Qdos pump doses for three years without fault

A Qdos 60 PU peristaltic pumphead from Watson Marlow Fluid Technology Solutions has completed three years of maintenance-free operation without any leaks in a trial at the City of Oak Ridge water treatment plant (WTP) in Tennessee, US. The trial began in May 2020 with the prototype Qdos 60 peristaltic pump with ReNu PU (polyurethane) pumphead dosing polyaluminium chloride, a polymer used in water purification which enhances flocculation and coagulation of pollutants. Throughout the period, there has been no need to stop production for maintenance downtime or to fix a polymer leak - which are expensive and time-consuming to clean up.  

The Qdos 60 ReNu PU pumphead is specifically designed for polymer dosing, and has performed without requiring replacement, providing efficient, safe, leak-free and reliable polymer metering.

“The Qdos 60 pump that is used to feed coagulant - a polyaluminium chloride polymer called DYPAC 5461 - and the prototype pumphead that Watson-Marlow provided has been absolutely amazing,” said, plant manager Mark Terry.  “The pumps that were previously used to add coagulant into the plant’s raw water were old and prone to clogging. It was decided to use a Qdos 60 PU pump and there has been no disappointment with the performance. The Qdos 60 and ReNu PU pumphead was installed and began feeding the coagulant on May 14, 2020. Other than when the plant has been down for a few hours for reasons such as temporary power outages, the Qdos 60 pump and the prototype pumphead has run non-stop for three years. “Another Qdos 60 pump was purchased to act as a back-up but is has not been needed,” Terry said.

The Qdos 60 PU offers precise and repeatable flows for many hard-to-handle fluids, including viscous fluids and aliphatic hydrocarbons, at linear flow rates of up to 60 L/h (15.8 GPH) and pressures of up to 5 bar (73 psi). The ReNu pumphead is a single, safely contained, component for rapid no-tools maintenance​ ​with no additional valves or ancillary equipment to fail or vapour lock.

“The obvious benefits that the Qdos pump has provided to the water treatment plant is no polymer leaks since it was put into service,” said Terry. “Aside from occasional calibrations, the pump has maintained a very consistent and accurate feed rate of the coagulant that is added to the raw water. Low maintenance and non-stop running of the Qdos pump at the plant is vitally important because, aside from a few unplanned episodes, it runs 24 hours a day, seven-days-a-week.  Based upon these realities the Qdos pump has been a great choice.”                                                                              

The benefits of the Qdos 60 PU include:

• Excellent compatibility for complex polymers including polyacrylamide (PAM) and other flocculants and coagulants used in wastewater treatment
• The contained pumphead design with integral leak detection reduces wastage and eliminates operator exposure to chemicals
• Precision dosing of ±1%, even under varying conditions, minimises chemical expenditure
• Low-shear, gentle peristaltic pumping protects polymer chains and consistency, maintaining product integrity

The city of Oak Ridge water treatment plant is using seven Qdos peristaltic pumps - both the 30 and 60 models - to feed chemicals such as 20% sodium permanganate, 12.5% sodium hypochlorite, fluorosilicic acid, and a poly/orthophosphate corrosion inhibitor to the plant’s current coagulant.

“The Qdos 30 pump that is used to feed fluorosilicic acid at the water treatment plant has performed admirably considering the pressure it works against and because of the corrosive nature of the chemical, like the hypochlorite feeding Qdos 60 pumps,” Terry said. 

The Oak Ridge WTP is decommissioning the existing 1943 plant that provides the city’s drinking water and constructing a new facility to treat over 45 million litres (12 million gallons) of water per day and provide water to 31,000 residents.

The new plant will be ready to provide water by spring 2025 and will be using ten Qdos 60 pumps for a variety of chemicals for water treatment such as hydrogen peroxide, sodium permanganate, and fluoride. In addition, WMFTS will also be providing two Bredel Apex 15 pumps for sodium hypochlorite.

Chris Miller, district sales manager at WMFTS, said, “Oak Ridge was having problems with its older diaphragm pumps, so a trial was suggested of the Qdos 60 PU. It has been one of Watson Marlow’s great success stories and in working with Mark Terry and the City of Oak Ridge, we are excited to see that Qdos will be the chemical feed pump of choice for the new water plant.”

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