Basic Assessment Report - Transnet

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Transnet LimitedProposed RO Plant: Port of SaldanhaFinal Basic Assessment Report• A number of alternatives for dust suppression measures and water supplywere considered prior to the start of the Basic Assessment process, but werenot viable and were excluded as alternatives mainly due to engineeringconstraints and prohibitive financial costs, while some also had potentialadditional environmental concerns;• Water is a scarce resource along the west coast of the Western Cape Province,and in the absence of a more suitable alternative, it is proposed that water besupplied to the port through the desalination of seawater, making use ofReverse Osmosis technology;• The proposed RO would produce 3 600m³/day potable water once all threemodules have been installed, although it is proposed that only one module beinstalled initially. All infrastructure will make allowance for the full capacityof the plant. The Basic Assessment and associated specialist studies have allconsidered impacts associated with the plant operating at full capacity;• RO is the process whereby seawater will be forced through semi-permeablemembranes under pressure, resulting in the production of fresh water, andproducing a high salinity brine as a waste product;• Brine produced as a result of the RO process (approximately 4 400m³/daybrine once operating at full capacity) containing certain biocides will bedischarged into Saldanha bay, while wastewater from the cleaning processcontaining potentially harmful chemicals will be disposed of either via themunicipal sewer system, or at a waste disposal site;• It is proposed that the RO Plant be located at the Iron Ore Handling Facilityin Saldanha Bay, and three site alternatives within the Port boundaries havebeen identified and assessed;• The three sites proposed for the RO Plant are on Transnet’s property, and thearea is already heavily impacted on by industrial activities;• For each of the site alternatives, various infrastructure alternatives have beenidentified, relating mainly to the methods of seawater intake and discharge(beach/quay wells vs pipelines) and the positions of the intake and dischargeinfrastructure;• Site 1 (with beachwell intake and beachwell discharge) was originally thepreferred alternative; however following initial consultation with numerousspecialists a number of additional alternatives were developed and assessed,and the preferred alternative evolved - Site 3 (with intake wells along thequay, and discharge via a pipeline situated towards the end of the quay);• The construction footprint of the RO Plant and associated infrastructure variesfrom 11 000m² to 23 000m² (1.1 – 2.3 ha), depending on the site, intakeinfrastructure and discharge infrastructure;51Prepared by the PDNA/SRK Joint Venture
Transnet LimitedProposed RO Plant: Port of SaldanhaFinal Basic Assessment Report• Site 1 has been disturbed in the past by activities at the Iron Ore HandlingFacility, but has recovered well and the parabolic and primary dune system atthis site are of ecological importance;• The flora and vegetation at Site 1 is considered rare and sensitive, and apermanent loss of dune habitat as well as the loss of at least one Red Datafloral species is likely if the RO Plant is located at this site;• The dune system and vegetation at Site 2 has been heavily impacted on byactivities at the Iron Ore Handling Facility, while there is no flora at Site 3;• No heritage resources of significance have been identified at any of thealternative sites;• No groundwater impacts associated with the proposed intake or discharge forthe RO Plant of significance have been identified, although geohydrologicalstudies have indicated that the initial proposal for discharge via beachwells atSite 1 would not be viable due to the nature of the sediments in the area;• Discharge of brine will result in the creation of plumes of brine, which are ofa higher salinity, contain biocides or co-discharged water and have apotentially slightly higher temperature than the receiving water, before thebrine is dispersed and mixed with the surrounding seawater;• Chemicals used for cleaning the RO membranes (CIP chemicals) will not bedischarged with the brine but will be disposed of via the municipal sewersystem or a waste disposal site;• Modelling of the brine discharge plumes (by the marine specialist, refer toAppendix G3) for each of the following factors:• Increased salinity;• Increased seawater temperature;• Increased biocide concentrations; and• Potential co-discharge impacts (as a result of the use of certainchemicals in the pre-treatment or RO membrane cleaning process)indicate that these plumes do not extend as far as any existing or proposedmariculture activities, seawater intakes for fish processing factories,recreational and commercial gill-netting areas, National Parks, MPAs, or theLangebaan Lagoon if the RO plant is positioned at Sites 1 or 3;• At Site 2, however, the plumes for increased salinity, increased seawatertemperature, increased biocide concentrations and potential co-dischargedconstituents extend close to the eastern boundary of the area demarcated forseaweed harvesting.Relevant observations with regard to the overall impact ratings, assuming mitigationmeasures are effectively implemented, are:52Prepared by the PDNA/SRK Joint Venture
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Basic Assessment Report - Transnet

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