Over the past few decades, wastewater has been changing, and continuing environmental concerns and a growing world population make many more aware of their personal water use. In an attempt to decrease water usage, people worldwide are installing low-flow faucets, toilets, shower heads and other fixtures. While this helps to decrease the amount of water used, the amount of solids that goes down drains does not change. Industrial companies have also been under the same pressure to decrease their water usage. It is almost impossible to talk with an industrial water user today who does not have a company-wide goal to decrease water usage year over year, while increasing production of their products. Using less water while producing more (without decreasing solids) means the solids concentration in wastewater has been increasing for at least the past 20 years, if not longer. As the solids concentration in wastewater increases, the standard semi-open, open and enclosed nonclog-style pumps used in the past are beginning to clog more frequently. Depending on the severity of the service, the nonclog-style pump impellers may experience anywhere from a partial clog to a complete blockage, which prevents any water from passing through. When solids concentrations increase in wastewater, alternative pump types beyond the typical nonclog pump should be considered. When the alternative pump type is selected correctly, clogging problems can be greatly reduced or even eliminated.
How a single-vane screw pump avoids typical pain points.
Weir Specialty Pumps
10/03/2018
Image 1. Caught rag moving through screw centrifugal impeller (Images courtesy of Weir)
Image 2. Spiral groove machined into the liner
Image 3. Impeller tip cover