Sampling & Analysis Plan

Continuous improvement of sampling and testing data

In the spirit of continuous improvement, the ZDHC Wastewater and Sludge Laboratory Sampling and Analysis Plan (SAP) will be reviewed on a regular basis and revised as needed to incorporate learnings and opportunities identified during the practical application and implementation of these procedures. 

All ZDHC Accepted Laboratories must refer to both the ZDHC Wastewater Guidelines and the SAP when conducting sampling and testing/analysis, as both documents complement one another.

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The standard for wastewater and sludge testing

Large quantities of water are often used to manufacture and process apparel, textile and footwear products. At the end of the production line, wastewater gets released. If that's not properly treated, it poses a threat to the environment. 

Making wastewater cleaner has generally been a big task for every brand and supplier involved. ZDHC encourages the industry to take a collaborative approach in tackling challenges, as part of a joint ambition to improve the quality of discharged wastewater and sludge.  

Together with leading brands, suppliers, academia, testing laboratories, technology providers, and other stakeholders, we created comprehensive, unified ZDHC Wastewater Guidelines. These Guidelines provide a harmonised set of wastewater and sludge parameters, limit values and test methods. They help brands and suppliers work to the same set of expectations. 

These are the first guidelines to define pass and fail criteria for hazardous chemicals covered in the ZDHC MRSL. The standards in these Guidelines cover conventional wastewater parameters while also going beyond regulatory compliance.

For suppliers wishing to share the outcome of testing with multiple brands, the ZDHC Gateway – Wastewater Module makes that entire process easier. The Gateway is a global web-based platform for sharing verified data on wastewater and sludge testing.

Wastewater Guidelines parameters and limits as they refer to leather

Although the current ZDHC Wastewater Guidelines do not apply to leather processing (including beam house, tanning, dyeing, and finishing), some brands and suppliers have adopted them as part of their testing policies. We encourage and support leather wastewater testing to help us to gather data to update the Guidelines to reflect leather specific limits, however, we advise that brands do not compare the following conventional parameters: COD, BOD5, Total-N, and Chromium - total, to the limits given in the ZDHC Wastewater Guidelines for leather facilities.

These Guidelines were created to expand the scope to include the leather industry, and are an addition to the current ZDHC Wastewater Guidelines Version 1.1. They were developed in collaboration with a wide range of stakeholders from the leather industry including manufacturers, brands, chemical suppliers and laboratories. 

These ZDHC Leather Wastewater Guidelines must be read in conjunction with ZDHC Wastewater Guidelines Version 1.1 and the instructions given in sections 9.0-16.0 must be followed. Sections 9.0-16.0 apply to textiles and leather, and describe the requirements for sampling, testing and reporting into the ZDHC Gateway, as well as conformance to the Guidelines. The ZDHC Leather Wastewater Guidelines are a list of conventional and Manufacturing Restricted Substances List parameters, and their limits specific to wastewater discharged from leather manufacturing processes.

An important element of the value chain

Fibres are an important part of the value chain. Therefore it’s a logical next step for ZDHC Roadmap to Zero Programme to include fibre production processes and their raw materials. In 2018, the scope of the Programme extended to include the production of Man-Made Cellulosic Fibres (MMCF). This is the first fibre production area included in the Programme. More materials will be added in the future.

Global viscose production is growing fast, which is why the initial focus is on Man-Made Cellulosic Fibres (MMCF; including viscose, modal and lyocell). MMCFs are produced from natural feedstock like wood or plants, using hazardous chemicals. Within the production process of viscose and modal, particularly where that’s not an integrated (closed loop) process, chemicals react with the cellulose. This creates by-products, which can be released into the air, water and soil, so we’ve been working to tackle the issue.

An 2018 industry expert report commissioned by ZDHC concluded that restricting chemicals via the ZDHC MRSL approach would not work. The restrictions would halt most MMCF production processes. We would achieve most impact by collaboratively setting guidance around good chemical management and limits for wastewater, sludge, and air emissions during fibre production. At the same time ZDHC can continue researching MMCF production processes using less hazardous chemicals.

In March 2018, ZDHC hosted the first multi-stakeholder MMCF roundtable with representatives from approximately 80% of the global MMCF production. Several ZDHC Signatory Brands attended, including C&A, Coop Switzerland, Esprit, Inditex, H&M, M&S, Primark, PVH Corp and F&F, as well as Value Chain Affiliates Lenzing Group, BIRLA CELLULOSE, Sateri, Canopy, Textile Exchange, Bluesign and the China Chemical Fibers Association (CCFA), the Collaboration for Sustainable Development of Viscose (CV) and the Partnership for Sustainable Textiles. 

The roundtable agreed that ZDHC should lead a collaboration to develop a framework of guidelines for wastewater, sludge, waste and air emissions specific to MMCF production, and expectations for process by-product recovery rates. The guidelines will, for now, focus on MMCF production. Dissolving pulp production processes will be considered at a later stage.

ZDHC Air Emissions Position Paper

ZDHC broadens its scope of work to address the management of air emissions within the textile, apparel, leather and footwear industry, in recognition of the impact that air emissions of hazardous chemicals may have in communities and the environment. 

The ZDHC Air Emissions Position Paper is the result of the collaborative effort that included representatives from relevant stakeholder groups with the aim to minimise air pollution across the textile, apparel, leather and footwear value chain.

What is the focus of the Air Emissions Position Paper?

This Paper focuses on two types of air emissions, those air emissions generated in a facility related to its operations (combustions or other air emissions sources) and process operations air emissions (related to production process, production line equipment and manufacturing processes), sharing aligned expectations and highlighting areas of opportunity.  The aim of this paper is to build up the needed understanding of air emissions management and best practices, and it should be implemented by brands and facilities to understand the gaps with current air emissions control and tracking efforts to prepare for the transition of this document to the ZDHC Air Emissions Guidelines. No new air testing is described in the paper beyond those legally required.

What is the timeline for actions to be taken?

2021 - There is no immediate action needed for Suppliers but to stay informed on the developments of the air emissions project and take the opportunity to self-assess operations against the expectations outlined in the Paper. During this year ZDHC will work on developing a streamlined reporting mechanism, monitoring requirements, and testing that will allow this paper to transition into the ZDHC Air Emissions Guidelines.  

2022 - ZDHC will develop the Position Paper into a Full Guideline and publicly release it. Suppliers should continue to self-assess operations against the expectations outlined in the Paper and check that they will be ready to implement the Guidelines in 2023.

2023 - Air Emissions Guidelines implementation will begin.

Supporting data integrity on the ZDHC Gateway

These guidelines highlight the expectations, criteria and specification of data uploaded electronically onto the ZDHC Gateway. 

Data integrity on ZDHC Gateway - Wastewater Module is a cornerstone of the ZDHC Roadmap to Zero Programme. One of the mechanisms used to achieve that is the implementation of the EDR. In fact, ZDHC Accepted Laboratories are expected to adhere to these guidelines.

As part of our continuous improvement efforts, we are moving away from manual data entry to electronic data submission. This guideline explains the automated system Accepted Laboratories must use to submit wastewater and sludge testing data on the ZDHC Gateway - Wastewater Module. It also helps them do so in a resource effective way. 

The system is backed by a data validation mechanism, which ensures data uploaded onto the Gateway is consistent and conforms to the data rules and quality requirements.

The ZDHC Gateway Electronic Data Reporting System is currently being developed and will be rolled out in 2020 (exact time to be determined).


Better Outputs

Safer and cleaner - for producers, people and planet

Measuring indicators such as, wastewater, sludge and air quality validates the work that is being done with chemical inputs and processes. It helps us to determine if
the output water and air is safer.


Wastewater Guidelines

Version 1.1

These Guidelines standardise wastewater testing requirements in the global apparel, textile and footwear supply chain. They define the standard for wastewater discharge and sludge quality. The input of key stakeholders was used in their creation, adding to their credibility. Leading brands, suppliers, academia, laboratories and tech companies were all part of this industry breakthrough.

supportive Document

Sampling and Analysis Plan  

(SAP) Version 1.3

This document is a key support for implementing the ZDHC Wastewater Guidelines. It provides ZDHC Accepted Laboratories with a set of requirements. Those requirements guide labs as they sample and test to determine the concentration of parameters in wastewater and sludge. We want to achieve the integrity and comparability of wastewater and sludge test data. The implementation of the SAP helps us to do that.

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supportive Document

Electronic Data Reporting System

(EDR)  Version 2.1

The EDR gives directives to ZDHC Accepted Laboratories on submitting test data to the ZDHC Gateway - Wastewater Module. It explains the standardised way in which data should be submitted to the Gateway platform. By showing these laboratories what data we expect them to upload, it increases the consistency and comparability of test data on the platform.

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Accepted Laboratories

Laboratories must meet ZDHC’s minimum acceptance criteria. This is crucial to sample and analyse based on the ZDHC Wastewater Guidelines, and to submit test data to the ZDHC Gateway - Wastewater Module. For consistent data quality, insight is needed on the personnel, equipment and processes being used. With that in mind, the ZDHC Laboratory Acceptance Programme was created.

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Already more than 87 laboratories in 23 locations

Wastewater Treatment Technologies

This document, which is purely informational, was gifted to ZDHC in 2018. It provides helpful knowledge for decision-makers and managers at wet processing facilities. The document's main purpose is to provide a technical overview of wastewater treatment processes. Wastewater treatment is a complex process and treatment solutions may vary from plant-to-plant. Therefore additional (bespoke) guidance, and resources such as regional training programs are needed. 


Wastewater Treatment System Operator Minimum Qualifications Guidelines  

The ZDHC Wastewater System Operator Minimum Qualifications Guidelines standardise the minimum qualifications for education, training and experience required of operators and technicians operating wastewater treatment systems at all manufacturing facilities and other facilities operating effluent treatment plants (ETP). The Guidelines help facilities to identify skill gaps and prepare for focused training solutions.


Leather Wastewater Guidelines Addendum

These Guidelines set a single unified expectation for sampling, testing and reporting of industrial wastewater and sludge resulting from leather processing. These Guidelines must be read in conjunction with the current ZDHC Wastewater Guidelines Version 1.1 and the instructions given in Sections 9.0-16.0 must be followed.


Man-Made Cellulosic Fibres

This document standardises wastewater, air emissions and chemical recovery requirements for MMCF manufacturing facilities. Define a standard approach for MMCF fibre manufacturing emissions control. The creation of this document is a collaborative effort from the industry: MMCF manufacturing facilities, brands, service providers and subject matter experts.

supportive document

ZDHC MMCF Guidelines


This support document underlines the steps and actions necessary to implement the ZDHC MMCF Guidelines and support the involved stakeholders during the implementation.

Air Emissions

ZDHC Air Emissions Position Paper

The ZDHC Air Emissions Position Paper promotes the management of air emissions and sharing best practices with the aim to minimise air pollution across the textile, apparel, leather and footwear value chain.



This platform integrates the global facility monitoring of wastewater testing completed in accordance with ZDHC’s Wastewater Guidelines, with the performance evaluation of how facilities are managing their sustainable process chemistry.


Wastewater Module

Test wastewater once - share results simultaneously

The ZDHC Gateway - Wastewater Module saves time and supports transparency throughout the value chain. Manufacturing facilities can test wastewater once and share the results simultaneously with all clients. Suppliers are assessed against uniform standards like the ZDHC Wastewater Guidelines or the ZDHC MMCF Wastewater Guidelines. They can show their performance and take corrective action if needed.

Brands also benefit. They can see test results from multiple suppliers - on one single platform. There are exciting future possibilities too, like the potential to link to other business analytics platforms for fuller performance analyses.