All winemaking activities, no matter how sustainable, will add some residual organics, nutrients and salinity compounds to wastewater. When discharged to land or subsurface, these winemaking outputs can cause odors, degrade soil and impact groundwater or surface waters.
Managed effectively, however, these winemaking outputs can be assimilated into the environment without harmful impact and may even be ‘recycled’ in ways that benefit plant growth.
An important first step towards efficient water quality management is to identify and understand the potential sources of wastewater loading in the winery.
The top three wastewater outputs to look out for are:
from solid waste, including grapes and stems
e.g. sodium, potassium and sulfate, from cleaning and softening chemicals
primarily nitrogen, from wine and solid waste
Loading is the total mass of a constituent in the wastewater stream, usually expressed in lbs (e.g. "50 lbs of Nitrogen")
Loading rate describes how that mass is applied to a given area per unit time (e.g. "50 lbs Nitrogen/acre/year")
SOURCES OF WASTEWATER LOADING
Common winery waste materials that may be sources of organics, salts or nutrients include:
Grapes, stems and other solid waste
Spilled juice and wine
Lees from tanks, barrels, filters and other equipment
Bentonite and diatomaceous earth
Cleaning, sanitizing and softening chemicals
[Adapted from the Comprehensive Guide and Water & Wine.]