KEMRON was contracted to perform a dewatering study for coal ash from the Emory River Ash Pond Site. The objectives of the treatability study included: 1) evaluate the potential for dewatering of the site material (Ash slurry), 2) provide information for users of the study to determine the scale of operation required, 3) evaluate filtration effectiveness of free liquids removed from the site material, and 4) evaluate the handling characteristics of the site materials.
All treatments performed during the treatability study were based on discussions with the client and KEMRON’s experience treating similar types of sludges. After initially characterizing the moisture content, bulk density to confirm the ash slurry represented the ash at the site, The ash slurry provided to KEMRON already contained a treatment of 2% polymer. Therefore, KEMRON proceeded to the Treated Dewatering Evaluation phase of testing. Filter press testing was performed to evaluate the reduction in moisture content that can be achieved by the application of a positive pressure to the untreated ash material. Bench-scale testing was performed at a positive pressure of 150 pounds per square inch (psi) using a Baroid filter press apparatus designed to simulate a plate and frame filter press.
KEMRON generated a 20 % solids ash slurry using site groundwater ratio and used three filter media in the preliminary evaluation. The filtering medium was a coarse grade filter paper with a pore size of 40 micron (um), 20 to 25 um, and 10 um. Filter press testing was performed at a positive pressure of 150 pounds per square inch. The time to reach breakthrough (either no water drained or air blew through drainage) was recorded. Each filter cake was then removed, weighed, measured, and subjected to moisture content testing, bulk density testing, and subjective visual and manual handling evaluation. The objective of the handling evaluation was to determine if the material can be handled by heavy duty machinery and/or stacked.
Based on the results of evaluation, the use of filter press technology was effective in reducing the ash slurry to a relatively dry material which can be stacked, loaded, and transported.
study revealed that the use of a 20 to 25 um filter media and a 40 um filter media increased the 20 % solids ash slurry to an approximate 80 % solids material, with no free liquid. The percent solids of the filtrate significantly increased from 0.88 % to 5.5 % in the 20 to 25 um and 40 um samples, respectively.
FMC manufactured chemicals on several parcels of its property in Newark, California from 1929 through 1995. Chemicals manufactured at various times included quick lime, bromine, Ethylene Dibromide (a soil fumigant), magnesia compounds, phosphates, and phosphoric acid. The bromine towers, EDB plant, and magnesia plant were shut down and the manufacturing facilities were removed in 1968. The phosphate plant and phosphoric acid plant were shut down in 1994 and 1995, respectively. All manufacturing facilities were removed by the end of 1996. FMC’s activities at the site currently consist solely of maintaining engineered asphalt caps at the former EDB plant (EDB Cap Area) and the phosphorus storage pit areas, and continued operation of a groundwater remediation and monitoring system. ERM contracted with KEMRON ATG to perform an ISS, Slurry Wall, and Chemical treatment treatability study. The concentrations of the contaminants of concern were up to 10x IDLH conditions. KEMRON Applied Technologies Group (ATG) designed and built a negative pressure treatability room with supplied air (Level B) capabilities to perform the treatability study. The environmental room was constructed and ready for operations in eight business days. The objectives of this highly complex study included:
- Evaluate potential remedial technologies to determine which are viable based on EDB Cap Area physical and chemical characteristics of soil, DNAPL, and groundwater in the source zone parcels and down gradient parcels
- Evaluate slurry wall amendments mix designs for down gradient locations
- Evaluate the potential for grout slurry wall incompatibilities resulting from the geochemical (saline/brackish conditions) and chemical constituents in the targeted site soil and groundwater
- Determine the hydraulic conductivity resulting from various slurry wall mixes
- Evaluate solidification/stabilization reagents capable of improving strength of materials and reducing the permeability of the source zone soils
- Evaluate solidification/stabilization reagents capable of reducing leachate generated by the new EPA LEAF (EPA 1315) Method while implementing an innovative proprietary sampling methodology modification to this EPA method developed by KEMRON
- Reduce the COC mass in soil and groundwater through chemical treatment
- Evaluate which amendment is most effective at reducing concentration/leachate of all primary COCs without mobilizing naturally occurring metals
- Evaluate effectiveness of chemical oxidant/reductant reagents in combination with ISS amendment at reducing COC/leachate concentrations.
The treatability study successfully achieved the objectives of the study.
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.
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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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:
- Determine the treatment temperatures for BTEX and Naphthalene distillation from sand and peat materials at the site
- Evaluate the potential for thermally enhanced mobilization and removal of Dense Non-Aqueous Phase Liquid (DNAPL) from the sand and peat site materials
- Perform an assessment of soil property changes induced by thermal treatment
- 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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