Watson-Marlow’s polymer dosing pumphead proved its worth when dealing with a brewery’s waste water processes...
Suez is contracted by a major UK brewer to operate and maintain the site’s effluent treatment plant, working to identify and optimise the operating processes and reduce the client’s environmental footprint.
There is growing worldwide demand for polymer dosing systems in wastewater treatment, while dewatering sludge waste can considerably reduce transportation and disposal costs.
Previously, 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.
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 and which produces methane gas that can be used by boliers for heat.
“After the wastewater has passed through the main bioreactor it is aerated, which further reduces the COD,” explains Dave Burrows of SUEZ UK, who is responsible for the effluent plant. “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, for spreading on agricultural land. Nothing is wasted.
“When we first got the centrifuge, we identified a liquid polymer that would work well with our sludge,” says 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.”
In response to the enquiry via distributor CSS Ltd, 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.
“They made three pumpheads for me with PU tubes and I have to report they all lasted really well,” recalls 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. CSS supplied us with the skids and pumps.”
Previously, 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
For Watson-Marlow it provided an opportunity for a third party to testify to the product’s effectiveness thanks to an early stage trial.
“We don’t have any such issues with the Qdos, which reliably doses polymer for around 12 hours every day,” explains Burrows. “I really can’t fault the reliability or simplicity of the Qdos pump or the ReNu PU pumphead. 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 time saver, while thanks to the success of the two installations, SUEZ has just taken delivery of a third Qdos pump with the ReNu PU pumphead, for a manufacturer of convenience foods in the north of England.