Latest Qdos pumphead for polymer dosing proves itself at leading brewery

Specialists in water and waste management SUEZ had been contracted to operate and maintain a major UK brewery’s effluent treatment plant, optimise the operating processes and reduce its environmental footprint. As part of the process, diaphragm metering pumps that were frequently becoming clogged with polymer needed replacing.

SUEZ looked to the Qdos ReNu PU pumphead from Watson-Marlow Fluid Technology Group (WMFTG) for dosing polymer as part of its wastewater treatment processes.

All of the brewery’s waste is sent to the site’s AD (anaerobic digestion) effluent plant where it is treated. The brewery’s waste is digested by the bacteria which then produces methane gas.

“After the wastewater has passed through the main bioreactor it is aerated, which further reduces the COD,” explains Dave Burrows of SUEZ UK. “From here it goes through a DAF (dissolved air flotation) process where we remove solids and introduce polymers using a Qdos pump from Watson-Marlow.”

The brewery’s effluent plant will treat up to 200m³ of wastewater per hour, a process which generates sludge that requires separation. Here, polymers are dosed into the wastewater stream, which causes flocculation, after which a centrifuge process is applied. From there, the sludge is disposed offsite, often to other AD plants to extract further gas or, alternatively, as a form for spreading on agricultural land. Nothing is wasted.

Tube requirements

“When we first got the centrifuge, we identified a liquid polymer that would work well with our sludge,” adds Burrows. “However, it was petroleum-based and at the time Watson-Marlow did not have a suitable tube, namely PU (polyurethane), which would be resistant to aliphatic hydrocarbons such as petroleum distillates.”

The Watson-Marlow design team set about creating a special pumphead that would become the new Qdos ReNu PU. A small number were initially supplied to SUEZ for use at the brewery.

We don’t have any such issues with the Qdos, which reliably doses polymer for around 12 hours every day

Dave Burrows, SUEZ UK

“They made three pumpheads for me with PU tubes and I have to report they all lasted really well,” says Burrows. “We’re using the pumpheads on two Qdos pumps. We have installed these at two different breweries, one running on a belt press and one on a centrifuge.”

Before installing the Qdos pump, the brewery used a diaphragm metering pump. However, the small non-return valve within the diaphragm pump would easily become blocked by the polymer. In turn, the pump would require frequent cleaning, a process made more challenging by the polymer’s high viscosity.

“We don’t have any such issues with the Qdos, which reliably doses polymer for around 12 hours every day,” says Burrows. “In addition, when the pumphead reaches its end of life, you get a useful notification. Replacement is quick and easy – we’re up and running again with 5-10 minutes.”

Chemical containment upon pumphead failure is also assured; an important point as cleaning up polymer spillages can be very time consuming.

Such has been the success of the two installations to date that SUEZ has taken delivery of a third Qdos with the ReNu PU pumphead which has been installed at a manufacturer of convenience foods in the north of England.