Winery wastewater can contain various other constituents, but the biggest one to look out for and monitor is nitrogen. Winery wastewater can contain high concentrations of ammonia (NH3) and organic nitrogen, and potentially some nitrates (sometimes from source water).
Nitrogen is an important plant nutrient, and depending upon the form of nitrogen in the wastewater, a portion may be ‘recycled’ via irrigation to help meet crop or landscaping needs. Some nitrogen will be volatilized or stored in soil humus.
Depending on soil conditions and the method of application, however, other forms of nitrogen may convert to nitrate and leach to groundwater or surface waters. Nitrate in drinking water can cause significant health problems when ingested by humans, and the State of California has numerous efforts in place to reduce nitrate impacts on groundwater.
Some potential sources of nitrogen in winery wastewater include:
pH neutralization inputs (e.g., ammonium hydroxide)
Nitrogen in wastewater can be removed with biological treatment (e.g., nitrification and denitrification processes), but source controls, including solids removal and procedures to reduce wine loss, will reduce back-end treatment costs.
[Adapted from the Comprehensive Guide.]