-source heat pumps, turning plants from "energy consumers" into "energy producers"; the resource recycling dimension examines reclaimed water reuse rates and sludge resource-recovery rates, echoing the wastewater resource recovery direction; and the management coordination dimension requires enterprises to have carbon accounting capability and a closed data loop, making reductions measurable and verifiable.

The 19 indicators are not weighted evenly but linked through the logic of "collaboration": for example, raising reclaimed water reuse earns resource-recycling points while also indirectly lowering the embedded carbon emissions of fresh water intake; promoting photovoltaic and biogas utilization earns energy-optimization points while also reducing absolute carbon emissions. This "one improvement, multiple scores" design guides enterprises toward systematic low-carbon retrofits rather than piecemeal responses.

TIANYI TECH's Action: Using Collaborative Carbon Reduction to Turn a Hard Constraint into Competitiveness in Three Steps

TIANYI TECH will use GB/T 46725-2025 as its operating calibration benchmark, moving "synergistic pollution and carbon reduction" from concept to daily practice and turning a hard constraint into next-stage competitiveness in three steps.

First, immediately build the carbon accounting foundation. Within 30 days, TIANYI TECH will launch carbon accounting system construction for operating and to-be-acquired wastewater plants with a capacity of ≥10,000 m³/d, adding energy consumption, chemical consumption and emission items to operating ledgers, ensuring every plant has measurable and verifiable carbon data collection capability.

Second, proactively pursue a low-carbon benchmark rating. TIANYI TECH will make "low-carbon operator" the main line of its brand building, explicitly targeting a high score in the collaborative carbon-reduction performance rating, proactively presenting its carbon performance record in client renewals and government cooperation, and turning compliance requirements into differentiated reputation.

Third, move carbon accounting upstream to the project's early stage. TIANYI TECH will embed photovoltaics, biogas recovery, reclaimed water reuse and intelligent aeration into the process-package stage of new and upgrade projects, turning carbon accounting from "after-the-fact catch-up" into a "built-in standard" to secure a high rating at lower cost and with less disruption.

Industry Perspective: Carbon Accounting Capability Is Becoming the "New Infrastructure" of Water Utilities

From an industry standpoint, the mandatory implementation of GB/T 46725-2025 turns "carbon accounting" from a polished number in ESG reports into a hard subject at the operating site. In the future, owners tendering projects are likely to write carbon performance commitments into contracts, and regulators may tie ratings to discharge permits and differentiated electricity pricing.

This means that carbon accounting capability is itself a form of infrastructure — not just bookkeeping but a data platform connecting processes, energy and reuse. If TIANYI TECH turns "low-carbon process packages + carbon accounting platform + reclaimed water reuse" into a standardized deliverable, it can both satisfy the standard's mandatory requirements and build a moat in the "green water" track.

Conclusion

The implementation of GB/T 46725-2025 marks the entry of municipal wastewater treatment into an era of hard "synergistic pollution and carbon reduction" constraints. For TIANYI TECH, writing carbon accounting into daily operations and embedding low-carbon processes into early project stages one step sooner means securing the ticket to green benchmarks one step sooner. Compliance is no longer a cost but the most certain competitiveness of the next stage.

Source: Standardization Administration of China (GB/T 46725-2025, effective 2026-02-01); TIANYI TECH operations observation.