A NSW council has just upgraded their vacuum sewage system transfer pump. They were using a lobe pump to transfer raw sewage from their vacuum tank to their sewage treatment plant, but the need for continued maintenance on the pumps was causing cost and logistics issues.
The council had heard of the success the Bundaberg Regional Council had when changing their Lobe Pumps to Gorman-Rupp Ultra VS Series two-stage self priming pumps. The application was virtually the same, in that they have a vacuum tank that draws sewage through a network of sewer lines that are kept under negative pressure by the vacuum tank. Then the vacuum tank fills, it needs to be pumped out. Because the tank is under a vacuum (up to -80kPa), the transfer pump needs to be able to pull a “suction lift” equivalent to this, and still be able to produce discharge pressures high enough to transfer sewage to the WWTP (in this case, an additional 60 metres, for a total dynamic head of 68 metres).
After reviewing the system, Hydro Innovations selected the Gorman-Rupp VS3A60-B with a 45kW motor. The pump is one of Gorman-Rupp’s Ultra VS Series of two-stage self priming sewage pumps, capable of producing heads to 90 metres. Being a self priming pump, it is more than capable of producing the required vacuum to overcome the negative pressure inside the vacuum tank. The pump comes standard with a self cleaning wear plate system to enable it to handle stringy materials such as rags, has a large open impeller to handle larger solids and has a large removable cover-plate for access into pump internals to remove large blockages or for inspection.
The council is happy with their investment.