JG Afrika helped deliver a R74-million desalination project swiftly from inception to allow Hillside Aluminium smelter to continue operating despite severe water restrictions in Richards Bay.
Construction of the plant commenced in April 2016 and the first water was pumped into the plant by September of the same year.
Neal Bromley, a lead project manager at JG Afrika, says the firm had already started discussions with South32 on possible ways of reducing the use of, or reuse of water, prior to the introduction of the water restrictions.
“The desalination of seawater was identified as the preferred alternative to municipal water, providing a reliable water supply and creating a secondary benefit to the region by reducing demand on the municipal system,” Bromley says.
Conceptualised in February 2016, the plant produces 2Ml of industrial process water by removing minerals from seawater abstracted from Richards Bay harbour.
JG Afrika was responsible for the overall conceptual solution development, as well as the detailed civil engineering works, raw water pipeline, pump selection and brine pipeline designs.
The engineering team was able to accelerate the project by focusing on existing infrastructure owned by South32, Foskor and Mhlatuze Water.
Existing abstraction infrastructure at the harbour provides Foskor with an emergency alternative process water supply for the Mondi effluent that is used under normal operations.
The Foskor extraction point has a design capacity of 1 250 m3/ h, and the phosphate and phosphoric acid producer’s estimated demand for seawater is 700 m3/h. This made them a suitable partner to deliver 280 m3/h to Hillside, while still remaining within the current licensed approved limit.
The existing abstraction infrastructure comprised two pump chambers, of which only one was being used. It was agreed that South32 would add a second pump, sharing a portion of the existing rising main to abstract the seawater.
A new 2,3 km 355 mm diameter HDPE pipeline traversing the area between the harbour abstraction and Hillside was constructed inside and alongside the South32 conveyors. Most of the infrastructure, including sections of the pipeline to transfer seawater, was already in place.
As the conveyor system runs adjacent to a wetland, environmental impacts and the required approval for a conventional buried pipeline were also avoided. This allowed for the identification, design, construction and commissioning of the entire raw-water pipeline route in as little as 24 weeks.
Meanwhile, an existing concrete slab within the Hillside complex and its relative proximity to the Hillside process water-storage reservoir and the deployment of a fully-containerised modular plant also assisted in swift implementation of the project.
The plant comprised raw-water clarifiers, ultra-filtration and reverse osmosis technology.
An existing 1,5 km 300 mm diameter pipeline between Hillside and the decommissioned Bayside smelter was also used for brine disposal.
Requiring minimal refurbishment, it was extended by 335 m to connect the Bayside smelter into the existing Mhlatuze Water licensed discharge outfall.
Robust public and private partnerships right from the outset also played a major role in the successful outcome.
Contributions and approvals from Foskor and Grindrod were invaluable, while Mhlatuze Water and the Mhlatuze Local Municipality enabled quick approval for South32 to discharge brine into the sea outfall. Meanwhile, co-operation from the Department of Economic Development Tourism and Environmental Affairs during the EIA approval process ensured a positive Record of Decision.