Laserfiche WebLink
The calculations detailed in Appendix 4 indicate a recovery <br /> rate of 3.6 to 15 gpm is necessary to recover dissolved <br /> hydrocarbons which have moved approximately 70 feet <br /> downgradient. The proposed hydraulic control plan will <br /> utilize a pump in well MW1 initially operating at B-10 <br /> gallons per minute. This rate may be adjusted based on field <br /> observations. Using well MW1 will allow the greatest <br /> recovery from the area of highest documented contamination <br /> and also this well is the only well capable of accommodating <br /> a 4 inch pump. <br /> A .5 HP stainless steel, explosion proof, submersible pump <br /> will be installed in well MW1 for recovery. The pump will be <br /> capable of producing from 5 to 15 gpm and will be throttled <br /> as necessary. All power supply and discharge lines will be <br /> run underground in separate conduit. The discharge will be <br /> conveyed from the recovery well to the treatment compound <br /> " (Figure 2) by two inch PVC pipe. The discharge line will be <br /> valved and check valves installed as shown on the figure. At <br /> the time the underground conduits are installed well MW6 <br /> - will be plumbed for possible future use as a recovery well. <br /> If warranted, a two inch stainless steel submersible pump <br /> can be operated in this well to supplement or replace the <br /> primary well (MWI). Decisions regarding the pumping rate of <br /> MW1 and the need for a second recovery well will be made <br /> after reviewing long term (at least 3 months) operational <br /> data from well MW1. <br /> 5.2 Water Treatment and disposal <br /> The water pumped from the recovery well(s) will be conveyed <br /> to the treatment compound where dissolved hydrocarbons will <br /> be removed by activated carbon filtration. The carbon <br /> filtration units will be located within a fenced enclosure <br /> and will consist of .four 200 lb. carbon canisters in two <br /> _ parallel paths as shown on Figure 2. The carbon filtration <br /> units will be fitted with sampling ports for monitoring. <br /> A distribution box will be located downstream of the carbon <br /> filters. This box will serve as a chamber for reaerating the <br /> treated water before discharging to an infiltration gallery. <br /> The gallery will be located as shown an Figure 2 at a depth <br /> - of approximately 6 feet below grade. Discharge to the <br /> gallery will be permitted through the Regional Water Quality <br /> Control Hoard. <br /> 5.3 Monitoring <br /> Monitoring of the remediation program will consist of <br /> sampling to comply with waste discharge and quarterly <br /> -- ----- ---- - --groundwater__monitoring__-_requirements,_ and the tracking of <br /> system performance parameters including aquifer response, <br /> pumping rates, dissolved oxygen levels, and line pressures. <br /> �- 5 <br />