Distillery Tasting Rooms – Alcohol’s Effects on Septic Systems

Even small amounts of distilled alcohol that is put down the drain can impact an onsite system

Distillery Tasting Rooms – Alcohol’s Effects on Septic Systems

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Distilleries are popping up from across the U.S. with over 2,200 locations making and selling their own brand of products to the public in 2022. These distilleries produce two main types of waste:

  1. Wastewater related to distilling
  2. Wastewater from tasting rooms and/or restaurants

The wastewater from distilling is typically composed of both spent grain, which is handled as a solid, and liquid waste from distilling and sanitizing. Depending on the size of the distillery and its location the volume may not be appropriate for a septic system and this waste may fall under different regulations since no human waste has entered the stream.   

There are more small distilleries that are operating outside of access to municipal wastewater treatment plants and questions are arising as to the characteristics of wastewater from tasting rooms. In typical tasting rooms there is distilled alcohol that is not consumed, and wastewater from bathrooms. If the tasting room involves a kitchen that would also be adding to the load. The University of Minnesota did a small study to see what the alcohol portion may be adding to the wastewater stream. Unconsumed alcohol is not only a source at tasting rooms but any establishment serving hard liquor. The study tested commercially available brands of vodka, rum and whiskey, and the results are shown below.

It is important to note that this data represents straight alcohol that has not been mixed with another beverage, water or ice. The most concerning data from this table are the oxygen demand (BOD and COD) of the samples. Even small amounts of distilled alcohol that is put down the drain will add oxygen demand to the system. Care should be taken when working with owners of such establishments to limit the amount of alcohol going down the drain, test the effluent from existing facilities, and then design and manage for the loading.

About the author: Sara Heger, Ph.D., is a researcher and educator in the Onsite Sewage Treatment Program in the Water Resources Center at the University of Minnesota, where she also earned her degrees in agricultural and biosystems engineering and water resource science. She presents at many local and national training events regarding the design, installation and management of septic systems and related research. Heger is the President of the National Onsite Wastewater Recycling Association and she serves on the NSF International Committee on Wastewater Treatment Systems. Ask Heger questions about septic system design, installation, maintenance and operation by sending an email to kim.peterson@colepublishing.com.


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