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More “offshore technology” to wastewater treatment plant

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1 December 2021 – Following a successful pilot project through use of equipment that is normally utilized on board offshore vessels, Norwegian wastewater treatment company Vestfjorden Avløpsselskap (VEAS) har ordered several new agitators to the company’s large sludge tanks at its Slemmestad treatment plant south of Oslo. PG Flow Solutions will supply the agitators.

 Two-and-a-half years ago, VEAS installed equipment that is normally used on board offshore vessel at its Slemmestad wastewater treatment plant. VEAS then acquired tree hydraulically driven agitators for one of the bio tanks at the facility, which is located in Røyken municipality in Viken county, Norway.

 Following a public tender, VEAS has now chosen to acquire 20 additional agitators – five to each of the four large sludge tanks at Slemmestad – with associated hydraulic power system outside each tank. This means that even if one or two of the agitators are deactivated, there will still be sufficient circulation in the tank to maintain operational reliability.

 PG Flow Solutions has been chosen as supplier of the agitators. PG Flow Solutions was selected in competition with three other suppliers.

 “The pilot project has shown that bottom-fixed agitators are highly effective in avoiding build-up of sludge and additives at the bottom of the tank, and they do not leave any ‘blind spots’ in the tank. We are very pleased to have been chosen as supplier of agitators to VEAS,” says Are Hjertvik, sales manager at PG Flow Solutions.

 PG Flow Solutions is located at Sande in Vestfold, Norway. The company has delivered in excess of 3,500 agitators to more than 1,500 offshore and platform supply vessels worldwide, used amongst other things for treatment of mud from drilling operations.

 The agitator, which is named PG-Submix 100-3200, is a slow moving, paddle-type propeller with large diameter and high torque. The agitator is placed at a pedestal at the bottom of tanks to prevent that sludge and additives settle at the bottom, as build-up of solids could cause problems for outlets and pumps if pieces of deposition were to detach.

 The advantage with PG-Submix 100-3200 is that it does not leave any “blind spots” in the tank, as the agitator slowly pushes sludge and wastewater towards the bottom of the tank, where the highest velocity is needed, and then up against the walls of the tank. This ensures that the liquid is kept in continuous suspension and that sediments and waste products do not accumulate at the bottom of the tank.

 “The principle of keeping fluids in motion is exactly the same offshore and onshore. Our agitators have kept heavy drilling mud in suspension for several decades. We therefore knew that they were more than robust to handle sedimentation of sand and pebbles and keep in continuous motion in VEAS’ tanks at Slemmestad. We aim to use this contract, and the results from the previous pilot project, as a door-opener to other wastewater plants in Norway and Scandinavia,” says Steve Paulsen, CEO at PG Flow Solutions.

Read more: Typical processes we solve with agitators

 The VEAS plant is Norway’s biggest wastewater treatment plant and a key contributor to keeping the Oslo fjord clean. VEAS is an inter-municipal partnership owned by the municipalities of Asker, Bærum and Oslo. Wastewater from more than 600,000 inhabitants in Oslo, Bærum and Asker are transported via the VEAS tunnel from entry points in the municipalities to the treatment plant at Bjerkås in Asker. VEAS also cleans wastewater from the municipalities of Røyken and Nesodden.

 PG Flow Solutions provides proprietary solutions, systems and products for companies within the energy, maritime, aquaculture and land-based process industries. The company’s headquarters and manufacturing facility is located in Sande, Vestfold, Norway.



For media information, please contact:

Endre Aaberg Johansen, Corporate Communications, tel: +47 41 61 06 05, e-mail:




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