ISSN:1051-5658    

DOI:10.1002/rem.3440080302

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1998

数据来源: WILEY

摘要:

AbstractMTBE in groundwater has been shown to travel over 1,000 feet downgradient from its source in several comprehensive field studies conducted across North America. The biodegradability of MTBE is examined by summarizing all the significant literature on the subject and by detailing the findings of recent field investigations of MTBE transport. In Orange County, California, the persistence of MTBE is analyzed and statistical representations of source variability are presented. Regional and far field transport of MTBE in groundwater sourced from underground gasoline storage tanks are summarized in comprehensive tables of frequency and plume length. Estimates of source mass and duration allow for comparison of associated plume size. The conclusion reached after reviewing all the available literature on MTBE is that its biodegradability seems slight and the size of the plumes are surprisingly large. Intrinsic or natural attenuation remedies for MTBE merit close scrutiny.

ISSN:1051-5658    

DOI:10.1002/rem.3440080303

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1998

数据来源: WILEY

摘要:

AbstractNatural attenuation has recently been recognized by the U.S. Environmental Protection Agency (EPA) as an appropriate remedy for sites contaminated with chlorinated solvents. Because natural attenuation does not require active remediation, it is considerably less expensive than other groundwater remedies. However, as laid out in EPA's recently released guidance, careful, systematic evaluation of natural attenuation must be conducted to ensure that the remedial approach is appropriate for a given site. The guidance requires that data be collected to demonstrate that natural attenuation is occurring and a fate‐and‐transport model must be conducted to estimate the extent to which a contaminated plume will ultimately migrate. Finally, the proponent of natural attenuation must be prepared to conduct long‐term groundwater monitoring to verify that natural attenuation is controlling plume migration and that human health and the environment are not adversely aff

ISSN:1051-5658    

DOI:10.1002/rem.3440080304

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1998

数据来源: WILEY

摘要:

AbstractThe potential effectiveness of a new composite‐aggregate capping technology, AquaBlokTM—in physically isolating contaminated, fine‐grained sediments derived from an Ohio, Lake Erie tributary—was evaluated in the laboratory. In particular, large‐scale settling‐column studies were conducted to determine the degree to which composite‐aggregate material penetrates into and/or mixes with the sediment, perhaps affecting the degree to which sediment could be physically isolated through capping. Additionally, large‐scale flume studies were conducted to determine resistance of the composite‐aggregate material to significant and long‐term, fluvial‐like erosive forces; the resistance of other potential capping materials was also evaluated for comparison. Experimental results indicate that the composite‐aggregate material effectively isolates sediment through the formation of a continuous and relatively erosion‐resistant, hydrated capping

ISSN:1051-5658    

DOI:10.1002/rem.3440080305

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1998

数据来源: WILEY

摘要:

AbstractThe distribution of air around injection wells is an important determinant of the effectiveness, design, and cost of air sparging remediation systems. High‐level air sparging field tests were conducted at two sites for the purpose of determining the pattern of airflow under widely different subsurface conditions. One site consisted of relatively homogeneous dune sand (Site A). The other consisted of highly heterogeneous glacial till (Site B). At both sites, cross‐borehole electrical resistance tomography (ERT) was used to image the principal region of airflow in the saturated zone. The response of conventional monitoring data was compared with the ERT results. At Site A, the principal region of airflow was approximately symmetric about the sparge well and only 2.4 m in radius. At Site B, the pattern of airflow was much more complex and had a major horizontal component. In both site studies, conventional monitoring data provided a much more ambiguous indication of the region of airflow in the saturated zone than did ERT. The investigations at these two sites demonstrate that, while the exact distribution of injected air is not readily discernible by conventional monitoring, the character of the airflow pattern can be recognized when appropriate physical response data are collected. Such response data can be used to evaluate site suitability for air sparging and to improve the system design and operat

ISSN:1051-5658    

DOI:10.1002/rem.3440080306

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1998

数据来源: WILEY

摘要:

AbstractThe Introduction to Therm Net technology is an overview of how radio frequency (RF) beating can be implemented to enhance conventional remediation technologies. Included in the article is a case study of a project conducted in March 1996 at a gasoline release site. The project consisted of a “hot spot” application to reduce BETX concentrations to achieve site closure. The application consisted of RF heating, soil vapor extraction, and groundwater ventilation. A bench scale study was also conducted to measure the effects that RF heating and vapor extraction had on the removal of PAH constitutents from a coal tar sludge. Up to 100 percent reductions were observed for some of the constituents in the study. Also included is a graphical representation of temperature versus vapor pressure for contaminants typically encountered at remediation sites, illustrating that as temperature increases, the removal rate increa

ISSN:1051-5658    

DOI:10.1002/rem.3440080307

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1998

数据来源: WILEY

摘要:

AbstractSince the early 1970s, technologies for remediating organic contamination in soils and groundwater have evolved through three stages with primary emphasis on (1) gross removal processes, (2) activein situtreatment, and (3) risk‐based closure and natural attentuation. Technologies for treating metals contamination are evolving through similar stages. In the late 1990s, metals remediation has arrived at the second stage in which a wide range ofin situtechnologies are available either to extract metals directly from the subsurface or to render them immobile and harmless.In situgeochemical fixation is an example of a commercial technology capable of addressing a wide range of metals contamination sites. Four case histories demonstrate the versatility of this approach. Other promising technologies for treating metals contamination are also emerging. These include geokinetics, biocatalytic precipitation processes, phytoremediation, and artificial wetlands. As our knowledge continues to grow, the most elegant solutions to metals contamination will rely more and more heavily on the soil's natural capacity to stabilize and immobilize metals over tim

ISSN:1051-5658    

DOI:10.1002/rem.3440080308

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1998

数据来源: WILEY

摘要:

AbstractFar too often private industry is caught in situations where they become responsible for environmental characterization and remediation projects. The processes involved in successfully completing such tasks may be foreign to the responsible industry. In such cases, an environmental contractor is hired to perform the necessary work. While many environmental contractors claim a high level of ethics and customer orientation, the very essence of their jobs should make the responsible industrial client wary. Far too often, environmental characterizations and remediations become too drawn out and costly. Far too often, environmental contractors need “just a little more data” to complete otherwise simple tasks. To guard against the phenomenon of “never‐ending environmental work,” responsible industrial clients that do not have environmental expertise on their staff would do well to retain a senior level independent environmental contractor to watch out for the best interests of the responsible industry. While the hiring of a contractor to watch a contractor may seem redundant and cost inefficient, the truth of the matter is the exact opposite. By bringing in an expert in environmental characterization and remediation, the responsible industrial client essentially hires another technical employee. It is best to hire this person as a member of the company to avoid additional overhead costs. If such an “environmental guardian” cannot be hired or found, then the responsible industrial client must learn to recognize the warning signs of an environmental characterization or remediation project that is out of control and should be stopped and regrouped. These warning signs become more apparent as time goes on (and money is spent). Having an experienced independent environmental contractor “look over the shoulder” of another contractor is just good business sense. One could say that it is the “potentially responsible party's” (PRP's) righ

ISSN:1051-5658    

DOI:10.1002/rem.3440080309

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1998

数据来源: WILEY

摘要:

AbstractA description of a complete remedial scheme for a uranium‐contaminated site is presented. Results for the example site are discussed. Volume reduction for the contaminated soil was greater than 99 percent and secondary waste volumes were kept to a minimum. The stages of physical separation for radioactive segregation, and chemical separation and immobilization of soluble uranium are universally applicable to all uranium contaminated sites when tailored to specific site requirements. Discussion is presented for adaptation to different soil types and different chemical forms of uraniu

ISSN:1051-5658    

DOI:10.1002/rem.3440080310

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1998

数据来源: WILEY

ISSN:1051-5658    

DOI:10.1002/rem.3440080311

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1998

数据来源: WILEY