Wastewater Treatment Plant Digester Feasibility Study

Citizens Energy Group owns and operates two advanced wastewater treatment (AWT) plants, the Belmont and Southport AWT Plants which serve Marion County and the City of Greenwood. Primary sludge and secondary sludge are a product of wastewater primary and secondary treatment processes which then need to be dewatered and processed. Currently, the sludge is processed at the Belmont AWT plant where it is dewatered and then either incinerated or landfilled.
Past studies have looked at completely converting from incinerators to anaerobic digesters but have generally not considered supplementing the incinerators with digesters. The senior design team will focus on how to implement digesters at the Southport AWT facility including the use of generated methane and reuse of processed biosolids.
UPDATE
The goal of our project is to assess the feasibility of adding anaerobic digesters to the Southport Advanced Wastewater Treatment Plant. Implementation of these digesters would allow Citizens Energy Group to reduce the amount of sludge that is pumped from the Southport Plant to the Belmont Plant for incineration. Our team has been able to visit the Southport Plant to see the plant’s current functions and visualize how future anaerobic digesters would fit in at the plant. Based on the scope of the project, we have researched specific targets and created a 50 percent submittal to Citizens Energy Group. The targets we have evaluated include: methane production, sludge reduction, high strength disposal, food waste co-digestion, fate of biosolids, and phosphorus removal.
To finish the project, our primary focus is to quantify potential methane production rates, select an optimal method for sludge reduction, and perform a preliminary cost analysis of mesophilic and thermophilic stage digestion. We have conceded that an Upflow Anaerobic Sludge Blanket (UASB) Reactor is the appropriate digester for the needs of our client, and we are currently working on creating design specifications for this reactor. Our team is hopeful that our design can benefit Citizens Energy Group in reducing energy costs for treatment processes and making water utility more innovative.