A contract to upgrade Mangaung Metro Municipality’s Maselspoort low- and high-lift pumpstation has been awarded to water services company Veolia Water Solutions & Technologies South Africa.

The 12-month contract, which comprises mechanical and electrical upgrades, started in September last year and aims to ensure that the plant continues supplying 34% of Bloemfontein’s treated water

The upgrades include replacing four low-lift vertical turbine pumps with two low-lift centrifugal self-priming pumps, the motor sets and associated pipework, as well as replacing five horizontal centrifugal pumps with two high-lift split-casing centrifugal pumps.

Each low-lift pump has the equivalent capacity of two of the dated pumps, effectively providing a combined capacity equivalent to the four replaced pumps. The duty pump will be controlled remotely online and the other pump using a variable-speed drive (VSD), enabling the operator to regulate pump speed while monitoring delivery flow.

The low-lift pump sump will be changed from a dry to a wet well sump requiring additional suction pipework.

“To incorporate the new piping into the exist-ing pipework infrastructure, installation will take place in conjunction with a section of the discharge pipework,” says Veolia Water Solutions & Technologies lead engineer Michael Haig.

The high-lift split-casing centrifugal pumps, which join an existing refurbished pump, will run on VSDs to regulate them according to water demand. As part of the contract, the refurbished pump will have its impeller replaced and motor size increased to bring its capacity in line with the two new ones.

“The pumps and motor operation will be installed with features that enhance maintenance efficiency and overall system reliability, while pump and motor operations will be remotely monitored,” he says.

“The high-lift pump suction pipework remains primarily the same, comments Veolia Water Solutions & Technologies business development manager Thabo Mogadima.

He notes that the only exceptions are that the weir needs to be extended and the suction pipe replaced. The contract also calls for new pump legs to be incor- porated into the existing header pipe and, accord- ing to Mogadima, there is also an unconfirmed possibility of replacing the existing header pipework.

“We feel that the maximum design pressure, which is just under 30 bar, may create overburden on the current header pipework,” he explains.

The upgrade, due for completion in August, includes soft starter and VSD installation, power supply and switchgear modernisation, as well as replacing appurtenant valves.