BNR Froth Control for Anaerobic Digestion

Nutrient removal wastewater treatment plants for nitrogen reduction in New York City have operating parameters which can lead to growth of filamentous froth-forming bacteria, especially Nocardia, more frequently than a conventional activated sludge plant. The risk of increased development of froth poses challenges during plant retrofits for nutrient removal if the possibility for froth to enter the anaerobic digesters and become trapped exists. Such a scenario may lead to serious equipment damage, health issues, and process upsets. Using research from nine New York City plants and operating staff at all levels, the authors evaluated more than fifteen froth mitigation techniques including preventative, physical, and chemical measures and used this research to recommend those strategies best-suited for a nutrient removal plant upgrade while avoiding excessive cost.