Author Archive

Dewatering Study

The Applied Technology Group of KEMRON Environmental Services, Inc. (KEMRON) conducted a dewatering laboratory bench scale study on impacted sediment from a river site located in the Boston, Massachusetts area. The purpose of the dewatering study was to evaluate dewatering techniques in order to increase the material percent solids and density for potential disposal.  Four site sediments were evaluated during the bench scale study.  The sediments showed a variation in particle size distribution from coarse sand to silt and was impacted with Hexavalent Chromium. KEMRON evaluated the effectiveness on the site materials for three different dewatering techniques including Recessed Plate Simulations through the use of Baroid filter press testing, Belt Filter dewatering using a Crown® Belt Filter Press, and GeoTube® dewatering through the use of the GeoTube® Rapid Dewatering Technique (RDT).  The study included polymer evaluations as well as evaluating the dewatering technology on the “as received” material and material screened through a #200 sieve (de-sanded).

Perfluorinated compounds (PFCs)

KEMRON’s Applied Technologies Group performed an ex-situ thermal remediation bench scale treatability study on soil which was impacted with compost impacted with Perfluorinated compounds (PFCs). Common PFCs include perfluorooctanoic acid (PFOA), used to make fluoropolymers such as Teflon, among other applications; or perfluorooctanesulfonic acid (PFOS), used in the semiconductor industry, 3M’s former Scotchgard formulation, and 3M’s former fire-fighting foam mixture; or perfluorononanoic acid (PFNA), used as surfactant in the emulsion polymerization of fluoropolymers; or perfluorobutanesulfonic acid (PFBS), used as a replacement for PFOS in 3M’s reformulated Scotchgard; or perfluorooctanesulfonyl fluoride (POSF), used to make PFOS-based compounds; or perfluorooctanesulfonamide (PFOSA), formerly used in 3M’s Scotchgard formulation; and FC-75, a 3M Fluorinert liquid; and perfluorinated cyclic ether (PFCE).

The treatability study was performed to determine the treatment temperatures potentially capable for thermal destruction of PFCs in highly organic soil at the site. The site test material consisted of highly organic soil which had been composted at different decomposing time intervals. Four candidate site materials with decomposition times of 3, 6, 12, and 18 months were subjected to thermal treatment performed at three target temperatures and one retention time. The materials in the study were initially heated to 100 Celsius to completely remove all moisture prior to subjecting the material to the target temperatures of 200, 398, and 1,100 degrees Celsius. Treatment durations were approximately 15 minutes at the target treatment temperature. Throughout treatments KEMRON performed constant temperature monitoring of the soil. All vapors were passed through an activated carbon off-gas treatment prior to releasing into the atmosphere.

KEMRON was not provided with the results of PFC analyses conducted on the treated test materials. However, discussions with the client indicated that treatment temperatures in excess of 1,000C showed successful reductions in total PFC concentrations.

Well 12A Superfund Site

Under a task order issued by the USACE Seattle District under our USACE Kansas City PRAC, KEMRON, as the prime contractor, completed the Well 12A Shallow Excavation Remedial Action located within the larger Commencement Bay – South Tacoma Channel Superfund Site. The site is a former oil recycling facility where off-site migration of chlorinated solvent-contaminated groundwater impacted the City of Tacoma’s drinking water well (Well 12A). Other site soil and groundwater contaminants include polychlorinated biphenyls (PCBs), volatile organic compounds (VOCs), metals and dense non aqueous phase liquid (DNAPL). Following a decrease in the effectiveness of the previous pump and treat remediation strategy, a Record of Decision (ROD) Amendment specified a combination of soil excavation, in situ thermal remediation, and enhanced anaerobic bioremediation to reduce groundwater contaminant mass leaving the site by 90%.

KEMRON prepared a Remedial Action Work Plan (RAWP) which described the intended remedial action to include abandonment of existing monitoring wells; removal of the 12-inch concrete pad and associated rebar; a geophysical survey using EM61 and GPR; removal of any USTs and other metal debris; and removal of the highly contaminated soil and filtercake. Metal debris was targeted for removal to prevent interference during future implementation of thermal remediation. Use of green construction technologies was also prioritized as part of the excavation strategy. Excavation was planned for two areas approximately 50 ft by 50 ft predicted to contain greater than 1,000 ug/kg VOCs in shallow soil (0-5 ft bgs) based on modeling of historical soil concentrations measured in nearby borings. In addition, the RAWP included a Green Remediation Plan, a Waste Minimization Plan and an Accident Prevention Plan (APP).


Unforseen field conditions encountered increased excavation complexity and impacted project schedule. . First, following removal of the concrete pad, elevated soil contamination levels encountered led to multiple rounds of soil sampling and analysis to better delineate the excavation footprint and determine disposal requirements and options. Second, the initially unknown dimensions of the one known UST were identified as being on the upper end of anticipated sizes (8-foot diameter and 38 feet long). Furthermore, the UST, thought to be nearly empty, contained a concrete “plug” approximately 3’ by 4’ that blocked the former access point, nearly 7,000 gallons of liquid waste, and 35 tons of pea gravel that had to be removed. The pea gravel was believed to be non hazardous based on previous data but was sampled and shown to exceeded Land Disposal Restriction (LDR) treatment standards for trichloroethylene (TCE) and lead. Additionally, oily filtercake and soil near the northwestern corner of the UST was sampled and determined to contain much higher contaminant concentrations. This material was excavated and fount to extend vertically to approximately 15 ft bgs. The horizontal extent of the filtercake abutted the former Time Oil building footings requiring excavation using trench boxes, piano key removal and use of controlled density fill. On-site chemical oxidation treatment using persulfate (and hydrated lime as an activator) was proposed and implemented as an innovative solution to the extremely high concentrations of VOCs which otherwise would have required disposal via incineration. A total of 2,131 tons of filter cake and contaminated soil were treated on site, excavated, then loaded and trucked offsite for disposal at a Subtitle C landfill. The excavation area was backfilled with clean backfill, new storm drains and storm piping were installed and then asphalt was installed to complete the restoration.

KEMRON implemented an on-site in-situ chemical oxidation treatment of the material containing high concentrations of VOCs, metals and PCBs to reduce VOC concentrations to below LDR thresholds. This allowed for excavation and disposal to a landfill approximately 270 miles away as material that will meet LDRs. This is an environmentally sound and cost effective alternative to simply digging and hauling to an off-site incinerator (located approximately 900 miles away).

Fort Sheridan Fixed Price Remediation

KEMRON was awarded and completed a $17.1 FFP remediation with performance-based remediation for the US Army at Fort Sheridan, an Army installation being closed under BRAC. KEMRON successfully managed 13 task areas which included regulatory agency negotiation, remedy selection, remedy implementation, LTM, O&M, construction, site documentation, community relations, and managing the Administrative Record. Under this contract, KEMRON was responsible for achieving RIP or RC for task areas. RC was achieved for seven task areas including an NFA DD for another task area which encompassed seven separate sites. For the additional task areas, KEMRON was responsible for implementing land use controls (LUC), closing monitoring wells and/or preparing an approved DD. For the RIP sites, KEMRON was responsible for LTM. KEMRON developed and received regulatory approval for site plans including safety plans and other reports and documents. In addition, KEMRON prepared all CERCLA documentation and the first CERCLA five-year review. The following is an overview of a few task areas.

KEMRON finalized the design and constructed a 13-acre RCRA Subtitle C cap over Landfills 6 & 7. The RCRA cap consists of multiple layers of geosynthetics, drainage layers, and low permeability clay.KEMRON also installed a leachate and gas collection system. The finished area is used as an open green field and hiking trail with prairie grasses, plants, shrubs and trees. KEMRON gained approval from IEPA, Army and the Navy to irrigate a 1.8-acre parcel using leachate collected from Landfills 6 & 7 as part of a pilot study for alternative disposal of leachate (compliant with EPA Region 2 Clean Program). The six-month study saved $50,000 in off-site disposal costs for the summer watering season. This pilot study, approved as a long-term disposal option, could ultimately save the Army approximately $2 million in life cycle costs over the next 30 years.

Five additional task areas included the demolition of a lead-based paint contaminated structure and the remediation of four areas with contaminated soils. KEMRON elected to meet residential standards on these five sites, thus eliminating the need for LTM and LUCs. KEMRON’s SOW required preparation of DDs. As a means to accelerate closure and gain immediate regulatory concurrent, KEMRON proposed to the BCT to prepare a non-time critical Action Memorandum instead. As a result, the approval time was cut dramatically and the remediation was completed a year ahead of schedule. The excavated soils were transported to the low areas in Landfill 6 & 7 as part of the required subgrade preparation beneath the liner, thus saving disposal costs.

KEMRON prepared the DD and design documents including LUCs for Landfill 5 and Coal Storage Area No. 3 (CSA3). The key design features of the 2.2-acre modified Subtitle C landfill cap on Landfill 5 included two feet of compacted clay overlying an impervious geosynthetic clay liner which included improvements to the existing storm water control system beneath the landfill, installation of a new perimeter drainage pipe, ravine slope stabilization, and elimination/realignment of the overhead utilities.

Landfill Picture from Lake Michigan

The CSA3 consisted of excavation of PAH contaminated soils from remnants of the former CSA. The removal action was completed in and around residences which required coordination with homeowners. KEMRON managed a comprehensive community involvement program designed to keep the local residents informed and involved. KEMRON developed a project website to provide construction updates, pictures, and other information, providing immediate status to stakeholders.

One of the challenges at Fort Sheridan was the management of the remedial activities amid the concerns of multiple stakeholders. Although the Army maintains environmental liability on a majority of the site that has not already been transferred to the community, the Navy and Army Reserve now occupy all of the properties that were covered under this contract. As a result, it was necessary for KEMRON to ensure that the remedial approaches being proposed and conducted site-wide met the requirements of all of the multiple stakeholders to include the Navy, Army, AEC, USACHPMM, Reserve, the surrounding towns and the community.

PCB Excavation and Removal – Port Heiden, Alaska

Through our Worldwide Environmental Remediation Services (WERS) contract with USACE-Huntsville, KEMRON was contracted by USACE-Alaska to perform excavation, packaging, transportation and disposal of approximately 33,000 tons of PCB-contaminated soil from the White Alice Radio Relay Station (RRS) in Port Heiden, AK. The work was performed for the benefit of US Air Force, who is responsible for the environmental cleanup of the White Alice RRS. Alaska Department of Environmental Conservation (ADEC) provided regulatory oversight of the work of the CERCLA non-time critical removal action.

Since work at the remote area of Alaska is performed only during the warm summer months of May through September, KEMRON and Jacobs, our team subcontractor, coordinately closely with the native village officials and the local construction subcontractor, Aniakchak Contractors LLC. Close coordination with the community is maintained to ensure adequate housing and meals for field workers and availability of the limited labor pool and heavy equipment at Port Heiden during the limited field season.

Crozet Arsenic Cleanup

An abandoned three square mile peach orchid in the Crozet, Virginia Township had developed into a residential neighborhood over several years. Due to regulatory concerns sampling and analysis of the soil showed elevated levels of arsenic from pesticides used over the lifetime of the orchid use. EPA issued a Task order to KEMRON to remediate several neighborhood yards in the area. The EPA START contractor sampled over 50 properties identifying contaminated areas to be remediated and EPA would obtain access agreements for each yard if the arsenic levels exceeded 58 ppm. If the resident requested relocation during the remediation KEMRON would relocate the resident to a local hotel during the remediation process. KEMRON excavated a majority of the yards and the soil disposed of at a local Subtitle D landfill. The areas were backfilled with clean soils and new sod installed to give the home owners a completely restored yard after the remediation. KEMRON hand excavated around trees to protect the root zone from damage that could kill the trees. EPA agreed with residents on all original vegetation including trees, shrubs, and flowers as to what was to be removed and replaced or to be left with restrictions on future use of the property. Two of the properties were heavily wooded and it was determined that excavation would do more harm than good to the property. EPA developed a Phytoremediation strategy by planting ferns that would absorb the arsenic from the soil. KEMRON obtained and planted the ferns and installed a solar powered irrigation system to enhance the growth and the arsenic reduction in the soil. KEMRON harvested the ferns in the fall and sampled for disposal criteria and total arsenic to determine proper disposal options. During continuous monitoring, START will resample the soil to see if the areas will be replanted next year with some plots being replanted consecutive years. KEMRON worked on the property under two different contracts with separate task orders issued for each contact.

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Canon Road Site

The Cannon Drum Site is a former cotton mill located on 3.84 acres in a mixed-use zoning area. The site was referred to EPA by the city of Social Circle. Residential homes are located within 100 feet to the west and south of the property. The mill operated at site from 1901 to 1982. The mill’s main structure was severely damaged by fire. The property has since been leased, by the owner, to tenants for various types of business use. The most recent tenant used the property to store thousands (est. 10,000-20,000) of containers of mixed hazardous substances. Reports indicate the bulk of these substances were procured from the Department of Defense Surplus Warehouse. The containers were abandoned at the site when business operations ceased at the property.

KEMRON mobilized to the site and had to develop access due to a city water line construction project operating on the site cutting across the current entrance. Site grading, construction of access roads and a construction of a pad for an office trailer were completed. Debris was removed from around the main structures on site to facilitate access to the warehouses containing drummed waste. A site drum staging area was constructed and chain link fences were constructed in two areas to develop security. An office trailer was brought in and site power, telephone, and water utilities were installed to develop a base of operation. The site was cleared and grubbed to allow safe access to all the building. Site roads were built and gravel used to make all weather access to the buildings possible.

KEMRON completed waste removal and segregation at the main warehouse where many pallets and drums were stacked on top of each other up to four high. All pallets and drums were carefully placed at floor level. Containers were then evaluated and staged for characterization. Debris was removed from the adjoining warehouse to create a drum staging area out of the weather. An open area outside of the warehouse was prepared for drum staging for containers that could withstand being outside without damage.

Waste characterization began with content evaluation that was based upon MSDS sheets and label information. Materials were then bulked and staged into waste stream hazard classes. Hazardous categorization evaluation was performed on the unknown materials to determine the hazard class. As the material was bulked in waste containers, a list of material was developed to allow competitive bidding on the disposal. Several thousand CO2 canisters were on-site and KEMRON developed a safe mechanism to allow depressurization of the canisters on-site to lower disposal and shipping cost. Radiological waste that discovered on the site was removed and sent off-site for disposal. Acids and bases were mixed on-site to neutralize the pH to a safe level and allow for non-hazardous disposal. After all hazardous materials were disposed of the non-hazardous material was loaded into roll-off containers for recycling or disposal. The site was restored leaving the access road intact.

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Solidification / Stabilization Treatability Study

KEMRON performed a solidification / stabilization treatability study for WRS Compass on materials sampled from the Edgewater, New Jersey site. Testing was conducted to determine potential reagents, and reagent addition rates capable of reducing the leachability of volatile, semi volatile, and inorganic constituents from the site materials as determined by the Synthetic Precipitation Leaching Procedure (SPLP).

KEMRON received four individual materials from the site for testing. The results of characterization testing indicated that all four materials had relatively similar physical properties, but varied widely in contaminant concentrations indicating substantial heterogeneity in the field. The treatment designs evaluated during this study were developed and provided to KEMRON by WRS Compass. KEMRON evaluated the mixture designs as a non-biased third-party laboratory. Geotechnical and chemical analyses performed on the treated site materials indicated that significant improvements in physical properties, including strength and permeability as well as dramatic decreases in leachable contaminant concentrations as determined by the SPLP were achieved with the treatments evaluated.

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Manufactured Gas Plant

KEMRON performed an in-situ thermal remediation treatability study for TerraTherm, Inc. on soil materials from a Manufactured Gas Plant (MGP) site located in Americus, Georgia. The treatability study was performed to:

  1. Determine the treatment temperatures for BTEX and Naphthalene distillation from sand and peat materials at the site
  2. Evaluate the potential for thermally enhanced mobilization and removal of Dense Non-Aqueous Phase Liquid (DNAPL) from the sand and peat site materials
  3. Perform an assessment of soil property changes induced by thermal treatment
  4. Evaluate the potential for settlement of the thermally treated site materials

Two candidate site materials were subjected to ISTD distillation treatment performed at two target temperatures and two retention times. During treatment, De-Ionized (DI) water was injected into the test material via a low volume peristaltic pump. The quantity of water injected was outlined by TerraTherm and included specified pore volumes, based on the treatment duration.

Throughout treatments, KEMRON performed constant temperature monitoring of the soil and injected water, and organic vapors in the off-gas via a flame ionization detector (FID). All vapors were passed through a distillation treatment and indicated that total volatile organic compound concentrations were reduced by more than 98%, and Diesel Range Organics (DROs) were reduced by more than 87%. Total semi-volatile organic compounds were reduced for many compounds but in general proved more difficult to treat than the volatile compounds.

The mobilization of DNAPL was evaluated by passing a specified pore volume of chilled water through the test soil while at ambient temperature. An additional specified pore volume of water was then passed through the test soil during heating. Throughout testing, KEMRON monitored the soil and water injection temperatures, the pressure within the test system, and visual clarity of the water exiting the system.

Geotechnical testing of certain treated site soil types was performed to ensure that thermal treatment did not adversely affect the physical properties of the site soils.

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KEMRON Environmental Services, Inc.
1359-A Ellsworth Industrial Boulevard
Atlanta, GA 30318
Tel: (404) 636-0928
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