1. EHC-O (TM) is a buffered source of slow-release oxygen plus inorganic nutrients for accelerated bioremediation of soil, sediment and groundwater environments impacted by organic constituents amenable to aerobic biodegradation processes (e.g., petroleum hydrocarbons). EHC-O significantly stimulates the catabolic activity of the indigenous microflora, thereby accelerating the rate of contaminant removal. Installation techniques vary widely depending on the application. For example, the powder can be mixed with soil and placed at the bottom of an excavation where prior soil removal had been conducted (Figure 1). A slurry can be made and the mixture can be injected into the subsurface using techniques such as direct injection through Geoprobe rods or hydraulic fracturing. In addition, O-Sox™ canisters are available in various diameters for direct placement into existing or newly installed wells (Figure 2). EHC-O O-Sox are advanced in their design and construction; they are simple to use and represent a significant improvement over existing sock technologies. CASE STUDY: LEAKING UNDERGROUND STORAGE TANK (LUST) SITE Site groundwater was impacted by petroleum volatile organic carbons (PVOCs) as a result of leaking underground storage tanks (LUSTs). The LUSTs were removed in the early 1970s, and in October 2004, STS Consultants, Ltd. treated the groundwater plume various times using an alternate oxygen-release compound (Regenesis “orc” compounds). However, in Spring 2005, PVOCs were still detected at significant levels. To facilitate site closure, a second round of oxygen release compound injections was conducted in August 2005. But this time, EHC-O was used as a source of slow-release oxygen, due to its ability to supply oxygen plus inorganic nutrients and buffering capacity in a more cost effective manner. The primary PVOC concentrations were reduced by 99% within 1 month, and all compounds were below the State of Wisconsin’s Groundwater Enforcement Standards (ES). A second sampling event, four months after the injections, showed additional reductions in PVOC levels and a “No further action” letter was issued in June 2006 following only two sampling events.. Other oxygen-releasing products are available on the market; however significant cost savings are realized through the use of EHC-O due to its lower price. Table 1 provides a price and performance comparison with other products commonly available. Product Description Price (US$/lb) lb of Oxygen Delivered per 100 lb Nutrients in Product Buffering Capacity in Product EHC-O4.00 to 5.252.5Yes Calcium-based7.00 to 8.002.0No Magnesium-based7.50 to 11.001.0No Table 1:Comparison of Price and Performance of EHC-O Versus Market- Leading Oxygen Releasing Products. In August 2005, a total of 450 lbs (205 kg) of EHC-O were introduced into 9 injection points at the hot spot area from 5 to 15 ft (1.5 to 4.6 m) bgs. The EHC-O powder was mixed with water on site into slurry (20% solids) using a handheld drill with mixing attachment, and injected using direct push technology (Geoprobe grout system GS-1000 series). The injection points were spaced about 1.8 m (6 ft) apart to cover an area of approximately 6 m x 6 m (20 ft x 20 ft). Figure 3 shows the concentration of PVOCs in groundwater before and after the EHC-O injection. Four weeks following the injection, six out of eight constituents of concern had decreased below the laboratory analytical detection limits. The concentration of the remaining PVOCs had also decreased significantly; the benzene concentration decreased by >99% (from 750 to 1.4 ppb) and the MTBE concentration decreased 88% (from 240 to 29 ppb). A second sampling event conducted 4 months following the injections confirmed the decreasing trend; benzene had decreased below the laboratory analytical detection limit and MTBE had decreased to 13 ppb. The total PVOC concentration decreased about 99% (from 2,290 to 13 ppb). Figure 3. Concentrations of PVOC in groundwater before and after EHC-O injection. La Biodégradation In Situ des Hydrocarbures Pétroliers utilisant EHC-O ® : Une Source Contrôlé d’Oxygène et des Nutriments Inorganiques In Situ Bioremediation of Petroleum Hydrocarbons Using EHC-O ® : A Timed-Release, Buffered Source of Dissolved Oxygen and Inorganic Nutrients. Fayaz Lakhwala, Josephine Molin, David Hill and James Mueller* (The Adventus Group - Europe) EHC-O In Situ Remediation Treatment Figure 1. Powdered EHC-O in the bottom of an excavation. Figure 2. EHC-O O-Sox components. The Challenge The Solution The Result 2871 W. Forest Road, Suite 2  Freeport, IL 61032  Tel: 815.235.3503 1345 Fewster Drive  Mississauga, Ontario  Canada L4W 2A5  Tel: 905.273.5374 EHC, EHC-O, and O-Sox are registered trademarks of Adventus Intellectual Property Inc. www.adventusgroup.com Cost and Contact EHC-O = € 7/kg O-Sox 5 cm diam = €97; 10 cm diam = €126 (Delivery from within the EU for all materials; volume discounts may apply) ADVENTUS EUROPE Franz-Plattner Str. 28F 6170 Zirl, Tirol, Austria tel (+43) 5238.53262 fax (+43) 512.219.100333 www.ADVENTUS.eu Info@AdventusGroup.com www.ADVENTUS.eu Info@AdventusGroup.com