Rock Products

MAR 2017

Rock Products is the aggregates industry's leading source for market analysis and technology solutions, delivering critical content focusing on aggregates-processing equipment; operational efficiencies; management best practices; comprehensive market

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56 • ROCK products • March 2017 provide a single-source flocculant that is far more cost-effec- tive in treating at the top of the tank for clear water overflow, while also treating at the bottom to allow the sludge to dewa- ter more quickly," said Lamb. Key Features One of the key features of the new system, said Yerington, is the tri-arm variable-speed rake that aids in thickening and maintains the consistency of the mud. A pressure-sensitive gauge on the rake monitors the mud level. As that mud level reaches a designated point, a pinch valve is activated to discharge the material. Yerington goes on to explain that a meter on the pinch valve reads the width of the valve opening, allowing the automated flocculant system to properly dose the solids again as the material enters the discharge pipe. "Maintaining the proper mud level is so important," Yer- ington said. "The compaction of the mud squeezes out the water but if the mud level is too high, the solids will not settle out and the clean water does not go over the weirs." The operation is washing four different benches in the quarry. "Each bench offers a differing recipe – so we refine the flocculants that go in and we refine the speed of the rake, he said. "We might also have to adjust the mud level to get our desired results. Now that we get consistent results, the fine tuning really makes a difference," said Yerington. Yerington created a spreadsheet that notes the material feed per bench, thus dictating the required operational settings of the clarification system per bench. "This allows me to prop- erly monitor the results, making needed adjustments as we go along. We want to pinpoint the consistency even more closely," he said. Lamb explained that Clearwater is more than an equipment and polymer supplier. "We are a business resource with the ability to analyze dirty wash water. We do a particle size distribution test and a percent of solids test to determine the most cost-effective solution for the plant. These tests will tell producers how many tons of fine sand can be recovered as a dry stackable material, and how many tons of fine silt and clay will be treated with flocculant," he said. It's said that "strategic thinking is the what and why, while tactical thinking is the how." In creating this custom-engi- neered system, Wendling Quarries and Clearwater Industries clearly identified the what, why and how of cost-effective wash water clarification. Carol Wasson is a Forth Wayne, Ind.-based freelancer. SUSPENDED SOLIDS The clarification system has dramatically increased the percentage of solids in the discharge. The thickened mud, at an estimated 68 percent solids, is transferred to a containment area where it dries in less than a week.

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