Remediation System Evaluations

It has commissioned over 40 third-party optimization evaluations known as Remediation System Evaluations (RSEs) at Superfund, RCRA, and Leaking Underground Storage Tank sites. 

Effective design of a remediation system for dissolved hydrocarbons in groundwater requires consideration of more than only the effectiveness of the technological process involved. At many sites a variety of techniques are capable of completing the cleanup. However, design of a project that is efficient in all aspects — technically, in terms of time, and economically — requires an evaluation of the entire life cycle of the project from inception to closure. Typically, at sites where remediation is expected to continue over a 4-year project life, operation and maintenance account for between 50 and 80% of the total project cost. These percentages increase each year thereafter. The principal components of operation and maintenance are power, labor, and parts. Identification and quantification of these components are critical to the overall cost of a project. 

Superconducting magnetic equipment will be required for any full-scale treatment of large quantities of waste. These systems have been used for industrial applications, but not for remediation purposes. Until such remediation systems are designed, built, and used, performance and cost cannot be evaluated (D103786, p. 38). 

Evaluate Effectiveness on the Basis of Outputs and Acceptance Once the system has been implemented on its chosen site, its effectiveness needs to be evaluated at frequent intervals so that corrective action can be taken in the event of problems. The first criterion for success is that the system must generate unique insights into the causes of errors and accidents, which would not otherwise have been apparent. Second, the system must demonstrate a capability to specify remedial strategies that, in the long term, lead to enhanced safety, environmental impact and plant losses. Finally, the system must be owned by the workforce to the extent that its value is accepted and it demonstrates its capability to be self-sustaining. 

Use of higher plants has attracted attention for the remediation of TCE-contaminated aquatic systems, and in particular the use of hybrid poplar (Newman et al. 1999). Although this was encouraged by the removal of labeled TCE to >90% using hybrid poplar under hydroponic conditions (Orchard et al. 2000), and the ability of hybrid poplar to metabolize TCE (Newman et al. 1997 Shang et al. 2001), there are additional considerations that must be evaluated to determine its general applicability. 

Although the providers of proficiency testing schemes should have a quality management system in place, on occasions problems can arise which will affect the quality of the data evaluation being carried out. These can include transcription errors during data entry, mistakes in the report, software problems and inappropriate criteria for evaluation being used. Such problems should be remedied by the provider once the problem has been identified. 

Runkel, R.L. Kimball, B.A. 2002. Evaluating remedial alternatives for an acid mine drainage system - application of a reactive transport model. Environmental Science Technology, 36, 1093-1101. 

Information about construction materials used in the system may be contained within the plant records and can be useful in evaluating the fate and transport of a particular chemical contaminant through a system. For example, a particular contaminant may adsorb to the pipe material used in a utility s distribution system, and this type of information would be critical in evaluating remediation options following a chemical contamination incident. 

The cost of a vertical Lasagna system was evaluated by DuPont using a cost optimization model. For remediation of TCE to a depth of 40 to 50 ft (12 to 15 m) in clay on a 1-acre (4047-m ) site, costs were estimated to range from 40 to 90/yd ( 52 to 117/m ). Soil properties, depth of contamination, cost of emplacing electrodes and treatment zones, required purge water volume, cleanup time, and cost of electrical power were all included in the estimate (D12500Y, p. 10). 

Terrapure Systems, L.L.C. (Terrapure), is currently developing palladized iron remediation technology (PIRT). The deposition of small amounts of palladium (approximately 0.05 wt%) on the surface of iron particles may result in a bimetallic surface that can cause the dechlorination of aqueous organic compounds. The developers claim that the technology can be used as an in situ or ex situ process and can be applied to aqueous contaminants and soil. PIRT has been evaluated in bench-scale tests and is not currently commercially available. 

Few studies have evaluated the potential for use of microorganisms in the remediation of sea water however, the problems encountered are similar to those of other aquatic systems. Stupakova et al. (1988) proposed the use of the marine bacteria Deleya venustus and Moraxella sp. for copper uptake from sea water. Additionally, Corpe (1975) performed metal-binding studies with copper using exopolymer from film-producing marine bacteria and found that insoluble copper precipitates formed, effectively decreasing copper toxicity. 

In any evaluation of a remediation scheme utilizing surfactants, the effect of dose on HOC distribution coefficients must be quantified. Very often, only one coefficient value for HOC partitioning to sorbed surfactants has been reported in the literature, presumably because the experimental data covers only the sorption regions where the surfactant molecule interactions dominate at the surface (Nayyar et al., 1994 Park and Jaffe, 1993). However, all of the characteristic sorption regions will develop during an in-situ SEAR application as the surfactant front (i.e., mass transfer zone) advances through the porous medium. Therefore, the relative role ofregional HOC partition coefficients to sorbed surfactant should be considered in any remediation process. Finally, the porosity or solid volume fraction for the particular subsurface system must be taken into account when surfactant sorption is quantified. 

The objective of this portion of the research was to experimentally evaluate surfactant effects on the liquid-liquid separation of hydrophobic oils from a surfactant system. For pump-and-treat subsurface remediation in the absence of surfactant, contaminated ground water would be pumped from the subsurface and through a liquid-liquid extraction column where the contaminant partitions from the aqueous phase into an extraction solvent phase. In the absence of surfactant, the driving force for partitioning is a function of the contaminant hydrophobicity. In the presence of surfactants, the contaminant is subject to competitive partitioning (i.e., into the micelles and into the extracting oil). 

In summary, research reported in this chapter illustrates not only the complexity of surfactant enhanced remediation of hydrophobic NAPLs, but also demonstrates the ability of properly designed surfactant systems to effectively remediate these hydrophobic oils (EACN of 10-20). Future research will further evaluate this area, including field studies. This research also explored surfactant systems for attacking even more hydrophobic, low viscosity NAPLs (EACNs)20). Addressing the highly hydrophobic oils (EACNs))20) and highly viscous oils may require combined approaches, (i.e., surfactants plus alcohols/solvents and/or temperature) such will also be the focus of future research. 

The procedural controls to be followed if the system fails or breaks down should be defined, and specified. Any failures and remedial actions must be recorded and evaluated. 

The evaluation of computer systems performing regulated operations is the first phase to achieving an organized, prioritized, and balanced Part 11 Remediation Project approach. The objective of the evaluation is to identity the system s functional and/or procedural gaps results of the evaluation will determine whether the operational, maintenance, or security procedures specific to the system will provide a controlled environment, which ensures the integrity of the electronic records and/or signatures as stated in the Part 11 requirements. 

Using the evaluation reports, the remediation activities, available resources, and project schedule, the business cost of the remediation approach can be estimated. This will enable a business decision to be made regarding the remediation or replacement of the current system based on the cost-effectiveness of the system and its operational feasibility. 

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