Gorman-Rupp pumps, including the advanced Super T-Series and V-Series models, offer superior performance in evacuating grit chambers quickly, reliably, and efficiently. Gorman-Rupp pumps are made from durable ductile iron and other abrasion-resistant materials. This makes these pumps ideal for handling grit and other solids-laden wastewater.

The pump’s low Net Positive Suction Head Required (NPSHR) and excellent repriming capabilities make them ideal for pumping grit from grit chambers in flooded suction and suction lift applications.

The Grit Removal Process

Grit removal takes place during the initial stage of wastewater treatment. The grit removal process is crucial in a wastewater treatment plant (WWTP). It helps maintain the functionality and efficiency of downstream equipment. Grit consists of heavy inorganic materials such as sand, gravel, and small debris with specific gravities substantially higher than organic solids in wastewater. The primary goal of the grit removal process is to separate inorganic materials from the influent wastewater.

Ineffective grit removal can lead to the following:

• Clogging of pipes and channels
• Premature wear of equipment like pumps, valves, and conveyors
• Reduced capacity in downstream treatment basins

Role of Grit Pumps in Wastewater Treatment

Grit pumps are essential for transferring the grit from the grit chambers to a grit classifier. This guide provides the operators with a practical overview of grit pumps for plant operators. It focuses on their operation, maintenance, and key factors to consider.

Design Guidelines for Pumping Grit

Recommended design guidelines for effective grit pumping:

• Pump Selection: It’s essential to select a pump that matches the application’s specific needs regarding flow rate, head, NPSHr, and motor horsepower. A poorly matched pump can lead to inefficiency and excessive wear.
• Material Composition: Due to grit’s abrasive nature, pumps should be constructed from wear-resistant materials such as hardened ductile iron or steel for greater durability.
• Flow Control: Grit pumps typically operate intermittently. Smaller grit systems often use full-voltage non-reversing (FVNR) starters. Larger systems frequently employ variable-frequency drives (VFDs) to adjust flow rates based on the system’s grit load.
• Positioning: Place grit pumps as close as possible to the grit chamber to keep suction piping as short as possible.
• Piping: Use a minimum of 3-inch diameter piping and maintain pipeline velocities between 3 and 5 feet per second.
• Freeze Protection: Pumps installed outdoors need casing heaters and insulation jackets. Suction and discharge piping should be heat-taped and insulated.

Why are Gorman-Rupp Pumps Ideal for Pumping Grit?

Gorman-Rupp pumps are well-suited for pumping grit due to several key design features that enhance their durability, reliability, and efficiency in challenging environments:

• Abrasion-Resistant Materials: Gorman-Rupp uses high-quality materials, such as hardened ductile iron and steel, in areas exposed to high wear, which helps withstand the abrasive nature of grit and other suspended solids.
• Robust Impeller Design: Impellers in Gorman-Rupp pumps are specifically engineered to handle solids and abrasive materials. These impellers maintain efficient operation while preventing clogging, even with high solids content.
• Easy Clearance Adjustment: Gorman-Rupp pumps have external clearance adjustments to enable operators to keep the pump operating at optimal hydraulic performance, maximizing flow rates, minimizing energy consumption, and resulting in less clogging.
• Ease of Maintenance: Gorman-Rupp’s self-priming pumps have a large removable inspection cover for easy access and servicing. This makes it simple to clear blockages, inspect wear components, and minimize downtime, which is crucial in demanding grit-handling applications.
• Flexible Installation Options: Gorman-Rupp pumps are flexible enough to operate effectively in flooded suction and suction lift installations. This provides consistent performance in various site conditions common to grit pumping.
• Longevity in Harsh Conditions: Focusing on rugged construction and wear-resistant components, Gorman-Rupp pumps offer extended service life even in highly abrasive environments, reducing the need for frequent replacements and providing reliable long-term operation.

Conclusion

Grit removal is integral to the efficient operation of wastewater treatment plants. It ensures the removal of abrasive grit before it can cause damage to downstream equipment. By understanding the specific requirements of grit pumps and following routine maintenance schedules, operators can maintain reliable performance and avoid common issues. Gorman-Rupp pumps are a great choice for grit pumps at wastewater treatment plants.

Contact Envirep

Envirep/TLC serves the water and wastewater market in Pennsylvania, New Jersey, Maryland, Delaware, the District of Columbia, Virginia, and West Virginia.

Do you need help selecting the right equipment for your application? Contact Envirep at 717-761-7884 or sales@envirep.com.

By Michael Gillespie, President at Envirep/TLC