Water treatment company Veolia Water Solutions & Technologies South Africa announced in April that it has been awarded the contract to upgrade Mangaung metropolitan municipality’s Maselspoort low- and high-lift pumpstation.
Maselspoort is a town in Mangaung, in the Free State. It is situated on the banks of the Modder river, 23 km from Bloemfontein.
The year-long contract, which started in September last year, aims to ensure the plant continues supplying 34% of Bloemfontein’s treated water. The contract comprised mech- anical and electrical upgrades.
The improvements comprise replacing four low-lift vertical turbine pumps with two low-lift centrifugal self-priming pumps, the motor sets and associated pipework, while two high-lift split casing centrifugal pumps take the place of five horizontal 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 remotely controlled by direct online (Dol) and the other by variable speed drive (VSD), enabling the operator to regulate pump speed while monitoring delivery flow.
Sump and Pipework
The low-lift pump sump will be changed from a dry to a wet well sump requiring additional suction pipework.
“To tie the new piping in to the existing pipework infrastructure, installation will take place in conjunction with a section of the discharge pipework,” says Veolia Water Solutions & Technologies South Africa lead engineer Michael Haig.
The high-lift split casing centri- fugal pumps, which join an existing refurbished pump, will run on VSDs to regulate them according to water demand, he explains.
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 new ones.
“The pumps and motor operation will be installed with features that enhance maintenance efficiency and overall system reliability,” says Haig. The pump and motor operations will be remotely monitored, he adds.
Additional Requirements
“The high-lift pump suction pipework remains primarily the same,” comments Veolia Water Solutions & Technologies South Africa
business development manager Thabo Mogadima.
The only exceptions are that the weir needs to be extended and the suction pipe replaced, he adds.
The contract also calls for new pump legs to tie in to the existing header pipe and 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 this month, includes soft starter and VSD installation, power supply and switchgear modernisation, as well as replacing appurtenance valves.
Veolia has been retained for a five-year monitoring and maintenance contract to meet specific mean-time-to-failure and mean-time-to-repair requirements.