摘要:

AbstractGround water remediation of volatile organic compound (VOC) contamination at a site in Michigan was initiated as a result of a consent agreement between the Michigan Department of Natural Resources (MDNR) and the responsible party. Under the direction of the MDNR, the responsible party conducted a remedial investigation/feasibility study using federal guidelines to define the extent of contamination at the site and to select a response action for site remediation. The selected alternative included a combination of ground water extraction, treatment, and recharge, and soil flushing. The extraction system withdraws ground water from various depths in heavily contaminated areas. The ground water is treated using an air stripper. A spray distribution system spreads effluent from the stripper over a recharge basin constructed over the most contaminated areas. Additional contaminant removal is achieved by volatilization from the spray and percolation through the gravel bed. Recharge water moves downward through the contaminated soils, thus flushing residual soil contaminants. The initial operating data demonstrated that the system can effectively remove trichloroethylene (TCE) from ground water (approximately 95 percent overall removal efficiency). The annualized capital and operation and maintenance (O&M) costs of the remedial action were estimated for several operating periods (15, 20, and 30 years).

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1989.tb01124.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractThe Geonics EM‐39 borehole induction tool was field tested to evaluate its performance under controlled conditions. The effects of temperature changes and borehole fluids were found to be negligible under most conditions. The instrument can be calibrated in large bodies of water of known electrical conductivity. When properly calibrated, the ± 5 percent accuracy claimed by the manufacturer is obtainable. A geologic unit must be at least 4m thick for the electrical conductivity of the unit to be accurately measured. Geologic units thinner than 4m thick can be detected if the conductivity contrast to adjacent units is sufficiently lar

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1989.tb01125.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractOn‐site biological cleanup following spills of biodegradable hazardous organic compounds in lagoon, soil, and ground water environments is a cost‐effective technique when proper engineering controls are applied. Biodegradation of hazardous organic contaminants by microorganisms minimizes liability by converting toxic reactants into harmless end products.Three case histories presented in this paper detail:• Bench‐scale evaluation of the potential for biological remediation in the spill site matrix• Field implementation of biological treatment techniques.Cost‐effectiveness, minimal disturbance to existing operations, and on‐site destruction of spilled contaminants are several of the advantages identified for implementing biodegradation as a technique for spill cleanup and environmenta

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1989.tb01126.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractFree‐phase hydrocarbon product occurs as perched zones on the capillary fringe beneath numerous petroleum‐handling facilities. Under such site conditions, too much emphasis is placed on the time‐frame required for remediation by federal, state, and local regulators, notably in respect to monitoring the efficiency and effectiveness of the respective remediation program. The time required for remediation within the scope of present‐day technology is a calculated or educated guess at best. Typically, remediation duration is determined by a number of estimates. These estimates have innate compounding errors. Areas of estimation include physical measurement accuracy; “true” vs. apparent thickness; validity of bail‐down testing; extrapolation of free hydrocarbon product thicknesses between monitoring points; contouring of thickness maps, extrapolation of geologic information, planimetering, and estimation of porosity; specific yield and retention; all of which are key factors used in ultimately determining the volume of free hydrocarbon product in place.Once an initial estimated volume is determined, pilot testing of a recovery system should commence to determine recovery rates.Factors that will affect recovery rates include the areal distribution and geometry of the hydrocarbon pool, type, and number of recovery system(s) selected, and the performance or efficiency of these systems with time. Effectiveness of the recovery program is thus best estimated based on barrels recovered to date divided by the total volume of barrels that are considered recoverable.Remediation time frame at petroleum hydrocarbon recovery sites can be estimated. However, regulators at all levels need to be aware of the large number of compounding errors associated with these calculations. Estimations should be used with extreme caution, because they are usually overestimations. Once a realistic time frame for remediation is mutually agreed upon, it should be clearly understood that it is flexible. It is recommended that a range be initially determined and that as a project progresses and new data are introduced, the remediation time frame be adjuste

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1989.tb01127.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractIn situ bioreclamation is a proven technology that cost‐effectively treats organic contamination in subsurface environments. As a remediation strategy, it reduces both the contamination dissolved in ground water, as well as residual soil‐bound contamination.To maximize biodegradation, the technology is applied after conducting laboratory studies. Application of the technology involves infiltrating necessary nutrients to the contaminated subsurface.Results of a specific case study indicate excellent performance with rapid cleanup of petroleum hydrocarbon contamination from soils and ground water.Costs associated with in situ bioreclamation technology showed a savings of approximately 50 percent over simple pump‐and‐treat technology. Time frame for cleanup was shown to be approximately 30 percent of the projected time frame of simple pump‐and‐treat

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1989.tb01128.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractA practical pumping system for the recovery of free petroleum hydrocarbon product from shallow aquifers has been developed. The system is patterned after suction‐lift well point dewatering systems used in the construction industry. Pumping equipment consists of double‐diaphragm suction‐lift pumps manifolded to up to four recovery wells. Recovery wells are constructed with screens below the water table and sealed wellheads to enable vacuum‐assisted flow of fluids to the wells. Pumps utilized are pneumatically driven, can be pumped dry without damage, induce a vacuum on the wells when pumping dry, and provide delivery of pumped fluids to fluid separation and storage facilities. The system is effective in both low‐ and high‐permeability formations due to the wide range in available pumping rates afforded b

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1989.tb01129.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractRecent advances in high throughput/automated compositing with robotics/field‐screening methods offer seldom‐tapped opportunities for achieving cost‐reduction in ground water quality monitoring programs. An economic framework is presented in this paper for the evaluation of sample compositing as a screening tool in ground water quality monitoring. When the likelihood of occurrence of a contaminant in a well is very small, the use of sample compositing instead of routine exhaustive sampling will lead to reduction in analytical efforts. Such reduction will be maximum when there are no contaminated wells in the network. An N‐fold reduction will result when none of the wells in a network of N wells are contaminated. When 25 percent or more wells in a network are contaminated, the use of sample compositing will require, at the most, an additional 50 percent analytical effort compared to exhaustive sampling. A quantitative measure of the cost‐effectiveness of sample compositing as a screening tool is shown to be dependent on two factors: a ratio (f1) of laboratory analytical cost to that of well installation and field sampling costs and a ratio (f2) of the expected number of contaminated wells to that of the total number of wells in the network. Several useful mathematical results of primary interest are derived and illustrated with case examples in the paper. Selected areas for further research are also

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1989.tb01130.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractAs part of an agricultural non‐point‐source study in the Conestoga River head waters area in Pennsylvania, different methods for collecting ground water samples from a fractured carbonate‐rock aquifer were compared. Samples were collected from seven wells that had been cased to bedrock and drilled as open holes to the first significant water‐bearing zone. All samples were analyzed for specific conductance, dissolved oxygen, and dissolved‐nitrogen species. Water samples collected by a point sampler without pumping the well were compared to samples collected by a submersible pump and by a point sampler after pumping the well. Samples collected by using a point sampler, adjacent to major water‐bearing zones in an open borehole without pumping the well, were not statistically different from samples collected from the pump discharge or from point samples collected adjacent to major water‐bearing zones after pumping the well. Samples collected by using a point sampler without pumping the well at depths other than those adjacent to the water‐bearing zones did not give the same results as the other methods, especially when the water samples were collected from within the well casings. It was concluded that, for the wells at this site, sampling adjacent to major water‐bearing zones by using a point sampler without pumping the well provides samples that are as representative of aquifer conditions as samples collected from the pump discharge after reaching constant temperature and specific conductance, and by using a point sampler after

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1989.tb01131.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY