Archives: Case Studies

SME’s client occupies and operates a large plant and its wastewater treatment systems. In recent decades, the plant has seen a significant decrease in population and wastewater flows, and an increased need to rehabilitate aging, outdated, and oversized wastewater treatment infrastructure.

The client and their partner have decided to regionalize the plant’s sanitary wastewater treatment systems by connecting wastewater from the plant to the local county sewage system and publicly owned treatment works (POTW) for treatment. The client retained SME to provide wastewater engineering and environmental consulting services to support all phases of the County Wastewater Connection (Tie-On) Project.

The Tie-On Project included installation of a new wastewater lift station, force main, and gravity sewer to establish the sewer connection to the County system; modifications to the client’s Sanitary Treatment Plant (STP) facility to bypass existing treatment operations and discharge wastewater to the County; and elimination of the direct discharge of treated wastewater from the client’s permitted wastewater outfall.

The Tie-On addresses critical needs at the client’s STP facility, stemming from aging equipment and oversized treatment units, to ensure that sanitary wastewater treatment for the plant is reliable and capable of meeting current and future wastewater treatment regulations.

SME worked closely with the client to provide:

• A comprehensive study to assess feasibility of the Tie-On and identify foreseeable implications, requirements, and costs
• An Environmental Assessment and Finding of No Significant Impact (FONSI) for the Tie-On and alternatives per all local, state, and federal regulation agency requirements
• Environmental permitting applications, regulatory coordination, and stakeholder communications for the Tie-On
• Engineering design for multiple phases of construction for the Tie-On, and closure plan for demolition of the STP facility, and
• Construction oversight services.

The site is a former semiconductor production facility that operated from 1965 to 2005. Manufacturing processes involved the use of chlorinated solvents, including trichloroethene (TCE) which was later found in site soil and groundwater. SME has provided extensive site investigation, remediation, and monitoring support services at the site which has been successfully redeveloped as a car dealership.

Challenges

The manufacturing facility covered approximately five acres, with wastewater lagoons adjacent to the building. TCE and other volatile organic compounds were found in groundwater downgradient from the facility. SME worked closely with facility owners and operators to investigate and assess the extent of contaminants in soil and groundwater and potential migration to off-site receptors.

Early investigations focused on the lagoons, which were remediated and closed in the 1990s. The facility closed and went through RCRA closure with SME support in 2005, and the building was removed in 2010. Initial investigations did not locate a source of residual TCE in site soil or groundwater, but concentrations in downgradient groundwater indicated that a source remained present. Further investigation by SME identified TCE concentrations in soils beginning about 20 feet below the former building.

SME conducted a focused Corrective Measures Study to evaluate remedial options for the “hot spot” soils. Excavation and off-site removal was the remedy selected; however, there were technical and engineering challenges associated with removing the impacted soils without generating a large excess of soil that would be expensive to manage or potentially dispose of off-site as hazardous waste.

Project Outcome and Value Added

SME sought to limit the soils handled for off-site disposal to those within the tight boundaries of the hot spot. SME’s remediation design included excavating and stockpiling soils that could be reused on-site, providing access to the hot spot soils, and establishing a sheet pile wall around the 60-by-20-foot area with steel sheets driven below the base of excavations (more than 40 feet below grade).

The enclosure was kept filled with water to maintain outward pressure on the sheet piles.  Soils were removed and stockpiled in a lined area constructed in such a way that water saturation could drain back into the excavation. Once excavated soils were sufficiently dry, they were containerized and disposed of  off-site under hazardous waste manifest. Activities were confined to an area that did not impact site development.

Following successful completion of hot spot remediation to the satisfaction of the regulatory agency, SME continues to perform water quality monitoring at the site, focused on downgradient conditions and limiting impact to the client’s budget and to the car dealership’s operations.

Woodland Pulp LLC owns and operates a semi-integrated, kraft pulp mill in eastern Maine. In 2018, Woodland sought to permit the construction and operation of two new tissue machines and re-permit two existing tissue machines to relax self-imposed licensing restrictions. As a major source of air pollutants, this permitting action resulted in a major modification with significant emission increases of particulate matter (PM), nitrogen oxides (NOx), carbon monoxide (CO), volatile organic compounds (VOC), and greenhouse gases (GHG).

Challenges

Project Acceleration – Because Maine is in the Ozone Transport Region (OTR), projects that are classified as Major for NOx or VOC require the application of the Lowest Achievable Emission Rate (LAER) and obtaining offsetting emissions. In 2014, the EPA granted Maine a waiver from the NOx LAER and offset requirements; however, mid-project, Woodland learned that the NOx waiver would no longer be valid following the finalization of the EPA’s 2015 Ozone Designations. To avoid LAER and offset requirements for NOx, Woodland needed to receive a final permit before the 2015 standard became effective in August 2018.

VOC Offsets –The Northeast offset credit market is scarce, with offsets for VOC and NOx costing up to $10,000 per ton of pollutant. SME prepared a successful application to certify 185 tons of VOC and NOx credits from the shutdown of a nearby Woodland facility, saving Woodland significant money and time.

Emissions Modeling – Applications for major modifications must include an analysis demonstrating that the project will not exceed ambient air quality and increment standards. Woodland last completed mill-wide modeling in 1999, before new and more stringent standards were established for NOx, SO₂, and PM_2.5 . SME developed emission model inputs and partnered with a local firm to complete the modeling which resulted in Woodland taking on slightly more stringent emission limits for some pulp mill sources.  In addition, because Woodland is located within 50 km of two federally protected lands, the U.S. Fish and Wildlife Service required Woodland to conduct a visual plume impact analysis for one of the areas. The analysis results convinced the National Park Service that additional analyses were not required for the other area, as it is located downwind and farther away.

Project Outcome and Value Added

SME’s excellent relationship with Woodland, project partners, and MEDEP allowed expediting of a very challenging project. The entire permitting process was completed in approximately six months, about half the typical length of time. Approval of the final permit for all four machines was granted in July 2018.

SME’s innovative Packer-Purge System™ technology (U.S. Patent No. 11,021,937) provides  a cost-effective alternative in the redevelopment and maintenance of relief wells.  The system reduces pore-water pressures under dam structures and powerhouses to support compliance with the Federal Energy Regulatory Commission’s (FERC’s) allowable limits, known as Design Basis Value (DBV), for dam safety and stability.

Challenges

In 2000, the client installed three relief wells with an underdrain adjacent to the existing powerhouse of a hydroelectric dam to reduce aquifer potentiometric levels beneath the foundation. Slope stability analyses were performed, and piezometers were installed to monitor pore-water pressures at the powerhouse.

Over the next decade, relief well flow rates slowly declined while pore-water pressures increased to levels exceeding the FERC DBV. In 2011, the dam owner had the three wells redeveloped, which reduced the pore-water pressures to acceptable levels, yet only for a couple of years.

In 2014, SME was retained to oversee a second round of relief well redevelopment. SME’s analyses indicated the well screens were becoming clogged with formation particles due to deteriorating gravel packs, thus reducing the relief wells’ capability to fulfill their function of maintaining acceptable pore-water pressures across the area.

Project Outcome and Value Added

SME designed and installed the Packer-Purge System™, an innovative relief well purging system using packers and natural gradients to restore flow to the relief wells and maintain pore-water pressures below the FERC DBV. The purging system uses packers to halt, then release, the flow in the well, thereby creating an instantaneous surge across the well screen. The surge removes particles from the screen area and restores flow to the well. A PLC system governs the packer method and purging frequency for year-round pore-water pressure control, with little or no well maintenance.

Installation of the Packer-Purge System™ produced significant favorable operational results:

• Well screen clogging was reduced as evidenced by 1) clogging particles being purged from the screened areas of the relief wells, and 2) an increase in flow from the wells of over 10 percent;
• Potentiometric levels at the relief wells have been maintained below allowable FERC Design Basis Value; and
• Significant financial cost savings have been realized as no further investment in relief well redevelopment has been required since the installation of the Packer-Purge System™.

Challenges

Since 2009, SME has provided engineering and support services for ground-mounted solar photovoltaic installation projects throughout Maine. These arrays, with power generating capacities ranging from 63kW to 26MW, have been installed on private and public properties, such as municipal landfills, business parks, farmland, and previously undeveloped land.

To date, SME has provided professional consulting services for over 200 projects with a total generating capacity of more than 700MW. Our clients include private landowners, municipalities, and leading commercial solar energy developers.

Project Outcome and Value Added

SME provides preliminary site analysis, surveying, environmental review, civil engineering design, and environmental permitting for projects. For many typical projects, this encompasses a suite of site/civil services performed by SME in-house staff and in coordination with qualified subcontractors:

• Due diligence analysis to identify legal and physical design constraints of a site
• Phase 1 ESA to determine suitability of a site for the project
• Property line and topographic survey plans
• Site plan design for site plan review/special permit applications (e.g., Site Location of Development Act (SLODA))
• Environmental services to identify and evaluate factors such as wetlands delineations, flood zones, underlying rights, and archaeological significance
• State and local permitting
• Public hearings and stakeholder communications
• Easements plans
• ALTA/ACSM survey plans
• Construction layouts
• Construction documents, and
• Construction administration

The result is a seamless and streamlined site/civil development process that contributes to keeping projects on track.

SME worked closely with Bangor Savings Bank in the redevelopment of their 4.6-acre corporate headquarters campus in Bangor’s Waterfront District. SME provided Phase I environmental site assessment, geotechnical investigation, geothermal well investigation, civil/site design, permitting, utility coordination, and construction oversight for this project which incorporated green infrastructure for long-term sustainability.

Challenges

The project included renovation and expansion of an existing 5-story, 28,268-square-foot historic structure and the construction of a new 5-story, 115,000 square-foot corporate office building. In conjunction with the office building, a new 5-story parking garage with approximately 450 parking spaces was constructed to accommodate parking needs for the owner and the community.

A 659-kilowatt solar canopy was installed over the top level of the new parking structure to supplement the electrical needs of the facility and an 80-unit geothermal well field was installed in the landscaped area between the buildings to assist with the heating and cooling of the new office building.

To accommodate the new construction, a portion of existing South Street was closed and utilities were relocated. Extensive coordination was required with the City and utility companies to relocate and/or abandon critical service lines, including water, sewer, electric, and high speed fiberoptic communications lines.

Additional features include construction of a new 43-space surface parking area and updated entry plazas with ornamental landscaping and site lighting. Buildings are connected by a meandering walkway through a large landscaped campus area accented with cobblestone textured retaining walls, expansive lawn areas, and a combination of native and ornamental plantings. The stair and walkway constructed at the corner of South Street and Pleasant serves as a public connector to Railroad Street and the waterfront.

Stormwater management was accomplished through new green infrastructure measures including tree box filters, porous pavement and a closed system of catch basins and underground storm drain piping connected to the municipal storm drain system.

Project Outcome and Value Added

Project design and permitting were completed in two phases to accommodate an accelerated project schedule. Each phase of work required a City of Bangor Land Development Permit and Maine Department of Environmental Protection permitting for stormwater runoff. Through extensive coordination with regulators and preparation of accurate and complete application materials, permit approvals were expedited to maintain project milestone dates.

In addition, SME’s design of the project eliminated an existing portion of combined sewer in conformance with the City’s Long-Term Control Plan (LTCP) for combined sewer overflow (CSO) reduction.

The 2,000-acre Pineland Farms property was developed by the State of Maine in 1908 as the Maine School for the Feeble Minded. During the 1950s, the facility housed 1,500 residents and included a power plant, a wastewater treatment plant, 27 buildings, forests, and a self-sufficient farm. October Corporation (a subsidiary of Libra Foundation) purchased the property in 2000 and redeveloped the property into a viable office/business campus and agricultural center.

SME provided engineering design and permitting expertise for the redevelopment of Pineland, including demolition of select structures, and renovation and new construction of over 300,000 square feet of buildings. SME’s services extended to the construction of a working farm, one of the largest equestrian centers in the northeastern United States, a cheese-making facility, a year-round hydroponic greenhouse, and 30 kilometers of cross-country ski trails.

Challenges

At Pineland, SME was tasked with providing quick turn-around environmental investigations, design drawings, and permit applications for many of the projects. We prepared the necessary applications; coordinated informational meetings; and through close cooperation with the regulatory agencies, obtained approvals allowing the Owner to begin redevelopment within just five months of SME receiving authorization to proceed.

Project Outcome and Value Added

For this project, SME conducted a hydrogeologic investigation and successfully located a groundwater supply for the campus and agricultural use areas. We also completed RCRA closure of the former institutional Pineland facility and the design and permitting for closure of three on-site landfills. Other project highlights include engineering for 10,000 feet of roadway reconstruction on campus (including State highway and intersections), parking for 1,200 vehicles, 13,000 feet of stormwater drainage lines, and evaluation and planning for additional site utilities. The wastewater disposal system we designed is one of the largest subsurface disposal systems in Maine with 10,000 feet of wastewater pipelines leading to four engineered wastewater systems that can treat 36,000 gallons per day.

SME provided construction services for campus redevelopment projects and continues to serve as the campus environmental consultant.

SME assisted ecomaine and its subcontractor RMP-EM LLC in preparing site excavation and development plans to systematically remove, process, and replace incinerator ash in the ecomaine ash landfill.

In developing this project, SME considered several existing site conditions and site sensitivities. The mined area had been filled and a plastic cover placed on the ash to allow diversion of clean surface water to run off the covered landfill area.

The excavation plan needed to sequence the removal and replacement of the cover to both limit the additional leachate generation and maintain the diversion of clean surface water runoff for the covered areas of the landfill. The site excavation plan also had to factor in the low strength soil conditions that underlie the landfill. This required designing the excavation and development plans with consideration to the stability of the foundation soils. The excavation plan prescribed a very specific sequencing plan for both excavating and then replacing the ash once it was processed.

Project Outcome and Value Added

SME prepared state and local permits for this project. These permits addressed siting issues such as visual impacts, traffic, noise, odor, dust, stormwater management, and erosion control. The application also described process design for removing, processing, stockpiling of recovered metals, and replacing the ash. SME worked with RMP-EM to develop a project layout that allowed all of these activities to occur within the existing landfill footprint, minimizing overall project impact to the surrounding site environs. This was beneficial in both the state and local permitting process, and allowed for a quick review and approval of the project.

Permits were received in a timely manner. The project was instituted and operated for several years. By removing and recycling the metals from the ash, ecomaine recaptured valuable air space for additional ash, extending the landfill life.

The Wishcamper Companies retained SME and ReVision Energy to design, permit, and install a solar array on a portion of the Westbrook Heights Business Park in Westbrook, Maine. The project included the installation of 598 solar panel modules, associated utility trench construction, a gravel access drive into the site, 7-foot-high chainlink fence around the panels, and screening plantings between the panels and an adjacent street.

Challenges

It was decided that construction of the project should minimize ground disturbance to the greatest extent possible, which would limit the impervious area of runoff for stormwater permitting.

Project Outcome and Value Added

SME and ReVision Energy, who constructed the project, selected an innovative earth screw mounting system which eliminated the need to clear and grub large areas of the site. As a result, earth disturbing activities were limited to 0.05 acres, including the installation of the earth screws, construction of the gravel access road, and excavation of the utility trench. The solar panels were installed using small, compact, rubber-tracked machines so as to not disturb the vegetation under and around the solar array.

After final stabilization of the site, there were only 0.02 acres of impervious area, consisting of only the solar array foundations and gravel access drive. Ground disturbance between the rows of solar panels was minimized, and sheet flow from the solar panels onto and across vegetated areas was maintained. SME also prepared an erosion and sediment control plan.

SME has worked closely with Woodland Pulp LLC and its predecessors (Domtar and Georgia Pacific Co.) to manage the No. 3 Landfill. In 2000, SME was retained to develop and implement closure of a 26-acre bark/sludge/ash waste disposal unit at the facility.

SME continues to provide ongoing landfill permitting, engineering, and operation assistance at this facility.

Challenges

The closure involved the relocation of more than 130,000 cubic yards of waste, final grading of the bark pile surface, and placement of an engineered cover system. The grade was very steep in some places, and waste material needed to be excavated, repositioned, and re-graded to achieve a final landfill topographic surface suitable for long-term slope stability and cover construction without expanding the footprint of the bark pile. This re-graded bark pile then needed a cover system constructed to reduce infiltration and leachate production.

Project Outcome and Value Added

SME supported Woodland Pulp through all phases of regulatory permitting, and provided construction oversight, quality control testing, and closure documentation for the bark pile.

Our exploratory investigation, which characterized the types and limits of waste comprising the 26-acre deposit, was used to prepare closure plans. Plans included the completion of excavation and waste exclusion plans and design drawings and specifications for excavating and closing the 26-acre waste pile.

For the landfill construction/closure, SME performed the engineering necessary to permit the 0.5 million cubic yards on-site borrow source.

SME also calculated gas generation rates for the biodegradable portion of the waste deposit and designed a gas collection and venting system that was included in the cover system.

With limited available space for dewatering and settling ponds for the low-strength lime waste, SME performed an extensive geotechnical evaluation on the sediments and is using this information to develop a space-efficient settling pond sediment management plan. Additionally, SME provides operating guidance for highly-efficient waste placement in order to maximize the life of the operational landfill areas.