Achieving Many Benefits of Phased Digestion and Avoiding the Pitfalls

Operations data for full-scale biosolids digestion facilities are summarized with emphasis on the potential for attaining added benefits such as biological foam control and biogas increase within existing infrastructure, maximizing the existing capacity. Factors that allow higher loading rates to phased digestion systems and the lessons learned from these full-scale case studies show that phased digestion can be implemented by staging the existing digesters to improve pathogen reduction, odor generation potential, and volatile solids reduction, also reducing the off-site transport costs. More importantly, under the current push for attaining sustainability, energy efficiency and reduction of carbon footprint of wastewater treatment facilities can be achieved through improving solids handling practices by various methods of phased digestion implementation.