No, If a ZDHC Approved Laboratory is approved for the ZDHC Wastewater Guidelines V2.1 there is no requirement to re-approve for V2.2.

Please refer to our website for a list of ZDHC Approved Wastewater Laboratories for testing in accordance with the ZDHC Wastewater Guidelines: link.

Please refer to Find your Expert

If there is more than one discharge point at a facility, a sample from each discharge point should be collected and tested separately as per the applicable type of discharge (direct, indirect)

General considerations:

Point 1: In an HT (homogenized tank) the retention time needs to be 12 hours (calculated and confirmed by the laboratory sampler as per the formula given below).

Indirect discharge with pretreatment:
The laboratory collects untreated wastewater (point 1: single grab in the HT) and also collects effluent (point 2: single grab if HT is present or point 3: 6 hours sample if no HT is present).

Indirect discharge without pretreatment:
The laboratory collects only untreated wastewater (that is also effluent) as a single grab from HT (point 1) to test MRSL & 5 metals.

Grit removal systems are generally classified into three categories A:

In a situation where multiple factories with separate business licenses are discharging to a Central ETP owned by one facility with a separate business license, the following sampling and testing are acceptable:

• Sample and test the untreated wastewater from each facility to which the ETP does not belong. Consider them as “indirect discharge without pretreatment” facilities and test relevant parameters based on the discharge volume of each facility.

• Consider the facility with the ETP as a “direct discharge” facility. Sample and test its untreated wastewater for MRSL parameters based on the discharge volume and treated effluent for the conventional parameters, anions, and heavy metals. Sludge should be tested based on the major sludge disposal pathway. Those values are applicable only to the facility with the ETP, not to the other facilities.

There could be two scenarios here.

• Scenario 1: “direct discharge” if the third-party facility only treats the wastewater of this particular factory without mixing it with any others. Maybe due to the lack of space to build an ETP, the factory may have it externally. All MRSL parameters, conventional parameters and anions, and heavy metals, and of course, sludge parameters should be tested according to Table 4A-C based on the disposal pathway.

• Scenario 2:” Indirect discharge without pretreatment”. If the facility stores the effluent and then sends it to an external treatment plant. The sampling point should be from the container and the parameters applicable to indirect discharge without pretreatment (i.e. the MRSL and 5 metals) should be checked. If any pretreatment to the effluent is carried out before storing it in a tank and sending it to the external treatment agency, then the effluent sample, taken before this pretreatment process, should be sampled to test MRSL and 5 metal parameters. Any sludge that is generated due to this pretreatment process (such as flocculation) should be collected and tested according to Tables 4A-C based on the disposal pathway.

At an indirect discharger, if the residue is not disposed/incinerated, but goes back into the production process on-site, it is not considered to be pre-treated. Therefore is not required to be tested as sludge.

Then the lab needs to estimate the flow rate based on the below formula and mention that in the EDR. Data for the calculation could be obtained by the facility itself.

Flow rate in m3/hr = Total volume of effluent treated (m3/day)/ Total hours of ETP operation (hr/day)

The borate, zinc salt limit value is applicable to textiles as well as leather, the limit is 100 μg/L.

This is based on results for total boron and total zinc individually as determined by the ICP test. This means that total boron and total zinc values should be less than 100 μg/L to be conformant to the ZDHC WWG v2.2.

Where total boron is > 100 ppb and total zinc is < 100 ppb (or vice versa) the sample is still conformant to the ZDHC WWG v2.2.

Labs should input the values for total boron and total zinc in the EDR template when uploading the test results.

• The temperature difference parameter in ZDHC Wastewater Guidelines V2.2 is only applicable to those facilities that are directly discharging the treated effluent to an upstream receiving water body. Where effluent is discharged directly to the ground, in a municipal sewer or another environment, the temperature is not to be evaluated. The sampler must confirm that the discharge is made to an upstream water body during the site visit to sample the wastewater.

• Where the receiving body is inaccessible,

  • The sampler's own safety is at risk

  • Equipment is at risk of damage

  • The upstream receiving body is located far away from the facility (e.g. a pipeline from the facility that goes several kilometres into the sea)

  • The effluent is discharged directly into the ground.

then the sampler should not carry out this on-site test and the temperature parameter will be not applicable.

In both the above cases, since the temperature parameter is not measured, it will appear as a white row (not applicable) in the ClearStream Report and the maximum score for conventional parameters will be lowered by 3 points in the ClearStream Report.

In case the receiving body is not accessible or risky to access for the sampler, a visual estimation of the foam in the aeration basin should be done. If the foam is higher than 45 centimetres in height  (by visual estimation) then it could result in permanent foam being discharged onto the surface of receiving waters and should be reported as ‘fail’ for foam parameter.

A negative delta result for temperature difference indicates that the discharged effluent temperature does not cause any increase in the temperature of the receiving body. This should be reported as a negative value by the testing laboratory and it will be treated as “Aspirational Level” and scored accordingly in the ClearStream Report.

Labs can refer to the list of ‘marker chemicals’ given in the ZDHC MRSL V3.1 document and test these marker chemicals in the wastewater sample to identify the related substances of PFOS and PFOA. Labs can also refer to the PFAS Guidance Sheet document given in the e-MRSL V3.1 to gather the list of PFAS and CAS numbers.

As per ZDHC SAP V2.1, ZDHC Approved Sampling Personnel can collect separate samples by hand for no less than 6 hours, with no more than 1 hour between separate samples. That means the sampler should collect no less than 7 samples and each separate sample shall be of equal volume and combined to produce 1 composite sample. The composite sample container must be cooled at 4 degrees Celsius during sampling.

This means that the analysis/testing procedure should be similar to wastewater testing since this is "liquid" sludge, not solid sludge. But the lab needs to report this as sludge using parameters applicable to sludge only on a weight/volume basis (mg/L).

The minimum amount of samples is 7 and the lab can collect them within a time period of 6 hours (or a length of time that represents the entire production process cycle which could be less than 6 hours). Ensuring no longer gap than 1 hour between 2 samples.

https://knowledge-base.roadmaptozero.com/hc/en-gb/articles/8285141301021-ZDHC-Approved-Wastewater-Laboratory-frequently-asked-questions-testing-and-sampling-

Samples to test both MRSL parameters and five heavy metals should be collected from the raw (untreated) effluent which directly comes from the facility before discharging into the Central Effluent Treatment Plant (CETP).

The footnote ‘Sample and Report only for mock leather.’ has been deleted as this applies to all leather and mock leather facilities, not only mock leather. The reason for this is it was not possible for the testing laboratories to know if a facility was a mock leather or not a mock leather facility.

Within the ZDHC Wastewater Guidelines we do not identify synthetic materials eg PU, so these are classed into the same category as leather.

Dyes-navy blue colourant: Component 1: C39H23Cl-CrN7O12S 2Na and Component 2: C46H-30CrN10O20S2 3Na, are not required to be tested within ZDHC wastewater testing. These parameters are not in the scope of wastewater testing.

However, we have kept these parameters in the guidelines to prevent the intentional use of these in the chemical inventory and production process.

Silica (CAS no: 14464-46-1) is not required to be tested within ZDHC wastewater testing. This parameter is not in the scope of wastewater testing.

However, we have kept this parameter in the guidelines to prevent intentional use in the chemical inventory and production process.

Previously, there were no limit values applicable for leather for:

• Flame retardants

• Other/miscellaneous chemicals

• UV absorbers

• Tuolene

• Xylene

From November 2024 these are required to be tested within the ZDHC wastewater testing. The reason for including these into the scope of testing is to align the ZDHC MRSL V 3.1, in which these parameters are require testing on leather.

This will be with effect with the implementation of WW 2.2 and earlier parameters.

Previously, there were no limit values applicable for leather for:

• Dissolved Oxygen (DO)

• Total Dissolved Solids (TDS)

• Total chlorine

The Wastewater Council has analysed the data collected across the reporting cycles and found that a large proportion of facilities could achieve the required limit. Therefore, it has been decided to apply a single limit for these parameters rather than just Sample & report.

No. It does not depend on the size of the facility. It depends only on the discharge type and daily discharge volume of industrial wastewater as below.

Previously, there was a footnote for antimony stating to Sample and Report for polyester facilities. However, it was observed that testing laboratories were unable to confirm whether a facility was a polyester facility or not.

The Wastewater Council has analysed the data collected across all textile facilities and found that a large proportion of facilities could achieve the required limit. Therefore, it has been decided to remove the footnote and apply the limit to all textile facilities, including polyester facilities.