Corral Farm Landfill, Fauquier County, Virginia - The Corral Farm Landfill has a Subtitle D liner under Cell V, where waste filling is currently taking place, and is in the process of constructing the same liner system under Cell IV. The County has been recirculating leachate on Cell V both by spraying the liquids on the working face and by injection into a dual gas/leachate horizontal pipe system provided by a landfill equipment vendor (LTI). Daily cover is a spray-on product called Posishell and soil is used to provide interim cover.

SCS’ role has been to develop an integrated LFG collection and leachate recirculation design plan for Cell IV and the remainder of Cell V (with provisions to expand into future Cells I, II, and III). Working in cooperation with the equipment vendor, SCS has provided input on leachate injection, collector dewatering, and gas extraction tests. The design plan includes a series of horizontal LFG collectors interspersed with the dual gas/leachate piping. Collected gas will be conveyed to a blower/flare station with future consideration for onsite utilization.

SCS has also provided odor consulting services to address odor complaints from the neighboring community college. The addition of passive flares to leachate collection and recirculation components controlled the odors.

Egyptian Bioreactor Landfill Projects - The project is being funded by Industry Canada and includes the siting and design of bioreactor landfills in Sadat City and Cairo, Egypt. Work on this project by SCS Engineers will be in the capacity as lead LFG consultant. SCS work will concentrate on aspects of the project that pertain to in-landfill conditions (moisture/ temperature), and to the LFG collection system.

Project tasks include the following:

• Identification of Solid Waste Quantities and Characteristics, and Site Selection
• Site Assessment and Preliminary Design of Bioreactor Cells
• Consultations with Stake Holders in Egypt and Canada
• Final Design of the Bioreactor Landfill Cells
• Construction of Bioreactor Landfill Cells including LFG Utilization Equipment and Monitoring Instrumentation
• Evaluation of System Performance.

Millersville Landfill Bioreactor Study, Anne Arundel County, Maryland – The client is testing the bioreactor landfill concept (pilot project) over a portion of one of its active cells, and retained SCS for engineering and consulting related to this effort. The Millersville landfill generates approximately 8,000 gallons of leachate per day. The pilot project will involve injecting leachate using injection devices into a 160’ by 200’ portion of Cell 8 over a four to seven year period, and monitoring the settlement. Currently, leachate from Cell 8 is collected from its subcell sumps and piped into a storage tank for pretreatment.

The objectives of the project are as follows:

• Design and construct a bioreactor test area in an active cell of thelandfill;
• Perform leachate recirculation in a controlled manner using different recirculation methods;
• Monitor surface settlement an recirculation rates over a period of time; and
• Evaluate results and ultimately select the method that will most effectively increase the landfill’s waste capacity.

The Client has developed a detailed stakeholder participation plan that will ensure full involvement of federal, state and local groups in the pilot project. The County plans to monitor the project’s success and will publish updates on its Website and in a local newsletter.

Southeast County Landfill 60,000 g.p.d. Leachate Treatment Facility, Tampa, Florida - SCS designed a 60,000 gallon per day leachate treatment and spray irrigation project for the Southeast County Landfill. Effluent from the treatment system is spray irrigated on sections of the landfill that have received interim cover. In addition, the County of Hillsborough, Florida recirculates 5,000 to 10,000 gallons per day into the active working face of the landfill.

The project involved significant regulatory challenges in order to establish allowable spray irrigation criteria. The Florida Department of Environmental Protection (FDEP) ultimately instituted stringent spray irrigation limitations on the system based on rainfall patterns. This has resulted in some changes to the overall leachate management plan for the site. Construction of the system was completed in 1996, at a construction cost for the entire project of $3.8 million. SCS continues to provide operational support for the treatment plant.

NSW State Government Waste Management Body of Australia - Mr. Nocholas Lambropoulos of SCS designed and managed construction and operation of both laboratory and field scale bioreactor landfills for the NSW State Government Waste Management Body of Australia. The objectives of the projects were to accomplish the following:

• Reduce post-closure care costs and long term liabilities;
• Acceptance of the bioreactor concept by regulators and the public Reduction in greenhouse emissions and optimization of energy (methane) recovery rates;
• Optimization of airspace usage; and
• Determine the true costs including capital, operating, and environmental.

The challenges identified in the projects include effectively collecting moisture and redistributing it, monitoring moisture movement in the landfills, efficient landfill gas collection and measurement, and improving waste bed permeability. Mr. Lambropoulos is focusing efforts on better understanding these challenges as the projects proceed.

Burlington County Landfill, New Jersey - SCS performed an in depth evaluation of leachate recirculation for the Burlington County Landfill No. 2. The County sponsored the evaluation to study the feasibility of maximizing the airspace in a new landfill and to prepare the landfill for possible future landfill mining, recycling, and residue consolidation. SCS reviewed recent technical papers, selected a landfill model for the evaluation, and developed design parameters for consideration by the County. Recommendations for the configuration of the leachate recirculation system were developed along with the probable efficiencies and difficulties with the proposed system.

Fink Road Landfill, Stanislaus County, California -SCS performed a detailed leachate evaluation of Landfill LF-3 and the surface impoundment SI-1 to correct overfilling that occurred during the wet 1998 winter season. Our evaluation involved water balance calculations to determine the balance of free liquid in the landfill and surface impoundment, and a preliminary design of a new impoundment. This evaluation resulted in the redesign and reconstruction of SI-1 using a double geomembrane liner system with leak detection capability.

North Waikato Regional Landfill, New Zealand - SCS performed a leachate handling evaluation for this new landfill, which included leachate recirculation, physical/chemical treatment, and thermal treatment options. Each of the options were screened by criteria including process, state of process development, ability to meet permit conditions, performance record, and cost.

Redvale Landfill, New Zealand - SCS assisted client with permitting of a leachate evaporation system for Revale Landfill. The work involved preparing permit support documents and responding to questions from regulatory agency. The system has been approved and installed at the landfill.

Prados de la Montana Landfill, Mexico City - SCS developed a conceptual design for a system to extract and treat leachate at the Prados de la Montana Landfill in Mexico City. The project included estimation of the volume of leachate present in the landfill and identification of optional methods of extracting and treating it. Treatment by evaporation was the initial recommendation because the City’s sewerage treatment agency would not allow conveyance to and treatment of leachate at the regional sewage treatment plant, the preferred and least costly disposal option. Subsequently, the sewerage agency reconsidered and SCS prepared a conceptual plan for the construction of a pipeline to the nearby sanitary sewage system.