Pollution Engineering - November 2008 - (Page 49)

Advertorial HOWTO: Install a Trench Without Open Excavations By DEWIND ONE-PASS TRENCHING INC. R MT Inc. was awarded a contract to install a zero-valence iron (ZVI) wall at a site in Poughkeepsie, New York, to remediate soil contaminated with trichloroethylene. Among the array of considerations in choosing the installation method, three were prominent. A concern universal to most projects of this nature is site conditions. In this case, the ZVI wall was to be installed in a lightuse industrial park where traffic would be ongoing. According to Greg Mitchell, RMT’s lead engineer, because traffic in and out of the commercial park could not be halted or diverted during the construction process, what was needed was an installation method having a small footprint. Mitchell wanted to keep construction activities concisely situated. The second imperative was the ZVI wall’s structural consistency. RMT wanted to assure a uniform wall thickness from trench bottom to grade. This is particularly hard to accomplish with many conventional installation methods. The third concern was the internal consistency of the wall itself. This particular ZVI design called for a 20 percent ZVI to 80 percent sand ratio. Although a number of methods were considered, including bio-slurry, ultimately the unique characteristics of the DeWind DEEP One-Pass© trenching process proved to be ideal for meeting each of the primary concerns RMT had. First the DEEP One-Pass© trenching process is the most effectual system in areas of tight space parameters. DeWind could accomplish the installation inside a tighter work area than other installation methods allowing no interference in traffic flow. Second, the goal of achieving uniform wall thickness, which is much harder to effectually achieve in conventional meth- ods of installation, is virtually built-in with DEEP One-Pass© trenching. DEEP OnePass© trenching is a controlled cut with trench width corresponding exactly to the width of the selected One-Pass© trencher’s dual laser-guided cutting boom and chain, and maintained at the desired width by the delivery system until the trench is filled with the iron/sand mix. This assures uniformity of width from trench bottom to grade with the exact ratio of iron to sand assured by onsite controlled monitoring of the mixing process and regular testing. The laser-guided accuracy of the DEEP OnePass© trenching process simultaneously backfilled the cut with the precisely mixed ZVI/Sand, again, all in a single pass. Further because there are no dangerous open excavations, unavoidable when using conventional installation methods, this results in a super safe construction site. This relieves the owner and engineer of excess liability when working to such deep depths literally within feet of pedestrian traffic. Additionally with One-Pass© trenching technology there are no excess spoils to manage or dispose. Although not an issue on this project, a final consideration, especially at seriously contaminated sites, is the possibility of a request for proposal mandating a Level B respiratory capability. This can raise the stakes for a project in terms of both site work safety and cost if level B conditions occur. Because OnePass© trenching is not an open trench method and is a quick backfill process, it is virtually unheard of to have site environmental air conditions go to Level C much less level B status. This is something to consider when designing a collectioncontainment-remediation system at highly contaminated sites. In the end, DeWind managed to smoothly install a 220 linear foot 27 feet deep by 18 inches wide wall in approximately 1 week at a significant discount to other approaches and in a significantly reduced time frame, making RMT well pleased with their decision to use DeWind One-Pass©. (616) 875-7580 • dewind@iserv.net • http://dewinddewatering.com HOWTO GUIDE | NOVEMBER2008 www.pollutionengineering.com 49 http://dewinddewatering.com http://www.pollutionengineering.com

Table of Contents Feed for the Digital Edition of Pollution Engineering - November 2008

Pollution Engineering - November 2008 Contents The Editor's Desk EnviroNews PE Events Legal Lookout Casebook Canada Environment Management The Green Files Waste Island Phase I ESAs and Vapor Intrusion Meeting the Mercury Target Wet ESPs - The Sky's the Limit Most Successful IFAT China Ever Thermoplastic to the Rescue Install a Trench Without Open Excavations Remediate Impacted Soils Without Accumulation of Metabolites Apply an Alternative to Wet ESP Solve These Common Pump Problems Minimize Risks Handling Ammonia Monitor International Regulatory Developments for Audits Skim Oil and Save Prevent Chemical Vapor Intrusion Spill Control and Containment Products Pumps and Systems Equipment PE Products Classified Marketplace Advertisers Index State Rules

Pollution Engineering - November 2008

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