Tubing technology pumps polymers for dewatering efficiency

As part of the Little Traverse Bay Environmental Project in northern Michigan, environmental consulting firm Pescador LLC treats groundwater using a niche polymer. When its diaphragm metering pumps proved ineffective in handling this chemical, they worked with Watson-Marlow Fluid Technology Group to install a new low maintenance, high-accuracy pumping solution. Rob Martindale from Watson-Marlow expands on the project.

Polyacrylamide (PAM) acts as a flocculant. As one of the steps utilised in Pescador’s process, this anionic polymer attracts huge numbers of the miniscule organic material, pinflocs that float in the solution to concentrate them as a larger floc. Once gathered in this way, dissolved air floatation (DAF) can push the debris to the surface so it can be skimmed off.

However, PAM and other polymers challenge traditional off-the-shelf pumping systems. Using a diaphragm metering pump, equipment failure plagued Pescador with downtime and high costs.

The chemical attacks standard santoprene tubing, and with highly viscous polymers such as at this site, rapidly wrecks pumps that are not specifically designed for such a task. In search of a lower maintenance solution, Pescador contacted Watson-Marlow Fluid Technology Group. Our experts suggested a new product, the Qdos ReNu PU.

The Qdos 20 ReNu PU pumphead installed at the site on the DAF application lasted over two years and never failed (application details: 0.015 USGPH, 24/7, 365) before being replaced due to minor calibration drift.

SPECIALISED TUBING FOR POLYMERS

At the heart of the solution is a new tube technology that increases the chemical compatibility range of Qdos. Specifically designed with polymers in mind, the tubing is aliphatic hydrocarbon resistant, so the chemical does not attack the tubing in the way it otherwise would. In addition to protecting the pumphead, the peristaltic pump protects the chemical itself. Polymers are susceptible to mechanical degradation. If agitated and mixed prior to use, the chemical will not work as intended. Through Watson-Marlow’s peristaltic technology, the pump protects the chemical Pescador is injecting in the process.

The Qdos 20 ReNu PU pump is made up of two main components: the drive, which includes the pump’s intelligence, and a separate pumphead, which is the only consumable part of the pump. This makes the Qdos a drop-in solution, whereas diaphragm metering pumps need four or five ancillary systems (backpressure valves, pulsation dampeners, strainers, float switches)—each with their own maintenance schedules. For example, the check valves on Pescador’s original diaphragm metering pump set-up proved inadequate in the face of high viscosity. The Qdos pump also eliminated the need for flooded suction which the diaphragm metering pump depended on.

This consolidated system is also entirely enclosed, offering a major improvement for spill reduction. Polymer is a very slippery chemical.

‘Water treatment facilities that use polymers in the dewatering process can limit costs and downtime by switching to a specialised pump with purpose-designed tubing technology’

Any leak entails a lengthy and involved clean-up process, and attempts to clean up polymer with water expands the chemical and perpetuates the clean-up operation.

LIMIT COSTS AND DOWNTIME

Water treatment facilities that use polymers in the dewatering process can limit costs and downtime by switching to a specialised pump with purpose-designed tubing technology.

As polymer usage continues to grow internationally as a part of primary, biological, mixed, and digested sludge processing, polymer-specific pump systems will prove a critical technology for the next generation of environmental and industrial dewatering.

The Qdos 20 ReNu PU pumphead installed for Pescador LLC

Watson-Marlow Fluid Technology Group www.watson-marlow.com