'Spiroflow' Dosing System Keeps Water Sweet at One of the Largest Listed Water Firms

CHARLOTTE, N.C. - United Utilities is the largest listed water company in the United Kingdom. The company owns, operates and maintains numerous utility assets, including water, wastewater, electricity and gas. A Financial Times Stock Exchange (FTSE) top 100 company with an annual turnover of $3.3 billion US Dollars, United Utilities sees themselves as stewards of natural resources in Northwest England, in the United Kingdom and worldwide.

At the new United Utilities Cowm water treatment facility located within the Watergrove Water Treatment Plant at Wardle near Rochdale 10 miles northeast of Manchester, United Utilities needed to add Powdered Activated Carbon (PAC) to the water it draws from the Cowm Reservoir. Adding PAC neutralizes a naturally occurring material known as Geosmin that literally translates as 'earth smell'. Geosmin is an organic compound produced by microbes and algae that give the untreated water a harmless but undesirable earthy taste and aroma.

A sister company to Spiroflow Systems, Inc. located in Monroe, North Carolina, Spiroflow Ltd is an approved supplier to United Utilities. As such, Spiroflow was well positioned to bid on the PAC dosing system required by the new Cowm water treatment facility.

Purchase of the dosing system was through GCA, an alliance of main contractors compromised of Galliford Try and its joint venture partners Costain and Atkins.
Spiroflow was selected based on price, according to Darren Glover of GCA. "The equipment is very good," Glover said. "We had an initial teething problem caused by unexpected clumps of PAC that Spiroflow quickly remedied by fitting a vibrator to the collection hopper. The system has worked well ever since."

Facility Described

In the United Kingdom, Spiroflow works closely with Transvac Systems Ltd in supplying dosing systems for water and effluent treatment applications. Transvac is a world leader in ejector technology and supplied the skid-mounted components at Cowm that introduced the solids into the water stream.

Components supplied include a second buffer hopper that feeds PAC into the ejector. The hopper incorporates 'high' and 'low' level probes that, along with the flow sensors in the by-pass pipe-work, make up the highly reliable monitoring system developed by Transvac. The monitoring system shuts down the dosing system and triggers an alarm if a foreign body would happened to cause a disturbance to the balance of the treatment process.

The dosing system also consists of a 'Spiroflow' Type 6 Bulk Bag Discharger, with an integral lifting hoist on a runway beam for the easy loading of the PAC bags into the discharger, and a 'Spiroflow' Flexible Screw Conveyor to transfer PAC from the discharger up to a volumetric metering feeder with a buffer hopper on top.

From here, the conveyor transfers the PAC to the second buffer hopper that maintains a constant head of material above a 'Transvac' venturi ejector. In this ejector, the PAC is drawn under vacuum from the second buffer hopper and metered proportionately into a by-pass water stream to form a slurry. The PAC slurry then re-enters and is mixed with the main water flow into the water treatment plant and subsequently the distribution system that services both homes and businesses in the Rochdale area.


The 'Spiroflow' Type 6 Bulk Bag Discharger comes complete with its own bag hoisting system. This eliminates the need for a lift truck and only requires the use of a hand operated pallet truck to move the bags from the storage area to the discharger. Once the loops of the bag are attached to a lifting frame, the bag can be hoisted up, traversed across and then lowered into position on the discharger.

The 'Discharger at Cowm is fitted with an optional bag outlet clamping system that lets the operator safely untie the bag's neck seal within the dust cabinet located below the bag. The operator then closes the door and opens the clamp remotely, allowing the PAC material to discharge in a totally contained manner to protect both the operator and the working environment. This is particularly important when handling light, fluffy powders such as PAC that readily become airborne.

Bag massagers are also fitted to the bag support dish. In the event a well-compacted bag's contents are reluctant to flow, the bag massagers automatically break up any bridges and ensure a continuous flow of PAC.

From the Discharger, the PAC material is transferred to the Flexible Screw Conveyor. The conveyor's only moving part is a motor driven spiral that rotates within a sealed tube to gently move material without degradation. This results in a system that is high in efficiency and performance.

The conveying system is totally sealed and does not use air as the conveying medium, eliminating any risk of dust contamination.

Throughputs of up to 10,000 cubic feet per hour can be accommodated.


Spiroflow is a worldwide supplier of a wide range of both standard and custom powder handling equipment, specializing in Bulk Bag Dischargers and
Fillers, Mechanical and Pneumatic Conveyors, a range of 50 lb Bag Packing and
Unloading Equipment and Flexible Storage Silos. The company offers a wide range of innovative designs and design options.

The company would be pleased to work with U.S. suppliers of ejectors (jet pumps) to meet the requirements of Water and Effluent Treatment customers in North America, Central America and Latin America.

For more information on Spiroflow Systems, its complete range of bag
fillers, 'Spiroflow' Bulk Bag Dischargers or other powder handling equipment, visit
www.spiroflowsystems.com, call 704-291-9595, fax 704-291-9594 or email info@spiroflowsystems.com.

Dick Stark

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