Anaerobic Digestion of Dairy and Cheese Wastewater -- How Dairygold Found Success with Low-rate Technology

Dairy processing wastewater generally contains biodegradable organic compounds, high concentrations of fat, oil, and grease (FOG), nutrients, calcium and other inorganic compounds. Dairygold Co-operative Society, a large dairy processing plant in Ireland chose a low-rate anaerobic ADI-BVF® reactor system to integrate with its existing biological nutrient removal (BNR) system. The system anaerobically pretreats a large portion of the process wastewater with little maintenance and operator attention, while significantly reducing operating costs for the entire treatment system (electrical, waste solids disposal, chemicals, dissolved air floatation [DAF] operation, etc.). Biogas generated in the ADI-BVF® system is utilized in an in-plant dual fuel boiler to produce hot water for the plant. Details of its four-year successful operation are presented in this paper.Consistent excellent system performance and significant cost reductions demonstrate that the BVF® system is a simple, yet robust, efficient method for treating dairy wastewater.