[1] Classical analysis for VA involves distillation in a Cash or Markham still, followed by titration with standardized sodium hydroxide, and reporting of the results as acetic acid.
[1] In the some countries, including the United States, European Union, and Australia, the law sets a limit on the level of allowable VA.[1][7][8] In wastewater treatment, the volatile acids are the short chain fatty acids (1-6 carbon atoms) that are water soluble and can be steam distilled at atmospheric pressure - primarily acetic, proprionic, and butyric acid.
[10][11] In a well functioning digester, the volatile acids will be consumed by the methane forming bacteria.
[13] The acceptable level of volatile fatty acids in environmental waters is up to 50,000 ppm.
[15] Titration provides approximate but relatively quick results; it is widely used by wastewater treatment plants to track a status of a digestor.
[18] Volatile acid concentration can be used to detect adulteration of butter with less expensive fats.