Organoclays Trap Recalcitrant Organic Compounds and Metals in Sediments Simultaneously

George R. Alther, Biomin, Inc., P. O. Box 20028 , Ferndale , MI 48220
Eric C. Hince, P.G., Eric L. Zimmer, Geovation Engineering, Rochester , NY  

Extensive research at a university, which was conducted over the last few years, has revealed that certain organically modified clays are well suited to fixate organic hydrocarbons of polar and non-polar nature, anionic organic compounds and metals, and cationic heavy metals, in sediments.

Organoclays are blended with sediments in permeable barriers, landfill liners, slurry walls, and sediment caps.

Organoclays have been used in permeable walls to block the movement in groundwater of DNAPL plumes from abandoned wood treating sites, and for sediment stabilization at an old MGP site (from a power and light company).

Laboratory column and batch tests with various types of organoclays have revealed that a standard, non-polar organoclay fixates all heavy metals, including lead, zinc, nickel, chromium and cadmium, but also inorganic aqueous mercury. In terms of organic hydrocarbons, such diverse compounds as dioxin and nitro-benzenes, potassium sorbate, as well as PCB, PCP, PNAH, BTEX and oil are effectively trapped. 

Polar organoclays will fixate arsenate, selenite, phosphate, nitrate, fluoride, silicate, perchlorate and the like.

This article presents the capabilities of organoclays based on lab tests, and recommendations as to how to use them.

Case Study of the Design and Operation of a Deep Air Sparging System to Remediate Petroleum Impacted Groundwater

James F. Cuthbertson, P.E.,  Delta Environmental Consultants, Inc., 39810 Grand River Avenue, Suite C-100, Novi, Michigan, 48375, Tel: 248-699-0259, Fax: 248-699-0232, Email:  jcuthbertson@deltaenv.com  
Jason Phillips, Delta Environmental Consultants, Inc., 39810 Grand River Avenue, Suite C-100, Novi, Michigan, 48375, Tel: 412-217-6794, Fax: 248-699-0232, Email:  jphillips@deltaenv.com

Air sparging is a very well known technique for the remediation of petroleum impacted groundwater near the upper portion of the groundwater table.  However, the application of this technique at a depth significantly below the groundwater table is not a common approach and the design considerations are not well documented in the literature.   Review of available literature indicated a scarcity of information and widely varying pressure requirements needed to initiate air flow.  Case study results of the pilot study, system design, installation and effectiveness for a site in Michigan where the sparge points are installed approximately 50 to 60 feet below the groundwater table will be presented. 

Performance-Based ERH Remediation of DNAPL in a Tight Soil Matrix

Robert F. Davis, Jr., PE, Tetra Tech NUS, Inc., 661 Andersen Road, Pittsburgh, PA 15220, Tel: 412-921-7090, Fax: 412-921-4040, Email: Robert.Davis@ttnus.com  
Christopher Pike, PE, Tetra Tech NUS, Inc., 661 Andersen Road, Pittsburgh, PA 15220, Tel: 412-921-7090, Fax: 412-921-4040  
Anthony B. Robinson, Commander, Southeast, Naval Facilities Engineering Command, Southeast, ATTN:  Anthony Robinson (Code EV4), 2155 Eagle Drive, P.O. Box 190010, North Charleston, SC 29419-9010, Tel: 843-820-7339, Fax: 843-820-7465  
Dan W. Waddill, Ph.D. PE, Environmental Engineer, Technical Support Branch, Naval Facilities Engineering Command, NAVFAC Atlantic , ATTN:  Dan W. Waddill (Code EV32), 6506 Hampton Boulevard , Norfolk, VA 23508, Tel: 757-322-4983, Fax: 757-322-4805  
Howard Hickey, Dept. of the Navy, NAVFAC Midwest, ACOS Installation & Env., Building 1A, Code N45313, 201 Decatur Ave., Great Lakes, IL  60088, Tel: 847-688-2600, Fax: 847-688-2319

Remediation of tetrachloroethene (PCE) in a tight soil matrix was completed at a former dry cleaner located at Naval Station Great Lakes in Illinois.  The site lithology consists of low permeability silt and clay (mean hydraulic conductivity of 0.19 feet per day).  The maximum PCE concentration in soil observed at the site was 1,500 mg/kg, indicating the presence of DNAPL; the maximum depth of contamination observed was 20 feet.  Electric Resistance Heating (ERH) was utilized to address the DNAPL and other areas of high concentration PCE-contaminated soil. 

The remedial goal for the site was to reduce average PCE concentrations in the soil matrix from 445 milligrams per kilogram (mg/kg) to less than 20 mg/kg (95.5 percent reduction).  Pore water concentrations, though expected to decrease as part of the remediation, were not utilized in determining the performance-based goals.  The success in meeting the goal was based on the analytical results of soil samples collected from 15 locations at various depths prior to and following treatment. 

The ERH system contained 16 electrodes designed to treat a total area of 2,400 square feet.  The treatment area was divided in to three smaller regions to treat various depth intervals; Area 1 extended from the surface to a depth of 25 feet; Area 2 extended from the surface to a depth of 18 feet, and Area 3 extended from the surface to a depth of 8 feet.  The total soil volume treated was 1,400 cubic yards.  Start-up of the system occurred on May 23, 2006 and the system operated for approximately 4 months.  During operation, the ERH system removed 1200 pounds of VOCs from the subsurface.  The final average VOC concentration in the soil was 4 mg/kg; this equates to a reduction of greater than 99 percent, surpassing the project goals. 

Habitat Restoration and Challenges Faced in Remediation of Coal Tar in the Connecticut River

Nathan Henderson, Metcalf & Eddy | AECOM, 701 Edgewater Drive, Wakefield, MA 01880, Tel: 781-224-6504, Fax: 781-224-5986, Email: nathan.henderson@m-e.aecom.com  
John Albrecht, Metcalf & Eddy | AECOM, 860 N. Main Street Ext., Wallingford, CT 06492, Tel: 203-269-2826, Fax: 203-269-8788, Email: john.albrecht@m-e.aecom.com  
Paul J. Boison, Northeast Utilities Service Company, 107 Selden Street, Berlin, CT 06037, Tel: 860-665-3650, Fax: 860-665-5078

The Holyoke Gas Works operated from 1852 until 1951 and played an important role in the industrial development of the city of Holyoke , Massachusetts .  A legacy of its operation included releases of coal tar to the Connecticut River , resulting in the deposition of hardened, asphalt-like tar patches on the river bottom.  These coal tar deposits were subsequently identified in an area known to provide habitat for the federally endangered shortnose sturgeon (Acipenser brevirostrum) and two state-protected mussel species.  The National Oceanic and Atmospheric Administration and the Massachusetts Department of Environmental Protection (MADEP) made presumptive determination that risk to an endangered species existed and mandated remediation, consequently, a site-specific ecological or human health risk assessment was not conducted.  The Remedial Action Plan, involving mechanical excavation methods in both dewatered and submerged conditions, predicted that remediation efforts would be completed within a two year period.  Remediation efforts began in 2002 but due to significant logistical and technical challenges, including limited site access, sensitive biological resources and large variations in river flow, velocity, and depth, remediation of the originally identified patches has not been completed. In addition to these technical challenges, a significantly larger quantity of coal tar was uncovered during excavation and during episodic storm events.  Further delineation efforts conducted in 2006 within a three mile stretch of the river has resulted in the discovery of significantly more surface exposed coal tar than previously identified.  Due to the hardened physical nature and apparent inert characteristics of theses newly identified patches, a proposed risk assessment to prioritize cleanup goals is being reviewed by MADEP.   This paper discusses, remediation implementation, lessons learned and regulatory hurtles facing the project as it moves forward to complete its habitat restoration objectives. 

Pilot Testing Pneumatic Fracturing to Enhance Petroleum Hydro carbon Recovery

Chester A. Hitchens, Delta Environmental Consultants, Inc., 1343 South Garfield Avenue, Loveland, Colorado 80537, Tel: 970-292-1887, Fax: 970-292-1881

A number of service stations that operated in Glendo, Wyoming since the early 1930s had leaked and caused wide spread ground water contamination.  Results of a field investigation indicated that both free- and dissolved-phase hydrocarbon plumes were extensive.  Two large plumes were identified, and the areal extent of the free product plume was approximately 5.7 acres and the dissolved phase plume was approximately 100 acres in size. Over the project area, the free product thicknesses range from a trace to over seven feet.  The results of the subsurface investigation indicated that approximately 12 to 20 feet of unconsolidated silt and minor amounts of sand overly the buff-colored siltstone and claystone (Miocene). The soil contamination was not extensive, and the majority of the soil contamination outside of the free product plume appeared to be caused by contaminated water adsorbing onto the soil matrix.

The pilot test involved drilling nine borings for fracture wells, and then conducting pneumatic fracturing in both the saturated and unsaturated zone.  ARS Technologies Inc. was selected to perform the pneumatic fracturing. The pneumatic fracturing was conducted in a ten-foot zone that straddled the water table.  Nitrogen injection was conducted for about 15 seconds, at 150 to 380 psi, with a flow rate of about 800 to 3,000 scfm. After the pneumatic fracturing was completed, the pre-fracturing aquifer testing was repeated. Results of the post-fracturing aquifer testing showed that water production rates essentially doubled, with the same drawdown.  During the post-fracturing SVE testing, the operating vacuum could be reduced to 68 inches of water, and vacuum influence was measured in all nearby site monitoring wells. A graph of vacuum verses distance test suggested an SVE effective radius of influence of approximately 60 feet. A full scale remediation system is scheduled to be installed in the summer of 2007.

Economic Optimization of Existing Pump and Treat Groundwater Remediation Systems

Brad Johnson, P.E., CH2M HILL, 318C East Inner Road, Otis ANG Base, MA 02542-5028, Tel:  508-968-4754 x 15, Fax:  508-968-4755, Email: Brad.Johnson6@ CH2M.com  
Rose Forbes, P.E., Air Force Center for Environmental Excellence, 322 East Inner Road, Otis ANG Base, MA 02542-5028, Tel:  508-968-4670 x 4952, Fax:  508-968-4476, Email: Rose.Forbes@brooks.af.mil  
Ken Martins, P.E., CH2M HILL, 3 Hutton Centre Drive, Suite 200, Santa Ana, CA 92707, Tel: 714-429-2020 x 6284, Fax:  714- 429-2050, Email: Ken.Martins@CH2M.com

Treatment plant operating conditions at groundwater remediation sites typically change with time.  For example, contaminant concentrations may vary, the contaminant mix may change, and operating flow rates may be adjusted.  Equipment installed to operate at original conditions may perform inefficiently at revised conditions.  Reductions in operating costs can be achieved in many cases by including engineering reviews of equipment as a part of any changes to operating conditions.

As sites at the Massachusetts Military Reservation have been remediated, the flow rate of water entering some of the treatment plants has been reduced.  The pumps in the plants were designed for higher flow rates and were throttled back or flow was recirculated in order to operate at lower flow rates.  Variable Frequency Drives (VFDs) were installed to allow pumps to operate at lower speeds, reducing the electricity demand to pump the required amount of water.  The resulting annual reduction in electricity costs totaled $125,000.  For smaller systems, it may be more economically attractive to resize a pump.  For instance, if the flow rate to a remediation system is reduced, installing a pump that operates more efficiently at the new flow rate without the need for throttling or recirculation can reduce operating costs.  Depending on the cost of electricity, reducing power requirements by one horsepower can reduce annual operating costs by $500-$1000.

Another potential area for optimization is treatment plant lighting systems.  Plants may be designed and built with incandescent or metal vapor lighting systems that require large amounts of electricity to produce adequate lighting.  Additionally, some lighting systems require a warm-up period before full output is reached.  This may result in personnel leaving lights on at all times.  Replacement of metal vapor lighting systems with high efficiency fluorescent lighting at MMR plants is estimated to reduce annual electricity costs by $55,000.

Evaluation of Pneumatically Induced Fractures for Enhanced Delivery of Substrates within Low Permeable Soils 

Michael Liskowitz, ARS Technologies, Inc., 98 North Ward Street, New Brunswick, NJ 08901, Tel: 732-296-6620, Fax: 732-296-6625  
Charlotte Riis, NIRAS, Sortemosevej 2, 3450 Allerod, Denmark, Tel: 45 48 10 42 00, Fax: 45 48 10 43 00  
Anders Christensen, NIRAS, Sortemosevej 2, 3450 Allerod, Denmark, Tel: 45 48 10 42 00, Fax: 45 48 10 43 00  

This study presents the results of a pilot scale investigation performed in December 2005 at a site in Hedehusene, Denmark. The purpose of the study was to assess the effectiveness of pneumatic fracturing technology as a permeability/hydraulic conductivity enhancer and delivery mechanism to augment reagent and/or substrate distribution within low-permeable formations.  Contaminated sites are frequently located in areas with low permeable soil types requiring permeability enhancement methods to provide direct access to these contaminants resulting in accelerated cleanup times.  The results generated from the study were used to ascertain the fracturing characteristics and/or mechanism through evaluation of achievable radius of influence, uniformity and apparent density of the induced fracture network within a clayey till.  Fracture mapping was accomplished using different tracers which were injected with the nitrogen gas used during the fracturing process.  The tracers provided visual identification of the fractures at various distances and depths from the fracturing well thereby allowing documentation of the actual radius of influence, mass balance and fracture density obtained through  pneumatic fracturing. The results identified a number of induced fractures in core samples taken at distances of up to 3 meters from the fracturing well. The use of digital imaging under UV-light proved to be a very efficient way to locate the fractures in the core samples. A preliminary mass balance indicated that 90% of the tracer mass was distributed within 1-2 meters from the fracturing well. Distinct fractures with high concentrations of tracers were observed over the entire fracturing interval (3-8 meters bgs) at distances up to 6.8 meters from the fracturing well.

EDC Remediation with Microbubble Ozone Diffusion

Dennis L. Mast, Ph.D., Shine Holdings, Inc., 5620 Merion Station Dr., Apex, NC 27539-6347, Tel: 919-372-9421, Fax: 919-882-8244, Email: Mast2sail@msn.com

The Problem:

Endocrine Disrupting Compounds (EDCs), and other chemicals of concern are now practically omnipresent in wastewater wherever modern human habitation is encountered. Contemporary wastewater treatment systems, (WWTPs) were never intended or designed to accommodate such materials.

Goals and Objectives:

Numerous published studies have reached a consensus view that identifies the enhanced oxidative properties of ozone as a most potent removal mechanism for most EDCs and the many compounds of emerging concern. The principal goal of this study was to perform construction of an individual ozone diffusion technology.

Approach:  

The analog for such a system presently exists. Using a proprietary high-efficiency aeration technology for wastewater, an oxygenation system was designed in 2001 that initiates upstream wastewater treatment. These O2 systems are presently in nationwide operation. It is now for EDC removal applications downstream of WWTPs that a new ozone prototype device has been constructed, albeit with changes in materials.

The existing oxygen system consists of a reduced pressure Mass Transfer Contactor (MTC) where production of microbubbles of 5 microns in diameter and bubble rise rates of 0.2 to 0.8 cm/sec yield Standard Oxygen Transfer Efficiencies (SOTE) exceeding 60%, with Standard Aeration Efficiencies (SAE) of 3.17-kg/KW hour have been measured. A high transfer efficiency of oxygen or ozone into the effluent occurs due to the exponentially increased surface area provided by the small micron-sized bubbles and the long duration of bubble persistence. The ozone diffuser data is expected to produce similar efficiencies as those described for the oxygen diffusion technology. The SOTE data points for the oxygen diffuser were actually 60.9%. Corresponding efficiencies are expected in the ozone-based system with field trials now to be completed by Fall 2007.

Pilot Experiment of Immobilization of Contaminants In-Situ

Jiří Mužák and Ludvík Kašpar, DIAMO, s. p., o. z. TUU, Machova 201, 471 27 Straz pod Ralskem, Czech Republic, Tel: +420 487 894 324, Email: muzak@diamo.cz, kaspar@diamo.cz

At the end of 2006 the project of pilot experiment of immobilization of contaminants in-situ was in DIAMO, s. p., o. z. TUU prepared. Realisation of the experiment is planned for years 2007 and 2008.

The principle of immobilization of contaminants in-situ is to develop special conditions in water bearing sandstone sediments when transformation of contaminants from mobile form to immobile form can happen. Under the conditions of remediation after chemical mining (using sulphuric acid) of uranium on the deposit Straz it means injecting suitable alkaline medium and it’s spreading in contaminated sandstone aquifer. It will lead to decreasing of acidity of contaminated groundwater and precipitating of contaminants (SO42-, Al, Fe) in pores. This process leading to decreasing of concentration of dissolved contaminants in groundwater is followed by co precipitation and sorption of other toxic contaminants as As and Be.

The numerical model of groundwater flow and contaminant transport for evaluation of pilot experiment results was developed. The model mesh covers the all influenced area of the aquifer. It is sufficiently fine in the area of planned pilot experiment. It follows from the testing preliminary calculations that for example effect of gravity separation of solutions cannot be omitted. During the preliminary phase of pilot experiment another tests of calculation accuracy will be performed. These calculations will allow us to determine rates of change of follow-up parameters and consequently the necessary frequencies of piezometric head measuring, groundwater sampling and analysing.

The results of the pilot experiment will be used for design of application of method of immobilization in-situ in the frame of remediation after chemical mining of uranium on the deposit Straz with the aim to decrease time and costs of the whole remediation process.

Design and Implementation of a Comprehensive Thermal Remedy at a Former Drum Disposal Site

Thomas J. Phelan, Carl R. Elder, Douglas G. Larson, Christopher A. Sullivan, Robin R. Swift, Peter J. Zeeb, Geosyntec Consultants, Inc., 289 Great Road, Suite 105, Acton, MA 01720-4766. Tel: 978-263-9588, Fax: 978-263-9594

Drum disposal sites face many challenges to effective remediation and eventual site closure.  The large variety of contaminants often present at these sites makes many remedial technologies inefficient or prohibitively expensive.  In the 1930s, a portion of a residential property in southeastern Massachusetts was excavated for fill for an off-site construction project.  Between 1950 and 1965, the resulting borrow pit was gradually filled with an estimated 2200 drums containing a variety of volatile and semi-volatile organic wastes.  Client and regulatory concerns drove the selection of In Situ Thermal Desorption (ISTD) as the principal remedial technology employed at the Site.  ISTD heats the subsurface to volatilize and steam strip contaminants.  At this Site, a target temperature of 150 °C was to be achieved through 70 heater wells installed over a 420-m² area.  Volatilized contaminants were removed via vapor collection trenches, treated by thermal oxidation, and discharged to the atmosphere.  This remedy was augmented with a dual-phase recovery and treatment system, which removed dissolved constituents in groundwater outside of the thermal treatment zone and extracted nonaqueous phase liquid (NAPL).  NAPL in the extracted liquid was removed by phase separation via gravity.  Contaminated groundwater was then treated to remove volatile and semivolatile organic compounds, trace heavy metals, and iron and manganese.  Extracted NAPL was disposed off-site.  Preliminary data indicate that over 15,000 kg of mass have been removed from the subsurface to date.  This presentation describes the selection, design, and implementation of the combined remedy at this site.  The aggressive nature of this remedy presented many technical challenges, and innovative approaches to these challenges will be highlighted.  Additionally, preliminary data on the efficacy of the implemented remedy will be discussed.

Case Study - The Excavation of MGP Residuals in Soil Adjacent to an Active Rail Line and within a Residential Community

Mikel Pype, Jacques Whitford Company, Inc., Plymouth Meeting, PA 19462, Tel: 484-322-0301, Email: mpype@jacqueswhitford.com  
Barry Raus, P.G., Jacques Whitford Company, Inc., Plymouth Meeting, PA 19462, Tel: 484-322-0301, Email: braus@jacqueswhitford.com  
Lindsay Guiliano, Jacques Whitford Company, Inc., Plymouth Meeting, PA 19462, Tel: 484-322-0301, Email: lguilian@jacqueswhitford.com  
Joseph Foglio, GZA GeoEnvironmental, Inc., Fort Washington, PA 19034, Tel: 215-591-3800, Email: jfoglio@gza.com

A remedial action was completed at a former MGP in New Jersey involving the installation of sheeting, active de-watering, and the deep excavation of 20,717 tons of soil.  The former MGP encompassed a 0.2-acre property in a residential setting adjacent to an active rail line.  Impacted soil was delineated at the site and two adjoining properties during remedial investigation activities requiring the excavation of soil to depths ranging from 2.5 to 34.5 feet below ground surface (bgs) to provide for future unrestricted use.  Due to the small size of the work area, proximity to an active rail line and the presence of an active roadway that bisected the proposed excavation, the project posed several logistical challenges related to work zones, traffic controls, and the approach to sheeting installation in close proximity to residential dwellings.

Technical challenges included, but were not limited to, the excavation of soils to the top of a competent clay unit (approx. 34.5’ bgs) which required the depressurization of two highly permeable silt layers that exist within the top 20’ of the extensive clay unit.  Excavation was completed adjacent to the right-of-way of an active rail line at depths ranging from 2.5’ to 25.5’ bgs which required the earth-support design to comply with requirements set forth by the rail road.  Construction of an on-site groundwater treatment facility with the capability of addressing MGP related impacts prior to discharge was one of many physical challenges overcome during the project.

Design and implementation challenges and outcomes regarding remediation of contaminated soils will be presented in detail.  Post excavation, groundwater data is being evaluated as part of a proposed monitored natural attenuation remedy.

Low Permeability Barrier Wall for Control of Groundwater Contamination: Performance  Verification and Case Histories

David Smyth, B.Sc., M.Sc., Golder Associates, 2390 Argentia Road , Mississauga , ON L5N 5Z7 Tel:  905-567-4444, Email: David_Smyth@golder.com
Robbie Laird, B.Eng.(Mech), P.Eng., C3 Environmental Limited, 350 Woolwich Street South , Breslau , ON   N0B 1M0 , Tel:  519-648-2161, Email: Robbie.Laird@c3group.com
Robin Jowett, B.Sc. Waterloo Barrier Inc., PO Box 385 , Rockwood , ON   N0B 2K0 , Tel:  519-856-1352, Email: robin@waterloo-barrier.com

The control and remediation of contamination in the subsurface can benefit from the application of low permeability barrier systems. In combination with natural geologic features, barriers can be used to entomb zones of contamination in the subsurface, either for long-term isolation or to facilitate active in situ remediation. Barrier systems can also be used for partial isolation or to enhance groundwater control in the vicinity of subsurface contaminant sources.

Waterloo Barrier® (sealable-joint steel sheet piling) has provided excellent hydraulic and contaminant containment in subsurface applications over the past fifteen years where geological and geotechnical conditions are appropriate for sheet-piling use. Recent large-scale laboratory testing has generated hydraulic conductivity values of an individual sealed joint consistent with bulk hydraulic conductivity values (<10-8 cm/sec) determined for field-scale systems in the past. Site driving trials have confirmed that installation of the piles to depths of more than 30 m can be achieved using conventional equipment. In combination, the availability of sealants compatible with a wide range of contaminants, the documented low permeability characteristics of the sheet piling and sealed-joint system, and a demonstrated ability to install the system to depth, Waterloo Barrier® systems are suitable for contaminant control and isolation at many commercial, industrial and waste management sites.

A full enclosure Waterloo Barrier® was installed at a former MGP site to facilitate dewatering during excavation of coal-tar contaminated soils and prevent further lateral migration of contaminant into the adjacent waterway.  At a refinery, a riverbank Barrier wall was keyed to bedrock at depths of 3 to 12 m with a pressure-grouted contact. In addition to contaminant control, the Barrier also acts as a structural shoring system. At an abandoned chemical manufacturing plant where Brownfields redevelopment has occurred, a Waterloo Barrier® wall was installed to enhance contaminant control for an up-gradient pump and treat system.

Exploratory Well Site Reclamation and Restoration in Albania

Krish Ravishankar, Occidental Oil and Gas Corporation, 5 Greenway Plaza, Suite 110, Houston, TX 77046-0521, Tel: 713-366-5039, Email: krish_ravishankar@oxy.com  
K. K. Srinivasan and G. P. Floreslovo, Premier Environmental Services, Inc., 4800 Sugar Grove Blvd., Suite 420, Stafford, TX 77477, Tel: 713-256-0429, Email: ksrinivasan@premiercorp-usa.com

Currently, Albania 's infrastructure and regulatory guidelines or requirements for site reclamation and restoration, including waste management (storage, treatment, and disposal) are limited to non-existent. This paper describes Occidental Oil and Gas Corporation (OOGC)'s efforts, experience, and worldwide standard of care in site reclamation and restoration related to exploratory well development in Albania . Site reclamation and restoration consisted of: onsite stabilization of drilling mud, backfilling of the drill pits with stabilized mud, spreading and capping the stabilized mud, grading the site to original contour, and returning the site to the farmers for agriculture. OOGC's worldwide standard of care, consisting of a human health risk-based approach for waste management and protection of human health and environment, enabled the site reclamation and restoration activities.

OOGC's standard of care included early identification and screening-level evaluation of risks associated with the use of all materials and chemicals at the site, including drilling muds. Although technically and economically it would have been beneficial and preferable to use oil-based or potassium humate drilling muds, a conscious decision was made to use benign glycol-inhibited, water-based drilling muds for the protection of human health and environment. Further, the spent drilling muds were stabilized using lime to prevent mobilization of, and exposure to, their constituents. To ensure that disposal of the spent stabilized drilling muds does not pose any adverse human health risk or environmental exposure, prior to backfilling and spreading the mud, samples were collected, shipped under chain-of-custody, and analyzed in the United States for indicator chemical constituents following United States Environmental Protection Agency (USEPA)-approved methods. Residual toxicity of the muds was evaluated by reviewing drilling mud MSDS’ and U.S. toxicity databases. An exposure assessment of current and foreseeable future land use was also done.

Analytical results were compared to the Texas Risk Reduction Program's Tier 1 values for residential/agriculture land use scenarios to assure that the site reclamation and restoration activity was protective of human health and the environment.

Design vs. Reality: An Analysis of the Design and Performance of a Dual Phase Extraction System

Paul Uzgiris, P.E., Project Engineer, Weston & Sampson Engineers, Inc., 5 Centennial Drive Peabody, MA 01960, Tel: 978-532-1900, Email: uzgirisp@wseinc.com  
Frank Ricciardi, P.E., Project Manager, Weston & Sampson Engineers, Inc., 5 Centennial Drive Peabody, MA 01960, Tel: 978-532-1900

A high-vacuum dual phase extraction (DPE) system was designed to recover LNAPL at an active maintenance facility that has had historical releases of petroleum from underground storage tanks and measured LNAPL thicknesses of up to 2.5-feet atop the groundwater table.  The DPE system encompasses a strategy to maximize recovery of LNAPL through groundwater table depression and an applied wellhead vacuum. Extracted groundwater is processed through the treatment system to remove contaminants and a wellhead vacuum provides airflow through the subsurface and oxygen to indigenous bacteria resulting in aerobic in-situ degradation of the hydrocarbons in the soil capillary fringe.  The DPE system was constructed between February and October 2006 and has been running 24-hour-per-day since October 12, 2006. 

System construction involved the installation of thirteen extraction wells and a DPE treatment system housed in a prefabricated building. Components of the DPE treatment system include: an aboveground storage tank for recovered LNAPL; groundwater treatment components such as an oil/water separator, air stripper, particulate filters, inorganic sequestering, and carbon canisters; and vapor phase treatment components such as an air/water separator, vapor-phase carbon canisters, and a catalytic oxidation unit.

Due to inconsistent field conditions, unique subsurface stratigraphy, and unpredictable aquifer responses to engineering controls, the actual performance of the constructed DPE system inevitably varied from the original design parameters.  This presentation will compare design parameters (i.e. flow rates, expected removal efficiencies, etc.) to actual field conditions and contaminant recovery from data collected during the start-up and the first nine months of operation and maintenance of the constructed DPE system.  In addition, this presentation will detail unforeseen field conditions and challenges, and describe equipment optimization efforts to meet the design parameters, including: 

• Adjustments to vapor-phase treatment equipment to increase removal efficiencies

• Adjustments to transfer pumps and sequestering agent dosing rates to improve flow through liquid-phase carbon vessels 

• Groundwater and vapor-phase treatment efficiencies during initial start-up and after equipment optimization

• Mass balance calculations to determine contaminant removal via granulated carbon vessels and catalytic oxidizer unit

• Field measurements showing groundwater, LNAPL, and vapor capture zones

Treating Dyeing Wastewater by Nanofiltration

Dr. Eng. Darwish Ibrahim Yousef, President of Yousef Office for Science and Engineering,  P.O. Box: 11159- Aleppo- Syria, Tel: 00963 254491, Email: darwishmail@hotmail.com  
Eng. Robin Ibrahim Yousef, Technical manager of Yousef Office for Science and Engineering, P.O. Box: 11159- Aleppo- Syria, Tel: 00963 254491, Email: robinyousef@hotmail.com

The treatment of textile effluents is of interest due to two concerns. At first, the textile industry, from its beginnings, has been hampered by the large volumes of water required for the preparation and dyeing of cloth. More recently, water consumption and waste generation have become considerable concerns for textile manufacturers and finishers. At second hand, the textile effluents are of interest characterized by their toxic and esthetic impacts on receiving waters. Textile industry wastewater is characterized primarily by measurements of BOD, COD, color, heavy metals, and total dissolved and suspended solids.  

While much research has been preformed to develop effective treatment technologies for wastewaters containing dyes, no single solution has been satisfactory for remediating the broad diversity of textile wastes. Many technologies, such biological treatment, chemical precipitation, carbon adsorption, have been studied to treat textile wastewaters. However, their application in an industrial plant becomes difficult due to the operation problems, efficiency, and to the costs.

The applications of membrane technologies in textile industries are not yet very common. Until now the reported applications are focused on the recovery of sizing agents from the desizing effluents and on the recovery of the indigo from the dyeing effluents.

Starting in the late sixties, membrane processes gradually have found their way into industrial applications and serve as viable alternatives for more traditional processes. Recapping the technology advancement of the 20th century, with respect to the treatment of fluids with membranes, one can see a significant shift from the traditional aspects of membrane treatment, to a more technologically refined process, where one can maximize ones resources and achieve higher quality and performance, all at less cost then what could have been previously achieved.

Nanofiltration (NF) is characterized by a membrane pore size between 0.5 and 2 nm and operating pressures between 5 and 40 bar. NF is used to achieve a separation between sugars, other organic molecules and multivalent salts on one hand and monovalent salts and water on the other. It is presented as an effective, selective, economical, and clean alternative for dealing with dyeing wastewaters.

Kinetic Study of Nitrate Reduction with Nanoparticle Bimetallic Fe-Ni

Kuang-Chung Yu, Department of Environmental Engineering and Science, Chia-Nan University of Pharmacy and Science, Tainan 717, Taiwan, Telephone: (886) 6-2660254, Fax: (886) 6-3662668, Email: kuchuyu@ksts.seed.net.tw  
Li-Jyur Tsai, Department of Environmental Engineering and Science, Chia-Nan University of Pharmacy and Science, Tainan 717, Taiwan, Telephone: (886) 6-2660254, Fax: (886) 6-3662668, Email:  lijyur@ms22.hinet.net
Shien-Tsong Ho, Department of Industrial Safety and Hygiene, Chia-Nan University of Pharmacy and Science, Tainan 717, Taiwan, Telephone: (886) 6-2660254, Fax: (886) 6-3662668, Email: hohc@ms28.hinet.net

Bimetallic iron-nickel nanoparticles with high surface area were prepared with two different procedures. One is synchronous chemical synthesis method, the other is mixture of Fe and Ni nanoparticles with different weight ratios. The BET surface area of Fe/ Ni(1:1) nanoparticles is 49.31 m2 /g. They were used as a reagent to evaluate the nitrate reduction efficiency in aqueous solution. The aim of this study is to realize the nitrates reduction efficiency and reaction kinetics treated with Fe/Ni nanoparticles in aqueous solution. Several factors, including pH, Fe/Ni weight ratio, nitrate concentration were discussed with batch experiment and the observed rate constants (Kobs) and half-life for nitrate reduction was calculated. Results show that the removal efficiencies of nitrate are all significant at the low pH (2 and 3) no matter what addition of Fe, Ni or Fe/ Ni ratio of nanoparticles. The reduction efficiency of 50 mg/L nitrate which was mixed with 2 g /L nanoparticles excellently fitted pseudo-first-order reaction model with coefficient of determination (r2) among 0.91~0.99. The values of observed rate constants (Kobs) were 0.1748 for (Fe/ Ni(5:1)), 0.0686 for (Fe/ Ni(1:5)), 0.0227 for Ni nanoparticle, and  0.0159 min-1 for Fe nanoparticle at pH 2 for 50 mg/L nitrate. The half-life for nitrate reduction was 4, 10, 31, and 44 minutes for Fe/ Ni(5:1), Fe/ Ni(1:5), Ni, and Fe, respectively. The value of Kobs decreased and the half-life increased with the increase of pH from 2 to 3. The higher Fe/ Ni ratio (9:1) had higher Kobs value (0.1185 min-1) than the Kobs value (0.0105 min-1) of Fe/ Ni ratio (1:9) at uncontrolled pH. The removal efficiency of nitrate by addition of bimetallic Fe/ Ni was better than only Fe or Ni nanoparticles. Meanwhile, the higher Fe weight percentage in Fe/Ni nanoparticle can improve the better reduction efficiency of nitrate. The influences of bimetallic Fe/ Ni on nitrate reduction with different manufacture methods also discussed. The different weight ratio of bimetallic Fe/ Ni nanoparticles synthesized from Fe and Ni ion solution have larger nitrate reduction efficiency than mixture of Fe and Ni nanoparticles power synthesized separately. The synchronous synthesis of bimetallic Fe/ Ni(5:1) nanoparticles could have 0.0379 min-1 of Kobs. However, the mixture (5:1) of Fe and Ni nanoparticles, which have synthesized before only had 0.0131 min-1 of Kobs. The higher ratio of Fe/ Ni nanoparticles will make better reduction efficiency of nitrate.  

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