Demonstrate a strong and complete response to all application criteria

To apply for acceptance as a ZDHC Approved Wastewater and sludge Laboratory, the applicant laboratory must request approval for the type of discharge (direct discharge, indirect discharge with pretreatment with sludge,  indirect discharge with pretreatment without sludge,  indirect discharge without pretreatment and ZLD). A ZDHC Approved Wastewater and sludge Laboratory is automatically approved to test MMCF facilities. The approval is requested per location. In addition, the following requirements must be met:

• ISO/IEC 17025 accreditation must include methods relevant to wastewater or sludge matrices or leachate. If not present, the laboratory can not be approved
• You can select more methods per parameter to be approved.

Coverage of 17025/PT

• At least 50% of all (wastewater and sludge/leachate) conventional parameters should be covered by an accredited scope.
  • For wastewater conventional parameters, if accreditation is not available for a specific method, the laboratory must provide evidence of a successful proficiency test performed using the method.  Exceptions: persistent foam does not need any accreditation/PT, temperature does not have a proficiency test available, if not accredited, the calibration certificate of the thermometer is needed.
  • For sludge/leachate conventional testing, accreditation is needed for pH and cyanide. As for the remaining parameters (e.g., faecal coliform, paint filter test, and percentage of solids), the submission of a Standard Operating Procedure (SOP) or a declaration referencing the applicable standard method is accepted.

• ISO/IEC 17025 accreditation must cover all metals and MRSL parameters.

Deviation in the ISO 17025 accredited method

It is possible to be approved even if:

• The accreditation refers to a different matrix.
• A substance is not within the scope of the accredited method, but can be tested using an accredited method. 
  • Special case: if a method is not indicated, but only the analytical technique AND the parameter is not under the scope of the proposed method for approval, a self-declaration to confirm that the specific parameter can be tested under the specific accredited method is needed
  • Documents required for the approval of equivalent methods for ZDHC Signatory Approved Wastewater Laboratory V2 - Learn more in this Knowledge Base article

Possibility to use methods not present in the guidelines

The test methods specified in the ZDHC reference documents, or equivalent methods*, must be used, except for colour and COD, for which only test methods included in the ZDHC Suppliers Roadmap to Zero, chapter ZDHC Wastewater and Sludge Guidelines must be used.

• If an analytical technique only is mentioned, any method accredited with the analytical technique required is fine (even if in a different matrix). Forbidden to use a different analytical technique.

 _{*Equivalent methods will be approved on a case-by-case basis.}

A few of the indicators used defining/understanding/evaluating such equivalency could be:

• Spiking recoveries in the matrix of concern (typically 70-120% is an acceptable range)
• Repeatability and reproducibility within 5% RSD values are acceptable.
• TOST (Two-one-sided-Students Test) can be applied using regression analysis.

Subcontract 

The rules regarding the subcontracting of analyses are defined as follows:

1. It is permitted to subcontract all and ONLY the conventional parameters.
2. It is permitted to subcontract all and ONLY parameters included in the ZDHC MRSL.
3. In the case of:

• a mix of conventional, metals and MRSL parameters, the following limitations apply:
  • A maximum of 5 conventional parameters.
  • A maximum of 2 metals.
  • A maximum of 5 MRSL parameter families.
• Subcontracting mixed groups of parameters, if the laboratory falls within the situation described above, the application will proceed directly to the standard evaluation process.

If this is not the case, the application will follow a different procedure and will be referred to an exception review, whereby the request will be assessed in details by ZDHC.

4. If only one parameter belonging to an MRSL family is subcontracted, that parameter will be considered as representing the entire family for counting purposes.

• The counts will be performed regardless of the matrix: the same parameter subcontracted for different matrices will be counted only once.
• Parameters to be tested in the field cannot be subcontracted.
• Subcontracting may be accepted solely on the condition that the testing is performed in-house by the subcontractor and is not further delegated or outsourced to any additional external parties.
• The subcontracted laboratory may be either an affiliate or an external laboratory.
• Only one outsourced laboratory can be selected per parameter. If more than one subcontract is needed per parameter, it should be communicated through the application on  SPP.

Group approval possibility

Laboratories that are part of the same group using the same method in all locations can contact ZDHC: quality@zdhc.org for more information regarding approval rules.

Limit of Quantification (LOQ) approval

LOQ approval rule:

• LOQ must be equal to or lower than the reporting limit
• If there is a difference between the reporting limit of textile and leather, the reference reporting limit is the lower one.
• For conventional and metals the reference reporting limit is the aspirational one.

Please note that in certain situations, ZDHC may request additional information and documentation or carry out specific evaluations, which may include allowances  on certain requirements or acceptance of equivalent quality assurance criteria, to grant a fair, consistent, high-quality implementation of the ZDHC Suppliers Roadmap to Zero on a global scale. If any extra fees are associated with this evaluation, the laboratory will receive advance notice.