WA ST Dept of Ecology Biosolids 9/8/2022

6 of 11 ix. The brightly colored line above the purple contour indicates the top of the sludge blanket. The depth from the bottom of the transducer to the top of the sludge blanket is displayed in the top left corner of the screen. When the value is flashing, the transducer is unable to locate the top of the sludge blanket, and is flashing the last known value. Drive to a new location, clean the transducer, and/or p ower cycle the Garmin to troubleshoot. i. Maneuver the boat around the pre-determined sample site, observing the contour and thickness of the sludge on the Garmin Chartplotter. Locate a site within the discrete sample section that appears to be of average depth and thickness for that area in order to obtain a sample that is as representative as possible of the biosolids blanket. j. Bring the vessel to a stop. k. With both ball valves in the open position, slowly lower the sludge judge to the bottom of the pond. Take a core sample through the solids to the bottom of the pond, taking care not to jam the sludge sampler into the clay pond-liner. l. Close the top ball valve with the sludge sampler gently resting on the pond bottom. m. With assistance from the boat captain, begin to withdraw the sludge sampler from the lagoon. When the lower ball valve is accessible, close the lower ball valve, then open the top ball valve. Note: If any indication of clay is present, i.e. a portion of th e material is tan/grey in color, discard the sample and re-sample. With the tip of the sludge sampler in a pre-labelled HDPE sample container, slowly open the lower ball valve. Allow the sludge to transfer into the sample container. Remove the tip of the core-sampler from the sample container as the supernatant reaches the bottom of the sampler . n. Eject any supernatant back into the pond. Avoid including any supernatant in the sample container. o. It is possible that the core sample may not completely fill the sample container. DO NOT mix multiple core samples in a single sample container, as multiple cores are a composite sample, and the biosolids sampling operator collects grab samples only. If the biosolids sampling operator determines that the sample withdrawn does not appear to be representative of the solids in that area, it is acceptable to eject the core sample back into the process, move the sampling vessel to another location that appears to be representative of the depth and thickness of the discrete sampling area and attempt a core sample at that location instead. p. Repeat steps h-m for the remaining sample sites allotted for the day’s collection. q. Return the vessel to storage or docking station.