This new system produces green energy through the production of biogas and will use an advanced anaerobic digestion process to treat the biosolids, wastewater byproducts, which will reduce the overall biosolids amount by around 50 percent when compared to the current system. The new system will feature an innovative process called a “thermal hydrolysis process," which acts as a pressure cooker to help to improve the anaerobic digester performance. This results in production of more biogas and reduces the amount of biosolids produced.
Additional Benefits: This project will generate a renewable fuel that will be used primarily to fuel the City's GoRaleigh bus fleet.
Besides the decreased biosolids amount, the project will also create biogas which will be captured and converted to a renewable natural gas and delivered to a nearby natural gas pipeline. This renewable natural gas will primarily be used as fuel for the City’s Go Raleigh bus fleet or it can be sold to a third party as revenue. The biogas is projected to produce enough fuel to run more than 70 City buses per day. Ultimately, the new project will produce green energy, allowing the City to make great strides in moving towards reducing its greenhouse gas emissions and meeting its sustainability goals.
This project will be the first municipal wastewater digester that will be producing renewable natural gas in North Carolina. This City of Raleigh will also be one of a just a few municipal agencies in the United States that are using their Renewable Natural Gas to run their own fleet.
Bio-Energy Recovery Project
The Bio-Energy Recovery Project is a new way to manage wastewater byproducts at the Neuse River Resource Recovery Facility, which is the City of Raleigh's main wastewater treatment plant. Historically, the wastewater byproducts, called biosolids, are highly treated at the Neuse River Resource Recovery Facility and applied to surrounding agriculture fields or taken offsite by a contractor. However, because the existing biosolids handling equipment is in need of replacement and the overall biosolids amount will increase with future growth, a new treatment system is needed.
The new process will produce a high-quality final solids product that will meet the Environmental Protection Agency's strictest standards, know as Class A biosolids, that will be beneficially reused as a soil conditioner.
New solids handling upgrades began in the spring of 2019, and it is scheduled to be completed by spring 2025.
