The ZDHC Wastewater and Sludge Guidelines (WWG) V2 will officially take effect on November 1, 2026. This article outlines the systematic upgrades in scope, sampling, testing parameters, limits, and sludge management to help factories prepare ahead.
1. Timeline
Before Oct 31, 2026
V1 (formerly Wastewater Guidelines V2.2) remains in force; V1 reports must be uploaded to the Gateway
Nov 1, 2026
WWG V2 officially takes effect, replacing V1
Before Nov 30, 2026
Samples collected in the current wastewater cycle (May–Oct) may be reported under V1
From Dec 1, 2026
All wastewater test reports uploaded to the ZDHC Gateway must comply with WWG V2
2. Applicable Facilities
WWG V2 applies to:
- Textile wet processing facilities
- Footwear wet processing facilities
- Leather wet processing facilities
- Raw wool washing facilities (newly added)
- Facilities involving sludge management
New areas of focus:
- Fiber fragment monitoring
- Standalone sludge assessment
- Gateway data upload
3. Six Key Changes at a Glance
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Area
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Key Changes
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|---|---|
|
On-site sampling & testing
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Persistent foam testing added
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|
MRSL parameters
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New and expanded controlled substances
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Limits & reporting
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Tighter NH₃-N and AOX limits
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Leather industry
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Further harmonization of limits
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Sludge management
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Standalone assessment module and disposal pathway management
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Gateway reporting
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Adjusted upload rules and transition arrangements
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4. Major Changes to Sampling and On-Site Testing (SAP)
Mandatory on-site parameters
- V1: pH and temperature difference ΔT
- V2: Persistent foam added as a mandatory on-site test
Temperature
- ΔT is prioritized
- Where ΔT cannot be measured, absolute temperature must be tested and reported
COD reporting requirements
- Reports must clearly state the wastew
5. Testing Parameters: What's New?
- New controlled substances added to wastewater MRSL parameters: dimethyl fumarate (DMFu), 2-methoxypropanol, dimethylacetamide (DMAC), dimethylformamide (DMFa), N-ethylpyrrolidone (NEP), N-methylpyrrolidone (NMP), free aniline, cyclic siloxanes D4/D5/D6, etc. The scope of control for banned flame retardants, per- and polyfluoroalkyl substances (PFCs), and phthalates has also been expanded. All newly added substances are derived from ZDHC MRSL V3.1.
- New mandatory sludge testing requirements for banned flame retardants, PFCs, and phthalates (V1 did not require these three categories in sludge).
6. Stricter Limits and Adjusted Reporting Modes
- Baseline limit changes for ammonia nitrogen and AOX:
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Parameter
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V1
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V2
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|---|---|---|
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Ammonia nitrogen
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10 ppm
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5 ppm
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|
AOX
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3 ppm
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2 ppm
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- Adjusted heavy metal reporting mode:
For indirect discharge facilities, five heavy metals – arsenic, cadmium, hexavalent chromium, lead, and mercury – shift from limit-based control to a “sampling and reporting” mode, with root cause analysis triggered upon detection.
- Compliance rigidity of baseline limits:
Baseline limits for conventional parameters, anions, and heavy metals are minimum compliance requirements; exceeding them constitutes non-conformance.
- Clarification of the flow threshold:
15 m³/day is no longer a limit value but a dividing line for testing requirements – facilities discharging ≥15 m³/day and <15 m³/day are subject to different testing requirements.
7. Leather Industry Parameter Alignment
1） V1 contained numerous “not applicable” exemptions for leather.
2） V2 harmonizes leather and textile limits:
- Limits now apply to leather for flame retardants, UV absorbers, and toluene/xylene VOCs.
- The antimony exemption for polyester is removed; antimony limits are mandatory for all textiles (including polyester wet processing) – V1 allowed exemptions for polyester plants.
- The total boron limit for boron-based flame retardants is adjusted to 500 ppb, with a unified standard for textiles and leather.
8. Upgraded Sludge Management: From Sub-Module to Standalone Assessment
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WWG V1
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WWG V2
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|---|---|
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Sludge as a sub-module of wastewater assessment
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Sludge becomes a standalone assessment module
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Main focus on heavy metals
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Expanded MRSL testing scope
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No disposal pathway requirements
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Disposal pathway determines testing requirements
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V2 assessment process:
- Disposal pathway (A–G)
- Determine test items
- Laboratory testing
- Gateway upload
Companies should note:
- Provide a signed sludge disposal pathway declaration at sampling
- Different disposal pathways correspond to different testing requirements
- Where the disposal pathway is unknown, treat as pathway F
- Test reports must include contamination grade and disposal pathway records
9. Actions Companies Should Take
Companies are advised to note the wastewater report submission extension during the transition period and take action:
✔ Arrange pre-testing for ammonia nitrogen / AOX
✔ Assess newly added MRSL items
✔ Confirm sludge disposal pathways
✔ Confirm the WWG V2 testing plan with your laboratory
WWG V2 is a systematic upgrade covering sampling, testing, limits, sludge management, and gateway reporting. PFI has obtained ZDHC Wastewater and Sludge Guidelines V2 testing accreditation and provides wastewater and sludge sampling, testing, and technical services for textile, apparel, leather, and footwear supply chains – helping businesses meet sustainability requirements.
