From Field to Bottle: Water Footprint Estimation …
123
does not deplete the natural water source(s) (i.e. a net increase to surface and/or
groundwaters when accounting for both water abstracted and natural recharge rates).
By contrast, the consumptive approach provides information regarding the volume
of rain and freshwater that is lost to ET during viticulture and/or is not returned to
the source from which it was abstracted during vinification.
As noted in Sect. 4.4, WWW effluents are often used for irrigation. Such reuse
activities would reduce the consumptive blue WF by reducing the volume of freshwater that needs to be abstracted from the environment for irrigation purposes. As
water is abstracted for process needs, this is captured in the Q winery term of Eqs. (5)
and (6). Under such reuse conditions, the values of Etc ,i and I from Eqs. (5) and
(6), respectively, would need to be adjusted to ensure that irrigation via effluent
reuse volume is not included to avoid double-counting this volume in the blue WF
calculation.
5.4 Grey Water Footprint
5.4.1 Approach
Rather than representing a direct measurement of the amount of water that is
abstracted from the environment, the grey WF represents the virtual volume of water
already present in the environment that is needed to dilute freshwater pollution during
wine making. Using the definition from Hoekstra et al. [28], the grey WF during viticulture would be driven by the volume of freshwater required to dilute contaminants
from vineyard leaching, runoff and drifting.
During vinification, the grey WF would be equivalent to the volume of freshwater
required to dilute pollutant loadings from the discharge of WWW effluents into
the natural environment. If effluent is used for irrigation purposes, the grey WF
associated with any potential runoff or drainage could be captured in the assessment
of viticultural grey WF and should, therefore, be excluded from the grey WF of
vinification. If WWW effluents are discharged to the environment via multiple pointsource discharge locations (e.g. treatment of a portion of the WWW via an on-site
treatment system with another fraction treated offsite, such as at a municipal WWTP),
then the overall grey WF would be the sum of the grey WFs calculated for each
discharge location.
Regardless of the wine-making stage or processes under consideration, the grey
WF is calculated as the minimum volume of water required to dilute the applied
contaminant loadings to the maximum allowable concentration in the receiver [28],
as follows:
W F grey =
˙
m e − ˙
m a
C max − C nat
(6)
123
does not deplete the natural water source(s) (i.e. a net increase to surface and/or
groundwaters when accounting for both water abstracted and natural recharge rates).
By contrast, the consumptive approach provides information regarding the volume
of rain and freshwater that is lost to ET during viticulture and/or is not returned to
the source from which it was abstracted during vinification.
As noted in Sect. 4.4, WWW effluents are often used for irrigation. Such reuse
activities would reduce the consumptive blue WF by reducing the volume of freshwater that needs to be abstracted from the environment for irrigation purposes. As
water is abstracted for process needs, this is captured in the Q winery term of Eqs. (5)
and (6). Under such reuse conditions, the values of Etc ,i and I from Eqs. (5) and
(6), respectively, would need to be adjusted to ensure that irrigation via effluent
reuse volume is not included to avoid double-counting this volume in the blue WF
calculation.
5.4 Grey Water Footprint
5.4.1 Approach
Rather than representing a direct measurement of the amount of water that is
abstracted from the environment, the grey WF represents the virtual volume of water
already present in the environment that is needed to dilute freshwater pollution during
wine making. Using the definition from Hoekstra et al. [28], the grey WF during viticulture would be driven by the volume of freshwater required to dilute contaminants
from vineyard leaching, runoff and drifting.
During vinification, the grey WF would be equivalent to the volume of freshwater
required to dilute pollutant loadings from the discharge of WWW effluents into
the natural environment. If effluent is used for irrigation purposes, the grey WF
associated with any potential runoff or drainage could be captured in the assessment
of viticultural grey WF and should, therefore, be excluded from the grey WF of
vinification. If WWW effluents are discharged to the environment via multiple pointsource discharge locations (e.g. treatment of a portion of the WWW via an on-site
treatment system with another fraction treated offsite, such as at a municipal WWTP),
then the overall grey WF would be the sum of the grey WFs calculated for each
discharge location.
Regardless of the wine-making stage or processes under consideration, the grey
WF is calculated as the minimum volume of water required to dilute the applied
contaminant loadings to the maximum allowable concentration in the receiver [28],
as follows:
W F grey =
˙
m e − ˙
m a
C max − C nat
(6)