Equipment contamination, field applicator

In the past, use has been made of Amberlite XAD-4 resin columns in the field for sample extraction of fenitrothion and aminocarb in rain water. The rain water was collected and extracted with the aid of a special sampling (collection) device equipped with Amberlite XAD-4 columns. It is possible that these types of extraction columns could have some field application in the extraction of large volumes of surface water for the determination of specific organic contaminants. However, one drawback associated with resin columns is the requirement of exhaustive cleaning with various solvents to remove all trace contaminants. Preparation of blanks, spiked blanks, spiked samples (in replicate), and sequential replicate sampling should be included as part of the specific QA/QCPs that are needed, if these Amberlite XAD-4 resin columns (or others) are used more extensively in the future. 

As mentioned above, insulation applied to externally located equipment can be subjected to rain and weather contamination if the outer cladding fails. Insulants with water-repellant, water-tolerant or free-draining properties offer an additional benefit in this type of application. In the structural field insulants used as cavity wall fills must be of those types specially treated and designed for this application. 

The efficiency of filtration must be matched to the needs of the particular application, and, this is true both quantitatively (in relation the anticipated build-up of solids in the filters) and qualitatively (in relation to the composition of the contaminants and their size). Dirt build-up varies considerably, but it is probably at its maximum with civil engineering equipment. In this field, diesel engines in trucks will steadily accumulate something like 10 ounces of solids in the crankcase oil within a month. 

During the field demonstration in 1997 at the Department of Defense s (DOD s) Operable Unit 2, Hill Air Force Base in Utah, approximately 908 gal of dense, non-aqueous-phase liquids (DNAPLs) were removed from contaminated soils. The cost of the demonstration was 230/yd of soil treated and 165/gal of DNAPL removed. These costs included the purchase of all the equipment and an extensive monitoring network. It is estimated that future applications at the site would require roughly half as many wells and the boiler rental would be restricted to a much shorter period. These conditions would lower the direct treatment costs to 103/yd of treated soil and 74/gal DNAPL removed (D18518W, p. 216). 

Two types of portable analytical equipment were approved by the Conference of State Parties for on-site analysis, that is, GC/MS and Fourier transform infrared (FTIR). Initially, it was anticipated that FTIR might be used in storage, destruction and Schedule 1 facilities for screening purposes to confirm the presence of declared chemicals. While FTIR analysis is suitable to identify pure chemicals or certain chemicals in mixtures at varying detection limits, FTIR cannot be used to analyze for absence of undeclared scheduled chemicals, for which the IT would have to carry in addition to the FUR a GC/MS. For GC/MS analysis samples are analyzed at very low concentration contrary to FTIR analysis, which minimizes the risk of contamination in the on-site laboratory and reduces the risk of exposure of OPCW inspectors and on-site personnel. Considering the limitations of FUR and the fact that GC/MS can cover the field of application of the FUR for OPCW purposes, a decision was taken in 2000 to focus on the use of GC/MS in the OPCW mobile laboratory subject to future developments. 

Before leaving the site, as was performed on arrival, all equipment should be thoroughly rinsed to remove traces of particulate material to avoid between site contamination. The field form should be checked to ensure that all observations have been noted. If any field observations are not applicable at a site, for example, there is no contamination, the relevant box should be struck through so it is clear that the observation was investigated but there was nothing to record. Finally, on departure, the site should be clear with all of the samples and field equipment packed in the rucksacks ready to be taken to the next site. 

Application Upgrade natural gas condensate and other contaminated streams to higher-value ethylene plant feedstocks. Mercury, arsenic and lead contamination in potential ethylene plant feedstocks precludes their use, despite attractive yield patterns. The contaminants poison catalysts, cause corrosion in equipment and have undesirable environmental implications. For example, mercury compounds poison hydrotreating catalysts and, if present in the steam-cracker feed, are distributed in the C2-C5+ cuts. A condensate containing mercury may have negative added-value as a gas field product. 

As far as chemical variables are concerned, especially in case of trace determinations, all the steps of sample collection, treatment in the field and storage must be carefully considered in order to maintain sample integrity before analysis. In this respect the selection of appropriate equipment and non-contaminant materials, as well as the application of efficient cleaning procedures, are of paramount importance. For the most critical applications clean chemistry laboratories (equipped with Class 100 laminar flow cabins) must be available in the field or on board. 

The application of SCFs to the treatment of wastes and pollutants and to the extraction of contaminants from soil will be extended to other fields in the near future. The cost for the construction of plants will be reduced by the improvement of equipment and materials. The Wnd of fluids to be used will also be improved and many other technologies will be developed according to world needs. On the other hand, reactivities of SCFs, the nature of intramolecular bonds and intermolecular interactions, which are closely related to the reactivities, are not well elucidated yet. Studies on thermodynamics and thermochemistry and intra- and intermolecular interactions from microscopic points of view of SCFs will help solve some of these problems. Furthermore structural studies of SCFs have rarely been made for compounds other than water. Structural investigations of liquids at high temperature and high pressure are also very attractive and important in relation to life sciences. Further investigations into this area should be encouraged. 

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