WORK PLANS FILE 2 - Laserfiche WebLink

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110 Second Avenue South,4D7,Pacheco,CA 94553 McCAMPBELL ANALYTICAL INC. Telephone:510-798-1620 Fax:510-798-1622 http://www.mccampbell.com E-mail:main@mccampbell.com EXPERIMENTAL DETAILS The experiment started on April 06 at 8 p.m. with 10 glass vessels each 1 L in size. A diagram is enclosed. Five vessels contained the sample, MS, MB, LCS, LCSD and the remaining 5 vessels contained 500ml DI for flow control purpose. The sample & MS vessels each contained 500g of soil and 500m1 of aquifer water that were gently shaken for 30 minutes prior to purging. The MS was treated like the sample except that it was spiked with 100mg of K2Cr�O7 which is equal 71 ppm of Cr 16 The MB is just 500m1 DI. LCS/LCSD contains 500ml DI and spiked with 100mg of K2Cr2O7 which is equal 71 ppm of Cr+6 Oxygen flow was initially set at 10 psi at the main regulator. Oxygen gas flowed to the ozone generator whose channel A and channel B were both set at 5 psi. The ozone flow from the ozone generator was directed to a glass splitter via Teflon tubing and then split into each vessel. The ozone gas exited from each vessel into an ozone scrubber that catalytically (no reactive chemicals) decomposed the 03. Purging continued for 5 days. All tubing& connections were Teflon or glass from the ozone generator to this point.The purge flow was monitored at the end of the scrubb tlet& tubing was restricted here to control the flow. See the following table for Ozone generating parameters. s reaction time progressed oxygen feed pressure nearly doubled but flows dropped two fold or more indicating that the system became "more restricted". This is easy to understand for the vessels that contained soil, but there is no definite explanation for those that contained only water. It is possible that condensed water in the ozone scrubbers is responsible. Comparison of this data with the ozone determinations shows that dissolved ozone concentration actually increases with lower flow rates, perhaps indicating that "self-purging" is significant. Dissolved ozone concentrations ranged from 0.029-0.066 mg/L&are tabulated in the results section. "Medial" sampling (during the 5 days of ozonation) was accomplished via a sipper tube that was immersed below the upper level of the aqueous phase&was accessed by disconnecting the reaction vessel outlet tubing& withdrawing 20- 30 ml of sample via a luer tipped syringe. Ozone flow was stopped during sampling. Generally 20ml of water was removed each time resulting in a 60/500 or 12%decrease in fluid volume. This factor has not been taken into account in the analytical data. Experimental Measurements of Oxygen Head Pressure&Ozone Flow Head Ozone Flow Measured at Scrubber Outlet(ml/min) Time of Measurement Pressure (psi) Sample MS MB LCS LCSD Initial: 8 pm,4/6/05 10 60 60 56 54 58 Day 1: 5 pm,4/7/5 13 43 48 58 56 59 Day 2: 5 pm,4/8/5 15 42 45 50 48 50 Day 5: 6 pm,4/11/5 18 13 13 24 26 26 At the end of Day 5 ozonation the ozone flow was permanently stopped & Final Water & Final soil samples were withdrawn. The Final soil was found contain 1 /0.8 = 125%more water than the Initial soil. This correction factor was `. significant for TTLC trace metals & this correction factor was applied to TTLC Final soil metals values i�s noted on their results page. A significant volume of water was removed for the Final water tests & —200ml DI was added to the sample for decay studies. Ozone & hexachrome were measured for another 8 days. Approximately 20-30m1 sample aliquots were withdrawn between 3-5 pm on each day from 04/12 —04/19. A syringe aliquot was withdrawn in the same way as for the medial samples except that the MB,LCS&LCSD were sub-sampled by pouring rather than by syringe withdrawal.