Design and Construction

Transcription

1 Design and Construction In December 2010, the ClosureTurf Surficial Gas Collection and Cap System was installed on approximately 10 acres of the IESI Timber Ridge Landfill in Richwoods, Missouri. The new system enabled Timber Ridge to integrate two distinct components of landfill operations closure and GCCS into one streamlined, cost effective approach that significantly reduces environmental impact. ClosureTurf has significantly improved membrane protection, accessibility, wind resistance and aesthetics when compared to Exposed Geomembrane Cover Systems (EGCS). Some regulators and owners have referred to ClosureTurf as a hybrid system providing long-term membrane integrity and accessibility like a soil cap, but with many of the maintenance and erosion protection benefits of an exposed cap. The ClosureTurf system consists of three primary components: (1) two layers of woven geotextiles sewn together with tufted UV-resistant polyethylene grass turf that is laid over (2) Agru America s Super Gripnet 60-mil LLDPE structured drainage geomembrane and (3) sand that serves as ballast. In addition to improved aesthetics, the turf provides two critical functions: it serves as a matrix that locks-in the sand and also creates a disturbed wind flow pattern that eliminates uplift and shear failure, even in 150+ mpg winds. ClosureTurf can be laid directly on the EPA required intermediate soil cover, eliminating the need for the final soil and grass cap and creating an additional two feet of fillable air space. Unlike traditional closure methods, ClosureTurf does not rely on vertical gas wells to convey landfill gas (LFG) but rather employs a Surficial Gas Collection System (SGCS) that captures emissions as they passively rise to the surface. Emissions are then collected underneath the system s impermeable membrane where they are pulled by an applied vacuum to the flare system. During the system s installation as a final cap, 5 foot wide geocomposite strips were placed below the Super Gripnet every 50 feet vertically to allow for gas transmissivity and to aid in vacuum influence throughout the field. The LFG is collected via 8 extraction points booted onto the geomembrane at approximate 200-feet centers along the perimeter at the toe of slope. Six pressure relief valves/risers located at mid-slope were placed on vacuum for additional LFG recovery. A Parnel Biogas Systems blower and candle-stick flare station provide vacuum for the field and destruction of the gas. A California Analytical continuous gas analyzer (methane, oxygen, and carbon dioxide) and a Thermal Instruments flow meter complete the recording requirements necessary for monetization of carbon credits through the combustion of LFG methane. Becoming operational in March, 2011, the system has surpassed expectations. LFG flow rates to the flare are approximately SCFM of 45-50% methane concentration. Storm water analytical results document improved water quality and perhaps most notably, monitoring indicates the elimination of all LFG odors at the project area. The absence of vertical wells eliminates the need for constant monitoring and adjustments to prevent fire hazards caused by the incursion of excess oxygen into the landfill. Also, the emissions at Timber Ridge are high-quality since little condensate is formed as the gas slowly rises and cools to ambient temperature. The system can easily incorporate vertical gas wells

2 at any time, avoiding the damage, environmental inefficiencies and time and labor expense common to a traditional soil cap. For ClosureTurf Director of Operations Delaney Lewis, it has been exciting to see Timber Ridge embracing the new technology. Our goal was to create a system that eased the monitoring burden. Timber Ridge s system is virtually maintenance free; you just turn on the vacuum and let it work. Over a 30 year period, IESI Timber Ridge estimates that it will save approximately$53,000 per acre on SGCS alone (this is in addition to a $70,000 per acre savings in final cap installation/ maintenance costs and additional airspace revenue). Further value will be realized in the sale of carbon credits and the development of LFG projects. Progressive Waste (IESI) regional engineer, Michael Friesen notes, Since the cap acts as our gas system, we basically have a landfill gas system free of charge.

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4 Environmental Controls The IESI Timber Ridge system demonstrates that new geosynthetic applications can revolutionize the reliability, environmental integrity, and performance of landfills. ClosureTurf, by adding a specialized synthetic turf to an exposed geomembrane cap, has significantly improved membrane protection, accessibility, wind resistance and aesthetics. These enhancements, combined with the system s inbuilt Surficial Gas Collection capabilities, increases long term performance while simultaneously reducing the carbon footprint by up to 75%. ClosureTurf is installed quickly (several times faster than a traditional closure) with minimal mobilization cost. The ease of construction provides an opportunity for the operator to close at smaller, more frequent increments of three to five acres at a time. This allows Timber Ridge to close as they go resulting in earlier control of odor, surface emissions and a reduction of green house gases a paramount goal of SWANA. It is no longer necessary to wait until 20 to 50 acres can be closed in order to obtain economies-of-scale. The system has stabilized slopes once subject to repeated failure. Since rainfall penetrates through the sand and into the high-transmissivity drain liner below (which can handle rainfall of more than 6 inches per hour), erosion energy resides in the structured geomembrane and not in the sand surface, preventing erosion and siltation. ClosureTurf eliminates the need for a final soil and grass cap, removing truckloads of soil from the road (5,300 truck trips for the Timber Ridge project) and prevents land being destroyed for borrow. The artificial turf requires no maintenance, ending the need for mowing, fertilizer and replacement soil. Compared to traditional closure methods, the new approach has reduced Timber Ridge s total carbon footprint from 652,400 Kg CO2/ha to 132,200 CO2/ha. Becoming operational in March, 2011, the Timber Ridge system has operated between 350 scfm to 500 scfm at the flare for over one year. Methane quality has consistently measured at 45% to 50%. Gas migration observed along the east side of the landfill was mitigated by the system s installation, due to the influence of the active system. SGCS allows for a very efficient gas collection process since the potential of oxidization within the waste mass is non-existent and condensate generation is substantially lower since the gas cools to ambient temperature as it travels through the waste mass and has much lower oxygen intake. With more and more landfills seeking to harvest landfill gas for energy generation, it has become important to maintain the quality of the methane produced. It is very exciting to see Timber Ridge and ClosureTurf transform what was once a hazard into a commodity with economic and environmental benefits, notes Cooter Callahan, Timber Ridge Landfill Manager.

5 Automated leachate control Controlled access to facility Emissions control Perimeter monitoring wellhead

6 Regulatory Compliance IESI Timber Ridge is a Subtitle D landfill that falls under the regulatory authority of the Missouri Department of Natural Resources (MDNR). Issued permit number , the landfill opened in 2003 and serves as the primary waste disposal facility for the Richwoods, Missouri area. Located on 690 acres of land, the site has a permitted disposal acreage of 176 acres, allowing a large buffer zone of unused land. Timber Ridge has accepted close to 2.2 million cubic yards of waste since opening and at the current level of activity, should reach maximum permitted capacity in MDNR approved a pilot study of ClosureTurf as an Alternative Intermediate Cover in The site is currently working with MDNR and Aquaterra to obtain a permit to install an evaporator for leachate disposal. The site and staff are involved in studies to further improve utilization of energy produced. Per MDNR procedure, Timber Ridge is inspected on a quarterly basis to ensure that operations are in compliance with guidelines set forth including: review of permits, certified personnel, solid waste acceptance plans, construction and operational plans, leachate control systems, gas (methane) control systems and documentation that demonstrates implementation. Other points of inspection include weather accessibility, erosion and erosion controls, litter and litter controls, and daily and intermediate cover. To date, the landfill has operated in full compliance with no violations. An annual performance report is submitted to MDNR. The report contains the visual monitoring records of the turf and sand ( satisfactory performance ), storm water analytical results ( improved water quality ), and the LFG monitoring of the gas probe network ( reduction of the methane migration previously observed proximate to the project area ). Tests to discover the geomembrane tensile strength and oxidative induction have no observed discrepancies. LFG odors at the project area have been eliminated. A summary assessment report will be prepared after the completion of the three year monitoring period.

7 Planning, Operations & Financial Management Operations and Inspections Timber Ridge s MDNR permit (# ) guides the short and long term design, construction and day-to-day operational activities of the landfill. The permit addresses every aspect of the landfill from Day One planning to its eventual close once all available airspace is consumed. Completed before the acceptance of waste, the permit originates as a facility plan and, once submitted and accepted, becomes the authorization. The permit addresses everything from environmental concerns (geology, water management, waste management, gas [methane] collection, leachate collection), to safety training, construction sequence, financial assurances and post closure. Safety meetings are mandated one time per month, or sooner if any safety-related incidents occur. Events that could prompt a safety meeting include employee, vendor, customer, and weather issues, a change in daily operations due to construction activity, moving to a new location, or a change in the route to the disposal site. In accordance with IESI Timber Ridge s Storm Water Protection Plan (SWPP), the Lead Operator conducts weekly inspections of the site, recording activity for the previous week and noting any conditional issues. Weather concerns, repairs completed and upcoming events are also recorded. All employees participate in Best Management Practices (BMP) to support the SWPP. BMP training is held after each safety meeting. The goal is to enable all employees to effectively identify and address SWPP problems. Load Inspections are completed weekly in accordance to the Solid Waste Acceptance Management Program (SWAMP). Three loads are randomly chosen and inspections include a driver interview and load examination. Written documentation is collected including driver signature and pictures of the load. Planning & Expansion IESI Timber Ridge Landfill has budgeted and permitted a beneficial reuse of LFG to evaporate leachate. Design and procurement is underway to utilize a booster blower skid to supply LFG via 4000 linear feet of 6-inch diameter HDPE piping to ENCON evaporation units. As waste disposal operations continue, additional ClosureTurf with SGCS will be permitted and installed. Financial Management IESI-Timber Ridge s 2011 operating budget was $1.25 million. It is estimated that over a 30 year period, Timber Ridge will save approximately $53,000 per acre in GCCS and an additional $70,000 per acre in final cap savings and additional airspace revenue.

8 Lead Staff W. Cooter Callahan, Landfill Manager Tenure employee; has been with the landfill since its establishment. He holds CPR certification, State and MOLO certification. Denis Callahan, Lead Operator Tenure employee; has been with the landfill since its establishment. He holds CPR certification, First Responder certification, EPG pump certificate, Certified Landfill Technician, and is also scheduled to attend the MOLO course and to obtain MOLO certification. Ron Cobb, Landfill Operator Tenure employee; has been with the landfill since its establishment. He holds certification in CPR and is a Certified Landfill Technician. Tony Gale, Landfill Operator Has been with the landfill for almost 6 years. He holds certification in CPR and is scheduled to obtain his certification from the State as a Landfill Technician in September David Boyet, Landfill Operator Has been with the landfill for close to 7 years. He holds certification in CPR and is a Certified Landfill Technician. Philip Blanford, Landfill Operator Has been with the landfill for almost two years. He is scheduled to obtain certification from the State as a Landfill Technician. Connie Keller, Administrative Support Has been with the landfill two years. She holds certification in CPR and is a Certified Landfill Technician. In an inspection report from July 26, 2011, the Minnesota Department of Natural Resources commended all personnel for their attention to the operating and maintenance requirements.

9 Utilization of Equipment/Systems and Technologies The IESI Timber Ridge flare station provides vacuum to the Surficial Gas Collection System (SGCS) integrated into ten acres of ClosureTurf landfill cover. ClosureTurf was installed as part of a 2010 pilot study of Alternative Intermediate Landfill Cover. The Timber Ridge SGCS utilizes an automated, skid-mounted, utility flare system. Designed and constructed by Parnel Biogas, Inc., the unit is intended for a maximum flow rate of 500 standard cubic feet per minute (scfm) at a static pressure of 40 inches water column (wc). The flare station consists of a knock out vessel, variable frequency centrifugal blower, actuator control valve, flare arrestor and utility flare. Instrumentation at the flare station includes: A thermal mass flowmeter for continuous landfill gas flow measurement. A continuous temperature controlled non-destructive infrared monitor (NDIR) for landfill gas quality. A Yokagawa DX1012 Digital Chart Recorder. After the first year of operation, the flare station was retrofitted with the following upgrade features: A 30 kw generator was added to provide back-up power if the flare system fails due to a power outage. A SCADA Monitoring System to allow real time monitoring of critical system parameters. The system also provides notification of system malfunctions and operational warning thresholds. SGCS condensate knockout SGCS wellhead

10 Skid mounted flare Leachate condensate storage tanks SGCS turf with header Automated backup generator

11 Public Acceptance, Appearance and Aesthetics The appearance of the IESI Timber Ridge Landfill reflects the pride and dedication of its staff. Considered one of the best maintained landfills in Missouri, its respect for the community and environment is evident throughout the site. Of ClosureTurf s numerous advantages over other closure methods, it is the visual improvement that is immediately noticeable. The continuous green turfed slopes and absence of vertical wells offer a marked contrast to the patchy vegetation and erosion rills of soil caps and the damaged, negative aesthetics of Exposed Geomembrane Cover Systems (EGCS). Care is taken to keep the entrance clean and well landscaped. Such attention is well appreciated among the community. Landfill Manager, Walter Cooter Callahan, takes pride in the landfill s efforts. I consider myself fortunate to be a team member of the IESI Timber Ridge Landfill. Our dedication to safety, efficient daily operation, training, the environment, community awareness and customer satisfaction is #1 to us every day. In addition to sponsoring the local Desoto Fire Department and the school district s annual Drug Awareness Program, Mr. Callahan and staff regularly provide tours of the site to students. I believe education is the key to understanding and acceptance, notes Callahan. It is important that residents know where their garbage goes and about the environmental protection systems in place.

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13 Innovation and Creativity The success of IESI Timber Ridge Landfill demonstrates the potential of new operating techniques and technology. The ClosureTurf Surficial Gas Collection and Cap System provides a new approach to solving the complications that have plagued the landfill industry from its inception. Its advantages include: Rapid Capping ClosureTurf allows for faster, close as you go capping during the operational life of the landfill. Faster capping reduces odors, improves gas collection efficiency and enhances compliance with Title V air quality rules. Safety The absence of vertical wells eliminates the fear of oxidation (fire, micro-organism impact) within the landfill as a result of applying too much vacuum. Financial Savings Over a 30 year period, Timber Ridge estimates that it will save approximately$53,000 per acre on SGCS alone (this is in addition to a $70,000 per acre savings in final cap installation/maintenance costs plus additional airspace revenue). Further value will be realized in the sale of carbon credits and the development of LFG projects. Environmentally Friendly Better for landfills in sensitive areas where soil erosion and sedimentation are a major concern. Soil loss is nonexistent during operations and post-closure. Eliminates the need for borrow sources, siltation ponds and associated environmental construction impacts. Steeper Waste Slopes Since soil stability problems, either through earthquake or gas pressure buildup, are eliminated, steeper waste slopes can be used. Reduced Cap Infiltration Surface water is rapidly drained off and is not restricted by the hydraulic conductivity of the cover drainage system. As a result, the impermeable layer hydraulic head and subsequent waste infiltration are minimized. Enhanced Visual Inspection - Because the synthetic materials are exposed, they are easily inspected for damage, which, if identified, may be easily and inexpensively repaired. Also, most synthetic caps are damaged by earthwork equipment during soil placement. By replacing the soil layer with ClosureTurf, this is no longer an issue. Easier Reclamation Access Landfill materials are readily accessible in the event of landfill reclamation for future piggyback areas or future waste lifts due to waste settlement or vertical expansion. The composite material allows owners access to the waste without having to remove the existing cover soils of a typical and traditional final cover system. No less important is the innovative attitude of the IESI Timber Ridge staff. Through hard work and continuous training, the Timber Ridge team is empowered to tackle the day-to-day tough decisions and the long term planning that are required of a successful site. Through training tools such as Best Management Practices, confident and creative thinking is nurtured in each employee.

14 Leachate collection hut SGCS wellhead SGCS turf with header Automated backup generator

15 Supporting Companies & Individuals Closure Turf, LLC Agru America, Inc. Aquaterra Engineering Camanco Parnell Biogas, Inc. Missouri Department of Natural Resources Mike Friesen, Regional Engineer, IESI John Brockman, Landfill Manager, IESI Walter Cooter Callahan, IESI Scott Fowler, IESI Mark Russell, Aquaterra Engineering Tracy Johnson, Camanco

16 IESI Timber Ridge Landfill Project Summary Modern landfills operate under many regulations. Under EPA Title V, landfills must prevent the escape of methane gas emissions through the installation of a Gas Collection and Control System (GCCS). In addition, EPA Subtitle D requires landfill operators to perform temporary, or intermediate closure once individual landfill cells are full, and then install a final cap once a landfill has reached its maximum permitted capacity and cannot be expanded. In December 2010, the ClosureTurf Surficial Gas Collection and Cap System was installed on approximately 10 acres of the IESI Timber Ridge Landfill in Richwoods, Missouri. The new system enabled Timber Ridge to integrate two distinct components of landfill operations closure and GCCS into one streamlined, cost effective approach that significantly reduces environmental impact. This project demonstrates that new geosynthetic applications can improve the reliability and performance of landfill closures. In particular, adding a specialized synthetic turf component to an exposed geomembrane cap can significantly improve membrane protection, accessibility, wind resistance and aesthetics. Additionally, the turf provides considerable economic and environmental savings. Construction and post-closure maintenance costs are greatly reduced and the new system results in substantial reductions in CO 2 emissions from the construction and the earlier capture of methane gas.