Technical Challenges to In-situ Remediation of Polluted Sites

Abstract

Throughout the world, subsurface contamination has become a widespread and pervasive problem. Toxic chemicals such as heavy metals and organic compounds are commonly used in a myriad of industries. However, largely through inadvertent or accidental release, these chemicals are presently polluting sites across the United States. In order to protect public health and the environment, further pollution must be prevented and sites with existing contamination urgently need remediation. Unfortunately, remediating subsurface contamination has proved to be a daunting task. Heavy metals and organic compounds often coexist and their distribution within the subsurface is highly dependent on particle and macro-scale heterogeneities. Vast resources have been invested to develop efficient remediation technologies, yet very few of these technologies have been successful. In-situ remediation is often preferred due to minimal site disturbance, safety, simplicity, and costeffectiveness. The effectiveness of in-situ remediation technologies depends largely on the contaminant chemistry and subsurface heterogeneities (including particle-scale heterogeneities such as fine-grained soils, soils with reactive minerals, and/or soils rich in organic matter as well as macro-scale heterogeneities such as irregular soil layers and/or lenses). Under such heterogeneous conditions, integrated electrokinetic remediation technology has great potential. As a safe and economical remedial option for so many contaminated sites, the application of integrated electrokinetic remediation offers enormous public health, environmental, and financial benefits.

Efficacy of nano calcium silicate (NCS) treatment on tropical soils in encapsulating heavy metal ions: leaching studies validation

“…Further, a non-dimensional leachability index (LI) was calculated based on caged TCLP tests and was found to vary between 2 and 4 for virgin soils, and for soils amended with nano calcium silicate (NCS), it varied between 5 and 6. As per USEPA, a leachability index (LI) of more than 6 is considered as better material to arrest the transport of contaminants, and in our study, the leachability index (LI) for amended soils varies between 5 and 6; this confirms that the material is attenuating or retaining heavy metals, but there needs to be a small increase in the percentage of NCS added to soil which shall increase the value of LI to more than 6 as per USEPA standards [16,19,23,24,27].…”

Electrokinetic remediation of metal-polluted marine sediments: experimental investigation for plant design

“…It can be applied, both in situ and ex situ, for several contaminants, also in combination [5,[9][10][11][12][13][14][15][16][17][18][19][20][21]. The EK technology is based on the application of an electric field to contaminated porous media by means of two series of electrodes introduced in the media.…”

Remediação de solos contaminados por processos Fenton: uma revisão crítica

“…5,9 Em decorrência destas características, processos de bioatenuação natural apresentam escassa aplicação, o que tem servido de incentivo para a proposta de vários procedimentos alternativos, incluindo sistemas de remediação in-situ, caracterizados pelo tratamento no próprio local da contaminação, e sistemas ex-situ, em que o solo contaminado é previamente removido do local. 10 Uma ilustração que representa algumas alternativas de tratamento in-situ e ex-situ é apresentada na Figura 2.…”