ARCHIVED REPORTS XR0001046 - Laserfiche WebLink

Home Browse Search

r4eologlul reelm"W Page 9 In Situ Remediation Pilot Test Work Plan Project No 507 2 June 10, 2003 The screened intervals of the wells are designed to intercept the infected chemicals from the ' ,screened interval of monitoring well MW-9 noted above [screened 15 — 35 feet below grade surface (bgs)] ' 3.4 Infection Process Well MW-9 will be infected with a dilute hydrogen peroxide solution The actual peroxide ' concentration utilized will be determined after GTI and APT staff review the pre-test chemical data described above The infection equipment will consist of fluid tanks, a ' compressor, pressure hoses and miscellaneous cap fittings After the peroxide is introduced it will be forced into the forination with pressurized air The injections will be made in "pulse" mode After the casing is filled with the infection ' solution, pressure is applied to help force the solution out into the formation The infection process will be temporarily halted to allow the material to percolate into the formation ' When the MW-9 casing fluid returns to static level (as monitored by pressure drop), the infection will continue Due to the tight nature of the soils this may be a time consuming process The actual volume added to MW-9 may vary based on effective porosity of the soil, soil moisture and depth to groundwater If subsequent monitoring warrants, then additional infections of hydrogen peroxide will take ' place The injections are expected to take place bi-monthly based on existing site conditions The injections may be augmented with nutrients (nitrates/phosphates) to stimulate bio-degradation, and may also include chasing the hydrogen peroxide with oxygen or ozone to provide additional oxygen for bio-degradation and more hydroxyl radicals, respectively The decisions to use these chemicals and modifications to the bi- monthly injection schedule will be made in conjunction with APT staff during the ' effectiveness testing process outlined below ' 4.0 EFFECTIVENESS TESTING Groundwater samples will be obtained from the monitoring wells GP-1 through GP-3 on a regular schedule to determine the effectiveness of the infection process The first monitoring event will take place one week after the initial peroxide infection Subsequent ' monitoring will take place on a bi-weekly basis Dissolved oxygen (DO) and oxidation- reduction potential (ORP) will be measured in the three observation wells plus MW-9 and the data used as an indication that the chemical reactions are spreading beyond the point of ' infection This is not expected to be a rapid process as silty/clayey soils are predominant at the site and the low permeability of these soils will result in slow chemical diffusion Once the chemical reactions are confirmed to be taking place, the amounts, frequency and composition of the infections can be altered to maximize process efficiency