By John Trotti

Gold Award: Waste Management of New Hampshire Inc. Turnkey Recycling and Environmental Enterprise

The Turnkey Recycling and Environmental Enterprise (TREE) facility is owned and operated by Waste Management of New Hampshire Inc. (WMNH), a subsidiary of Waste Management Inc. The facility is located in southeastern New Hampshire and consists of 1,213 ac. with three lined MSW landfills, a material recovery facility (MRF), a leachate treatment plant, and two landfill gas-to-energy (LFGTE) plants.

Visitor Center

Operations began in 1979 at the 46-ac. Turnkey Landfill of Rochester-I (TLR-I), the first lined landfill permitted in New Hampshire. In 1988, the 50-ac. TLR-II was permitted with a double 60-mil high-density polyethylene (HDPE) liner system. TLR-II was operated from 1990 to 1997.

In 1995, the 100-ac. TLR-III Refuse Disposal Facility was permitted and began operation. TLR-III currently is the largest solid waste landfill operating in the state. The facility accepts approximately 1 million tpy (an average of 3,500 tpd) of municipal, commercial, and industrial solid waste from various communities throughout New England by serving a population of approximately 1 million. The facility employs 45 people.

Landfill Design and Construction

TLR-I was divided into four phases, which provided for orderly development and served to limit the amount of open area for leachate management purposes. Phase 1 was constructed between 1979 and 1984, and Phase 4 constructed in 1985; both have a 3-ft. recompacted clay liner. Phases 2 and 3 constructed in 1986 and 1987, respectively, have composite liners consisting of 60-mil HDPE geomembrane overlying 18 in. of recompacted clay.

The final landfill cover system consists of a 24-in. compacted clay cap, 12 in. of granular material, and 6 in. of topsoil. The clay is compacted to provide permeability less than 1 x10^-7 cm/sec. The final stage of capping was completed in 1992.

TLR-II is divided into four phases. Originally the permitted liner system incorporated a double geomembrane liner consisting of two 60-mil HDPE layers with primary and secondary leachate collection. Although it was not required by state regulations, WMNH elected to include geosynthetic clay liner (GCL) beneath the entire primary liner to provide greater environmental protection. The GCL swells when hydrated and has a self-healing ability if the primary geomembrane is damaged.

The final cap for TLR-II consists of 6 in. of sand, a 40-mil HDPE geomembrane, geocomposite, 18 in. layer of drainage sand, and 4 in. of topsoil. Textured geomembrane with a double-sided geocomposite was used in areas where the slope of the final surface exceeded 10%. In other areas, a smooth geomembrane was used along with a single-sided geocomposite. Capping of TLR-II occurred sequentially during 1995, 1996, and 1997. Waste receipt at TLR-II ended in June 1997.

TLR-III is divided into eight phases: Phases 1 through 7 have been constructed sequentially from 1995 through 2002; Phase 8 is scheduled for construction during 2003 and 2004. Phases 1 and 2 have been filled to final grade along the lower portions of their sideslopes and final capped.

Leachate Plant

The liner system consists of two textured 60-mil HDPE liners with primary and secondary leachate collection. GCL is installed beneath the primary liner in the base areas and extends 10 ft. up the landfill sideslopes. The secondary HDPE liner is placed on 1 ft. of recompacted clay.

The leachate collection system in TLR-III consists of a primary and secondary leachate collection system with a sump for each phase. Pump controls are in place at each sump location to continuously monitor the level of leachate to ensure it is maintained below the regulatory standard and to automatically pump leachate from the primary and secondary sumps into a central pump station equipped with a 40,000-gal. StiP3 underground storage tank. Leachate then is automatically pumped through a double-walled forcemain across the road to the leachate treatment plant.

The TLR-III landfill was the first and still is the only overliner facility permitted in New Hampshire. Approximately 30 ac. of the closed TLR-I landfill will receive a double 60-mil HDPE liner system over the clay final cap so TLR-III can be filled against the TLR-I sideslope. This concept increased the TLR-III disposal capacity by approximately 30%. A vibrating wire settlement profiler is used on the overliner to monitor its performance at three locations. WMNH is pursuing utilizing this same design in the development of a future expansion area.

In 2000, WMNH received state approval to use tire chips in the primary leachate drainage layer of TLR-III; 10 in. of shredded tire material with 14 in. of drainage sand are used as an alternative to 24 in. of drainage sand over the primary liner, saving natural soils and putting a problem waste material to valuable use.

Located within the footprint of TLR-III is an open-topped tank used to solidify liquid wastestreams. These wastestreams are offloaded into a double-walled steel tank and mixed with other wastestreams used as absorbing media (such as sawdust). Mixing is accomplished with an excavator in a controlled fashion to ensure noncompatible materials are not put together. Typical wastestreams directed to the solidification tank are latex paints, off-specification syrups, slurries, adhesives, leachate from offsite facilities, and liquid nonhazardous drummed wastes.

During 2002, WMNH obtained regulatory approval to construct two mechanically stabilized earth (MSE) berms at TLR-III. These berms allow for an expansion of permitted airspace with limited increase in landfill footprint. The north MSE berm is 2,400 ft. long and 40 ft. high.

While a few projects of this kind have been undertaken in the United States at landfill facilities, the north MSE berm project is unique in that it required special provisions due to soft clay foundation soils. Deposits of this material posed stability and settlement issues for the berm and the landfill, which the design had to account for.

As part of the construction of the north MSE berm, the underlying clay was strengthened to achieve sufficient factors of safety. Strengthening the clay involved vertical wick drain installation followed by staged construction of the berm. The wick drains accelerated the rate of settlement to achieve 90% consolidation of the soft clay, allowing the project to proceed on schedule.

Geogrid reinforcement was placed in horizontal lifts to achieve a steep outer face (1:3). A second geogrid was installed at the face of the berm to increase soil shear strength and resistance to erosion. The geogrids aid in maintaining the face and act as reinforcement against slope failures.

Groundwater Monitoring

The TLR-I and TLR-III groundwater monitoring system is composed of 21 monitoring wells. Three wells are located hydraulically upgradient of the landfill while the remaining 18 wells are downgradient. The TLR-II groundwater monitoring system consists of 10 wells. One well serves as an upgradient location while the remaining nine are located downgradient of the landfill. TLR-II groundwater wells also have dedicated sampling equipment and are sampled semiannually utilizing micropurging.

Leachate Monitoring and Management

Leachate monitoring is conducted at each landfill three times a year. Monitoring at TLR-I involves collecting samples from three locations. At TLR-II, samples are collected from four primary and four secondary sumps. At TLR-III, leachate sampling is conducted at seven primary and seven secondary sumps. Each phase's primary and secondary leachate samples are analyzed independently.

Leachate is treated on-site at the leachate treatment plant or recirculated under New Hampshire Department of Environmental Services (NHDES) approval in the active disposal area of TLR-III. During 2002, the leachate treatment plant managed 14,838,987 gal. and 3,495,300 gal. were recirculated. Treated water is discharged to the Rochester's sewer system through an onsite pump station; the plant is permitted to discharge 60,000 gpd. The pump station was constructed as part of a 5,000-ft. sewer- and water-line extension, which WMNH completed in 1991 to bring these utilities to the facility.

LFG Monitoring and Collection

LFG migration is monitored through the use of permanent perimeter probes. Thirty-eight gas probes are installed around the three landfills and are screened in soil from 5 ft. to 15 ft. below the ground surface. Monitoring occurs monthly and involves sampling for combustible gas concentration, percent oxygen, and pressure.

Each landfill has an NHDES-approved active gas collection system designed to collect gas for management by one of the nine control devices at the facility. Each landfill has a series of 8-in.-diameter, vertical gas extractions wells installed in a 3-ft.-diameter boring and connected to a main HDPE pipe header system. More than 4 mi. of header pipe and 120 gas wells have been installed. TLR-III also has several layers of horizontal collectors installed in the waste mass. Blower systems at the control devices maintain a negative pressure in the landfills, drawing gas into the wells and horizontal collectors and to one of the control devices described below. Gas extraction wells are monitored weekly and adjusted to maintain optimum pressure. Monitoring of all of the control devices occurs continuously to assess the effectiveness of gas collection.

LFG Management

In addition to controlling migration, the collection systems collect gas for energy recovery for use at two gas-to-energy plants. The first plant consists of a brick building housing the control center, an engine/generating room, and a visitor viewing room. The plant contains four 16-cylinder Caterpillar engines with 800-kW generators connected to each. The plant began operation in February 1992 and runs at 100% capacity.

The second plant consists of a brick building with a compressor room, a turbine/generating room, a control center, and a visitor viewing area. This plant produces approximately 6 MW of power generated by two Caterpillar Solar LFG-fired turbines; it came on-line in January 1998 and runs at 100% capacity.

The two facilities combined produce 9,000 kW of electricity. Some of this electricity is utilized on-site to provide power to the gas-to-energy plants, the three LFG flares, the leachate plant, and the MRF. The remaining power is sold to two utilities under contract and used by 10,000 New Hampshire homes, saving approximately 175,000 barrels of heating oil per year. These plants are expected to operate throughout the life of the proposed expansion at TLR-III.

Three LFG flares burn excess gas not needed by the gas-to-energy plants. These include two utility flares each with a permitted capacity of 1,495 scf/min. of LFG. The third flare is an enclosed ultralow emissions flare installed in 2002 with a permitted operating capacity of 3,900 scf/min. The facility also owns a portable flare with a permitted capacity of 800 scf/min. for use as necessary.

Daily and Intermediate Cover

Daily cover is applied to the working face at the conclusion of each day. Originally this consisted of 6 in. of clean soil. Now the facility uses alternate daily cover (ADC) materials comprising geotextiles, ground-up construction and demolition materials, and contaminated soils. Contaminated soils that require the disposal of the material within a solid waste landfill are used for cover as long as all stormwater coming into contact with the material is handled as leachate. The geotextile cover program conducted at the TREE facility was the first ADC program of its type approved in New Hampshire. Geotextile covers are often superior to soil cover, and continued use extends site life by not filling airspace. At the beginning of each working day, the geotextile covers are rolled up from the active face and stored on a spool until the evening, when they are deployed over the area.

Onsite Facilities

In addition to the three landfills, onsite facilities include the visitor center, Forest Meadows condominium complex, and a golf driving range. The maintenance garage is responsible for repairs of heavy equipment, and the educational center houses facilities for tours and training seminars. A former office building houses a homeless shelter. The Homeless Center for Strafford County leases the space for $1 per year and opened during the fall of 2001. The center provides a shelter for women, children, and families and operates evenings from October through April. Adjacent to the shelter are barns used for storage and for housing livestock maintained on-site.

Also at the TREE facility is a MRF that began operation in 1991 and has a permitted operating capacity of 1,500 tons/week. Current throughput is approximately 1,000 tons/week of newsprint, corrugated cardboard, paperboard, paper, glass, aluminum, tin, ferrous metals, and plastics. The MRF operates two process lines for fiber and commingled containers. Additional onsite facilities include offices and a five-bay maintenance garage with a truck wash and a refueling island associated with the 100-truck refuse collection company.

Silver Award: Toland Road Landfill

Toland Road Landfill is managed by the Ventura Regional Sanitation District (VRSD), an enterprise public agency providing integrated regional waste treatment and disposal services to approximately 85% of the residents of Ventura County, CA, meeting the needs of 600,000 persons in more than 11,600 mi.²

Toland has been operational since 1970. In 1986 VSRD purchased the property and, faced with the impending closure of the area's major landfill in Oxnard, recommended that Toland be expanded to a 1,500-tpd-capacity to serve the needs of the west Ventura County communities of Oxnard, Ventura, Port Hueneme, Camarillo, Ojai, Fillmore, and Santa Paula. The landfill was retrofitted to meet established standards for a facility of that scope and officially was expanded in 1996 as the only remaining public landfill in the county.

Currently Toland is permitted to provide 30 years or 15 million tons (30 million yd.³) of landfill capacity. Development, which was scheduled in five distinct phases, will continue for an estimated 16 years followed by 30 years of postclosure maintenance.

The two other landfills in the area are Simi Valley Landfill, owned and operated by Waste Management of California (permitted to accept up to 3,000 tpd), and Chiquita Canyon Sanitary Landfill in Valencia (Los Angeles County), operated by Republic Services of California (permitted to accept 6,000 tpd).

Toland is manned by 23 employees, supported by a cadre of engineers, laboratory technicians, and administrative and technological support personnel.

Design and Construction

Working face with slope

Toland sits on 161 ac. with a 52-ac. access parcel located in a confined, V-shaped box - an ideal location backed against granite mountains and seated on 400-500 ft. of impermeable clay. Toland's first phase involved the expansion of the site from a 135-tpd local dumping facility to a 1,500-tpd countywide landfilling resource. This involved capping existing cells, applying new liner and grading and preparing the canyon walls to receive future decades of county refuse, installing deep vertical gas collection wells into the existing refuse, constructing a leachate collection system, and constructing a half-mile access road. Refuse capacity was one year. The cost of Phase I was more than $800,000.

Phase II of the Toland expansion project was completed in 1998, on time and under budget. This project, costing more than $8 million - for engineering and geotechnical services, excavation of soil and placement of 750,000 ft.² of composite liner on 1.5:1 slopes, and 1 mi. of new roadway - was the most ambitious project in the district's history. Refuse capacity of Phase II is approximately five years.

Recently Phase IIC was added to the mix when landfill managers realized that running a trashwork slope from the Phase II cap up the canyon wall at a gradual, more natural gradient would have a number of aesthetic, practical, and financial benefits. Plans were changed and new permits were procured. The results will be a more secure canyon wall and an additional one and a half years added to the life of the landfill,  not to mention 750,000 tons of additional airspace.

Phase III, which is scheduled to begin in 2004, includes excavation of more than 1 million yd.³ of soil, 12 ac. of composite landfill liner, and a half mile of new roadway. Although the existing 3-ac.-ft. detention basin has not overflowed since its inception in 1970, a 21-ac.-ft. detention basin is planned to replace it in this phase as well. Refuse capacity is estimated at 11 years with a projected $9 million cost.

Phase IV of the landfill is scheduled to begin in approximately 2013 and has a 13-year refuse capacity. This phase involves excavation of 400,000 yd.³ of soil, placement of 10 ac. of composite liner, and 1.5 mi. of new roadway. The estimated cost is $6 million.

The final phase of Toland, of course, is closure and postclosure, with estimated costs of $22 million. VRSD employees have a lot of experience in closure and postclosure. Within the last eight years they have closed two sites, one using force account labor and equipment. This experience, in fact, gives Toland employees a unique perspective. The coming closure of the landfill, though decades away, is a consideration in daily decisions and operations.

The landfill liner comprises a prepared clay liner with a permeability of less than l x 10^-7 cm/sec., a GCL, a 60-mil-thick HDPE flexible membrane liner (FML), a geotextile cushion to protect the FML, and a geotextile shear sheet to protect the liner system for earthquake movement. A 2-ft. protective soil layer protects the liner system from damage. During the next phase of landfill development, a massive liner containment berm is proposed for across the mouth of the landfill canyon.

Twelve wells monitor groundwater conditions monthly for water depths and semiannually for chemical composition. Groundwater rarely is found in monitoring wells at Toland Road Landfill. Nevertheless, engineers have installed several groundwater "trolls" that monitor the wells every few minutes around the clock and transmit the data to district computers. This allows the district to detect any quick flushes of water that might come through after rainstorms.

VRSD's laboratory offers a wide variety of analytical services for groundwater, surface waters, soils, sludge, compost, and gas condensates. The lab has been certified by the State of California Department of Health Services's Environmental Laboratory Accreditation Program and has a full-time laboratory staff. The lab can perform more than 60 different tests, including physical, bacteriological, and chemical analysis of water and sludge.

Leachate is sampled annually for a whole spectrum of chemicals that may be released or synthesized in a landfill. If a constituent is found in the leachate that was not detected in the past, another sample will be tested for that constituent to confirm that it is present. If that newly detected constituent is not currently monitored in the groundwater monitoring program, it will be added to the list of chemicals that will be tested for in future monitoring events. Leachate is collected by the leachate collection system and transported off-site to an appropriate treatment facility.

Currently Toland vents LFG through an enclosed flare system comprising a burning stack, scrubbers to remove particulate matter and moisture before combustion, blowers, and an automated control system, but the site is well suited for LFG energy recovery. The service connection to the gas collection piping is in place, making installation a straightforward process, and staff is researching LFGTE alternatives.

Because of this transfer station commitment, 90% of Toland's waste has been prescreened for hazardous materials and recyclables before it passes through the gate. Such "clean" waste is infinitely easier to fold into the waste column than waste rife with tires, washing machines, shopping carts, batteries, and other bulky and undesirable items. This precycling process has also added significant life to the landfill, extending the amount of time it will take to reach Toland's 30-million-ton maximum.

Toland has a contract with a local greenwaste recycling center to accept loads of less desirable "dirty" greenwaste, along with comparable loads of clean greenwaste. The dirty loads are used as ADC and in a number of other operational activities such as dust and erosion control. This material is also used as a wet-weather mat, which helps minimize mud tracking in unpaved areas, thereby decreasing undesirable dust production.

To preserve the native habitats impacted by the landfill operations, Toland has established a number of impressive biological mitigation areas, including creating new wetlands and homes for the desert wood rat, rare lichens, and coastal sage and a riparian seep along the canyon walls. These areas have been reclaimed at a 2:1 ratio.

Another way Toland enhances the environment is by providing a place for local contractors to recycle their concrete tailings. Toland then turns around and uses the rubble as road-base material. This offsets Toland's need to purchase and import crushed rock for road construction.

As part of Toland's dust suppression requirements, VRSD engineers have paved the roads leading to the pit face. Rubberized asphalt was used for this major construction project because the additional flexibility of this material will accommodate future landfill settlement. This stability is important, but there is an added benefit to using this product. Rubberized asphalt is made from recycled tires. Here a recycled material becomes a critical component of landfill construction and an agent of its future stability.

Operations Programs

Toland has an outstanding waste load checking program, which is guided by CUP Condition 77. The key elements of the load check program include an onsite hazardous-waste monitoring and diversion program, random truck inspections, rigorous recordkeeping, customer notification and referrals, and of course employee training.

Since transfer station loads have been preinspected before they arrive at the landfill, staff is able to implement random checks to ensure quality control. Hazardous waste is rarely found in transfer station loads.

To improve dust mitigation efforts, staff has constructed an improved water tank on-site. This saves considerable mileage for the water trucks, which are required to run constantly during operating hours and previously had to travel much farther to fill the truck.

Propane cannon and uniformed scarecrows are among other mitigation measures to control the population of unwanted pests.

One of Toland's most successful innovations is the integration of ADC as an operating strategy. ADC refers to a variety of nonhazardous substances used in lieu of earthen materials to cover the working face of a landfill cell. Toland employs a variety of materials, including greenwaste, sludge, cement dust, and geosynthetic fabric (tarps). ADC is often faster to apply, which represents a significant additional savings in staff time. Less equipment is needed in placing ADC since the scrapers are not needed to excavate the soil, so equipment savings are experienced in down-the-road maintenance.

Toland's Public Agency Image

Governmental agencies, in general, are vexed with battling often-unwarranted perceptions of incompetence and deep pockets. As Toland is run by a public agency, its employees are very aware that, in addition to meeting the challenges of effective and efficient waste management in demanding circumstances, they have negative perceptions with which to deal.

Toland has accomplished the following as part of its "Good Neighbor" policy:

• Built a sound wall along Toland Road to decrease traffic impacts
• Paved local ranch roads to help mitigate the particulate matter issues
• Cleaned up drifting litter on an ongoing basis and paid to remove airborne litter from neighboring properties after an unusually windy period
• Voluntarily augmented dust suppression, litter abatement, and bird control programs at an annual cost of more than $250,000
• Significantly curtailed activity on windy days to decrease landfill operations dust and litter impacts at a cost of more than $300,000 in 1999 alone
• Established and encourage open communication with neighbors, regulators, and the public that fosters the development of solutions rather than complaints
• Developed a landscape screening project, which includes 2,000 ft. of trees planted along the perimeter ridgeline, whereby 305 eucalyptus trees will grow to a height of 50 ft. and effectively break up the sharp angles of the landfill's cut and make the site appear more physically pleasing
• Instituted a bird control program to ensure that neighboring farmers are not impacted by birds naturally attracted to the landfill site. The district instated a full-time monitor in addition to the unmanned propane cannon, scarecrows, and other mitigation measures

Bronze Award: Newland Park Landfill

Newland Park Landfill, located in Salisbury, MD, was first used for disposal of MSW in the 1940s, when waste was placed in open pits and burned. In the 1960s waste was placed in trenches and covered with soil excavated from the next adjacent trench. In the 1970s the area-fill method was used in which waste was placed in a single lift over a large area. In the 1980s, waste was placed using the area-fill method in multiple lifts. Also in the 1980s, the county began to operate a recycling facility at the site to reduce the amount of waste disposed at the landfill. Each of the waste disposal areas used before 1990 was unlined, and leachate was not collected in any of the areas.

In the early 1990s, the Maryland Department of the Environment (MDE) notified Wicomico County government that the facility's waste disposal practices were in violation of MDE regulations and that enforcement action would be considered unless the county improved the control of leachate, managed stormwater runoff better, performed a comprehensive evaluation of groundwater quality, and developed a plan for placing waste in a lined area. The county immediately responded by performing a comprehensive site characterization and groundwater-quality evaluation and creating a conceptual plan for development of a new, lined disposal area. The plan for the new disposal area called for developing a series of 10 cells, each of which would be lined with a composite liner and a leachate collection system. Also, a leachate storage area would be constructed and, after the new landfill was constructed, the old multiple-lift landfill would be closed and capped. The disposal capacity of the new, lined disposal area is about 6 million yd.², which will provide about 60 years of disposal capacity at the county's current waste disposal rate.

The MDE approved the county's plan to develop a lined disposal area in 1994, and in 1995 and 1996 the first two cells of the disposal area were built. In August 1997, the first waste was placed in the new, lined cell (Cell 4), and in 2000, closure of the old, multiple-lift disposal area began. In early 2002, the construction of the closure system was completed in addition to construction of an active LFG extraction and treatment system for the old multiple-lift disposal area. Also in 2002, the next two cells (Cells 1 and 2) were constructed and a new citizen convenience center was constructed. As of the end of 2002, all of the improvements that were conceived in the 1994 plan had been implemented.

Over the last 10 years, the Wicomico County Department of Public Works (WCDPW) has achieved several management successes at Newland Park Landfill that demonstrate the excellence of the facility:

• Development of a new, lined disposal area that uses innovative engineering design approaches to overcome several potential limitations of the site
• Installation of a new, active LFG management system to limit emissions of LFG and to prevent air-quality or groundwater-quality impacts
• Development of an innovative and integrated leachate management system that incorporates low-cost, aboveground tanks and collaboration with the City of Salisbury Wastewater Treatment Plant (WWTP) to dispose of sewage sludge as fertilizer
• Significant improvements in groundwater-quality monitoring of the site and groundwater quality in general
• Implementation of a long-range, forward-thinking, and honest approach to funding operations and management of the landfill

Design and Construction

Newland Park Landfill improvements were developed with the intent of providing a single location for serving all of the county's waste management needs. The new landfill was constructed over and adjacent to the old, multiple-lift disposal area. The design of the liner system included careful attention to constructability, protrusions (there are no penetrations through the liner system), and damage during operations. The liner construction was highly successful; because there were no failures of destructive tests during construction, it is expected that the liner system will provide excellent containment and outstanding protection of the environment.

In 1996, WCDPW implemented a test program to evaluate the use of scrap tires as leachate collection layers. The results of this five-year study, which was funded and administered by the MDE and the Maryland Environmental Service, concluded that tire chips are a good alternative to natural earth materials in leachate collection and protective cover layers. This application of scrap tires not only allowed Wicomico County to dispose of about 1.3 million tires in an environmentally sound manner but at the same time it provided valuable research results to the MDE and other designers and owners of landfills.

The old landfill was not lined, and therefore there was no leachate collection system for that disposal area. When the new landfill was constructed in 1995, a storage system consisting of two 1-million-gal. geomembrane double-lined tanks within a lined secondary area was put in place at a cost of only $750,000 - much less than the cost of providing similar storage capacity using traditional leachate storage tanks. In the eight years since the tanks were installed, they have required very little maintenance and no significant repairs, and they appear to have many, many years of service life remaining.

Landfill Features and Facilities

LFG Management System. A comprehensive LFG management system was installed in 1998 during construction of the final closure system for the old multiple-lift area. At this time, Newland Park Landfill is not subject to the requirements of the New Source Performance Standards of the Clean Air Act; however, the facility is expected to be subjected to these requirements in the near future. Therefore, the gas management system was designed and constructed so that it could be easily converted to an active extraction and management system. In 2001, LFG was detected in monitoring wells at the edge of the landfill; at that time, it was decided to begin operating the active extraction system to prevent releases of LFG to the subsurface environment (which likely occurred in response to capping of the landfill, effectively cutting off the upward discharge of LFG and caused migration toward the edge of the capped area).

Scale and Welcome Facility. Waste transport vehicles enter Newland Park Landfill through the scale and welcome facility. This facility is designed to efficiently process vehicles, accurately document the source of waste for billing purposes, and quickly route trucks to the working face or recycling area.

Citizen Convenience Center. A Citizen Convenience Center was designed and constructed in 2000 to provide efficient traffic flow and to allow several vehicles access to the facility at the same time. The center has disposal containers for glass, cardboard, metals, brush and yardwaste, waste oil, antifreeze, and MSW. The facility is used by about 400 customers per day during the week and about 600 customers per day on the weekend.

Recycling Center. In 2002, the recycling center processed 9,098 tons of mulch and 3,554 tons of aluminum, metal, cardboard, glass, metal, newspaper, and plastics. An important benefit of recycling to WCDPW is the capacity saved in Newland Park Landfill. Through careful attention to the material in the wastestream, WCDPW has been able to conserve the capacity of the landfill by diverting recyclable materials under its recycling program.

Yardwaste Management Facility. WCDPW has found that the mulch is very effective at stabilizing slopes and preventing erosion during nonseeding times (i.e., late fall through early spring). WCDPW also processes pallet mulch that is used instead of CR-6 on access roads during foul-weather events, which helps keep down operating costs. WCDPW supplies mulch materials to other county agencies at no cost to help maintain the county's operating budget and enhance the grounds of their buildings, schools, and parks. The yardwaste management facility also has benefited Newland Park Landfill by diverting material from the landfill, thereby conserving the disposal capacity of the landfill.

Related Waste Management Activities

There are a number of other programs that WCDPW conducts to enhance the environmental performance of the landfill, to protect the disposal capacity of the landfill, and to enhance the benefits of the landfill to the community. These programs include sludge management, borrow soil management, and dredge material reuse.

Sludge Management Program. WCDPW manages a program to apply sewage sludge from the Salisbury WWTP to farm fields in the county. The program, which is implemented jointly by WCDPW and the City of Salisbury Department of Public Works, involves removing used sludge from the WWTP digesters and transporting it to local farm fields, where it is applied as fertilizer.

Dredge Material Management Program. WCDPW has been excavating dredge from the area since 2001 and uses the material for a variety of purposes, including daily cover, topsoil, and final cover construction. Because the soil has a relatively high organic content, it is ideal for use as a vegetative support soil material. Using the dredge material placement area as a borrow source has benefited the county in two important ways. First, it extends the useful life of the onsite borrow area. Second, it extends the useful life of the dredge material placement area.

Environmental Controls

Environmental Monitoring Program. WCDPW developed a comprehensive groundwater and gas monitoring program for the facility in 1994. One of the problems was that some contaminants had been detected in groundwater samples from near the landfill. In the early 1990s, operations were improved to provide better management of leachate and to manage waste on a lined disposal area; as these improvements were made, groundwater quality also improved. As of 2002, there are no groundwater-quality problems at the site and the facility is implementing a detection monitoring program. Also, there are no significant LFG problems.

Groundwater Protection. Groundwater at the site is protected from leachate and LFG impacts by the liner system beneath the new waste disposal area. This system provides containment and removal of leachate. Leachate is contained using a composite liner, which has a calculated collection efficiency of more than 99.9%. Further, testing of the liner system during construction indicates that there were no failures of destructive tests, which is indicative of outstanding quality of construction of the liner and likely no significant holes in the liner system. Further, leachate is removed using a sideslope riser system (i.e., no penetrations of the liner) and transferred to a forcemain, which routes the leachate to the storage area. This closed system, which includes double-walled piping outside the lined areas, offers few opportunities for leachate to escape from the containment system.

Groundwater Monitoring. Groundwater elevations at the site are monitored biannually at 23 monitoring wells and 12 piezometers. Groundwater samples are collected from the 23 monitoring wells with disposable bailers after the wells are purged of three well-volumes using a submersible pump.

Air-Quality Protection.Air quality is protected by containment of LFG. LFG is contained by the final cover and an active extraction system. The cover system consists of a low-permeability geosynthetic cap. The LFG extraction system currently collects an estimated 36% of the gas generated by the landfill and routed to a flare, which has 98% destruction efficiency. Continued enhancements to the gas collection system are expected to increase the collection efficiency. Gas is collected at a rate of about 400 ft.³/min. Over the last 10 years, there have been no odor complaints in relation to the landfill.

Air-Quality Monitoring. LFG migration monitoring is performed quarterly and includes routine checks of percent methane, percent oxygen, and percent carbon dioxide (balance gas). Methane concentrations at the property boundary historically have exceeded regulatory limits, but a general downward trend has been observed more recently. The installation and operation of the LFG extraction system is credited with limiting LFG migration. Currently there are violations of LFG limits at the landfill boundary; however, continued tweaking of the collection and extraction system is expected to lower the gas concentration at all boundary monitoring points.

Operations

Newland Park Landfill facility manages approximately 290 tpd of waste at the working face and employs a staff of 30. Nineteen are operators at the landfill, two are laborers at the landfill facility, six are administrative staff, and three are technicians or equipment maintenance personnel. Of these personnel 19 are cross-trained on all tasks.

Using area-fill method of waste placement method, staff places waste in a daily cell and covers the waste at the end of each day. In general, the size of the daily working face is about 50 x 100 ft. At the beginning of each day, daily cover or intermediate cover is stripped from the current day's work surfaces (to promote downward drainage of leachate and to minimize the potential for formation of leachate seeps) and then the work area is prepared.

Operating Budget

The annual operating budget for the facility is approximately $4.7 million. This includes approximately $2.7 million for landfill operations, $0.64 million for recycling operations, and $1.23 million for capping, construction of cell closures, and postclosure care. The tipping fee is $55/ton of waste received across the scales at the site. The Newland Park Landfill budget is provided by the Wicomico County Council based on a budget prepared and managed by the director of public works. During the last 10 years, the revenue from operations has been sufficient to cover not only the cost of all of the operations but also the reserves for capping, construction, closure, and postclosure-care costs despite the significant number of programs and construction occurring at the facility and several significant changes in the local and national economy that have taken place over that time period.

John Trotti is the editor of MSW Management.

MSW - September/October 2003