Robeson Creek Water Reclamation Facility is a wastewater treatment plant located in Pittsboro. 

The facility uses two conventional basins to treat raw sewage and discharge clean water back into Robeson Creek. The facility is certified to treat up to 750,000 gallons of wastewater per day.

Homes and businesses in Pittsboro that are connected to the sewer distribution system send their waste to this facility. However, work is underway to connect Pittsboro's sewer distribution system to the Big Buffalo Water Reclamation Facility in Sanford. When this connection is completed in 2027, it will provide more sewage capacity and resiliency for Pittsboro customers. 

While the water filtration process to create drinking water is a chemical process, the wastewater treatment process is a biological one. Wastewater plant operators utilize microscopic organisms -- bacteria, protozoa, and metazoa -- to break down and clean the wastewater. 

The Water Reclamation Process

1 - The Headworks

All sewage flows into the facility and is filtered through a bar screen, which catches large debris like rags, toys, sticks and rocks. Removing the large debris helps prevent damage to other parts of the facility later in the treatment process.

2 - Conventional Basin

The sewage then flows into one of two conventional basins at the facility. Each basin is made up of two zones: one for aeration and one for clarification.

• The first step, aeration, mixes the sewage with activated sludge that's teeming with microorganisms. Oxygen is pumped through the mixture to help the microorganisms thrive, which results in them breaking down organic matter and nutrients in the sewage. This process converts harmful pollutants into less harmful substances.
• After aeration, the mixture goes into the clarification part of the basin. Here the mixture settles, alloing sludge to sink to the bottom of the tank and clear water to remain at the top. 

At this point the process breaks up into two different areas with the water continuing on in one direction and the sludge heading in another.

Water

A1 - Sand Filters

Clear water from the clarifiers flows through sand filters to remove any remaining fine particles.

A2 - UV Disinfection

The cleaned, filtered water then flows through a UV disinfection channel filled with ultraviolet lamps. The lamps shine UV light throughout the water. The UV light is extremely effective at sterilizing any remaining bacteria, viruses and protozoa. Sterilization inactivates the microorganisms, thus rendering them harmless. Doing that is safer for the environment than using chemical disinfectants, which would then be in the water when it is discharged in the next step. 

A3 - Discharge

Robeson Creek Water Reclamation Facility discharges its fully treated water into Robeson Creek, which eventually flows into the Haw River.

Sludge

B1 - Sludge Storage

Sludge from the clarifiers goes into a sludge storage facility on site. 

B2 - Drum Thickener

The sludge is eventually processed through a drum thickener. This device separates water from the sludge--until the sludge is dehydrated to the desired consistency. The water removed in this process returns to the headworks for retreatment.

B3 - Biosolids

When the sludge reaches the right consistency, it is saved and stored. During storage more biological processes take place, ultimately transforming the sludge into biosolids that can be shipped to local farmers in the land application program. Those farmers are approved to use the biosolids as fertilizer for crops that will not be used for human consumption.