Using Metabolic Selectors to Facilitate the Development of Activated Sludge Granules

Technical Scope of Project

As water resource reclamation industry is transitioning towards adopting the nutrients, energy, and water (NEW) recovery technology, it is crucial to utilize wastewater for constructive reuse. Resources recovered from wastewater will allow water resource reclamation facilities (WRRFs) to meet demanding effluent discharge criteria and potentially become sustainable, net producers of energy and chemical nutrient products.

The transition towards adopting NEW recovery technologies depend on various factors including engineering feasibility, technology maturity and reliability, capital cost, operating cost, safety issues, recovered product resale value, market factors, and environmental impacts.  In order to accelerate the adoption of NEW recovery technologies, there is a critical need to demonstrate that existing technology can be used in these sustainable recovery processes. It is postulated that extractive nutrient recovery technologies that facilitate the biological accumulation of phosphorus can also be used to improve sludge settling characteristics at WRRFs, resulting in improved performance as well as capital and operating savings.  

Project Goals and Description

The goal of this research is to improve sludge settling characteristics in metabolic reactors at a local WRRF in the Susquehanna River Valley in order to treat wastewater more effectively and recover resources, specifically phosphorus, within wastewater for reuse. This local WRRF is one of a select few locations that uses SBRs. The sequencing batch reactor system has several advantages over conventional wastewater treatment systems.  Typically, wastewater undergoes several phases of treatment before being discharged as purified effluent.  The first phase is a primary treatment phase that involves passing wastewater through screens to settle out sludge. In the secondary treatment, the sludge is activated through aeration and microbes that are grown within the tank.  Finally, the wastewater heads for tertiary treatment before being discharged into a body of water.  In the tertiary treatment, activated sludge settles out and is pumped back into the secondary treatment tank.  This sludge is called return activated sludge (RAS).  As RAS is pumped in a conventional wastewater treatment systems, it experiences shear stress, resulting in a decrease in its ability to settle efficiently.

My work includes sampling to characterize the internal storage phenomena associated with phosphorus accumulating organisms (PAOs) in order to develop granular sludge that is able to settle out of wastewater more efficiently than non-granular sludges.

Preliminary Results

Preliminary results from research show that: 1) biomass has some potential for granulation and 2) biomass has strong phosphorus-accumulation potential. These two results will be presented in details in the poster. Ultimately, it is desired that the information acquired from this research can be shared with and applied to waste resource recovery facilities throughout the country and beyond so that they can operate more efficiently and sustainably.