ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1996.tb00566.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1996.tb00567.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1996.tb00568.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1996.tb00569.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1996.tb00570.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractDepth‐discrete aquifer in formal ion was obtained using recently developed adaptations and improvements to conventional characterization techniques. These improvements included running neutron porosity and hulk density geophysical logging tools through a cased hole, performing an enhanced point‐dilution tracer test for monitoring tracer concentration as a function of Lime and depth, and using pressure derivatives for diagnostic and quantitative analysis of constant rate discharge lest data. Data results from the use of these techniques were used to develop a conceptual model of a heterogeneous aquifer. Depth‐discrete aquifer information was required to effectively design field‐scale deployment and monitoring of an in situ bioremediation technology.Geophysical logging and point‐dilution tracer test results provided the relative distribution of porosity and horizontal hydraulic conductivity, respectively, with depth and correlated well. Hydraulic pumping tests were conducted to estimate mean values for transmissivity and effective hydraulic conductivity, Tracer lest and geophysical logging results indicated that ground water flow was predominant in the upper approximate 10 feet of the aquifer investigated. These results were used to delineate a more representative interval thickness for estimating effective hydraulic conductivity. Hydraulic conductivity, calculated using this representative interval, was estimated lo be 73 ft/d, approximately three limes higher than that calculated using the full length of the screened test

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1996.tb00571.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThis report summarizes the initial results of subsurface remediation at Terminal 1, Kenneth International Airport, to remediate soil and ground water contaminated with Jet A fuel. The project was driven and constrained In the const ruction schedule of a major new terminal at the facility. The remediation system used a combination of ground water pumping, air injection, and soil vapor extraction. In the first five months of operation, the combined processes of dewatering, volatilization, and biodegradation removed a total of 36,689 pounds of total volatile and semivolatile organic jet fuel hydrocarbons from subsurface soil and ground water. The. results of this case study have shown that 62 percent of the removal resulted from biodegradation, 21 percent occurred as a result of liquid removal, and 11 percent resulted from the extraction of volatile organic compounds (VOC's).

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1996.tb00572.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractStudies have shown that materials, such us polytetra‐fluoroethylene (PTFE), rigid polyvinyl chloride (rigid PVC). flexible polyvinyl chloride (flexible PVC), stainless steel (SS). low‐density polyethylene (LDPE), and high‐density polyethylene (HDPE), have the potential to influence certain analyte concentrations in ground water samples. The effects of HDPE, LDPE, PTFE, rigid PVC, and SS on aqueous concentrations of nitrate‐N, atrazine, deethylatrazine (DEA), and deisopropylatrazine (DIA) were evaluated in a field study A laboratory study was conducted to evaluate sorption of atrazine DEA, DIA, cyanazine, alachlor, metolachlor, and butachlor to PTFE, HDPE, and SS materials. Butachlor is rarely use in the United States, but was included because of its expected high sorptivity. No significant differences between HDPE, LDPE, PTFE, rigid PVC, and SS were determined for any of the analytes tested in the field study. In the laboratory study, sorption of DIA to PTFE and SS was significant at 2.6 × 10−5and 4.1 × 10−5μg/m2respectively. Sorption of DIAA to HDPE was not significantly>0 sorption of all other compounds to HDPE, PTFE, and SS were also not significantly>0. Results of the two studies indicate that for these analytes (relatively polar or ionized compounds), representative ground water samples are not dependent on the materials used for multilevel sampler construction. When considering these compounds, it appears that the least expensive materials (HDPE, rigid PVC, and LDPE) are good choices for the construction of ground water mo

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1996.tb00573.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractMicellar‐enhanced ultrafiltration (MELT) and air stripping were evaluated for surfactant‐contaminant separation and surfactant recovery. Two linear alkyl diphenyloxide disulfonate (DPDS) surfactants were evaluated with the contaminants naphthalene and trichloroethylene. A separation model developed from micellar partitioning principles showed a good correlation to batch MEUF studies, whereas flux analysis highlighted concentration polarization effects in relation to hydrophobe length. MEUF effectively concentrated the surfactant‐contaminant system (93 to 99 percent retention); however, this did not result in surfactant‐contaminant separation. Batch and continuous flow air stripping models were developed based upon air/water ratio, surfactant concentration, and Micellar partitioning; model predictions were validated by experimental data. Sensitivity analyses illustrated the decline in contaminant‐surfactant separation with increasing surfactant concentration (e.g., TCE removal efficiency declines from 83 percent to 37 percent as C‐16 DPDS concentration increases from 0 to 55 mM). This effect is greater for more hydrophobic contaminants (naphthalene vs. TCE) and surfactants with greater solubilization potential (C16‐DPDS vs. C‐12 DPDS). The resulting design equations can account for this effect and thus properly size air strippers to achieve the desired removal efficiency in the presence of surfactant micelles. Proper selection and design of surfactant‐contaminant separation and surfactant recovery systems are integral to optimizing surfactant‐enhanced sub

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1996.tb00574.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractAn investigation of elevated concentrations of nickel and chromium in certain ground water samples collected at Williams Air Force Base (AFB) indicated that type 304 stainless steel well materials are the source. Chloride in the ground water has apparently caused crevice corrosion of the stainless steel well screens installed during site characterization. An evaluation of site geochemistry suggested that chromium released from the well screen would precipitate, while nickel would remain dissolved. Thus, low‐flow purging and sampling significantly reduces the chromium found in the ground water samples because such sampling minimizes the collection of artificially entrained particulates. In contrast to chromium, nickel concentrations did not decrease during low‐flow purging and sampling, indicating that it is dissolved. Nickel and chromium concentrations are both low following high‐volume purging when turbidity levels are stabilized below 10 nephelometric turbidity units prior to sampling. In the latter case, chromium concentration is low because particulate collection is minimized, and nickel concentration is low because of increased dilution. Based on these results, it is recommended that elevated levels of nickel and chromium in ground water samples collected from stainless steel monitoring wells be carefully evaluated, because well materials may be the source. In addition, although low‐volume purging is increasingly becoming the sampling method of choice, high‐volume purging may be a useful means of determining whether the well materials influence nickel and chromium conce

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1996.tb00575.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY