Pittsboro, NC – Sludge aeration at the Pittsboro wastewater treatment plant is reportedly causing an unpleasant odor for some people living near South Small Street.
This is the second time in as many months that the regular sludge aeration process has caused complaints from neighbors.
The sludge aeration process at the plant has not changed in more than two years. Approximately every six weeks, operators at the plant mix up the sludge basin to prepare it for the addition of lime. Lime then sits in with the sludge for 24 hours to effectively inactivate viruses, bacteria, and other pathogens as well as raise the sludge’s pH level above 12.
Once that is complete, the sludge can then be hauled off to permitted farmland in the area and reused as fertilizer — providing moisture, nutrients and conditioning to the soil.
Exactly why the odor for some residents near the plant has been more noticeable the last two times the plant has activated the process remains unknown. The recent odor reports have come from neighborhoods south of the plant; longtime plant operators said reports in the past have tended to come from areas northeast of the plant. Recent land clearing in the area has been proposed as one possible reason for the odor being more noticeable south of the plant. Climate conditions may also have played a role in the dispersion of the odor.
As for the current status of the process, plant operators plan to add the lime to the sludge basin Wednesday and haul the sludge off Thursday.
TriRiver Water continues to investigate this situation and possible ways to mitigate the odor emitted during this process.