Amendment No 1 to OEA - Design Srvs. Edison WTP Proj No. 123-067 – United Consulting

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AMENDMENT TO OWNER -ENGINEER AGREEMENT NO. 1— ATTACHMENT NO.2 WesTech Gravity Filter Media Analysis Overview The below information was shared with Owner and United Consulting on December 1, 2023. Pricing and information provided below are subject to change. Owner will be alerted of any changes to the below details as soon as they become known to Engineer, if any. FILTER MEDIA CORE SAMPLING PROCEDURE The filter media must be thoroughly backwashed prior to collecting any sample. After backwashing the media, drain the filter completely. Remove the manway cover if required. It is a good idea to have a new manway gasket on hand. Using a sanitized 11/4" to 11/2" diameter by 4' to 6' long (depending on the bed depth and amount of freeboard) piece of thin wall tubing, insert the tube approximately six inches into the media with a twisting motion. Empty the media into a clean bucket by tapping the side of the tube. Repeat this procedure, being sure to sample the same hole, at six-inch increments until the entire media bed has been sampled and the gravel or gravel retaining screen, if such has been installed in the unit, has been intersected. The composited sample should then be thoroughly mixed to obtain a representative sample and no less than one quart of the material forwarded to us for laboratory evaluation. If one core sample does not yield a full quart, a second core sample should be obtained and mixed together with the first so that a full quart is available for analysis. CAUTION: Be sure to sample only the filtering media. DO NOT force the sample tube into the sub -fill or the underdrain. Mud balls or foreign material on or in the media should be included in the core sample. A separate sample of any foreign material or mud balls should be sent along with the core samples. Note the depth of the filter media (by inserting a ruler into the sample hole) and the general condition of the bed surface. Note observations such as the media level, media mounding, and fissures (channels) on the media surface. Include with sample: • Person, Company, Address, Phone Number • Type of Media sample (Greensand, Anthracite, etc.) • Date sampled • Reason for sample (low capacity, poor quality, etc.) • Purchase Order Number