Sludge Judge

Watch as a "sludge judge" pole is put into a 14-foot deep primary clarifier at the wastewater treatment plant, to measure the depth of solids in the tank. A thicker sludge layer, or blanket, means that there is less water (more solids) going into the digesters for the MWMC's biosolids program. This means there is less pumping of water required, and during the dewatering process, there is less polymer used. Too thick of a blanket means that solids may pass through the primary clarifier and would have to be processed in the much more expensive secondary treatment system. A range of 12 to 24 inches for the primary sludge blanket thickness is usually the proper level to achieve a desired 5% solids ratio.