Mixing Zones
The mixing zone is defined as an allocated impact zone where numeric water quality criteria can be exceeded as long as acutely toxic conditions are prevented. Water quality standards apply at the boundary of the mixing zone, not within the mixing zone itself.
The US EPA and WV DEP allow the use of a mixing zone in permit applications. The mixing zone may be defined by the WV DEP as a numerical dimension where the applicant must demonstrate that the existing or proposed discharge meets all applicable standards for conventional pollutants; or, for the criterion continuous concentration (CCC) of toxic pollutants, at the edge of the specified mixing zone.
Bio-Chem Testing has the equipment and manpower to offer the following services to establish a Mixing Zone:
- Upstream background concentrations for all toxic pollutants of concern
- Effluent concentrations for all pollutants of concern
- Downstream concentrations for all pollutants of concern
- Physical characteristics of outlets and receiving streams
- Effluent dye study (if applicable)
- Zone of Initial Dilution (ZID) determination
When Bio-Chem furnishes all of the above data to an applicant, it will be ready to submit to the DEP for Mixing Zone Determination.
