Restoration of Ezakheni pump station during lockdown

While the Covid-19 pandemic disrupted the implementation of various water projects last year, the refurbishment of the Ezakheni pump station was completed successfully.

By Kirsten Kelly

Residents within the Ezakheni and Ladysmith areas of Kwa-Zulu Natal can now enjoy an uninterrupted and consistent supply of quality water due to the refurbishment of the pump station at Ezakheni Water Treatment Works (WTW).

This is one of three WTWs that bulk water services provider Umgeni Water has been contracted to manage within uThukela District Municipality.

Yovesh Danilala, project manager at Umgeni Water, said that when they took over the infrastructure, they found that the pump station had fallen into a state of disrepair: “A month after accepting control of the plant, there was a catastrophic failure at the raw water line where we lost three pumps. Funds were made available to bring the pump station back to its original condition. This meant that we had to install six vertical 18 HC three-stage pumps plus auxiliaries.”

APE Pumps

In 1983, APE Pumps supplied the WTW with six vertical 18 HC two-stage pumps. Being at the forefront of pump innovation within the Southern African market for close to seven decades, APE Pumps conducts manufacturerwarranted repairs and supplies new OEM pumps and valves. The company also offers a turnkey consulting, installation and commissioning service.

According to John Montgomery, general manager for APE Pumps, the pump station never used the OEM for maintenance, repairs or spare parts. Upon inspection, the pump station was found in disarray.

“The pumps that we had installed 38 years ago were all exactly the same, but when we inspected the pump station last year, we found that some pumps were vertical, some pumps were submersible, and nothing was the same. This makes servicing the pumps very difficult because the parts are not interchangeable. Furthermore, over the years, non-OEM replicated parts were used. That has serious implications for overall system performance, since it’s rare for replicated parts to exactly fit the original OEM tolerance specifications. The precise tolerances that need to be achieved can be as exact as one thousandth of a millimetre,” explains Montgomery.

Umgeni Water contracted APE Pumps to restore the Ezakheni pump station to its original condition. This included desilting the intake chamber by using divers and specialised equipment, as well as installing and commissioning the two transformers, six variablespeed drives (VSDs) and all the necessary electrical auxiliaries and instrumentation. APE was tasked with the manufacture, transport, and commissioning of the pumps and had to complete all required electrical, piping and structural work.

Lights and cranes were also set up and all base plates were replaced to reduce vibration.

Manifold

When ‘pump A’ was installed at the far left of the pump station, the original manifold burst and there was a massive break in one of the pipes. The manifold was placed under the MCC (motor control centre) and all of the electrical equipment was damaged.

To prevent this from happening again, APE mechanical and structural engineers decided to extend the platform, place the manifold and pipework outside the pump station, and turn the pumps 180 degrees to face the river and not the building.

Danilala adds that the design also aids with friction loss, as the pipework has a smoother curve for the water flow. “The manifold discharges into two pipelines: a 600 and 400 pipeline. A bypass was also installed to ensure that all six pumps can pump water up either pipeline. Three pumps are typically on duty and three are on standby. This makes any future maintenance of the pumps easier, as the water supply will not be affected.” says Danilala.

Other than a 12-hour shutdown to replace the existing manifold and turn around the pump suction, water supply was maintained. One pump was installed at a time and tied into the existing pipeline. At every point during the build, the impact on the volume of water going into the plant had to be considered.

New technology

“Pumps installed in 1983 and 2020 are all high quality and specialised, as they have to pump water straight out of the Tugela River. Each pump is capable of achieving a 60 m/h pump head and can pump between 500 m³/h and 750 m³/h per unit using VSD technology. The pumps have cover tubes to protect the shafts, reducing maintenance needs,” maintains Montgomery.

The major difference between pumps installed in 1983 and pumps installed in 2020 is in improved efficiency. The pump station has moved from using 200 kW/h of power to 120 kW/h.

Furthermore, VSDs are used instead of soft starters. This means that the speed of each pump can be adjusted, and the flow of water can be regulated. Pump performances (flow, pressure, temperature of bearings, vibration, running hours) can be monitored remotely.

Maintenance contract These readings assist with preventative maintenance. APE has a two-year maintenance contract with Umgeni Water, analysing all readings generated remotely and visiting the Ezakheni site once a month.

Regular maintenance ensures that pumps are working optimally, there is minimal downtime, and the life of the pump is extended.

Covid-19

“The entire project was completed within six months. The hard lockdown last year did not postpone this project because we manufacture our pumps locally and did not have to wait for international deliveries,” states Montgomery. “During these hard times, APE Pumps staff and suppliers worked tirelessly in order to complete this project on time – supplying the customer and community with exceptional service.”

Danilala adds that, due to Covid-19, there were a few additional safety protocols in place and an Umgeni safety officer frequently visited the site to ensure compliance. “We all travelled with the requisite documentation. The only Umgeni Water contracted APE Pumps to restore the Ezakheni pump station to its original condition issues we ever experienced were finding food and accommodation after hours.”

Today, the Ezakheni pump station extracts 38 Mℓ/day and supplies 32 Mℓ/ day of water to its regions. With the upgrade and implementation of six new pump units and the use of VSDs, these pumps are able to produce over 100 Mℓ/day.

The restoration of the Ezakheni pump station reflects Umgeni Water’s mission to provide innovative, sustainable, effective and affordable bulk water and sanitation services.