In February 2020, Glasgow contacted Clearwater with interest in removing fines from their process water without a settling pond.
“We looked at belt presses, and I had visited a few sites with them, but they require a lot of maintenance and attention. Plus, they’re very expensive,” said Jeff.
“I came across Clearwater online and happened to see the High Compaction Clarifying Thickener, and it seemed interesting,” added Jeff. “I made a phone call and connected with Joe, who started working with me to determine feasibility.”
Clearwater’s Senior Application Engineer, Joe Lamb, worked with Glasgow to understand their problem and site layout. “The Glasgow project presented several interesting application challenges,” says Joe. “The primary wash plant lies well below and far from the clarifier location. They have clay veins in the quarry and three wash plants that operate together and independently throughout the day, which changes the flowrate, solids concentration, and solids consistency.”
Clearwater collected process water samples to understand the fines’ solids loading and size gradations. Jar testing determined the proper coagulant and polymer flocculant chemistry to expedite the settling velocity of the solids. Finally, settling velocity tests verified the settling and compaction rates and underflow densities for a clarifier.
This information coupled with a flowrate of 1,800 GPM allowed Clearwater to design a process water treatment system that allowed Glasgow to remove their settling pond. The clarifier system included a sump, slurry pumps, CW1400HC clarifier, LQ50 coagulant system, M800SS dry polymer system, AutoFloc Dosing System, dry polymer dilution water filtering system, and two mud cells with a sump.
However, Glasgow’s site setup created two challenges. First, the primary wash plant lies 90 ft below and 1,150 ft from the clarifier location, creating 125 TDH. A massive clean water distribution and slurry collection system required Clearwater’s design to meet this historical constraint. Second, they wanted to use the clarified water as dilution water for their dry polymer preparation because well water was not available and city water was too costly.
To meet the demands of the site setup, Clearwater designed a 2,250-gallon sump with two 75 HP slurry pumps in series to reach the clarifier. The tank level is automated via an ultrasonic level transducer, and onsite tuning yielded a signal that automates both pumps.
To use the clarified water as dilution water for the M800SS Dry Polymer Make-Down System, Clearwater installed two bag filters and one 30-micron cartridge filter. The filters guarantee clean dilution water to prepare an efficient and uniform polymer solution.
The sump and slurry pumps feed continuous dirty water to the CW1400HC Clarifying Thickener. The CW1400HC employs automated sensor technology to control continuous sludge level monitoring and evacuation.
The LQ50 prepares and doses a coagulant into the clarifier’s slurry influent line. And the M800SS prepares a dry polymer into a liquid flocculant solution and doses in the clarifier center well.