Chapter 24

Winery Wastewater Treatment

Winery Wastewater Treatment Systems

Each winery generates wastewater with a unique quality, quantity, and seasonal variation pattern. Identification of an appropriate wastewater treatment technology or multiple technologies is strongly influenced by the characteristics of the wastewater stream and the degree of treatment needed to meet site-specific discharge requirements, which itself will depend on whether it is discharged into the public sewer network, into a natural waterway, or whether it is to be reused in the process, or to irrigate the vineyard.

Physical Treatment

Many wineries employ physical processes for the removal of solids from process wastewater. This type of treatment is a rapid way of reducing the BOD concentration in effluent before disposal or reuse. The treatment technologies employed are usually energy efficient. Typically, they are not standalone processes, but are used in conjunction with other processes in a treatment train.

Coarse and Fine Screening

Wastewater is usually collected in one or more sumps at the wineries. The first step in the treatment of winery wastewater is usually to remove the solids, such as grape pips, skins and stems, by passing the water through a coarse screen using technologies such as bar racks, fixed and rotary screens, and rotary disks.

Clarification

Clarification processes are used to separate suspended solids from wastewaters. Sedimentation is the most common process, although DAF is also being used where space is a consideration or where solids are easier to float (e.g., anaerobic biosolids). Some wineries have used centrifuges for removing organic solids such as seeds, stems, and skins from wastewater and suspended solids.

Chemical Treatment

The winery wastewater is normally acidic which requires neutralization. Wastewater with a low pH is generally neutralized using sodium hydroxide (NaOH), lime (CaO), magnesium hydroxide (Mg(OH)2), or calcium hydroxide (Ca(OH)2).

Biological Treatment

The reduction of organic compounds in wastewater is generally addressed through a combination of physical/ chemical treatment for solids and biological treatment. After the winery wastewater has undergone physical and chemical treatment, it can be biologically treated.

Aerobic Wastewater Treatment

Aerobic wastewater treatment systems include the addition of air (oxygen) within the wastewater reactor. Aerobic wastewater treatment encourages the growth of naturallyoccurring aerobic microorganisms as a means of renovating wastewater. Such microbes are the engines of wastewater treatment plants.

Anaerobic Wastewater Treatment

Anaerobic wastewater treatment processes use bacteria to breakdown BOD, COD, and other organic contaminants with the absence of oxygen. Anaerobic systems do not require the addition of air to the reactors, which lowers energy costs to operate the system. In many instances, anaerobic digestion systems can be energy positive.

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