Solid Waste Management Program
Odors - Bridgeton Sanitary Landfill
Updated Nov. 9, 2013
Odors surrounding the Bridgeton Landfill have been attributable to the subsurface smoldering event or corrective actions to address the subsurface smoldering event. Some of the odor causing events have included:
- An overall increase in the volume of landfill gas generated by the facility as a result of the subsurface smoldering event.
- In mid-January, a break in a leachate line resulted in a 1 1/2 week period with heightened odors.
- Drilling of gas extraction wells in mid-Feb. through mid-March, resulting in odors intensifying during several hours on days when pockets of pressurized landfill gas were encountered and venting occurred.
- During June and July, abandonment of 6 reinforced concrete pipes part of the previous leachate management system and installation of 25 perimeter collection sumps, changes in leachate management with tank storage and loading of trucks and maintenance issues with gas extraction wells.
Maximum Odor Dilution Graph
This graph provides odor trends from April 19, 2013 through Oct. 9, 2013 based on the highest odor dilution point as recorded by a portable olfactrometer and/or laboratory results. The department relies on American Society for Testing and Materials (ASTM) approved standards for odor measurement. The Dilution-to-Threshold (D/T) ratio is a measure of the number of dilutions needed to render the air neutral. The D/T ratio reflected in the daily air monitoring reports is determined by the amount of carbon-filtered air required to make the odors non-detectable divided by the amount of odorous air. The formula used is D/T = Volume of Carbon-Filtered Air / Volume of Odorous Air.
Daily monitoring events continued through completion of the interim cap on the South Quarry and are continuing. The department’s staff is conducting air monitoring at a minimum of 12 locations using an odor detector or field olfactometer, which is a portable odor detecting and measuring device. The device is used to measure and quantify odor strength in the ambient air. Sampling occurs around the perimeter of Bridgeton Sanitary Landfill at least two times per day and as needed, based upon community complaints received between the two daily cycles.
Additionally, during comprehensive sampling events, the department's contractor collected eight samples for odor analysis by the St. Croix olfactory method (ASTM-E679). ASTM E679 is an ASTM International standard method for determination of odor thresholds. The comprehensive sampling event results along with daily air monitoring reports are available on the Reports webpage.
Corrective Actions taken by Republic Services to Manage Odors
Oct. 28, 2013 - Republic Services advised the department today they are completing maintenance work on a leachate collection line that may result in short-term odors outside the facility's property boundry. Republic Services indicated the work should be completed later today.
Oct. 17, 2013 - Republic Services notified the department that later in the afternoon, the Bridgeton Landfill took the east side candlestick flare offline during installation of electrical and mechanical upgrades. The upgrade was expected to take approximately one hour at which time the flare was brought back on-line. As a result of this work, there was the potential for off-site detection of odors.
Oct. 5, 2013 - Republic Services advised the department that approximately five acres of the additional EVOH liner planned for installation in the South Quarry has been completed. In the coming week, Republic Services indicated work will continue on the EVOH liner installation. Continuation of these construction activities is weather dependent.
Oct. 4, 2013 - Republic Services notified the department that a perimeter sump in the southwest corner of the South Quarry required some maintenance. The repair required the opening of a small portion of the EVOH cap material and resulted in some local excavation. The work required several hours and had the potential to result in off-site detection of odor.
Sept. 30, 2013 - Republic Services informed the department that 4.65 acres of the additional 7.5 acres of EVOH liner have been installed on the north and east sides of the South Quarry. The work crew will continue installing EVOH material on the west side of the landfill. Additionally, two new candlestick flares are now operational and have taken the place of two older enclosed flares. The new flares, combined with a new blower that was also installed, will improve the efficiency of the landfill’s gas collection system.
Sept. 14, 2013 - Republic Services informed the department they received and have begun installing an additional 7.5 acres of EVOH liner over existing HDPE liner at Bridgeton Landfill for more effective odor control. As the new EVOH material is being placed over existing material, odors are not anticipated. However, some short-term odors may be generated as gas extraction wells in the placement area are prepared for installation of the new material. On Thursday and Friday, residents downwind from the landfill reported some slight to moderate odors during work hours.
Aug. 31, 2013 - Republic Services provided a work plan update to the department on activities for the coming weeks at Bridgeton Landfill. Republic Services' plans include continuing site preparations for installation of new candlestick flares, for a new leachate management system and for installation of an additional 7 acres of EVOH cap material to cover the remaining black High Density Polyethylene (HDPE) liner material for more effective odor control.
Aug. 19, 2013 - Bridgeton/Republic notified the department from ongoing review of landfill operations that some areas of the previously installed HDPE liner were not as effective at capturing odors as the EVOH material in the new South Quarry cap. As a result of the review, the facility will be covering the remaining 7.5-acre HDPE liner with the new EVOH material as well as extending its use into other strategic areas to target smaller sources of odor.
Aug. 9, 2013 - Bridgeton/Republic notified the department that as of Aug. 7, 2013 the interim capping system was complete. The new EVOH interim cap is installed over approximately 32 acres in the South Quarry. Upon completion of the interim cap construction, the total area covered by flexible membrane liner will be approximately 42 acres. Additional details and a copy of the capping plan are available on the Construction Schedule webpage.
June 3, 2013 - Bridgeton/Republic completed abandonment of 6 reinforced concrete pipes (RCP) and installation of 25 perimeter collection sumps, a part of the new interim capping system. The department created a Reinforced Concrete Pipes webpage to provide additional information on this topic.
Mid-March, 2013 - Bridgeton/Republic completed expansion of the facility's gas collection and control system, in part, to assist with managing odors generated by the subsurface smoldering event.
Jan. 2012 - Aug. 2013 - Bridgeton/Republic added approximately 11 acres of HDPE flexible membrane liner and significant volumes of soil to the landfill cap to assist in controlling odors generated by the subsurface smoldering event.