Landfills storing municipal solid waste are high-tech operations, compared to old "dumps." It's no longer acceptable to find an isolated tract of land not too far from an urban area, dig a pit, then build a mountain of garbage. Modern landfills are engineered and built as a series of cells. The cells include liners of plastic membranes and watertight clay on the bottom. At the end of each day, earth covers the trash deposited in the cell, to keep animals away.
When a cell is full, a thick cap of watertight clay is added at the top of each cell. This impervious clay blocks rainwater from seeping into the garbage and then into adjacent groundwater. Intricate plumbing systems are installed at different levels, to capture and release gases from decomposing waste before pressure builds up and cracks the clay covering.
The plumbing threaded through the landfill also collects the juices ("leachate") that are squeezed out of the garbage, plus groundwater/rainwater that manages to seep into the landfill and become contaminated. The pipes carry the leachate to wastewater treatment facilities, where the contaminants are separated from the water.
Sometimes the contaminants from the leachate are incinerated, and ash is buried in a specialized landfill for that product. In other cases, concentrated sludge from the water treatment plant is carried back to the landfill and buried there. Once a landfill is oficially closed and sealed with clay at the top, the waste is isolated from the surrounding environment - at least in theory.
Garbage gradually compacts and chemically changes. Decomposition of organic material is slowed in the anaerobic (oxygen-deprived) environment, but is not stopped completely. Anecdotal stories tell of landfills being opened after decades, and newspapers had hardly turned yellow. Hot dogs with mustard looked just as good as the day they were tossed in the trash. Decomposition takes time, but all that material will gradually degrade.
After several decades of decay, bacterial decomposition of waste should become minimal. Until then, surface inspections can ensure if the clay cap has settled or cracked, while monitoring wells can measure if the membranes, clay, and leachate collection processes actually prevent plumes of pollution from contaminating groundwater.
Virginia has roughly 60 solid waste landfills still in operation. There are 134 separate counties and cities, so obviously solid waste management is now a regional operation. In 1993, the General Assembly mandated in a law known as "HB 1205" that existing landfills that did not need new requirements must be closed. Old landfills would be permitted to continue accepting waste until their existing facilities were filled, but no horizontal expansion of old landfills would be permitted.
All new cells, at old or new landfills, have to meet state-mandated requirements for liners, clay caps, gas release systems, and monitoring. Old landfills must also be managed. The Catlett Mountain Landfill used by Front Royal and Warren County closed in the 1970's. Four decades later, excessive amounts of rainwater seeped through the clay cap and into nearby creeks. Those two jurisdictions spent nearly $200,000 to build a rainwater diversion system, even though that investment allowed no extra waste to be deposited at the old landfill.1
Landfills create methane and other types of gas that bubble up to the surface and can crack the cap from below, if the pressure is not released. In addition to lechate pipes, modern landfills have internal plumbing for gas collection. If you drive Interstate 66 near Fair Oaks Parkway after dark, you can see the flare used to burn the methane coming from the now-closed landfill adjacent to the interstate.
The original proposal in the General Assembly would have created new fees to compensate those affected by the more-stringent environmental mandates. The cost to close a landfill is relatively clear, compared to the social cost (especially in human health) if an unsafe site is permitted to continue operating, but the one-time expenses to close a landfill can be steep. Asking a small rural county to absorb those costs directly was not the original plan of the General Assembly, but Governor Gilmore effectively blocked imposition of new fees that he perceived as new taxes.
Based on the recommendations in the Prioritization and Closure Schedule for HB 1205 Landfills report (issued July, 2000), the Virginia Department of Environmental Quality (DEQ) could force the two Virginia counties on the Eastern Shore out of the landfill business by the year 2020. Northampton County closed its landfill near the community of Oyster by the end of 2012, and began to convert the site into Seaside Park for recreational use.
Accomack County also closed one of its two landfills in 2012. According to DEQ's initial plans, the unlined cells at the South Landfill should have closed in 2005. The South Landfill finally closed at the end of 2012, and was replaced by a transfer station to transport waste to the North Landfill 40 miles away until it closes (or is expanded) in 2017. Accomack County budgeted over $4 million to cover the one-time closure costs of the South Landfill, and additional funds for monitoring will be required for 30 years.2
The two Eastern Shore counties could have built new landfill facilities to replace the ones being forced to close. However, there are great economies of scale in landfill construction and operations. It's inefficient to build small facilities, and two rural counties could not afford to borrow the necessary funds for a large high-tech facility that would always require taxes for an operating subsidy. The experience in Page County offers a lesson. The county leased its Battle Creek landfill, and then permitted the operator to grossly exceed the 250 ton/day limit in ordder to generate greater volume and thus more fees. DEQ ultimately revoked the permit for that landfill, and Page County will struggle to repay the costs for decades to come.
On the Eastern Shore, as at Page County, there's just not enough population or industry to make a large landfill facility an attractive investment. The Eastern Shore counties could not recruit neighboring jurisdictions to share the cost of a regional facility. The Hampton Roads communities already have a regional disposal authority, and they were unwilling to ship garbage across the Chesapeake Bay Bridge to supply a regional landfill on the Eastern Shore. The greatest waste management challenge on the peninsula, especially in the Maryland portion, is disposal of chicken manure (and dead chickens), not municipal solid waste.
In 2009, Northampton County completed a $2 million transfer station, a facility where local garbage collection trucks deposit waste at a temporary collection point. The solid waste is the carried from the transfer station by large tractor trailers to a sanitary landfill far away in King and Queen County. The two-stage transfer process is more efficient than having gas-guzzling local garbage trucks drive all the way to the landfill. To reduce transfer costs, brush is burned at the transfer station and valuable scrap metal is recycled there, rather than shipped to the landfill.3
Virginia Beach used a creative process to close its landfill. It compacted and piled solid waste into Mount Trashmore, building the cells vertically over 60 feet high until creating the highest point in the city. After closing the landfill and capping it with clay, Virginia Beach made it into a public park - and the tallest spot of land in the city.
The garbage is decaying underneath the clay, burping gases out the vent pipes regularly, but the city succeeded in converting a waste site into a valued recreational asset. After closing the landfill, the city shipped its solid waste to the Southeastern Public Service Authority (SPSA) waste-to-energy plant in Portsmouth and the SPSA's landfill in Suffolk.
Grass is planted on the clay cover above closed cells of landfills to reduce erosion. The City of Portsmouth struggled to keep the grass cut at its landfill on the southern edge of Craney Island. It bought goats, figuring they would graze on the grass.
After discovering their goats were finicky eaters, city officials bought sheep as well - and the urban managers also bought a book on how to raise sheep. After a year, Portsmouth officials realized that using farm animals to cut grass was not the easy solution originally imagined. The final solution: Portsmouth acquired two lawn mowers to cut most of the grass on the landfill.4
In the 1980's, Arlington and Alexandria realized they were running out of landfill space for disposal of solid waste. They joined together to build a joint waste-to-energy facility, implementing a new technology to solve an old problem.
Fairfax has also built a waste-to-energy facility at Lorton. In Fairfax County, trucks haul solid waste between waste transfer stations (including one at the old I-66 landfill) and the waste-to-energy facility (incinerator) at Lorton or the Prince William County landfill. The trailers of those trucks are a distinctive tan color.
The county has closed all of its municipal solid waste landfills except one (the I-95 Landfill), and directed municipal solid waste to the incinerator. Construction and Demolition Debris (CDD) landfills remain open, including one at Lorton next to the I-95 Landfill. That 250-acre facility is scheduled to close in 2018, under a deal negotiated by EnviroSolutions with nearby residents in 2006. That authorized a short-term expansion, followed by conversion of the landfill into a public park.
In 2014, EnviroSolutions proposed keeping the landfill open until 2040. The 2008 recession had slowed construction projects dramatically, and the company was not receiving construction and demolition debris fast enough to reach the maximum authorized height of 412 feet (roughly 50' higher than its elevation in 2014) in 2018. In exchange for the 22-year extension of time to reach maximum utilization of the site, EnviroSolutions proposed to add solar cells, geothermal energy, and wind turbines to create a green energy park.5
County staff supported changing the commitments made in 2006, recognizing that redevelopment (especially in Tyson's) created debris and a nearby disposal site would incentivize further redevelopment. Local opposition was strong, in part because the company had already changed its commitment to build the public park in order to minimize long-term liability insurance costs.
The Board of County Supervisors in Fairfax finally rejected the last compromise proposal, to keep the landfill open until 2025, in a close 6-4 vote. The landfill operator made clear it would simply shift operations to a nine-acre parcel that it owned next to the landfill, using it as a transfer station. If implemented, the amount of construction truck traffic in the neighborhood will not drop once the landfill closes.6
Landfills are rich in organic material, so they attract rats, other mammals, and birds. Covering the discarded waste every night with a thin layer of clay or dirt reduces the problem in the evening, but during the day other techniques are required.
The 900 tons/day discarded at Prince William County's landfill attracted 25,000 seagulls and other birds daily. The annual Christmas Bird Count in the county found more eagles at that inland location than along the Potomac River waterfront; the seagulls fed on the waste, and the eagles fed on the seagulls. While the eagles were welcomed, the mass of other birds created their own solid waste problem. The county abandoned recreational ballfields at the landfill to avoid the excessive bird droppings, and paint on nearby vehicles and buildings were damaged by the steady rain of fecal material.
The county contracted with US Department of Agriculture - Wildlife Services to reduce the bird concentration through non-lethal techniques (bird repellents, pyrotechnics, shooting with paintball guns) and also through lethal means. Since the birds were protected by the Migratory Bird Treaty Act, killing or disturbing their nests/eggs required approval of the Federal government. In the first winter of control measures (2013-14), the bird population at the landfill was reduced by 70% to just 7,500/day.7