Chapter 25

Brewery Wastewater Management

(book excerpts)

The beer brewing process generates large amounts of wastewater effluent and solid wastes that must be disposed of or treated in the least costly way to meet strict discharge regulations set by government entities. Brewery wastewater typically has a high biochemical oxygen demand (BOD) from all the organic components (sugars, soluble starch, ethanol, volatile fatty acids, etc.). Brewery wastewater usually has temperatures ranging from 25 to 38 degrees C (77–100°F). The pH levels can range between 2 and 12 and are influenced by the amount and type of chemicals used in cleaning and sanitation (e.g., caustic soda, phosphoric acid, nitric acid, etc.). Nitrogen and phosphorus levels are mainly dependent on the raw material and the amount of yeast present in the effluent. Solid wastes consist of spent grains, spent hops, diatomaceous earth used for filtering, waste yeast, and trub. Broken glass, grit, paper, wood, and bottle caps that are classified as solid wastes too. Treatments of brewery wastewaters include the application of physical, chemical, and biological methods. Physical treatment is necessary to reduce suspended solids. Chemical treatment of wastewater involves pH adjustment as well as other treatments. Biological treatment uses bacteria to remove organic contaminants from wastewater. There are two types of biological treatment; aerobic and anaerobic. Aerobic wastewater treatment takes place in the presence of oxygen while anaerobic treatment takes place without the use of air or elemental oxygen.

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