Are galvanic in the scope of the ZDHC Wastewater Guidelines 2.0?
Grit removal systems are generally classified into three categories:
- Coarse screens that remove large objects. Typical opening size is 6-150 mm
- Fine Screens – that remove fine solids. Typical size is < 6 mm
- Microscreens – that remove the majority of solids. Typical size 10-35 µm
If a facility is using a coarse screen greater than 6-mm opening, it would not be considered a pre-treatment. If a facility is using a fine or micro screen, less than 6-mm opening, this will remove fine solids that MRSL compounds may be adsorbed to and would be considered a pre-treatment process.
In a situation where there are multiple factories discharging to a central ETP owned by one facility, the following sampling and testing are acceptable:
- Sample and test the raw untreated wastewater from each factory
- Sample and test the ETP-treated discharge (effluent) once, and all the factories can report that data. Individual factories do not have to collect and test the ETP effluent, they can share that data.
Yes, but only if there is sludge generated with the pH adjustment.
If the residue of the screening is NOT disposed of as sludge but is reused within the production cycle: how should we consider it?
It would not be considered to be pre-treatment (in the case of an indirect discharger) and not required to test as sludge if it is not to be disposed and not incinerated on site.
If there is no flow meter on the wastewater discharge and it is not possible to perform a calculation of the flow rate discharged because the pipe/tub is underground, what should be done?
On several occasions, it has happened that the drain was piped and the company did not have a flow meter. Not tested for risk should be reported.
How do we define a PASS or FAIL for “borate, zinc salt”?
If borate and zinc salt are greater than 100 ug/l, then a FAIL shall be reported.
In the case of Indirect Discharge, if homogenisation tanks are present, how should the sample be taken?
1-In HT, retention time needs to be 12 hours (calculated and confirmed by the laboratory sampler as per the formula given in point 8). The Retention time in the homogenisation tank can also be calculated as: Retention time (hours) = total volume of the tank (m3) flow rate of effluent (m3/hour).
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.