The wastewater treatment facility for the city of Starke, Fla., was experiencing a loss of detention volume and reduced water quality as a result of accumulated sand and grit on the bottom of its grit chamber.
The roughly 40-foot square grit chamber had an estimated 4 feet of sand submerged under less than 2 feet of water. Further, the accumulated sand and grit had reduced the efficiency of the grit chamber and was potentially exposing other elements in the treatment system to a buildup of sediments and particulates.
Solution
The facility was the site of one of Polston Applied Technologies' early demonstrations to remove the sand and grit. Using its PAT 949 Combination Truck with its 425-hp driven components and the proprietary Polston Process®, the crew used an 8-inch-diameter hose to pull sand, grit and water from the chamber and through the Polston system at a rate of 2,500 gallons per minute.
Sand and grit were immediately separated from the water, and the excess water was returned to the wastewater system. The entire cleaning process was accomplished without taking the system offline. (Previously, in order to clean the grit chamber, the system had to be shut down entirely, and the grit was removed by using only a vacuum and a few workers with shovels.)
Polston developed the PAT 949 truck and the Polston Process to address a pervasive problem in the wastewater industry: the absence of a system powerful and versatile enough to remove the accumulated sand, grit and rag material that are exposing wastewater collection and treatment systems to rising operating costs and decreased efficiencies.
In addition to removing this material from collection and pipe systems, the vehicle can clean stormwater and wastewater pipes up to 84 inches in diameter at invert elevations of up to 150 feet below the surface. For treatment systems, this equipment can effectively remove material from the headworks (lift stations, grit chambers and wet wells) and treatment basins (aeration basins, digesters and clarifiers).
The PAT 949 truck is equipped with a submersible "down hole" pump with a unique, patent-pending jetting system that is hydrostatically driven, with the capability to push material from depths of 150 feet without modification. The truck also features a hydraulic knuckle-boom crane, with up to 49 feet of reach from the center and 180-degree rotation to access even hard-to-reach places with ease.
Results
In the cleaning operation at Starke's wastewater treatment plant, Polston removed 90 percent of the sand (approximately 2 cubic yards) from the grit chamber and into their debris tank in less than three hours. Water quality and system efficiency were also restored. The client was very pleased with the results.
For more information on Polston Applied Technologies and the PAT 949 Combination Truck, visit www.polstonprocess.com.
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