ARCHIVED REPORTS_2011-2018 - Laserfiche WebLink

Home Browse Search

CORRECTIvt ACTIONS AFTER SOURCE INVESTIGATION: 1 Upon correcting the identified physical deficiencies, disinfect the water in the well casing using NSF 61 approved chlorine and AWWA procedures. Apply chlorine at 50 ppm concentrations into the well. Circulate the chlorinated water within the well, up through the pump column, into the pressure tank and back down into the well by turning on the well and opening a valve/hose bib at the pressure tank. Connect a hose to a hose bib at the pressure tank that terminates with a small diameter wand able to spray a circular spray pattern to wet the sides of the well casing and pump column above the water table, when the wand is inserted into the wellhead seal access port. Circulate the chlorinated water down the sides of the well casing for 30 minutes, as noted above. Test the chlorine residual through this process to ensure 50 ppm chlorine residual. Dose well as needed to maintain 50 ppm chlorine residual. After 30 minutes, turn off the well, close the valve/hose bib at the pressure tank, disconnect the hose, and seal the wellhead at access port to be water tight. Allow 12-24 hours for the 50 ppm chlorinated water to reside in the well. A successful disinfection requires a residual of at least 10 ppm to be present after the 18-24 hours. If the chlorine residual is found to be non-detectable, then the disinfection process may not have been successful. Repeat the disinfection process. If residual is at least 10 ppm, flush the well water to waste and resample the well for non-detect chlorine residuals. Contact your laboratory to collect a wellhead sample to test for chlorine residuals and TC bacteria, using enumeration test methods Once SOURCE is absent proceed with disinfecting DISTRIBUTION SYSTEM as noted below. Contact the EHD if you need guidance with this procedure. If Well Continues to Fails: Investigate the well casing using a camera and record the findings to determine the condition of the casing, movement of groundwater in and out of the well column, presence of oil from a turbine pump, tree roots, other contributing deficiencies that may cause the well to test positive for TC. Submit a copy of the well down-hole investigation recording to the EHD and contact the EHD for guidance at(209)468-3420. INVESTIGATION of a TCR MCL if the SOURCE is absent and the DISTRIBUTION SYSTEM is Positive for TC: Have your laboratory collect additional "Other" TC Bacteriological samples to determine if the pressure tank, storage tank, and/or treatment system is a TC source. Collect a sample down stream of these components to determine if the bacteriological problem begins at these components. If the initial "Other" result is absent for TC, then go to DISTRIBUTION SYSTEM & investigate the distribution lines down stream of these components. If the "Other' result is positive, then sample down stream of each component to further ID where the system begins to fail for TC. Perform an inspection as detailed below in the Treatment,Stora e,and Pressure Tank sections. TREATMENT USING CHLORINE FEED SYSTEM?Y/N If IN,then go to next section Plant ID Plant ID Plant ID COMMENTS Inspect each point where disinfectant is added and report, any leaks? Y Is the disinfectant feed tank full with chlorine &what is the ppm concentration? Are there contaminants in the chlorine feed tank?YC What is the disinfectant residual down stream of injection point? What is the disinfectant residual at the end points of the system or repeat sites? A drop in chlorine indicates the Repeat 1/ ,Repeat 2/ , Repeat 3/ End pt 1/ End location of the problem. Find where pt.2/ the initial decrease begins,down Is the disinfectant feed tank and equipment stored in a protected manner(i.e. Is tank stored out of the stream of the injection point. sun, protected from rain,lid is sealed on tank&lid sealed at tubes,no openings to tank, irrigation House equipment in an enclosure to water is not sprinkling over the equipment,birds/vermin are not nesting overhead)? Y/N exclude vermin and elements. Is the tank's water fill line protected by a back flow device or proper air gap? YIN Install a proper back flow device on TREATMENT USING MEDIA? WW If N,then go to next section. vessel ID vessel ID vessel ID fresh water fill line. Is a Treatment Vessel positive for Bacteria? If N,then go to next section COMMENTS What is the MPN concentration of bacteria in each vessel? What is the media in each vessel? Is a vessel not in use, is it valved off? Y/N Inspect each treatment vessel for leaks at joints,valves,connections at top and bottom of the vessels, man-was not closed. Note if a leak was found and where at each vessel. Was the media recently exchanged in a vessel or repair made to a vessel? Y/N Thiswwr may have caused TCR MCL. i