[Chinese Mainland] Pinghu, Zhejiang Implements "Classification and Tiered Pricing + Multi-Factor" Billing for Industrial Wastewater Treatment Fees: Six Pollution Factors with Tiered Progressive Rates, Double Charges for Exceeding Discharge Standards

Lead Summary: The Pinghu Municipal Government has issued a document explicitly implementing multi-factor composite charging for industrial enterprises connected to the public pipe network: six major key pollution factors — COD, Suspended Solids, Total Phosphorus, Total Nitrogen, Ammonia Nitrogen, and Chloride — are identified, with tiered progressive pricing based on concentration. Wastewater with concentrations exceeding the maximum discharge limit shall not enter the municipal pipe network, and for the portion already discharged, each tier shall be charged at a progressively doubled rate. Sewage treatment fees are shifting from "single volume-based pricing" to "quality-based multi-factor pricing."

Policy Highlights: From "Volume-Based Pricing" to "Quality-Based Pricing"

According to the "Notice on Determining the Pricing Method for Classified Tiered and Multi-Factor Collection of Sewage Treatment Fees" published on the Pinghu Municipal People's Government website 9月10日, in order to promote sewage treatment and improve environmental quality, the city implements classified tiered and multi-factor collection of sewage treatment fees for industrial enterprises that are connected to the city's public sewage pipe network and treated by municipal sewage treatment plants (or charged by reference to municipal sewage treatment fees), in accordance with the National Development and Reform Commission and other departments' "Guiding Opinions on Policies for Improving the Sewage Treatment Charging Mechanism in the Yangtze River Economic Belt" and relevant documents of Zhejiang Province.

The six key pollution factors and their pricing parameters for multi-factor composite charging are as follows:

• Chemical Oxygen Demand (COD) — baseline value 300 mg/L, tier value 100 mg/L, floating standard 0.5元/m³, maximum discharge limit 500 mg/L;
• Suspended Solids (SS) — baseline value 300 mg/L, tier value 50 mg/L, floating standard 0.2元/m³, maximum discharge limit 400 mg/L;
• Total Phosphorus (TP) — baseline value 6 mg/L, tier value 0.5 mg/L, floating standard 0.2元/m³, maximum discharge limit 8 mg/L;
• Total Nitrogen (TN) — baseline value 35 mg/L, tier value 5 mg/L, floating standard 0.5元/m³, maximum discharge limit 70 mg/L;
• Ammonia Nitrogen (NH3-N) — baseline value 30 mg/L, tier value 1 mg/L, floating standard 0.2元/m³, maximum discharge limit 45 mg/L;
• Chloride — baseline value 500 mg/L, tier value 50 mg/L, floating standard 0.2元/m³, maximum discharge limit 800 mg/L.

The pricing rules follow the "baseline value + floating standard" cumulative principle: if the concentration of a pollution factor exceeds the baseline value, the floating standard is added on top of the baseline value; if it does not exceed the baseline value, pricing is based on the baseline value. This means that the higher the discharge concentration and the more pollution factors involved, the more expensive the sewage treatment fees borne by the enterprise — water quality becomes a direct variable in pricing.

Hard Constraints: Over-limit Wastewater Prohibited from Entering Pipe Network, Progressive Doubling of Charges

The most rigid provisions of this policy lie in the discharge limit constraints:

• Prohibition of over-limit discharge — when the wastewater concentration at the connection point or of the connected enterprise exceeds the maximum discharge limit, the wastewater shall not enter the sewage collection pipe network of the municipal sewage treatment plant, otherwise penalties shall be imposed in accordance with relevant regulations;
• Progressive doubling — once over-limit wastewater that has already entered is discovered, that portion of wastewater shall be charged at a progressively doubled rate for each tier of the pollutant factor over-limit fee, and the discharge concentration shall be counted into the monthly metered charging concentration;
• High-frequency testing — the municipal sewage facility operating unit commissions qualified third parties to conduct pollution testing, in principle by sampling, with no less than 3 tests per enterprise per month, taking the average value and issuing a test report.

Combined, these three measures effectively draw a clear "concentration red line" for industrial enterprises: rather than paying over-limit fees, being penalized, or even being refused network access, it is better to treat the water within the plant — either by reducing pollutant concentrations or by directly implementing quality-based reuse to reduce discharge.

Mechanism Traceability: Deepening of Charging Reform in the Yangtze River Economic Belt

Pinghu's multi-factor pricing is not an isolated action. Its policy basis directly points to the 2020年 National Development and Reform Commission, Ministry of Finance, Ministry of Housing and Urban-Rural Development and other departments' "Guiding Opinions on Policies for Improving the Sewage Treatment Charging Mechanism in the Yangtze River Economic Belt" (Fa Gai Jia Ge 〔2020〕 561 No.), which for the first time systematically proposed "improving the cost-sharing mechanism for sewage treatment in accordance with the principles of polluter pays, compensation for treatment costs, and reasonable profit." Zhejiang Province explored this direction even earlier — the 2015年 Zhe Jiang Jia Zi 〔2015〕 252 No. document proposed accelerating the advancement of classified tiered and multi-factor collection of industrial sewage treatment fees.

From the perspective of policy evolution, "multi-factor pricing" is a substantive correction to the traditional model of "same network, same price, billing by volume": the wastewater treatment cost of high-pollution industries is significantly higher than that of ordinary wastewater, and a single rate effectively makes the municipal sewage system subsidize high-pollution enterprises. Multi-factor pricing internalizes external costs, allowing "polluter pays" to be implemented at the charging stage.

Industry Impact: The Value of Source-Based Quality-Segregated Pretreatment and In-Plant Reuse Becomes Prominent

For the industrial wastewater treatment market, the promotion of the Pinghu model will bring demand changes at three levels:

• Demand for in-plant pretreatment upgrades——factors such as Total Nitrogen / TN, Total Phosphorus / TP, and chloride are not always the focus of compliance in conventional industrial wastewater treatment. To control discharge-to-network costs, enterprises will proactively add targeted treatment units, especially Denitrification, phosphorus removal, and desalination processes;
• High-salinity wastewater treatment and salt separation resource recovery——chloride is listed as a separate charging factor with a maximum discharge-to-network limit of 800 mg/L, further enhancing the economic viability of membrane concentration and volume reduction, salt separation crystallization, and reuse pathways for high-salinity wastewater;
• Online monitoring and smart metering——third-party testing no less than 3 times per month combined with concentration-based charging will drive demand for online water quality monitoring equipment on the enterprise side, activating the commercial value of water quality data.

TIANYI TECH believes that quality-based pricing of wastewater treatment fees is a key link in the wastewater resource recovery policy system: when discharge concentration is directly tied to real monetary costs, quality-segregated pretreatment and advanced reuse of industrial wastewater transform from "environmental requirements" into "financial decisions," which is precisely the most solid underlying logic for the long-term growth of the industrial water market. Many cities along the Yangtze River Economic Belt have similar industrial structures, and the Pinghu model has strong replicability and is worth continuous tracking.

About TIANYI TECH: TIANYI TECH has long focused on frontier developments in global water environment governance and water resource recycling, deeply cultivating technical information and industry services in the fields of wastewater treatment and Reclaimed Water Reuse, and is committed to providing timely, professional industry observations and solution references for customers and industry partners.