WORK PLANS - Laserfiche WebLink

Home Browse Search

APR-22-1997 16:53 FROM GEOLOGICAL TECHNICS. TO 4640130 P.03 Pap 2 gwQSkAdTEd5zks Inc. Moresco(Gawne ltd.) Addm&m to 4W9-1 work Plan Pivjeet No.251.3 April 2l,1997 2.0 Design of Extraction and Passive Rmh!Rr Wells � Past expenMe has shown that screen lengths of 20 feet max=zes exUaWon efficiency in this type of sediment. The distances between extraction and recharge points of 20 to 30 feet ace effective for this site because that is the area that has the elevated.concent-3tions of gasoline. 3.0 Radial Influence Testing As documented in the work plan.of April 8, I997 a radial influence test will be conduvwd once the subsurface has equilibrated and the vapor extraction system is running at peak performance. owe the.optimum setup of the air recharge wells is determined the system will be run in this configuration with configuration adjustments made periodically to help prevent.channeling from developing. 4.0 Mouitormg Equipment Unless otheMse noted all monitoring equipment will be portable in order to reduce duplicate equiprnwt phases and the possibility of vandalism or theft. Flaw Meters- TO manure airspeed, and hence calculate extraction volumes, a Soiomat WM- 500e with a pitot tube will be used, Air speed measurements will be taken through a port in a six foot straight length of FVC piping between the exhwfian well and the T.O. unit. Early in the system startup it well be necessary to draw atmospheric air through a bypass valve_ Apart will be set in a six foot section of straight PVC pipe to allow for measurement of airspeed going through the bypass. Direct measurement of airspeed in the exhaust stack isnot possible due to high temperatures but if influent;volumes,both extraction and bypass, are known then influent is also known as influent M effluent. This has proven acceptable to the SNUAPCD. VacuumGaines-In order to determine vwuiun influence at the recharge wells either iviWwhelic gauges or the MPM-500e will be used. These will be attached W the recharge wells by hose barbs fitted to slip--on PVC caps. A permanent Vacuum gauge is ,attached to the TO unit upstream of the blower which shows vacuum in inches of mercury Wag pulled by the system. IgMgeratut;e_Sensors- Temperature is measured in the combustion chamber and displayed by a Honeywell UDC 2000 Mini-Pro. The Mini-Pro also has a temperature limit feature on it. If combustion temperature drops below 1450°F or goes above 1650°F .it shuts the system down automatically. A Rustrak Model Z-55 chart recorder provides a continuous record of combustion tempmVure, The Mini-Pro and Rustrak are both permanent pieces of equipment. To measure influent air temperatures the WM-500e will be used with a thermocouple. Temperature measurements will be taken through the.same port that is used for air d measurements. • Sampling Ports-One sampft port will be a hose barb set into the PITC piping between the Extraction Welland the TO unit. A second sampling port will be a bose barb that.is set into the"pipiurg downsM= of the bypass valve. We have found tins location to give more reliable samples. Due to high temperatures of the effluent stream we use a five foot length of capper tubing to pull. the etfluerit samples through. This method is approved by the .SJVUAPCD.