Hudson, Massachusetts Utilizes Dissolved Air Flotation Tertiary Treatment to Achieve

Over the past several years, state and federal regulations have become focused on water quality- based standards and nutrient criteria. Stringent phosphorus standards have been or will be imposed at many of our wastewater facilities. New technologies are emerging to address these limits. However, the majority of these technologies are water treatment based technologies and can perform very well during controlled pilot testing. Significant investigation must be undertaken to understand and address pilot test results and how those correlate to full scale process performance and success.The Hudson Wastewater Treatment Facility (WWTF), facing a stringent phosphorus limit of 0.1 mg/l, conducted pilot testing to ascertain the validity and performance of a dissolved air flotation (DAF) process to achieve compliance with their National Pollutant Discharge Elimination System permit. Following a successful pilot, extensive optimization of the full scale facility was required to achieve the expected phosphorus removal performance. The most significant cause of differences between the pilot test and full scale performance was determined to be influent phosphorus levels to the dissolved air flotation process (and resulting sludge production) and the water surface variability.Following the optimization period, the dissolved air flotation process has performed to expectations routinely achieving an effluent total phosphorus concentration of 0.1 mg/l.