Laserfiche WebLink
.r <br /> Mr.John Lane June 2,2006 <br /> Ground Zero Analysis,Inc <br /> The main difference between the ISOTEC process and the oxidation process using <br /> permanganate or persulfate is timeframe. Neutral pH modified Fenton's desorbs mass <br /> from the adsorbed phase into the dissolved phase, dissolves NAPL and oxidizes this mass <br /> in the dissolved phase, all in a matter of hours. fid, & <br /> Permanganate and persulfate oxidize the dissolved phase mass very quickly but the <br /> adsorbed and NAPL masses move into the dissolved phase due to the increased <br /> concentration gradient at a very slow rate where that mass is oxidized over a period of <br /> months. While the oxidant is present in the subsurface over a period of months it is also <br /> slowly oxidizing naturally occurring organic matter. <br /> With the above background in mind I will address Mr. Barton's specific work plan <br /> comments. - C/..Mf •r.Jr &Lw-t 4ss---Oµ� -e be Er✓e <br /> Comment A: Testing of the methodology to show effectiveness (technical and cost) of the <br /> remedial ion. <br /> The bench study should evaluate the technical effectiveness of the ISOTEC modified <br /> Fenton's process to treat the contamination present. I will leave the cost discussion to <br /> you. <br /> Comment B: Provide design criteria data for later phases of the remediation (i.e., pilot <br /> studies for ISCO injection — soil oxidant demand, injection point and monitoring wells <br /> spacing, etc.) <br /> The bench study will provide a qualit4ye starting point for the reagent design (volume <br /> and concentration). However, the subsurface ultimately governs volume injected per <br /> event. ISOTEC's rule of thumb for volume is between 3% and 8% of the pore volume <br /> that we are trying to treat. Trying to inject more than 8% of a pore volume creates high <br /> injection pressures and increases the likelihood that reagent will find a pathway to <br /> surface. The injection location design is based on lithology, contaminant mass and <br /> distribution. These design criteria are based on past experience at similar sites and are <br /> generally provided in the pilot test or full-scale work plan. The work plan is generally <br /> written with flexible guidelines to allow for volume and spacing modifications based on <br /> field observations. <br /> Soil oxidant demand (SOD) is mass of oxidant consumed per mass of soil over time. The <br /> test is conducted by adding a known mass of oxidant to a known quantity of soil and 1 <br /> measuring the amount of oxidant left after several days. SOD is not applicable for <br /> Fenton's reagent because the catalyst reacts with the peroxide and consumes it rapidly. <br /> Because of this when the vessel is sampled after a given period time all of the peroxide is <br /> gone, no matter how much was added. However, the bench study will measure the total °'' <br /> organic carbon (TOC) content of the site soil. Even TOC is not that helpful with the <br /> design because the oxidation reactions are so quick in the subsurface that natural organicsc c s� <br /> present in the soil (solids)do not have time to be oxidized with the ISOTEC process. The <br /> "TOC value will let us know that we do not have an unusual organic content (i.e., peat) <br /> that would hinder the peroxide injection. Permanganate on the other hand, requires an <br /> SOD measurement (using permanganate as the oxidant) in order to design an effective <br /> 6452 FIG STREET,SurrE C,ARVADA,COLORADO 80004 <br /> PHONE: 303-843-9079 FAX: 303-843-9094 <br />