Landfill Operations a Recipe for Success
It’s been said that failure is an orphan, but success has a hundred fathers. In the case of landfill operations, that saying is mostly true.
Though one man is in charge and ultimately responsible for the safe and profitable operation of a landfill, he needs a support staff of dozens of equipment operators, engineers, consultants, and employees to make success a reality. Each step along the way to success requires a different cast of characters.
First, as the idea of a landfill business germinates, the landfill developers have to formulate a business plan and obtain financing. At this stage, the primary players are bankers and issuers of surety bonds.
Second, the landfill has to be sited, which requires a thorough environmental and hydrogeological investigation of the proposed site. This effort requires the work of hydrogeologists, biologists, botanists, and other environmental scientists.
Third, once the site has been properly vetted the detailed design and permitting of the site can be performed followed by its actual construction once the permit has been obtained. Engineers, suppliers of piping and geosynthetics, and contractors are largely responsible for these tasks.
Fourth, after the site and its initial disposal cell have been constructed, the landfill can finally begin receiving waste. Everything done to date has been in preparation for this, the longest stage of a landfill’s operations. Here the landfill’s staff of equipment operators and office personnel can manage the site.
Fifth, concurrent with the fourth stage, the landfill and its immediate vicinity must be monitored to ensure it remains in environmental compliance and to prevent the release of pollutants into the local ecology and groundwater. Again, hydrogeologists, biologists, botanists, and other environmental scientists are required.
Sixth, also concurrent with the fourth stage, the landfill has to properly mange and dispose of leachate, landfill gas, and surface water runoff generated by it operations. This is also a job for the landfill’s staff of equipment operators and office personnel.
Seventh, as each disposal cell reaches capacity, new cells must be constructed and certified, and the final grades of the previous cells must receive final cap-and-cover installation. Both tasks are performed by engineers, material suppliers, and contractors. The last operational task is the final installation of the last section of final cap-and-cover over the last disposal cell.
Eighth, once final closure is performed, the site will be subject to postclosure care and monitoring typically for a period of 30 years. As the landfill closes its gates and its personnel and equipment are relocated, the site will be visited by those same kinds of scientists that investigated the site in the first place.
Financing and Business Planning
Nothing gets done without money, and nobody obtains money without a solid business plan. Business plans for a landfill have to take into account several market factors. First and foremost is the residential population of the landfill’s potential service area. Usually this is the county it is located in plus the surrounding counties, though not typically counties across a state line. Sometimes the landfill’s market area includes distant communities sending waste to the landfill via barge, rail, or long-haul trucking. All the contributing market areas should be evaluated for their population growth rates to provide a basis for estimating future returns. Given average annual per capita residential waste disposal rates, existing and future market potential can then be estimated. Depending on local competition from other landfills and the average regional tipping fees charged for disposing waste, an estimate of the landfill’s potential gross revenue over its operational lifetime can be calculated.
Evergreen National Indemnity Co. specializes in providing financial vehicles for the waste services industry. In addition to providing bonds for closure and postclosure care, Evergreen also provides bonds for waste collection operations. It also provides surety bonds to ensure faithful performance by contractors and operators working for government operated waste management agencies.
As the old saying goes, the three most important considerations in any real estate development are “location, location, and location.” Landfill developments have two sets of location concerns. The first are the formal location requirements and setback mandated by federal and state regulations. In short, 40 CFR 257, published in accordance with Subtitle D of the Resource Conservation and Recovery Act (RCRA), requires that landfills not be sited or built so as to interfere with flood plains, infringe on wetlands, impact the habitats of endangered species, or discharge pollutants into surface waters, airports, seismic zones and fault lines, or any underground source of drinking water. Certain states have additional location restrictions that (for example) forbid the location of landfill operations within specified distances of national parks, aquifers, quarries and sand pits, water supply wells, property lines, homes and businesses, schools, and hospitals.
These restrictions will limit the size and configuration of the landfill, which in turn will define its potential profitability. The basic equation to determine a landfill’s overall profitability is the ratio of total airspace disposal volume to total lined area. Landfills are different than any other comparable operation in that they require large up-front capital costs to construct the disposal cells and ancillary facilities, but have comparatively low operating costs on a per-ton-of-waste-received basis. Revenue per unit of waste can be very high once the site receives enough waste to meet it financial breakeven point. Therefore, revenue is a function of the amount of waste (volume) versus the cost of liner construction (area). The more regular (square) the shape of a landfill’s foot print is, the more waste in greater height can be deposited per acre of area.
Design and Construction
Design requirements are driven by the standards established by the various state environmental agencies to obtain a permit for the construction and operation of a landfill. The design of a landfill involves detailed analysis of various types of operating systems and environmental protections (landfill gas, geotechnical analysis, runoff, and erosion control design). The designs are presented in one or more formats (narratives, details, plans, specifications, computations, computer program print outs). Each design element has to be prepared by an engineer with the necessary skills and experience. Some, like landfill gas engineers, tend to have specialized skills.
The designs go through various stages of preparation and review, beginning with conceptual layouts, drafts, near final review packages, and final permit application submittals. Their contents and organization are usually dictated by the solid waste regulations of the state where the landfill is located. These standards vary in detail (one state may require a 3-foot-thick clay liner, another may need one that is 5 feet thick), but in general request the same information even if in a different format. Completeness of the design application is as important to the obtaining of an operating permit as is the quality of the engineering.
Once every design element has been approved, every plan vetted and every required permit obtained, construction of the facility can commence. Requests for bids are submitted, based on the design and the material quantities required by the design and a contractor chose to perform the work of constructing the first disposal cell. After the contractor mobilizes out to the site, it is then surveyed, grade-staked (or has a GPS surface generated in CAD), cleared, and grubbed. Excavation can then commence to establish liner construction grades, which are then surveyed to establish that they have been constructed to the design’s elevations and slopes.
Liner construction then follows, which is followed in turn by the construction of the leachate collection and management system. Each of these is also surveyed in turn to assure that they were built with the appropriate thickness. However, the material components of the liner and leachate systems are further tested to ensure quality of installation and that these materials meet the design’s construction specifications. These tests can include nuclear gauge readings of in-place clay moisture and density, destructive testing of the geomembrane seam strengths, permeability of leachate flow media, etc. All of these tests have to be performed by licensed technicians and laboratories with the appropriate experience and knowledge. Once the construction and testing is complete, a construction quality assurance report is submitted to the regulatory agency to show that the disposal cell was properly constructed and to obtain a notice of certification allowing the start of waste disposal operations.
Carlson Software provides software design packages for land development professionals and landfill engineers. In addition to the company’s survey data management and civil site design software, which can be applied to landfill design applications, it also produces the Landfill Grade GPS Management System. This software package is designed for use with landfill equipment (scrapers, dozers, and compactors) in real time. It provides 3D coordinate information both to the machine and to the landfill office, increasing productivity minimizing airspace consumed and the need for daily cover. It collates data and prepares reports on daily in-place waste density, number of compaction passes performed, and volume analyses. Monitoring and report reading can be performed from anywhere. Its Dynamic Data Exchange allows two machines to share data in real time to maximize field coordination of landfill compaction equipment.
Herzog Environmental Inc. provides management services for solid waste, landfill construction, and resource recovery to private and public sector (federal, state, and local government agencies) throughout the West and Midwest. Utilizing its in-depth construction and operational experience gained on other civil site development projects, Herzog was able apply this knowledge to the construction and operation of landfills and waste recovery facilities.
Layfield Geosynthetics is a manufacturer of a wide variety of geomembranes suitable for landfill construction applications. Its geomembranes are fabricated to applicable sizes and configurations in three locations in North America with installation resources experienced and skilled in the installation of geomembranes. In addition to manufacturing, supplying, and installing geomembranes Layfield also provides application design assistance including panel layout plans, detail drawings, and specifications. The company also has a service group that performs the tasks of cleaning, inspecting, and repairing geomembranes, along with three types of leak-detection surveys in water or soil.
Founded in 1993, Hallaton Inc. is a leading installer of landfill geosynthetics, having installed over 200 million square feet of containment lining. This includes most kinds of commercially available geosynthetic lining materials (HDPE, LLDPE, PVC, PP, XR-3, XR-5, and Hypalon). They are a certified installer for most major geosynthetic suppliers including Poly-Flex, Cetco, Agru America, Solmax, GSE, Tenax, Skaps, Watersaver, Lange Containment, and Mirafi. Using state of the art pipe fusing machinery, they also install piping systems for landfill gas and leachate management systems utilizing both PVC and HDPE pipes, appurtenances and fittings.
Agru America is a major supplier of geosynthetics for landfill construction applications. An innovator in the field, Agru has created a wide range of geomembrane products in addition to its standard Smooth geomembrane, including Micro Spike (structured textured products) Super Gripnet and Drain Liner in both LLDPE and HDPE. The company’s lines of geonets and geocomposites products are designed landfill drainage (leachate and cover percolation) as well as gas venting. Manufactured with a special flat die extrusion calendaring process, Micro Spike has a high-asperity surface structured with a series of regularly placed small spikes that are created by the process without affecting the core thickness of the geomembrane’s sheet. The result is a material with the industry’s highest interface friction angles, whose spikes mechanically bond with adjacent surfaces (either soils or geosynthetics).
Agru’s Drain Liner is a unique geomembrane with a high-drainage capacity along its surface plain, eliminating the need for a separate geonet layer when covered with an appropriate geotextile filter. The surface of the Drain Liner is manufactured with a series of studs that create a void space between the geomembrane and the overlaying geotextile. Both the HDPE and the LLDPE Super Gripnet Liner have spikes on their undersides, making them suitable for installation on steep slopes that would otherwise lead to stability problems.
Firestone Specialty Products manufactures both an ethylene propylene diene monomer (EPDM) synthetic rubber liner and a flexible Polypropylene (fPP) geomembrane. Tests using the EPA 9090A methodology have shown that both types of materials are resistant to landfill leachate, though their primary applications have been in landfill final-cap-and-cover installations. One unique application of these liners was to the construction of an exposed geomembrane solar cap at a major landfill in San Antonio, TX. This new configuration combined an exposed geomembrane serving as a mounting system for a series of flexible photovoltaic panels. The company’s reinforced membrane would stand up to extreme climate conditions and potential animal traffic. Furthermore, the PVC adhered securely to the thermoplastic liner.
Disposal and Compaction
Waste disposal and compaction operations are the reason why a landfill exists in the first place. The goal is to provide an environmentally safe and secure permanent disposal site for municipal solid waste—and do so at a profit. Supported by the office staff and maintenance shops, how well the equipment operators spread and compact the received waste can determine the landfill’s bottom line. Municipal solid waste arrives at the landfill with a typical average density of 20 pounds per cubic foot. Once the waste has been deposited, it is spread out over the current working face in a loose lift 2 to 3 feet thick. After spreading, waste compactors make several passes (usually three to five) over the loose layer to achieve optimum density. Once the waste has been spread out over the current working face, each compactor makes several passes over the loose layers. The goal is to reduce the volume of the waste by half, resulting in a doubling of its density to about 40 pounds per cubic foot.
Accurately measuring the amount of waste received is as important to the landfill’s profitability as the proper compaction of the waste. As waste collection trucks drive into and out of a landfill, they pass over a scale, which measures the weight both full and empty. These scales can be constructed either aboveground with high or low profiles or belowground in pits so the scale surface is flush with the adjacent pavement. The weights recorded by the scale are the basis for charging tipping fees and generating revenue for the landfill.
Columbia Industries LLC custom manufactures a full line of portable and fixed tippers for the management and unloading of solid waste at the landfill working face. This saves the landfill operator and waste hauler the trouble of operating and maintaining heavy, expensive self-unloading trailers. The resulting weight savings per truck allows the transportation of heavier payloads. The company’s Low Profile Landfill Tipper is an efficient method for unloading solid waste at the landfill. It is portable and can be modified to accommodate most commercial waste trucks.
Cardinal Scale is a supplier of aboveground and in-ground truck scales. Cardinal Scale provides the iCan system, a digitally controlled, high-performance weighing and diagnostic environment using advanced internationally standardized CAN serial bus. The iCan system features real-time load cell diagnostics (minimizing scale downtime), the 225 Navigator indicator allowing for immediate troubleshooting and operator notification of potential problems, onboard diagnostic displays, and the SmartCal system that allows for quick calibration without manual adjustments. Their unattended systems save on manpower. This unattended system can interface with WinVRS (windows vehicle recording system), which can be located any distance from a scale, since it is connected via short-haul or RF modems.
Caterpillar Inc., one of the largest heavy equipment manufacturers in the world, produces several models of waste and soil compaction equipment, from the “lightweight” 816F, with an operating weight of 52,793 pounds, through the 81,498-pound 826G. In addition to the main waste compaction equipment, Cat provides all the necessary support equipment (medium-size compactors such as the D4, D5, and D6 for working with the 816F and the larger D8 or D9 to team with the 826G). Cat compactor wheels come with either Pus Tips to resists abrasion and provide for long-term wear and tear, or with chopper blades to maximize the efficiency of waste shredding and compacting. The long-life Plus Tips utilize a design that incorporates abrasion-resistant materials in tips that are deployed in a wide-spaced pattern around the wheel drum to minimize clogging. The chopper blades are arranged in a self-cleaning, staggered chevron pattern. This allows for efficient operation and consistent compaction results.
Caron Compactor Co. manufactures innovative solid waste wheels and attachments for the specialized needs of landfill operations. The company is recognized for its high-alloy, field-replaceable Pin-On wheel cleats in traction and contour configurations that allow easy in-field replacement and which fit all major waste compactors, including those manufactured by Al-Jon, Bomag, Caterpillar, Komatsu, and Terex (CMI).
Caron Wheels come in two sizes, standard width and narrower, high-density wheels for greater applied pressure. These Maximizer wheels have been shown to increase compaction density by up to 15% over standard wheels. As a valuable reference for site operators, the Caron website, http://www.caroncompactor.com, features a Compaction Efficiency Calculator that demonstrates the impact of increased density on landfill life and profitability in specific applications.
In addition to wheels and cleats, Caron manufactures other landfill compactor components, guard groups, and trash blades, such as the Double Semi-U and Semi-U, offering solid-waste crawler/loader track shoes specially designed for the waste-handling industry, including landfill and transfer station applications. The company has recently introduced Caron Low Ground Pressure (LGP) track shoes, excellent for use on slopes.
HJ Industries Inc. is a manufacturer and distributor of customized compaction wheels for a wide variety of makes and models. Its most recent innovation is the patent-pending inner vertical barrier known as a Wire Wall. This addition prevents wire and loose waste from wrapping itself around a compactors axle while increasing compaction rates. The company also makes compaction wheel cleats with a hardened, angular, knifelike, stepped design called the Trac-Pac. These cleats improve compaction rates by up to 15%.
PC Scale Inc. offers a wide variety of software tools for landfill operators, waste haulers, and recyclers. These solutions provide systems for landfill billing, transfer station operations, gatehouse and truck scale ticketing, and MSW route billing. The company’s WR 5.0 Scale Management Software performs a variety of functions, single and multiple weighs of single or commingled materials per vehicle—or no weigh at all, allowing an operator to track waste receipts by volume, loads, or individual units (appliances, drums, tires, etc.). It generates invoices, captures new truck information, submits tare/expiration reminders, calculates tax configurations, produces and prints operational reports, while providing an accurate and secure management system.
Sierra International Machinery manufactures a wide range of waste shredding, baling and compaction equipment. The company’s Recycle Everything Balers (REB series) are ram balers designed specifically for scrap processing. The REB-1 handles all nonferrous material (aluminum, PET, OCC, paper, etc.) creating bales with densities, depending on the material, ranging from 20 pcf to 48 pcf for solid waste at production rates as high as 22 tons per hour. The REB-2 is a heavier-duty version that comes in two models, 150 horsepower and 250 horsepower. They are two-ram, wide box, high-density, fully automated balers that handle all nonferrous materials.
In addition to baling recycled scrap, Sierra produces a line of solid waste balers for bale-fill operations. Bale fills differ from standard landfills in that the waste is compacted into standard-size cubes prior to disposal. This increases in-place density and improves ease of placement, while reducing waste exposure and landfill gas formation. Sierra’s experience in operating its own bale-fill operation has been incorporated into the design of these machines. The Macpresse 108L can process up to 45 tons of MSW per hour while the larger Macpresse 112L can handle up to 70 tons per hour. At the opposite end of the waste-processing scale from balers are Sierra’s MAC 100, MAC 1500 and MAC 2000 large shredders for waste paper, banks, and confidential documents. Productivity ranges from 4-tons-per-hour bank shredders to 70-tons-per-hour mass wastepaper shredders.
Though primarily a maker and distributor of standard earthmoving equipment, Terex also manufactures a line of waste-handling equipment. With a special triangular wheel configuration (two wheels in the front for stability and maneuverability, and one wheel in the back covering the gap between the front two wheels) without a gap between the wheels, Terex compactors provide more coverage with each pass. Each wheel is large, with a 75-inch or 85-inch diameter and self-cleaning cleats. Big Dog cleats on each compactor wheel maximize waste application to the working face. Its line of waste compactors includes the Terex TC400 and the larger and heavier TC550.
Terra Compactor Wheel manufactures waste compaction wheels for all the major industry suppliers of compactors. Its specially designed Twist-Torque teeth bring a different part of the tooth in contact with the underling waste with each pass forward and backward, increasing the amount of waste in contact with the compactor. This pattern creates a motion in the trash that pulls trash from under the center of the compactor with each forward movement, piling up waste under the wheels for a second backward pass. This increases compaction while reducing wasteful wheel spin. Seven- to 8-inch Twist Torque coercion teeth are designed with a six-sided rhomboid shape with a matching, mirror-image cleat. A new innovation is the Scissor cleat, designed for compacting construction-and-demolition debris.
Carolina Software (Waste Works) publishes a family of related software packages providing a comprehensive reporting of waste management operational information. The centerpiece of this software ensemble is WasteWORKS, which accepts information from landfill weight scales as trucks enter the site. It automatically computes the tipping fee by ton, cubic yard, or other quantity. Once this computation is complete, it automatically prints out a ticket for cash or charge account transactions. The information printed on the ticket is also incorporated into customer billing and financial reporting without the need to acquire additional accounting software. Reports include graphical displays that clearly illustrate the time of highest productivity and a report-writer function that can generate dozens of different types of report formats.
Keeping the Workface Clean and Safe
During and after each workday, the landfill operator and his crew must ensure that the waste disposal workface is kept clean and safe and that it is not a source of windblown particulates or in danger of becoming a breeding ground for disease vectors. This is accomplished by the application of daily cover material over the exposed workface at the end of each day, as well as a thicker layer of intermediate cover over those slopes that will be exposed for a significant period of time before receiving final cover.
Usually this cover consists of a 6-inch to 12-inch layer of soil spread over exposed waste. However, significant airspace that could have been used for additional (and profitable) waste disposal can be lost to these soil layers. Many landfills now utilize alternate daily cover materials, such as spray-on foams, which decompose along with the waste, tarps, or plastic sheets that can be removed and reapplied multiple times. Daily cover serves several functions, including the minimization of windblown debris and dust, the containment of odors, and the warding off of insects, birds, and other disease vectors.
More active measures against odor, debris, dust, birds, and other vectors can also be taken. These include the strategic placement of netting to both catch blown debris before it leaves the site and to discourage birds from trying to land on the exposed waste. Birds can be scared off likewise with sound cannons. Odors can be masked with the application of various aerosols.
While tires are banned from landfills in many areas, they still manage to wind up on the doorstep, leaving waste managers with another problem. One solution is to invest in a high-torque, low speed grinder to turn into pellets that can then be sold for fuel or perhaps roadbed or sports field stabilization purposes.
Another approach favored by many operations is to outsource waste tire management to firms such as Upstate Shredding in Owego, NY. When nearby Tioga County found itself squeezed by New York State’s Waste Tire Management and Recycling Act, which required Tioga to ship its tires to a certified recycler at a cost of over $100 dollars per load, it saw no option but to charge fees to accept old tires, a situation encouraging hording or illegal dumping. It was at this point that Upstate Shredding offered to sponsor a tire removal program in which Tioga County now able to hold free—three-time-a year—tire drop-off events, each lasting from three days to one week in the towns of Owego, Barton, Candor, Spencer, and Tioga. As an added benefit, Upstate’s sponsorship covers the cost of disposal.
Landfill Service Corp. is best known for its Posi-Shell alternate daily cover, intermediate cover, vector control, erosion control, dust reduction, blown litter prevention and odor control. Posi-Shell is a spray-applied mineral mortar coating that can be applied in thin layers that mitigate the need for more bulky and expensive soil covers. The material is nonflammable, long lasting, easy to mix and simple to apply. The mix consists of a liquid water/leachate base, Posi-Pak P-100 Fivers and PSM-200 setting agent. Portland cement can be added to increase long-term durability and dyes can be added to increase aesthetic appearance.
Bird-X supplies the means to minimize bird impacts by scaring and repelling birds trying to land on a landfill’s exposed waste. The company’s line of products ranges from basic, low-tech bird netting to laser technology, ultrasonic/sonic repellant systems, animal sound, and visual scare devices. The laser is a 10-milliwatts-wide-beam laser with a constantly changing pattern to prevent acclimation. Other repelling devices blast birds with sound waves. Visual scares are induced with fake predators.
Though primarily a supplier of golf netting, Ace Netting also makes netting for landfill applications. Its debris-and-litter fence netting is built from 18 to 40 feet high. Designers take into account such factors influencing the potential for blown debris and litter leaving the landfill as prevailing winds, wind speeds, size, and terrain of the landfill. This netting is far more cost effective than old-style policing of the landfill and manual debris pickup.
Neptune Automated Wheel Wash Systems provides a wide range of sizes and applications for wheel-wash systems (compact, moderate, heavy-duty, and disinfecting). The Neptune Compact is a simple but effective unit for light-duty cleaning. It comes equipped with a one-tire-revolution dirt removal system called the Tracinator, which can also flush itself clean and rumble grates to shake off heavy solids, and which features a self-cleaning scraper conveyor system. The Maximums portable wheel-wash systems provide the service of a permanent facility with the operational flexibility to relocate as needed. The Neptune Disinfecting Truck Wash is designed to prevent possible cross-contamination by dispensing the appropriate disinfecting truck-wash solution and can be configured to spray the entire vehicle or just the wheel.
New Waste Concepts products cover the entire spectrum of workface management concerns, including cover and seeding, odor control, bird control, and dust control. For odor control, the company’s bio-augmentation applications use a combination of bacteria and enzymes to eliminate, not mask, offensive odors. The system utilizes a wide variety of selectively adapted bacteria, specifically engineered to counter specific odor-causing materials. Each product combines multiple strains of bacteria, select enzymes, and neutralizing chemicals to achieve optimum results.
Tarpomatic’s Automatic Tarping Machine (ATM) can be custom fitted and attached to standard workface equipment (compactor, dozer, etc.). This unit automatically unrolls to alternate daily cover tarps consisting of fabric panels and then removes them again at the start of the next workday. Using a hydraulic drive motor and engaging system, it can unwind and rewind the tarp spool with variable speed control. Once integrated into its carrying equipment, the operator can control the ATM’s engine, deployment height, speed and direction of movement, and forward or reverse rolling through a controller unit placed in the cab. Designed for the deployment of 40-foot-wide panels the ATM can be used to link a series of tarps together to cover or uncover larger areas of a landfill’s working face.
Airspace Saver supplies high-density, woven, polyethylene-coated fabric covers manufactured by Fabrene Inc. for use as alternate daily covers. Theses covers come equipped with high-tensile strength (6,000-pound) polyester web straps that are sewn into every seam and along the perimeter of the sheet to provide added strength against tearing during placement and removal. Steel D rings, precision sewn into the sheet edges at 12 feet intervals, allow for ease of placement, extending the life of the sheet over repeated uses. The Airspace Saver strapping system supports this cover sheet during application and removal.
Monitoring and Sampling
All landfills are potential sources of explosive methane gas, leachate that could affect local groundwater, or sediment-laden surface water runoff. These effluents have the potential to harm the health and the local environment, polluting the air, water, soil, and groundwater adjacent to the landfill. Continuous monitoring of the facility is necessary to ensure that no significant amounts of contaminants are leaving the site. This monitoring involves the regular sampling from designated extraction points of groundwater, leachate, surface water, and soil gas. The samples are analyzed for potentially harmful constituents at a laboratory, which provides regular reports on the monitoring results.
In-Situ Inc. is a manufacturer of onsite water and groundwater monitoring instruments. The company’s Aqua Troll line of instrumentation can monitor and log temperature and water levels while directly measuring important environmental parameters affecting groundwater quality, such as dissolved oxygen, conductivity, turbidity, and pH. The RDO optical dissolved-oxygen sensors are designed for harsh conditions without the need for hydration.
Thermo Fisher Scientific manufactures a line of whole-body contamination/radiation monitors, gamma portals, and material processing systems suitable for use in wastestream management operations. Its crane-mounted ASM 345C radiation detection system is one of a long line of ASM series vehicle-monitoring systems that can be used for sensitive vehicle scanning and industrial applications. The company’s LFM-3 portal radiation detection system is a multiple-use gamma ray and x-ray detection system. The system is specifically designed for monitoring materials bound for landfills, transfer stations, and other waste processing facilities.
Benzaco Scientific researches, designs, manufactures, and applies state-of-the-art chemical and equipment technology for odor control. Utilizing specific naturally occurring compounds to negate fouls odors, Banzaco’s products don’t merely mask odors with another, stronger scent. The formulas are incorporated into their ODOR-ARMOR odor elimination product line.
Managing Leachate, Landfill Gas, and Runoff
In addition to monitoring the site for emissions of leachate, landfill gas, and contaminated run-off, each of the effluents must be properly managed with the flows collected, removed, treated and disposed of in an environmentally safe manner. Leachate is contained by the underlying liner system and diverted to collection sumps where it is extracted by pumps and piped to disposal points or onsite pretreatment facilities. Landfill gas can be passively vented or actively accumulated by a series of extraction wells tied to a blower and flare apparatus where the gas is ignited in a controlled manner. Surface water is run through detention ponds where sediment carried by the runoff has time to settle out and produce a relatively clean discharge of water to nearby bodies of water.
HLS ECOLO/Hydrologic is an innovator of environmental chemicals and a manufacturer of the delivery systems used to apply these chemicals. Sold through strategic marketing alliances, its Airsolutions misting odor neutralizers can be applied to landfill work faces with the company’s Airstream automated misting equipment. Airsolutions is a completely nonhazardous, nonflammable, biodegradable, long-lasting formula. Airstream misting equipment is equally applicable in pest control, dust control, and environmental cooling as well as odor suppression.
A manufacturer of pneumatic and electric positive-displacement piston pumps, Blackhawk is a supplier of leachate- and landfill-gas extraction-well-dewatering pumps. For hazardous and potentially hazardous conditions, the company’s Trident pneumatic pump can be installed in vertical, horizontal, and high-head pumping conditions. This makes it suitable for use in most landfill-leachate-extraction sump configurations. Its enclosed, mechanically reciprocating motor lifts liquid to the surface with each stroke, generating a flow rate of up to 10 gallons per minute. Designed for harsh operating environments, it can operate wet or dry. Blackhawk’s Electric Anchor Pump is applicable for low-flow remediation, and the extraction of landfill leachate and landfill gas condensate. Its motor is located at the surface, so there is no need for extending potentially sparking electrical wires down into a well that might contain methane. The Anchor is designed for hazardous environments, hazardous weather, and explosion-proof applications.
Enercon manufactures switches and controls for a full range of power generation products. The company’s landfill-gas recovery package is a complete attenuated enclosure complete with controls and low-voltage switchgear for a customer-supplied, landfill-gas-fueled generator set rated at 1,600 kW. The unit produces power that is sold back to the local utility based on three-phase, 60-hertz service at 13.2 kV. Using customized manufactured switchgears, controls, and SCADA (supervisory control and data acquisition) systems, Enercon provides a custom-engineered system designed to increase the efficiency of electrical power production from landfill gas to fuel engine generator sets.
Advanced Drainage Systems manufactures and supplies high-density polyethylene (HDPE) drainage pipes for landfill leachate collection and extraction operations. These pipes are designed and manufactured with the necessary chemical, thermal and physical resistance against pipe crushing to handle applications in harsh landfill environments. ADS single-wall corrugated pipe (perforated pipe for water and leachate collection or non-perforated pipe for water transfer and outfalls) is available in 3-inch to 24-inch diameters and in long coils for easy installation with fewer joints. N-12 pipe is a dual-walled corrugated pipe that combines structural strength and a smooth interior for smooth flow. This pipe is applicable for the carrying either storm water or leachate. N-12 pipe is available in 4-inch to 60-inch diameters with both soil tight and watertight joints making its performance comparable to corrugated steel or concrete pipe. The unique panel-shaped geo-composite design of the AdvanEDGE pipe is designed for rapid drainage response. It has twice the soil contact area of 4-inch round pipe, and can drain a given quantity of water in about 60% of the time.
Forrer Supply Co. Inc. is a supplier of HDPE and PVC pipe, geomembrane valves, and fittings and provides a wide variety of landfill specific products. The company has an in-house engineering and fabrication department that can design and fabricate custom HDPE pipe products and fittings (including leachate storage tanks, sumps, manifolds, risers, pump stations, and manholes). Its standard line of products includes dual-walled HDPE pipe and associated fittings for transmission of leachate outside of lined areas, perforated HDPE pipe for leachate collection, PVC slotted well screens, and landfill-gas wellheads.
A 20-year veteran of the landfill gas industry, Landtec provides wellhead assemblies, flow meters, and condensate knockouts, as well as a wide variety of fixed and hand-held monitoring devices. The ACCU-Flow Wellhead and associated ACCU-Flow Meter are prefabricated and easy to install. They are available in either horizontal or vertical configurations and incorporate a built-in gas flow meter, gas temperature port, quick-connect sampling and pressure measurement ports, flow-control gate valve, and flexible connection hose for ease of installation. The gas flow measurement can be tied into the company’s Automated Extraction Monitoring System (AEMS), which continuously monitors gas flows for methane content. In addition to gas extraction, Landtec provides the Knock Out (KO) system for the efficient and safe extraction of condensate from the gas stream, complete with pneumatic or electric pumps and controls. Liquid flows (condensate or leachate) can be handled by the Landfill Automated Pump Station. A standalone unit, LAPS provides intermediate storage and pumping, controlled by a level controller.
NCM Odor Control has experience in the elimination of odors in landfills, transfer stations, railroad yards, and waste treatment plants. The company’s chemical agents are applied by a high-pressure (1,100 psi) delivery system. The SL-1000, SL-2000, and SL-4000 are effective against derivatives of sulfur and ammonia. These formulas can also be applied as part of a closed system such as a scrubber, where direct contact with odors can be maintained.
Houston Service Industries Inc. is a supplier of multistage centrifugal blowers and high-speed turbo blowers. Its multistage centrifugal landfill gas blowers are designed for operations in corrosive, high-moisture, and temperature-extreme environments. HSI has 13 models of multi-stage centrifugal blowers with performance ranges up to 25 psi pressure and 100 to 140 cfm flow rates. HIS also manufactures complete blower packages with control systems and customized accessories.
HSI is an ISO 9001-2008 certified company and is the leading manufacturer of blowers, exhausters, and control systems. Located in Houston, Texas, HSI houses state-of-the-art engineering, manufacturing, and testing capabilities as well as the largest multistage blower parts inventory in the world. HSI Multistage Centrifugal Series offers 15 models of heavy-duty, cast-iron, vertically split multistage centrifugal blowers and exhausters. Product performance ranges up to 25 psi pressure or to 18 in HG vacuum and flows from 100 to 40,000 CFM. HSI manufactures blower and process control systems as well as provides complete blower packages with accessories to meet a wide variety of applications.
St. Croix Sensory is a sensory testing and training company, providing not just odor-testing services but training in the use of odor-testing devices. In a field where the potential to be vague and subjective is great, St. Croix Sensory utilizes objective, definitive internationally accepted standards and practices and applies them in the evaluation air samples from a variety of industrial, agricultural, wastewater, landfills, composting and manufacturing operations.
Closure and Postclosure
Waste compaction and disposal, along with concurrent health and safety tasks, environmental monitoring, and management of landfill effluents, continues until the current call or the entire landfill achieve final waste disposal grades in accordance with its permitted design plans. Once these have been reached, final closure operations can begin. The final cap-and-cover system usually consists of a permeable gas-management layer (either loose soil or a geosynthetic blanket) that allows free migration of landfill gas under the cap, an impermeable cap similar to the liner underlying the site that prevents percolation of water down into the waste, and a layer of soil cover and vegetation providing protection against frost penetration and erosion.
After the site has been completely closed, the owner is still responsible for postclosure care and maintenance of the site, typically for a period of at least 30 years. All the previous environmental monitoring performed during the site’s operational lifetime continues, but usually at a reduced frequency. The closed landfill must be inspected on a regular basis and any damage done to its protective cover and repairs to its mechanical systems (leachate and gas extraction) will be performed.
Only after this post closure care period is completed can operations at a landfill be considered to be finished.
Author's Bio: Daniel P. Duffy, PE, writes frequently on the topics of landfills and the environment.