Developing a new landfill or adding a landfill cell is all about efficient and early planning.
By Christopher Lund, PE
When you say you are having a conversation about evaluating new landfill sites or thinking about expansion, you get second looks as to the sanity of your person. It is an engrossing and complex process. The following discussion only scratches the surface and serves to refamiliarize the listener to such an undertaking.
If you have the fortune of having a landfill asset in your integrated solid waste inventory, then an adequate lead time on looking for that next landfill site or additional landfill cell should at least begin 10 years in advance of running out of space. If you are not as fortunate and do not have such an asset, planning is always an ongoing process. Some entities can get by with less planning and development time, but it can be a long process and there is need for time to develop the necessary capital (political as well as financial) to fund that investment. Let’s discuss some of a myriad of considerations and factors.
A New Landfill Site
Type of Land
From a topographic perspective, land that is gently sloping is desirable, but not necessary. Land that has no defined water courses or wetlands is highly desirable as well as an area that can meet typical siting criteria for Subtitle D landfills.
Size Evaluation
The answer is large, large, large! There is great need to plan for not only adequate airspace for disposal planning over a typical horizon of 20 years, but also for buffer zone requirements to isolate the facility from sensitive receptors, and additional ancillary space for material processing facilities used to divert material from landfill disposal through a range of technologies and processes.
Location and Governmental Issues
The single most important aspect of landfill development is where the facility should and can be located. Siting a facility must be performed with required public involvement, which addresses equity and environmental justice aspects to decision-making and
approvals relative to the siting of the landfill. Important aspects of this process include:
• Traffic and Transportation—Along roadways near the development location
• Future Surrounding Development—Local Master Plan coordination
• Environmental Impacts—Odor, Air Quality, Groundwater Protection
Typically in the recent past, facilities were located as far away from large populations as possible—the rationale being the lower the population impacted the better. However, this unfairly targets people in rural communities that are typically less well off than communities of large cities. These cities and urban regions with significant tax bases are able to afford sending its waste out of their immediate region and long distances, therefore, not locating a landfill in their area. For smaller less affluent communities, their economic condition necessitates landfills to be a primary management practice until cost structures for landfill diverting management practices adjust favorably and private owners alike must provide proactive communication with the neighboring community. Even though a landfill may have a master plan to build several phases of landfilling, the facility could easily be stopped short of its full design life by relatively minor but vocal and active opposition to it by residents and businesses affected by the facility.
Equipment
For landfill development, a range of equipment and systems will be needed. For landfill operations, at a minimum, you should consider:
• Landfills need mobile equipment to landfill material that is brought in for disposal.
• Landfills need a leachate collection and removal system to manage leachate generated from the landfill.
• Landfills need a gas collection and control system to manage greenhouse gasses.
• Landfills need stormwater management structures to manage stormwater across the site and keep it from contacting waste.
• Maintenance facilities.
• Typically, planning and design of landfill facilities now plan for the future with space allocated for future co-located convenience/drop-off centers and transfer station facilities to divert materials from being landfilled.
Expanding to an Additional Landfill Cell
Most communities have a mission and vision associated with their solid waste management program. When implementing an additional landfill cell, the primary mission, typically, is to continue to serve the community with waste management services, which is a public health imperative.
Before starting the process, be sure that you have the capital and funding in place. In addition, each expansion is required to be approved if it is not already part of the master plan. Typically, when a landfill is first developed, a master plan is created that includes a plan for building out the entire site. However, if the government decides to change the master plan, it will typically need to go under review by the public and regulatory agencies because expanding landfill cell boundaries is always considered a major modification to the Plan and requires public comments. Start planning that early because there is typically a regulatory need to allow a certain amount of time be provided for these factors.
Will an Expansion Cell Work on the Existing Land?
That all depends on how much land remains in the landfill complex. Most new landfill developments have thought out their
future expansion (master plans) and have it planned to such a point that they have purchased enough land that accounts for full build out. Those eventualities, such as building out (filling up) the master planned space is accounted for including future development and its impact on use in that area. The development of landfills has come a long way, through trial and error when locating facilities, especially when meeting regulations in place to protect the
community.
The most important factor when expanding is to consider your hydrogeologic modeling into that new area because typically you do an evaluation for each new phase of a landfill, and you will want to get that additional groundwater monitoring data to understand the groundwater conditions before you move to expand. Also consider performing additional biological assessments to determine if rare or endangered species have moved into the property, and depending on the size of the site, whether you want to do a complete historical features evaluation of the land. This can be done in phases as well to see if there are features that need to be protected.
When Closing a Fully Filled Phase or Cell of the Landfill
When closing an area of the landfill, whether it is one phase or several phases, adding a cell is typically part of the process prior to the closure. Expansion and closure do go hand-in-hand. In typical operations, sites are constantly putting interim cover soil on cells to ‘temporarily close areas’. So when operations get to the point where the last year or two of filling a phase (or cell) is ongoing, facilities should be building a new cell. For cells with outside slope sides—that is, a side of the cell that is permanently going to be on the outside edge of the landfill configuration—these sides of those cells could be permanently closed. Typically, interim soil cover is placed, the slope is allowed to ‘age’ in which it will settle below the finished grade of the facility, gaining more airspace resulting from material decomposition. Operators will go back into this outside slope, strip the interim cover and place more material where settlement has occurred and then finish with permanent cover to close this slope area.
The interior side slopes of a cell that are going to have cells built up against it, would just require intermediate cover placement when finished. Operations would not place the final cover because having the option to go back into that cell after settlement and fill that part with additional material maximizes cell space use. After one or possibly two times of doing that, interim cover is placed until the next cell is built next to or over that cell. There should be at least 12 inches of cover material over the filled material, stormwater management controls implemented, and operators will need to evaluate slopes, berms, and down chutes to carry the stormwater offsite. This intermediate cover will need to be stabilized with grass or other erosion control methods to keep that cover material in place. This stabilization effort needs to occur in a relatively quick period after intermediate cover is placed.
Final cover to close the facility is required at the end of the life of the landfill and portions of the facility can also be incrementally closed, as described, by phase or cell, however, it will be more economical to place over a larger area all at the same time. Using an outside contractors, operators can get multiple phases closed quickly in a short construction period and cost-effectively.
The Importance of Strategic Planning
During this process, strategic planning needs to be considered as there are always options to diverting that material from landfills. Since less waste to landfill is a desired goal, when a community typically begins to look at a new cell outside of their master plan, they should do a planning analysis to see how big the future cells or phases need to be. However, it can be more expedient to put in a transfer station and have that material disposed of elsewhere, other than the current landfill or within their municipality, there may also be a compelling case to implement a material diversion program, municipal recovery facility, or sustainability park where the material is brought in and processed, with recycled commodities being recovered, reducing waste to the smallest amount of material practicable before the remaining residual material from the diversion program gets landfilled.
Note: A feasibility study is always useful to evaluate the cost of expanding a landfill relative to putting in a transfer station and transferring that material to another disposal location or developing material diversion program to divert more from the landfill and reduce that which is landfilled, extending its life and lessening the need for future landfill cells.
Strategic planning also allows organizations to pull together the different entities that need to be involved early in the process to get everyone engaged, and make sure things are moving more efficiently and equally. Another benefit of advanced planning is to be able to set aside the funding and capital that is needed for improvements. Do not wait until the community has hemmed itself in and there are limited options or no choices at all. I have seen communities paint themselves in a corner because they did not have forward-looking plans in place. Procrastination or no planning at all takes the control out of the community’s hands and they are left with what might be available in the market in the private sector.
Bringing in the Experts
The benefits to bringing in a solid waste and sustainable materials management consultant include efficiency and experience, sharing how other localities and communities have already navigated their needs. They can provide the proper planning, time management, and laying out the schedules so the process can be more efficient. Whether a community needs help, however, depends upon the capacity of the solid waste authority, the city, or the county—some of the entities might have the expertise in-house because they have been doing it for a long period of time and they may not need extra help, except for advisement on procurement or a peer review. Consultants are simply extensions of these community’s resources, so when these entities do not have expertise in house and they are in need of development, they can reach out, and consultants can provide that resource to augment their ability to serve the public. They can provide technical expertise and experience in strategic planning, siting and design development, execution, and operation. A larger entity may need additional resources, while smaller entities may need support because they do not have the staff capacity.
Planning Ahead
Developing a new landfill or adding a landfill cell is all about efficient and early planning. The public also needs to be properly engaged for its success, since it impacts everyone. They have a right to weigh in and have a say, on how the community can be protected, and if the location is equitable in addition to addressing environmental and economic impact. Is your public entity considering all the aspects of the community so there is environmental justice and equity across the board?| WA
Christopher Lund, PE, is a Senior Vice President of Gershman, Brickner & Bratton, Inc. He can be reached at [email protected].