Materials management for a sustainable future
The District has developed an integrated solid waste management program for the member communities of Dartmouth and New Bedford: recycling, composting and landfill disposal. The keystone is the Crapo Hill Landfill, a state-of-the-art lined facility that opened in 1995, and a 3.4 megawatt power plant fueled by landfill gas. The staff at Crapo Hill always welcomes tour groups; please download the request form if you are interested.
INFORMATION ABOUT LANDFILL ODORS
HOW TO REPORT AN ODOR
The District operates a 24/7 odor hotline. Residents can report odors they suspect are coming from the landfill by calling (508) 763-2423.
When calling, please:
· describe the intensity of the odor on a scale of 1 to 5, with 5 being the most intense
· provide the address or specific location where the odor is detected
· describe the odor as best you can (trash smell, gas, rotten eggs)
· if you would like a call back, provide a telephone number where a District representative can reach you
One of the goals of the District is to be a good neighbor by limiting our impact on those who live and work closest to us. As solid waste decomposes, it generates gases, consisting mainly of methane and carbon dioxide, with trace amounts of other gases. One of those gases is hydrogen sulfide, which is responsible for most landfill odors. Over the last few months, the District has experienced persistent odor issues associated with landfill operations. Investigations have shown that hydrogen sulfide concentrations are higher than normal, which is likely contributing to odors. We are aware of the inconvenience this can cause and are working to address this issue.
Below is a list of operational practices regularly used to reduce the potential for odor, as well as other actions we have taken to address the recent increase in odor events.
- Collect landfill gas via a network of wells in the landfill. The gas is piped to the landfill gas to energy plant on site, where it is burned to create electricity. The plant can produce up to 3.3 megawatts of electricity from landfill gas.
- Monitor the landfill to identify areas where landfill gas is being produced and which are not under the influence of the landfill gas collection system. In these areas, candlestick flares are used to burn landfill gas and reduce the potential for odors.
- Minimize the size of the “active area”, or the area in the landfill where solid waste is disposed
- Install daily cover material over solid waste at the end of each working day
- Monitor odor conditions during normal operating hours to determine whether odors are present
- On slopes where no landfill activities will occur, additional intermediate cover has been installed and seeded to establish a vegetative layer; the vegetative layer reduces the potential for erosion, creates more stable intermediate cover, and reduces the potential for gas to be released
- Immediately cover any odorous loads that might be received
In addition to routine operational practices, we have also taken additional measures over the last few months to reduce hydrogen sulfide concentrations in landfill gas and reduce odors. These include:
- Discontinued accepting material that might result in elevated hydrogen sulfide, such as material containing gypsum
- Introduced “ferric hydroxide” over the active area of the landfill to help neutralize hydrogen sulfide production.
- Covered the active area of the landfill with woodchips, which can act as a bio filter, and reduce the potential for odors.
- Installed additional clay soil cover on the outer slopes of the landfill. Clay is less permeable than most soils and can help to seal in odor.
- Increased the frequency of landfill gas leak checks within the landfill gas to energy plant from once per week to once every two days. Any leaks found are promptly repaired.
- Increased the frequency of monitoring and adjusting landfill gas wells containing elevated levels of hydrogen sulfide to ensure these wells are functioning efficiently.
- Changed the damper position for intake of engine combustion air to take combustion air from inside the engine room instead of from outside. This helps reduce venting air from the engine room to the outside, and more engine room air is used for engine combustion.
We pledge to continue working to confront odor challenges. Upcoming work includes:
- Hire a landfill gas expert to identify sources of persistent odor and develop a plan to address these.
- Investigate technologies to remove hydrogen sulfide from the landfill gas before it is combusted.
- Permanently cap approximately 7 acres of recently active landfill. This work is scheduled to begin by July 2016 and should be completed in fall of 2016. As part of this project, approximately 10 new gas wells will be installed prior to capping. This should improve gas collection capability in the area to be capped.
Occasionally, certain construction activities to reduce odors may actually result in temporary odors. In this section, we’ll provide periodic updates of any upcoming work that may produce a temporary odor.
Week ending January 27, 2017
Gas well drilling is ongoing. Some odors will be associated during these processes. Excavated areas will be backfilled before the end of the day. Any material removed and not placed back in the excavation will be disposed of in the landfill and covered before the end of the day. All excavation work will be conducted during normal business hours between Monday and Friday.