Since the opening of the South Wake Landfill in 2008, a significant number of neighborhoods have developed nearby. At that time, the closest neighborhood was approximately three quarters of a mile from the landfill. Today there are houses within 900 feet (less than a quarter mile) from the landfill. This has effectively led to a significant increase in odor related complaints over recent years.
Wake County's Solid Waste Management Division, along with our landfill operator (Waste Industries) have put into place numerous operational and constructed solutions that have not been fully satisfactory in minimizing odor complaints. However, we are constantly continuing to evaluate various methodologies to minimize odors.
It is important to note that due to proximity there is no solution currently available that will eliminate all possible chances for occasional odors, especially at the nearby neighborhoods (less than half mile). The goal is to minimize the occurrence and duration of those events.
It is important to note that there are two areas of odor control. First, the County's Solid Waste Division's primary focus is on
landfill gas related elements. As the waste in the landfill decays, methane (which itself is odorless) is generated and does its best to escape the landfill, taking with it a variety of malodors. Our landfill gas system is a series of wells, piping, blowers and a flare for destroying the methane and the corresponding odors. The Division works with a third party, Ingenco, in converting most of the methane to electrical power (5-6 Mwh). The second area of focus for minimizing odors is the
working face of the landfill (where the waste is placed and compacted daily). The working face, which moves daily, and its associated odors are the responsibility of Waste Industries. Based upon conversations with Waste Industries, beyond the minimization of the daily size of the working face and providing appropriate cover at the end of every day, they are also pursuing new and hopefully improved approaches to dealing with these odors.
Regarding
landfill gas odor mitigation, we are pursuing the following items:
- Installation of 13 additional landfill gas well pumps. This will triple the number of wells with pumps and allow the removal of further water blockage of wells for the purposes of extracting more landfill gas and destroying it before it becomes a malodor. This work was completed in late May.
- Installation of 30 automated landfill gas wellheads. All the wells (over 60) currently are manually adjusted on a weekly/every other week basis to maximize landfill gas collection. Unfortunately, with rapidly changing weather conditions this means that sometimes the wells get out of balance within days (or sometimes hours) of the weekly/bi-weekly adjustments. This can lead to the potential for malodors. The installation of automated wellheads (very new cutting edge technology) will allow the wells to stay in balance (samples are taken every hour and adjustments made every 3 hours) compared to weekly or even every other week for the manual tuning. Installation was completed in mid-May.
Wake County's Solid Waste Management Division is very excited about the above two projects and their potential to reduce landfill gas related malodors. Further, there are a couple of additional projects that are under consideration that will hopefully be completed in the next few months:
- Contract with a company called Envirosuite that will provide a mobile based app for complaints as requested by the Town of Holly Springs Board as well as a software/hardware solution that will allow the County to provide much more reliable information regarding malodors. The contract for this is in process with an expectation of the system being in place and fully operational by the end of July.
- Installation of additional landfill gas piping that will allow our system to be more efficient in collecting landfill gas. This work is expected to start in August and be complete by September.
Regarding the efforts to reduce working face odor mitigation, Waste Industries is pursuing:
- The use of a sprayed-on material that will be added to Waste Industries' daily closure process that has been used successfully in similar applications in landfill and compost operations. They expect to have an operational pilot test use of the material by mid-June.
- Wake County continues to work with Waste Industries to make sure that the landfill is fully closed at the end of the day per permit requirements.
- The equipment and rain issues mentioned previously have made the landfill closure difficult on a few occasions during the past few months. We will continue to insist that our facilities meet all requirements for closure daily. Note that the existing perimeter vapor-based odor control system is expected to stay in place and continue operations.
We believe the combination of items described above will provide the best opportunity to minimize odor related impacts.
Please be aware that our facilities are not the only potential source of odor related issues in the area. There is a privately-owned construction & demolition landfill next door to us (to the north next to 540) as well as both a municipal wastewater plant to our north (near Bojangles on 55) and south (Holly Springs industrial park off Green Oaks Parkway).
