Construction World January 2017

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CONSTRUCTION WORLD JANUARY 2017 18
PROJECTS & CONTRACTS
The plant will remove minerals from
seawater abstracted from the Richards
Bay harbour, thus enabling the company
to maintain operations during a time of
persistent drought, where the current water
crisis has resulted in the implementation of
stringent water restrictions in the Richards
Bay domestic and industrial sectors.
In March 2016 Level 4 water restrictions
were put in place by the uMhlathuze
Municipality and although South32
and JG Afrika had for some months
been discussing the need to investigate
methodologies to reduce or reuse current
water supplies, it then became clear that
an alternative to municipal water supply
urgently needed to be found to ensure
continuous smelter operations. The
knock-on socio-economic impacts on the
local, provincial and national economies
would be dire if the smelter plant were to
close: a loss of up to 10% of the GDP in the
region, a potential loss of 20 000 jobs in the
country directly or indirectly affecting the
livelihoods of around 80 000 people, and the
need to import aluminium into South Africa
at a cost of some R4,1-billion per annum.
The desalination of seawater was
identified as the preferred alternative to
relying on the municipal water supply.
Fast-tracking the investigations
JG Afrika recommended NuWater as a
technology partner and the team soon got
to work fast-tracking investigations and
conceptual designs for the installation of
a desalination plant, utilising membrane
technology, to produce process water at
Hillside. The urgency of the project re-
quired the engineering team to focus on
the existing infrastructure and mechanisms
owned by South32, Foskor and Mhlatuze
Water, where use could be made of
current licences, waste discharge permits
and structures.
Foskor, a producer of phosphates and
phosphoric acid, uses existing abstraction
infrastructure at Richards Bay harbour.
This seawater abstraction provides Foskor
with an emergency alternative supply of
process water for the Mondi effluent it
uses under normal operations. The Foskor
extraction point is designed for a capacity
of 1 250 m3/h. Foskor’s current estimated
demand for seawater is 700 m3/h and this
created the option to partner with them to
deliver 280 m3/h to Hillside while remaining
within the current licensed approved limit
of 1 250 m3/h.
The exiting abstraction infrastructure
has two concrete pump chambers of which
only one is in use. Foskor and South32
reached an agreement whereby South32
would add a second pump within the vacant
chamber, sharing a portion of the existing
rising main, to abstract the seawater
required to keep the smelter operational
during municipal water supply interruptions.
A new 2,3-km-long Dia 355-mm HDPE
pipeline traversing the area between the
harbour abstraction and Hillside was
constructed inside and alongside the
South32 raw material conveyors.
The upside of this agreement was that
most of the infrastructure and some of
the pipeline to transfer seawater from the
harbour to Hillside was already in place
or could be installed within the existing
conveyor servitude, significantly speeding
up the implementation and construction
programme. The raw water pipeline route
was identified, designed, constructed and
commissioned in 24 weeks.
Another identified benefit and its positive
impact on the implementation programme
was the existing concrete slab within the
Hillside complex and its relative proximity to
the Hillside process water storage reservoir.
This, together with a fully containerised
modular plant designed, supplied and
installed by NuWater, comprising raw
water clarifiers, ultra-filtration and finally
reverse osmosis kept the civil construction
requirements at the plant to a minimum.
As with any desalination technology,
the disposal of brine as a waste product
was a challenge. Again the lateral thinking
of the South32 and JG Afrika team
identified an existing 1,5-km-long pipeline
between Hillside and the decommissioned
Bayside smelter. This existing Dia 300-mm
pipeline required minor refurbishment and
a 335-m-long extension to connect the
Bayside smelter into the existing Mhlatuze
Water licensed discharge sea outfall.
JG Africa was appointed by South32
as the principal agent for the project and
was responsible for all civil engineering
works, raw water pipeline, pump selection
and brine pipeline designs. The project was
completed in an astonishing 28 weeks from
inception and concept identification to final
delivery of 2 Mℓ/day of process water to the
South32 Hillside smelter. 
NEW DESALINATION PLANT in Richards Bay
A R74-million desalination plant
was commissioned by South32
in September 2016 at their
Hillside Aluminium smelter in
Richards Bay, KwaZulu-Natal.