Resident Engineer and CQA for Landfill Closure

Client: City of New York, General Services, New York, New York - New 800-bed Jail Complex at Rikers Island, New York

SCS was retained by the New York City Department of General Services in 1989 to provide a variety of services at Rikers Island. Rikers Island contains a prison built atop of an old landfill. SCS was called in to develop a health and safety plan for methane gas monitoring during the construction of a 800-cell jail complex. The City was housing the inmates outside and was incurring fines, so the work needed to be performed on a fast-track basis. LFG was coming through the concrete slab, creating potentially explosive conditions. SCS prepared the health and safety plan within a month. The plan was designed to: prevent fire/explosion; identify oxygen-deficient locations; identify the presence of hydrogen sulfide; lay out the procedures to be followed by construction workers and others in the area.

The next task was the design of LFG controls. SCS designed an LFG control system, assisted in negotiating construction contract change orders, provided construction monitoring, assisted in the start-up, and prepared the O&M manual.

At another site on Rikers, SCS designed an extraction well system to draw LFG found in subsurface fill away from the buildings. An extraction test program was conducted and formed the basis of the design drawings. Again, SCS assisted in procurement of construction services. Other work included construction oversight and start-up, and preparing the O&M manual.

The next task involved a soil/soil gas/ambient air sampling program at the site of the proposed Nursery Beacon infirmary and kitchen per State requirements. SCS installed soil borings, test pits and monitoring wells, and then conducted sampling and analysis.

The sixth task SCS conducted at Rikers involved a methane investigation at the site of planned sprung structures around the island to determine if methane is present near the surface.

SCS was then asked to design, on an emergency response basis, passive methane gas control systems. The systems consisted of subslab membrane, roof vents and sensors for temporary inmate housing.

Construction engineering services were provided for a LFG control system under 20 sprung structures. Specific tasks included: assisting in procuring materials; providing consulting services; developing construction details; observing the construction; coordinating with regulatory and oversight agencies; and conducting testing to assess the system's effectiveness in controlling LFG.

Landfill Gas Engineering, Construction, and O&M Services

Client: Private Sanitary Landfill, Scranton, PA

SCS provides comprehensive landfill gas engineering, construction, and operation and maintenance services to Empire Sanitary Landfill. These services have included:

• Design/build of an interim LFG collection and open flare system.
• Design/build of a permanent enclosed flare station.
• Evaluation of LFG utilization feasibility and ongoing consulting during proposal and implementation of a high-Btu processing facility for sale of gas to the gas utility through a third-party developer.
• Air emissions consulting and permitting for the following:

  Three temporary candle flares

  Three enclosed flares

  Title V facility permitting including landfill, engine, quarry, and flare operations.

  RACT proposal for VOC emissions control for the existing landfill.

  Air permitting for a landfill expansion.

• Stack testing for an enclosed flare.
• Ongoing routine and emergency operations and maintenance for the LFG collection and flare system.

Landfill Gas Control and Utilization

Client: Roanoke Valley Resource Authority, Roanoke, Virginia - Rutrough Road Landfill Gas Collection System

The Rutrough Road Landfill is one of two landfills owned by the Authority. Monitoring data at this closed facility indicated that subsurface migration of landfill gas (LFG) was occurring off-site. SCS performed a field investigation to establish the nature and extent of methane migration pathways, as well as the effectiveness of an existing passive LFG control system. Measures to correct the situation were assessed under a fast time frame, due to potential hazards to a nearby active highway construction site.

Tasks included design of a new LFG collection system to migrate the problem and explosion potential, design of blower/flare station compliant with new air emissions regulations, engineering support for procurement of construction contracts, construction monitoring/start-up for the installed systems, system balancing for the LFG wellfield, and follow-up monitoring to establish that subsurface migration levels were below the facility threshold levels.

Landfill Investigations and Permit Modifications

Client: Private Landfill Operator -- Landfill Investigation and Assessment Monitoring, Roxana, Illinois

SCS conducted a study for the Roxana landfill which proved LFG to be a source of VOCs in ground water. SCS also developed a Subtitle D Assessment Program and a remediation alternative that recognizes the role of LFG in VOC transfer to ground water.

Scope of Services:

Landfill gas (LFG) monitoring at the Roxana facility indicated the presence of methane gas outside of refuse at levels exceeding the Illinois regulatory limit of 2.5 percent methane. The source of this methane appeared to be LFG. Groundwater monitoring at the facility confirmed the presence of seven volatile organic compounds (VOCs), including groundwater upgradient of the site. Potential sources for these VOCs (that were attributed the landfill) included leachate and LFG. To better identify the source and extent of potential contamination, SCS initiated a field investigation and sampling program.

The SCS field investigation concluded that, in general, both leachate and LFG were potential sources of the VOCs observed in groundwater monitoring wells. In addition, the likely source of VOCs in upgradient groundwater was identified as LFG; the data suggested that no single source was responsible for all the VOC increases observed.

The continuation of the project included the development and implementation of a State-approved Assessment Monitoring Program (AMP) for the facility. Activities under this program included further groundwater and methane gas monitoring, evaluation of the data collected, and subsequent actions to take based on the data evaluation.

Based on data from the AMP, which further corroborated the contention that LFG was a source of VOCs in groundwater, SCS designed a State-approved Interim Landfill Gas Control System which has been installed at the site. The purpose of this system is to initiate remediation of apparent LFG migration and thus reduce methane levels observed outside of refuse. Furthermore, as a part of the appropriate contingency remediation, control of LFG migration by the SCS system is recognized as having the potential to reduce VOC concentrations in groundwater that are attributable to LFG migration.

Permit Amendment for Vertical and Horizontal Expansion and other Landfill Engineering Services 

Client:  City of Port Arthur Landfill, Texas

Based on our qualifications in landfill engineering and permitting, SCS was selected by the City of Port Arthur, Texas, to develop the permit amendment application for the vertical and horizontal expansion of the Port Arthur Landfill.  This project included the following:

• Through negotiations with the U.S. Army Corps of Engineers, U.S. Fish and Wildlife Service, and the Texas Department of Parks and Wildlife, we resolved the wetlands issues for the site.
• A cost/benefit analysis of alternative expansion scenarios.
• Conceptual design of the expansion, including drainage, excavation optimization, soil management practices (including alternative daily cover), and entrance facility relocation.
• Conceptual geotechnical design of the liner system for vertical fill over a closed landfill.  
• Permit modification for a change in the Site Operating Plan.
• NSPS Tier 2 monitoring, Title V air quality permitting, and a Permit-By-Rule registration of on-site tub grinders.

The scope of work for the landfill expansion project includes landfill design, (including drainage, liners and leachate collections system, final contour plan, final covers system alternatives, geotechnical design), and hydrogeologic characterization.  One of the more creative aspects of this project has been the design of the liner and leachate collection system over a closed landfill.  Through our geotechnical analysis and consideration of various alternative materials and leachate management techniques, SCS principals developed an innovative design that addresses all of the site-specific issues and has been viewed favorably by TCEQ.  In addition SCS performed the following services:

• Obtained a permit modification from the TCEQ for extending the operating hours at the landfill.
• Developed a permit modification submitted to the TCEQ for a change in phasing plan and improvements in cell layout and leachate collection system.  (This modification is currently pending at the TCEQ.)
• Prepared a Site Operating Plan, including an alternative daily cover plan, for the landfill consistent with current TCEQ requirements.
• Prepared a compliance management plan for the site including consideration of solid waste rules, air quality rules, stormwater management rules, etc.

Air Quality and Solid Waste Permitting

Client: Long Point Landfill, Fort Bend County, Texas

SCS prepared the Air Quality Standard Permit application package including:

• The required TCEQ forms.
• Text describing (1) the proposed facility, including the landfill, the landfill gas (LFG) control system, the future LFG-to-energy project and other emission sources; (2) the proposed method of compliance with the New Source Performance Standards (NSPS) for MSW Landfills and (3) applicable monitoring, reporting, and recordkeeping requirements.
• Emission calculations and other supporting calculations and documentation for inclusion into the permit application. 

SCS also performed the Tier 1 non-methane organic compound (NMOC) emission calculations and prepared the related design capacity report, as required by the NSPS.