Landfill Closure
Municipal Solid Waste Operational Services, City of Presque Isle, Maine
CES has been providing municipal solid waste (MSW) related engineering services to the City of Presque Isle since 1980. In the early 1980s, CES sited, permitted, and designed the solid waste landfill facility currently used by the City. Since the construction of the landfill, CES has worked with the City providing permitting and design services for the expansion of the landfill, and operational assistance including cell development plans, leachate management, annual reporting, landfill gas (LFG) evaluations, operation manuals, construction monitoring, training, environmental monitoring, volume control surveys, compliance assistance, and on-going engineering assistance. CES provides assistance on issues related to waste characterization, compliance with the facility’s Operation Manual and Stormwater Management Programs (SWMRs), sludge disposal, storm and waste water discharges, and the on-site spray irrigation system. Within the past few years, CES has designed and prepared equipment specifications for leachate storage lagoons, leachate pump station, and a lagoon leak detection pump station. CES performed the construction monitoring, provided oversight for equipment installation, and assisted with trouble shooting during startup. CES is currently providing engineering services for a phased final cover and expansion of the municipal solid waste landfill. The project is being managed in three phases: 1) Phased final cover of north and east slopes; 2) Lateral expansion; and 3) Leachate collection system (LCS). Construction of the phased final cover system commenced in the Fall of 2007 for the north and east slopes. The phased final cover system consists of a composite system utilizing soils and geosynthetics which provides a secure cover for the portion of the landfill which will be permanently closed. The cover system also includes a redundant LCS and LFG collection and venting system. CES is currently providing design and permitting services for the City of Presque Isle to expand the landfill footprint to include a significant portion of the existing landfill. The footprint expansion will include a composite liner system consisting of a double geomembrane liner, leachate collection and leak detection system with pump station, and landfill gas considerations for future tie-in. The upper liner and LCS includes several design and engineering aspects including leachate collection and conveyance, landfill gas management, differential settlement, and slope stability. Geosynthetic reinforcements will be utilized in the base liner system on top of the existing landfill and piggybacked sideslope.
Concurrently, with the phased final cover of the north and east slopes, CES is updating cell development plans for the City to achieve final grades as repaired by the Maine Department of Environmental Protection (MDEP). CES has been working closely with the City and MDEP to achieve final grades once the expansion area is permitted and constructed. CES continues to provide survey control for volume and slope layout to landfill personnel on a regular basis.
The original leachate collection system at the Presque Isle Landfill consists of a layer of cobble stone draining to the perimeter where it is collected in stone and perforated pipe. The base and perimeter of the landfill slopes to the northeast corner where leachate is gravity fed into a manhole. The manhole feeds a pump station which conveys the leachate through a forcemain to a storage lagoon.
Leachate management upgrades have been ongoing at the Presque Isle Landfill for the past several years. The original leachate collection system below the landfill had clogged, resulting in significant leachate head accumulation on the soil liner and subsequent leachate break-outs in side slopes. CES installed several piezometers to closely monitor the leachate head above the soil liner inside the footprint of the landfill. Repairs to the original leachate collection piping and surrounding stone along the perimeter of the north and east sides were made in an attempt to relieve leachate build up in the landfill. A new redundant leachate collection system was installed above the original system on the north and east perimeters and tied into the leachate conveyance system. The interior limits of the landfill's leachate collection system could not be repaired, which contributed to the decision to close the east and north slopes with a phased final cover system. Current design and engineering for future expansion at the landfill includes a significant leachate collection system consisting of gravity piping, forcemains, pump stations, and collection network of perforated piping, soil, and geosynthetic materials.
CES continues to provide the landfill with consultation services for daily and intermediate cover applications. Alternative intermediate cover is currently being evaluated for areas above the phased final cover system. The placement and removal of intermediate cover is closely monitored by CES personnel from our Presque Isle office.
CES has prepared the Annual Report and Operations Manual for the Presque Isle landfill since operation began in 1982. CES personnel conduct the Annual Landfill Compliance Evaluations for submission to MDEP and continue to update the Operations Manual as required.
CES provides ongoing recommendations to the City of Presque Isle for operation issues at the landfill. We continue to work with the City to resolve issues and ensure compliance with MDEP regulations. CES continues to retain the services and consultation from SCS Engineers for LFG. SCS Engineers has been a national leader in the planning, permitting, investigation, design, construction, and operation of landfill gas control and energy recovery systems since 1970. CES provides recommendations to the City to address site safety concernsreguarding landfill gas. CES performs monitoring for the landfill with a four gas meter and/or GEM 2000 at gas vent locations, ground water wells, piezometers, and structures. CES is currently working with SCS Engineers to modify the landfill pump station to eliminate the migration of landfill gas through leachate collection and conveyance piping.
SERVICES
Engineering Services
Permitting
Design Services
Operational Assistance
Environmental Monitoring
Training
Compliance Assistance
Landfill Closures
Caratunks Forks, West Forks Landfill, Westforks, Maine
