Triplett Kingston J.L.,Haley and Aldrich |
Dahlen P.R.,Arizona State University |
Johnson P.C.,Arizona State University
Ground Water Monitoring and Remediation | Year: 2010
In situ thermal-based soil and aquifer remediation technologies (e.g., electrical resistance heating [ERH], conductive heating, and steam-based heating) have undergone rapid development and application in recent years. These thermal technologies offer the promise of more rapid and thorough treatment of nonaqueous phase liquid (NAPL) source zones; however, their field-scale application has not been well documented in the technical literature. A state-of-the-practice review of the application of these technologies was conducted in this study. Available documents from 182 applications were reviewed, which included 87 ERH, 46 steam-based heating, 26 conductive heating, and 23 other heating technology applications conducted between 1988 and 2007. Approximately 90% of the 182 applications were implemented after 1995 and about half since 2000. More specifically, this review identified the geologic settings in which these technologies were applied, chemicals treated, design parameters, operating conditions, and performance metrics. The results of this study are summarized in a table linking this information to five generalized geologic scenarios. Practitioners considering thermal technologies for their site can identify the geologic scenario that most closely resembles their site and then can quickly see which technologies have been applied in that setting, the designs employed, operating conditions, and the performance achieved. © 2010 The Author(s). Journal compilation © 2010 National Ground Water Association.
Miles O.W.,Haley and Aldrich |
Novakowski K.S.,Queen's University
Journal of Hydrology | Year: 2016
Rapid recharge events manifested as significant increases in hydraulic head have been observed in many fractured bedrock aquifers around the world. Often the response in hydraulic head exceeds what would be observed in an equivalent porous media by more than an order of magnitude. As the mechanisms that cause these events are poorly understood particularly under highly-transient conditions, a detailed investigation was conducted at a well-characterized field site in eastern Canada. During the spring and summer of 2012, frequent measurements of hydraulic head were obtained in gneissic terrain covered by a thin veneer of drift materials using 21 multi-level monitoring wells installed in the bedrock. Each of the wells was hydraulically tested from the water table to total depth using a straddle-packer system and fractures intersecting the wells were identified using a borehole camera prior to the construction of the multi-level piezometers. Rainfall and weather data were also collected over the same time period. A piezometer located on a bedrock outcrop which responded rapidly to rainfall was identified and used as a focus for numerical simulations. To determine the properties of the drift materials in the vicinity of the outcrop, a ground penetrating radar (GPR) survey was conducted over a 40 × 40 m area to map depth to bedrock and five in-situ permeameter tests were performed to estimate the hydraulic conductivity. Three-dimensional numerical simulations were conducted to reproduce the response in the piezometer for both short (24 h) and long (one month) timescales. The numerical simulations were used to determine what parameters have the greatest impact on controlling rapid recharge. Based on this study it was concluded that the large magnitude head rises recorded in this piezometer are a result of recharge to steeply inclined fractures exposed on or immediately adjacent to the outcrop. The hydraulic head responds rapidly because of the low specific yield of the rock to which the transmissive features are connected. The modelling also showed that as little as 0.4 m of drift material can completely eliminate the response in the well especially during times when evapotranspiration is high. © 2016
Muindi T.M.,Haley and Aldrich
Pipelines 2013: Pipelines and Trenchless Construction and Renewals - A Global Perspective - Proceedings of the Pipelines 2013 Conference | Year: 2013
Replacement of aging pipeline infrastructure is requiring construction along alignments that are highly contaminated and subject to costly and stringent regulatory controls. New installations where favorable routing is not available are also subject to similar constraints. Examples of where these installations can be found are: former industrial sites, reclaimed or filled urban lands, and rivers impacted by past industrial activity and navigation. This paper examines some adaptations to the trenchless construction processes that lead to risk minimization, thus enabling installation in these environmentally adverse ground conditions. To illustrate adaptability of trenchless methods, this paper presents a successful case study where pipe installation in highly-contaminated subsurface conditions was accomplished using trenchless methods, namely: horizontal directional drilling (HDD) launched from a former industrial site. © 2013 American Society of Civil Engineers.
Triplett Kingston J.L.,Haley and Aldrich |
Dahlen P.R.,Arizona State University |
Johnson P.C.,Arizona State University
Ground Water Monitoring and Remediation | Year: 2012
A recent study assessing the state-of-the-practice of in situ thermal remediation technologies (e.g., electrical resistive heating [ERH], conductive heating, steam-based heating, in situ large-diameter auger soil mixing with steam/hot air injection, and radio-frequency heating) identified 182 applications in the 1988 to 2007 period and summarized the geologic settings in which these technologies were applied, chemicals treated, design parameters, and operating conditions. That study concluded that documentation for less than 8% of those applications contained sufficient data to assess the effect remediation had on groundwater quality. Consequently, post-treatment data were collected at five ERH sites, with emphasis on assessing reductions in dissolved groundwater concentrations and mass discharge (mass flux) to the aquifer. For each site, dissolved groundwater concentrations and hydraulic conductivities were determined across a vertical transect oriented perpendicular to groundwater flow and at the downgradient edge of the treatment zone. Dissolved concentration and mass discharge reductions ranged from about less than 10× to 100×, with post-treatment groundwater concentrations ranging from about 10 1 to 10 4μg/L and mass discharges ranging from about 10 -1 to 10 2 kg/y. The primary factors differentiating sites with greater and lesser dissolved concentration and mass discharge reductions were the adequacy of pre-treatment source zone delineation, the extent to which the treatment zone encompassed the source zone, and the duration of treatment at the design operating temperature. The results suggest that ERH systems are capable of reducing groundwater concentrations to 10 to 100 μg/L levels and lower in some settings, but only if the source zone is adequately delineated and fully encompassed by the treatment system, and the treatment system is operated for a sufficiently long period of time. © 2012, The Author(s). Ground Water Monitoring & Remediation © 2012, National Ground Water Association.
Lin X.,Pacific Northwest National Laboratory |
Lin X.,Georgia Institute of Technology |
Kennedy D.,Pacific Northwest National Laboratory |
Peacock A.,Haley and Aldrich |
And 4 more authors.
Applied and Environmental Microbiology | Year: 2012
Subsurface sediments were recovered from a 52-m-deep borehole cored in the 300 Area of the Hanford Site in southeastern Washington State to assess the potential for biogeochemical transformation of radionuclide contaminants. Microbial analyses were made on 17 sediment samples traversing multiple geological units: the oxic coarse-grained Hanford formation (9 to 17.4 m), the oxic fine-grained upper Ringold formation (17.7 to 18.1 m), and the reduced Ringold formation (18.3 to 52 m). Microbial biomass (measured as phospholipid fatty acids) ranged from 7 to 974 pmols per g in discrete samples, with the highest numbers found in the Hanford formation. On average, strata below 17.4mhad 13-fold less biomass than those from shallower strata. The nosZ gene that encodes nitrous oxide reductase (measured by quantitative real-time PCR) had an abundance of 5 to 17% relative to that of total 16S rRNA genes below 18.3m and <5% above 18.1 m. Most nosZ sequences were affiliated with Ochrobactrum anthropi (97% sequence similarity) or had a nearest neighbor of Achromobacter xylosoxidans (90% similarity). Passive multilevel sampling of groundwater geochemistry demonstrated a redox gradient in the 1.5-m region between the Hanford-Ringold formation contact and the Ringold oxic-anoxic interface. Within this zone, copies of the dsrA gene and Geobacteraceae had the highest relative abundance. The majority of dsrA genes detected near the interface were related to Desulfotomaculum spp. These analyses indicate that the region just below the contact between the Hanford and Ringold formations is a zone of active biogeochemical redox cycling. © 2012, American Society for Microbiology.
Scarpato D.J.,Haley and Aldrich
48th US Rock Mechanics / Geomechanics Symposium 2014 | Year: 2014
The implications of ice build-up on surface rock excavations can prove to be costly over the design lifetime of a slope. In areas subjcct to significant precipitation and cold temperatures, ice accumulation can unknowingly wreak havoc on surfacc rock excavations and lead to an increase in the frequency of rock and icefall events. Ice build-up can destabilize a rock slope by expansive action (icc-wcdging), by surcharging portions of the slope face, and by inducing an ice-dammed condition where water-pressures arc allowed to build-up on discontinuity surfaces as a result of inadequate drainage during periods of thaw. Although icefall may logically be treated as a variant of the classic rockfall problem, there arc some significant differences between rockfall and icefall hazard evaluations. High-energy icefall impacts can also result in a significant amount of shatter, which can result in the release of ice projectiles. Ice build-up mitigation techniques can take the form of simple drainage elements and periodic cold-weather maintenance efforts, or can incorporate more advanced treatments like engineered topographic enhancements and bio-stabilization. In cases where source zone treatment is not permissible, engineered barriers may be incorporated for mitigating the risk of icefall impact to the traveling public where appropriate. Through our research and project case histories, this paper and presentation will describe some of the technical challenges associated with the burgeoning practice area of icefall evaluation, the importance of long-term monitoring and maintenance programs, and mitigation strategics for dealing with the under-appreciatcd problem of icefall at both the source and impact zone. Copyright © 2014 ARMA.
Martus P.,URS Deutschland GmbH |
Schaal W.,Haley and Aldrich
Environmental Forensics | Year: 2010
Signature metabolites provide direct geochemical indication that in-situ biodegradation of released organic compounds (e.g., oil and its refined products) is occurring. Experience shows that monitored natural attenuation site conditions are often more complex than in theory and often require a more profound comprehension of the governing natural attenuation processes. Frequently, there is lack of direct proof that contaminant degradation (mainly through biodegradation) is occurring. Advanced tools are emerging that aim to provide answers about whether contaminants of concern are actually (bio)degraded and to the extent. Signature metabolite analysis provides direct proof of mineral oil hydrocarbon biodegradation and is among these advanced tools. Yet, during the previous 15 years, metabolite analysis has only been used sporadically in research projects. The target metabolites consist of aromatic acids such as benzoates and benzylsuccinates and uniquely indicate in-situ biodegradation of individual contaminants of concern. Three case studies have been summarized to share practical experience with signature metabolite analysis for contaminants that include benzene, toluene, ethyl benzene, and xylenes; trimethylbenzenes; and polycyclic aromatic hydrocarbons. The summarized case study involving jet fuel-contamination was the first reported field study in which aromatic acid homologs were formed by microbial metabolism of C4 through C7 benzene. Signature metabolite analysis can be used to improve understanding of natural attenuation processes to close data gaps with respect to the general degradation mechanisms. Direct evidence for biodegradation (e.g., metabolite identity and concentration; microbial identity and quantity; daughter product degradation ratios, stable carbon isotope ratios) facilitates remediation planning and management; provides information useful to scientists and engineers that must determine the mechanisms that produced observed environmental conditions; and provides information for stakeholders involved in environmental cleanup litigation and cost appropriation. © Taylor & Francis Group, LLC.
Peacock A.,Haley and Aldrich
Pollution Engineering | Year: 2013
Many groundwater contaminants are subject to biological transformations, which may destroy the contaminant or convert it to a less toxic form. These reactions generally occur via oxidative or reductive processes associated with microbial respiration. For example, a wide variety of fuel hydrocarbons and oils are biologically oxidized, serving as sources of carbon and energy for microbial growth. Establishing cause and effect relationships demonstrates effectiveness of biological treatment strategies; such relationships prove desired bioprocesses are occurring now and will in the future. Traditional methods include a comprehensive groundwater monitoring program (particularly with MNA). In addition to assessing contaminant concentrations and trends, the monitoring program measures concentrations and distributions of numerous geochemical parameters considered major indicators of current and potential biological activity in groundwater.
Haley and Aldrich | Date: 2014-07-30
News Article | December 10, 2015
Nov. 19 was Day 379 in the construction of MIT.nano, the nanoscale characterization and fabrication facility scheduled to open in June 2018. It also marked the halfway point in the excavation phase of this ambitious and complex capital project situated in the center of campus. “Forty-nine percent of the dig is done, and we’ve hauled out 17,000 cubic yards of fill,” says Richard Amster, director of campus construction. “Only 621 days to go.” Day 379 was also when staff from the Department of Facilities, their contractors, and MIT.nano convened the third in a series of “tool talks” — sessions that provide the MIT community with an insiders’ view of construction tools and techniques in use on the site. Outside the session’s Building 4 conference room window, a 15-foot-deep hole and small hill of fill inside the footprint of the former Building 12 are the early indicators of a much larger project. Excavators and trucks edge carefully in and out of the site, hauling away what will eventually amount to 57 thousand tons of fill. “Coordinating the digging and hauling is tough on such a tight site,” says Travis Wanat, senior project manager. “And characterizing the dirt isn’t a trivial task either.” All of the dirt must be evaluated, explains Keith Johnson, a geotechnical consultant with Haley and Aldrich, a consulting company specializing in underground engineering and environmental science working on MIT.nano. “We collect soil samples at 5- to 5-foot depth intervals, and classify what we find using a portable scanning instrument,” he says. If the scans find high enough levels of volatile organic compounds, for instance, then the fill must be evaluated using analytical testing methods for the soils at that specific location. The test results for the soils at Building 12 indicate low levels of contamination for historic urban fill. For his soil studies, Johnson delves not just into the Earth but back in time. In addition to the original Building 12 plans, Johnson studied historical maps that show the campus rising on the edge of a sea wall constructed along the Charles River. “At MIT, we have going for us what they used for fill in the late 1800s,” said Johnson. The land on which campus buildings were constructed came from river dredging, and in this soil layer Johnson found “nothing unusual.” However, the dig has uncovered unmistakable evidence of the brackish origins of MIT fill, he says: the “overpowering smell of hydrogen sulfide,” a naturally occurring gas “that’s been under the organic soils for the last 100 years. It comes from clams.” With 600-800 cubic yards of fill leaving the site each day, it’s a “constant battle to minimize the amount of mud that gets on truck tires,” notes Peter Johnson, the project lead for Turner Construction. Rainy days pose enormous challenges for managers who need to avoid tracking excavation muck out of the site and onto Cambridge roads. So trucks moving in and out of the site use a road surfaced with “riprap,” a special kind of gravel that pulls debris from tires — like wiping shoes on a welcome mat. Workers also hose down truck tires constantly, and a street sweeper comes by multiple times a day. Sump pumps forcing 10 gallons per minute out of the bottom of the excavation help keep the site as dry as possible. As the excavation reaches the sand layer (about 15 feet down), contractors install diagonal steel tubes as corner bracing against the newly exposed slurry walls, said Johnson. This prevents the dirt on the outside of the walls from exerting excessive pressure on the perimeter of the dig. The goal is to avoid lateral or vertical movement in these walls, and to that end, said Wanat, “we take readings with a variety of instruments, and maintain a lot of monitoring points.” After the excavation concludes, at a depth of approximately 30 feet, MIT.nano will begin its next construction phase: the laying of a concrete ground floor slab. This process is scheduled to start in December, and spring will bring big, above-ground construction, and, at last, the rise of steel support towers and the structure itself. The leadership team for the MIT.nano project is holding community meetings on Dec. 10 and 11 to present information and hear about opportunities for engagement with the MIT community. Please join them Thursday, Dec. 10, from 2:30-3:30 p.m. in room 26-100, and Friday, Dec. 11, from 10-11 a.m. in room 1-190. For more information about the project, contact firstname.lastname@example.org or visit mitnano.mit.edu.