Water Consumption, Wastewater Generation and Integrated...

EIA FOR THE PROPOSED COEGA ALUMINIUM SMELTER WITHIN THE COEGA INDUSTRIAL

DEVELOPMENT ZONE, PORT ELIZABETH, SA

FINAL TECHNOLOGY REVIEW REPORT – JULY 2005

CHAPTER 6:

Water Consumption, Wastewater Generation and

Integrated Water Management 6. WATER CONSUMPTION, WASTEWATER GENERATION AND

INTEGRATED WATER MANAGEMENT _____________________ 6-1 6.1 Introduction and Methodology _________________________________________ 6-1

6.1.1 Background_______________________________________________________ 6-1 6.1.2 Objectives of the Specialist Study _________________________________________ 6-1 6.1.3 Approach to the Updated Water Consumption, Wastewater Generation and Review of Integrated Water Management Study _____________________________________________________ 6-2

6.2 Updated Project Description___________________________________________ 6-3 6.2.1 Water Use _______________________________________________________ 6-3 6.2.2 Wastewater discharge ________________________________________________ 6-4 6.2.3 Surface Water and Groundwater Environments _______________________________ 6-6 6.2.4 Applicable Legislation and Permits _______________________________________ 6-8

6.3 Key Issues Potentially Affected by Changes in the Project Proposal____________ 6-8 6.3.1 Construction Phase__________________________________________________ 6-8 6.3.2 Operations Phase ___________________________________________________ 6-8 6.3.3 Decommissioning Phase _______________________________________________ 6-9

6.4 Interpretation and Assessment of the Original Record of Decision ____________ 6-14 6.4.1 ROD Section 8.6 _________________________________________________ 6-14 6.4.2 Discussion of ROD Section 8.6 ________________________________________ 6-18

6.5 Updated Impact Assessment and Mitigation _____________________________ 6-21 6.5.1 Water Use During Construction ________________________________________ 6-21




6.5.2 Water Use During Operation__________________________________________ 6-22 6.5.3 Wastewater Generated During Construction ________________________________ 6-23 6.5.4 Wastewater Generated During Operation __________________________________ 6-23 6.5.5 Process Wastewater and Stormwater Treatment Considerations ____________________ 6-30 6.5.6 Integrated Stormwater Management Options ________________________________ 6-33 6.5.7 Summary of Process Wastewater and Stormwater Management Options ______________ 6-41 6.5.8 Impact Summary __________________________________________________ 6-44

6.6 Re-Consideration of the Best Practicable Environmental Option (BPEO) _______ 6-50 6.7 Review of Implications for the Record of Decision_________________________ 6-50

List of Figures Figure 6.1 Stormwater catchments included in the integrated stormwater analysis for the

CAS site ________________________________________________________ 6-34

List of Tables Table 6.1 Coega Aluminium Smelter water use___________________________________ 6-4 Table 6.2 Coega Aluminium Smelter wastewater discharges ________________________ 6-6 Table 6.3 Construction phase issues __________________________________________ 6-10 Table 6.4 Operations phase issues ___________________________________________ 6-11 Table 6.5 Decommissioning phase issues______________________________________ 6-13 Table 6.6 Required stormwater quality (95 percentile) for discharge from CAS site ______ 6-16 Table 6.7 Required fluoride limits for effluent discharges __________________________ 6-20 Table 6.8 Estimated fluoride concentrations in stormwater _________________________ 6-25 Table 6.9 Analysis of dry periods for Year 2000 (Port Elizabeth) ____________________ 6-26 Table 6.10 Analysis of dry periods for July 2003 to Present (April 2005) (Coega IDZ) _____ 6-27 Table 6.11 Contaminated stormwater composition ________________________________ 6-28 Table 6.12 List of relevant stormwater catchment areas that feed into the CDC stormwater

system leading to the port __________________________________________ 6-35 Table 6.13 Estimated fluoride concentrations in stormwater (Scenario 1: 20 mm rain in 1 hour

after 3 month dry spell) ____________________________________________ 6-36 Table 6.14 Estimated fluoride concentrations in stormwater (Scenario 3: As per Scenario 1 with

spillage of additional 50 kg of fluoride per month) ________________________ 6-37 Table 6.15 Estimated fluoride concentrations in stormwater (Scenario 4: As per Scenario 1 with

spillage of additional 100 kg of fluoride per month) _______________________ 6-38 Table 6.16 Estimated fluoride concentrations in combined stormwater to port ___________ 6-39




Table 6.17 Limits that could apply to stormwater releases from the Coega IDZ to the harbour______________________________________________________ 6-40

Table 6.18 Coega Aluminium Smelter options considered for management of contaminated stormwater and process wastewater __________________________________ 6-42

Table 6.19 Advantages and disadvantages of contaminated stormwater and process wastewater management options ______________________________________________ 6-43

Table 6.20 Base scenario: summary of impacts of the proposed AP35 Coega Aluminium Smelter_________________________________________________________ 6-47

Table 6.21 Upside scenario: summary of impacts of the proposed AP35 Coega Aluminium Smelter_________________________________________________________ 6-48




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6. WATER CONSUMPTION, WASTEWATER GENERATION AND INTEGRATED WATER MANAGEMENT

This section is based on the specialist study by Philip de Souza and Grant Mackintosh.

6.1 Introduction and Methodology 6.1.1 Background

During 2002, an Environmental Impact Assessment (EIA) was carried out on behalf of Aluminium Pechiney (AP) for a proposed smelter within the Coega Industrial Development Zone. The proposed smelter would operate using new generation smelting technology (AP50). Following the EIA process, the Department of Economic Affairs, Environment and Tourism (DEAE&T) granted AP authorisation for the development of the aluminium smelter subject to the conditions specified in the Record of Decision (ROD). The ROD clearly specified that additional investigations surrounding water consumption and wastewater generation were required. In particular, the ROD specified that treatment and re-use of process wastewater and stormwater be investigated. Considering the above, AP commissioned a study to investigate wastewater treatment options with special emphasis on stormwater and process wastewater. This study (de Souza et al, 2003) considered the technical feasibility of wastewater treatment options (including Zero Industrial Effluent Discharge) and included cost analyses of the various options. The project proponents could then use findings from the study to determine the most suitable solution. 6.1.2 Objectives of the Specialist Study

The overall approach of the specialist study is to identify the changes in technology and design from the AP50 to the AP35 proposal, determine where these might alter the predicted significance of the environmental impacts, and review the mitigation measures accordingly. A further objective of this study is to include the key findings of the wastewater treatment study for the Coega Aluminium Smelter that was undertaken in 2003 (CSIR, 2003). The primary objective of this study is to identify the significance of possible environmental impacts of water use, domestic sewage discharge, process wastewater discharge and stormwater discharge for a Coega Aluminium Smelter based on AP35 technology. The updated specialist study will therefore enable an informed decision to be made regarding the environmental feasibility of the proposed project. This report represents the specialist review on “Water Consumption, Wastewater Generation and Review of Integrated Water Management”. This review will be combined with the other updated




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specialist inputs in the form of a Technology Review report, which will be presented to DEAE&T for consideration. 6.1.3 Approach to the Updated Water Consumption, Wastewater Generation and

Review of Integrated Water Management Study

The general approach used in this study was to review findings from the existing studies based on AP50 technology, and to update models previously developed to take into account changes resulting from the use of AP35 technology (for both the base scenario and the upside scenario). The following sources of information were reviewed:

Final Environmental Impact Report – Chapter 9: Impact Assessment and Mitigation: Water Use and Liquid Waste, dated November 2002(CSIR, 2002)

Record of Decision ECm1/1/48-02, dated December 2002, issued for the EIA (available at http://smelter.csir.co.za)

Coega Aluminium Smelter: Review of Wastewater Treatment Options with Special Emphasis on Stormwater and Process Wastewater, dated September 2003 (CSIR, 2003)

Coega Aluminium Smelter: Terms of Reference for an Extension to the Coega Development Corporation’s Surface Water Quality Monitoring Programme and an On-site Hydrogeological Verification Study, dated November 2003. Prepared by CSIR.

Coega Aluminium Smelter: Terms of Reference for Drilling Groundwater Monitoring Boreholes for the On-site Hydrogeological Verification Study, dated November 2003. Prepared by CSIR.

Application: Integrated Stormwater Management, dated October 2003. Prepared by Coega Development Corporation.

Specific information provided by the project proponents, including:

Updated Coega Aluminium Smelter site layout provided by Alcan CAS Project: Terms of Reference Differences between AP50 and AP35

Technology South Africa – Coega Site, dated September 2004 (Alcan, 2004); and subsequent interactions with Alcan via email during early 2005.

In addition, the following information was updated:

Mr Dave Raymer of Nelson Mandela Metropolitan Municipality (NMMM) was contacted to review and update figures surrounding spare capacity of water and wastewater treatment works that had previously been proposed for use by the Coega Aluminium Smelter.

Dr Mark Zunkel and Mr Greg Scott of CSIR Environmentek (who are conducting the updated specialist study on air emissions), were contacted to provide updated figures surrounding maximum fallout of fluoride on the proposed site.




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NOTE: The original specialist study considered rainfall data and Coega River water quality data in some detail. As this information is still considered to be applicable for this assessment, updated rainfall data and Coega River water quality has not been considered. As per the original EIA specialist study, updated information was used to re-assess the impact of water use, and wastewater generation and in particular recalculate the potential fluoride concentrations in stormwater, with “worst case” scenarios used to determine the significance of impacts. Based on the significance of impacts, recommendations have been made regarding mitigation measures, environmental management and monitoring.

6.2 Updated Project Description The following section highlights changes to the water use and wastewater generation as a result of the proposed change in technology from AP35 to AP50. 6.2.1 Water Use

The following water uses were previously noted: Preliminary earthworks Smelter construction Smelter operation Drinking-water Process water Fire fighting water

From review of information provided for the AP35 technology by the project proponents, it appears as though the same quality of water as previously noted for the AP50 technology will be required. The quantity of water, however, is likely to change. Although quantities for the preliminary earthworks and smelter construction have not been finalised, it has been noted by the project proponents that the quantities required will be in relation to the smelter surface area. Therefore considering the decrease in total cleared area from 135 ha (for AP50 technology) to 120 ha (for AP35 technology), the water used in these phases is likely to be less. Furthermore, the project proponents have noted an expected increase in domestic drinking-water use from ~80 000 m3/yr (for AP50) to ~84 000 m3/yr (for AP35 base scenario) (i.e. an increase of 6.2%) and to ~87 000 m3/yr (for AP35 upside scenario) (i.e. an increase of 8.7%). An increase in process water use from ~500 000 m3/yr (for AP50) to ~940 000 m3/yr (for AP35 base scenario) (i.e. an increase of 88%) and to ~1 036 800 m3/yr (for AP35 upside scenario) (i.e. an increase of 107%) is also noted.




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Although no details have been provided with regards to fire fighting water, it is assumed that similar quantities of water would be required. Water use requirements for AP50 technology and AP35 technology are compared in the table below.

Table 6.1 Coega Aluminium Smelter water use Phase Water Use (AP50) Water Use (AP35) Base Scenario Upside Scenario Preliminary earthworks

2 ℓ/s Likely to be less (based on smaller surface area)

Likely to be less (based on smaller surface area)

Smelter construction

144 000 m3/yr Likely to be less (based on smaller surface area)

Likely to be less (based on smaller surface area)

Smelter operation – drinking water

80 000 m3/yr 84 000 m3/yr 87 000 m3/yr

Smelter operation – process water

600 000 m3/yr 940 000 m3/yr 1 036 800 m3/yr

Smelter operation – Fire fighting water

400 m3/hr during 1 hour

Not specified but expected to be similar

Not specified but expected to be similar

6.2.2 Wastewater discharge

The following wastewater discharges were previously noted:

Domestic wastewater Process wastewater Stormwater

From review of information provided for the AP35 technology by the project proponents the following is noted:

Domestic wastewater Domestic wastewater generated will still be discharged into the municipal sewer network for treatment at the Fish Water Flats Wastewater Treatment Works. The project proponents have stated that the same quality of domestic wastewater produced for the AP50 technology is expected for the AP35 technology. The quantity of domestic wastewater generated is likely to increase from ~80.000 m3/yr (for AP50 technology) to ~84.000 m3/yr (for AP35 technology base scenario) (i.e. an increase of 5%) and to ~87.000 m3/yr (for AP35 technology upside scenario) (i.e. an increase of 8.7%).

Process wastewater Although the project proponents state that the quality of the process wastewater produced would be the same for both AP50 and AP35 technologies, the quantity of process wastewater produced




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is likely to increase from ~300 000 m3/yr (for AP50) to ~470 000 m3/yr (for AP35 base scenario) (i.e. an increase of 56.7%) and to ~518 400 m3/yr (for AP35 upside scenario) (i.e. an increase of 72.8%). In the AP50 study, three options were investigated for process wastewater discharge, namely:

Process wastewater from re-circulating process cooling water circuits is discharged into the site stormwater system

Process wastewater is used for irrigation on site Process wastewater is sent to the Fish Water Flats Sewage Treatment Works.

In addition, the subsequent investigation of wastewater treatment options also considered treatment of process wastewater for re-use in the smelter. The applicability of the above four options will need to be reconsidered. Furthermore, other possible options arsing should also be considered.

Stormwater As per the study conducted for AP50 technology, high fluoride concentrations (from air emissions and on-site spillages) are likely to have the highest environmental impact. While the magnitude and frequency of fluorinated material spillages on the site is difficult to model/predict in a meaningful manner, experience at other South African aluminium smelters has shown that this source can contribute from 10 mg/ℓ to 50 mg/ℓ of fluoride to stormwater. It must also be borne in mind that, in terms of water use licensing and authorisation, the stormwater from the smelter site is to be regarded as a wastewater (CSIR, 2002, section 9.3.2). The quantities of stormwater are likely to be similar for AP35 technology as for AP50 technology and will vary according to the actual rainfall on the site. However, as the air emissions study has indicated an increase in the fluoride maximum fallout value from 150 mg/m2/month (for AP50) to 195 mg/m2/month (for AP35 base scenario) (i.e. an increase of 30%) and to 212.5 mg/m2/month (for AP35 upside scenario) (i.e. an increase of 41.7%), the stormwater quality is likely to be affected. In addition, a decrease in hardened surfaces from 50 ha (for AP50) to 42.5 ha (for AP35 base scenario) and to 45 ha (for AP35 upside scenario) will reduce the total quantity of fluoride that is captured in the stormwater (i.e. the amount of fluoride in the stormwater is dependant on both the mass of fluoride deposited on the hardened surfaces and the area of the hardened surfaces). Furthermore, the project proponents have stated that the stormwater system design principles proposed for the AP50 technology will be utilised for the AP35 technology (see Section 9.6 of EIR). This includes sediment capture (via a sedimentation basin), “first flush” collection (in an interceptor pond with volume of 14 000 m3) and by-pass of the interceptor pond with flow of stormwater to attenuation dam (when the interceptor pond is filled with “first-flush” stormwater).




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Wastewater discharges for AP50 technology and AP35 technology are compared in the following table.

Table 6.2 Coega Aluminium Smelter wastewater discharges

6.2.3 Surface Water and Groundwater Environments

Both the surface water environment and the groundwater environment are unlikely to have any additional impacts associated with the proposed change from AP50 to AP35 technology. The following is noted:

Surface water environment The Coega River is a relatively small sand-bed ephemeral river in the Coega IDZ and is the most significant surface water feature associated with the proposed project. As noted in the initial EIA, in the lower reaches of the Coega River (near to the proposed smelter location), the ecological state of the river is already critically modified and environmentally degraded. In addition, it was noted that the lowest section of the river (from the N2 road to the coast) would possibly be re-classified as a marine environment, as it is dominated by the activities of the saltworks. Linked to the above, and in order for the Coega Development Corporation (CDC) to monitor the environmental performance by industries in the future, an independent surface water quality monitoring system has been established where water quality is monitored at six locations along the Coega River (upstream, intermediate and downstream of the IDZ). Monitoring has indicated that the pH of the Coega River is neutral to slightly alkaline, while the electrical conductivity varied from 222 mS/m to a maximum of 8 630 mS/m (similar to seawater). Furthermore, the water is characterized by a Na/Cl signature, (due to the influence of sea water), while trace

Wastewater stream

Quantity (AP 50)

Quantity (AP 35)

Quality (AP50 vs. AP35)

Base Scenario Upside Scenario

Domestic wastewater 80 000 m3/yr

84 000 m3/yr

87 000 m3/yr

Same

Process wastewater 300 000 m3/yr 470 000 m3/yr 518 400 m3/yr Same

Stormwater

Varies according to rainfall

(NOTE: The average volume

of stormwater was previously

estimated to be approximately 250 000 m3/yr

(based on average rainfall in

Port Elizabeth (CSIR, 2003)

Varies according to rainfall (NOTE:

Considering the decrease in the

area of hardened surfaces, the

average volume of stormwater is estimated to be approximately 212 500 m3/yr)

Varies according to rainfall (NOTE:

Considering the decrease in the

area of hardened surfaces, the

average volume of stormwater is

estimated to be approximately 225 000 m3/yr)

Needs re-evaluation

(NOTE: The Technology Review

considers the change in predicted fluoride concentrations. The concentrations of the other constituents of

concern are considered unchanged)




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metals are generally within required specifications. In addition, bacteriological indicators (e.g. E. Coli, which is a direct indicator of faecal pollution) were detected. Rivers with high levels of faecal contamination are problematic from both a public and environmental health perspective. Finally, it is important to note that the project proponents have noted that no liquid wastes produced by the smelter would be discharged to the Coega River.

Groundwater environment As noted in the initial EIA, the shales found on the proposed site are expected to act as an aquitard on site (i.e. rainfall infiltration is limited), with no aquifer use potential. Use of groundwater for potable water use is therefore not currently considered as a viable alternative to surface water (i.e. the area is currently largely reliant on surface water sources for potable water requirements). Nevertheless, groundwater impacts on- and off-site should be considered with respect to: The current role groundwater may play in the natural environment (and its current degree of

modification from pristine conditions) Groundwater on the site may act as a pathway to receiving environments or users down

gradient of the site. It is expected that groundwater gradients will mirror the topography (following surface water drainage direction) and it is therefore expected that any groundwater flow from the site would be approximately towards the coast. The only evident potential receptor for groundwater impacts is therefore the coastal environment. This environment may rely on groundwater inputs to control salinity or provide nutrients or trace elements. As per surface water, the CDC has established an independent groundwater quality monitoring system in the Coega IDZ to monitor the environmental performance by industries in the future. At present, groundwater quality is monitored at eight locations in the Coega IDZ. Monitoring has indicated that the pH of the groundwater is neutral to slightly alkaline, while the electrical conductivity (salinity) increases towards the sea (from 745 mS/m to 3 148 mS/m). A sodium chloride signature characterizes the groundwater (influence of sea water). Furthermore, the groundwater contains higher concentrations of all trace metals than surface water samples. The highest trace metal concentrations (iron and manganese) are generally measured in samples collected nearest the coast (probably due to soil-water interactions). In addition, E.coli (bacteriological indicator) was detected. The previous sections have highlighted the status of both surface- and groundwater in the Coega IDZ, and indicate that the surface water quality is not ideal/pristine and that no potential for use of groundwater for drinking-water purposes exists.




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6.2.4 Applicable Legislation and Permits

All legislation previously applicable to the AP50 technology is also applicable to implementation of AP35 technology. In addition, granting of permits will be subject to satisfaction of the stipulations of the ROD. It is therefore necessary to re-evaluate the scenarios previously developed for the AP50 technology to assess whether the ROD conditions will be satisfied.

6.3 Key Issues Potentially Affected by Changes in the Project Proposal

6.3.1 Construction Phase

During the construction phase, water will be required for the preliminary earthworks, the construction of the various components of the Coega Aluminium Smelter and for domestic purposes. During the construction phase, pollution of ground and surface water resources can result from release, accidental or otherwise, of contaminated runoff from construction sites and discharge of construction water contaminated by, for example, chemicals, oils, fuels, sewage, solid waste, litter, etc. Nevertheless, during construction increased turbidity and downstream sedimentation (arising from erosion from construction areas) is likely to be the main water quality concern. During construction, adequate sanitation facilities (e.g. portable toilets) will be required. Although the project proponents have not confirmed the quantities of water required during construction, comparison between AP50 and AP35 technology indicates that similar quantities of water (or potentially less water) would be required. The aforementioned issues are summarised in Table 6.3. 6.3.2 Operations Phase

During the operations phase, the water usage for the plant is approximately 940 000 m3/year (or 107 m3/hr) for process water and approximately 84 000 m3/year (or 9.6 m3/hr) for domestic water for the AP35 technology base scenario, whereas water usage for the plant is approximately 1 036 800 m3/year (or 118 m3/hr) for process water and approximately 87 000 m3/year (or 9.9 m3/hr) for domestic water for the AP35 technology upside scenario. Key issues related to water utilization are the availability of water, the optimisation of on-site water use and the prevention of pollution arising from wastewater discharges. During the operations phase, the three main liquid discharges from the site will be domestic sewage, process wastewater and stormwater, in particular the “first flush” of stormwater (i.e. first rain run-off after a dry period) which usually carries a higher concentration of potential pollutants. In addition, any liquid wastes from on-site wastewater treatment will need to be discharged




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appropriately. A key issue related to water discharges from the site is the risk of pollutants reaching any environmentally sensitive areas. Comparison between AP50 and AP35 technology indicates that:

AP35 technology will require substantially more process water (~88% for the base scenario and ~107% for the upside scenario) and will subsequently produce more process wastewater.

Domestic water requirements and subsequent domestic wastewater discharge requirements are similar for both technologies.

The volume of stormwater is likely to decrease due to a decrease in the area of hardened surfaces from 50 ha to 42.5 ha (for the base scenario) and to 45 ha (for the upside scenario). Based on average rainfall in the Port Elizabeth area, the volume stormwater would decrease slightly from approximately 250 000 m3/yr to approximately 212 500 m3/yr (for the base scenario) and to approximately 225 000 m3/yr (for the upside scenario)

Fluoride concentrations in stormwater are likely to increase for the AP35 proposal as a result of increased atmospheric emissions of fluoride and associated deposition of fluoride on the ground. (NOTE: the increase in fluoride emissions is proportional to the increase in aluminium production).

The aforementioned issues are summarised in Table 6.4. 6.3.3 Decommissioning Phase

During the decommissioning phase, only problems related to containment and discharge of contaminated stormwater and other runoff from decommissioning procedures are envisioned. The aforementioned issues are summarised in Table 6.5.




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Table 6.3 Construction phase issues

Issue/concern identified Potential Source of Impact Potential Impact Risk Situation Will water used during the construction phase have a significant impact on water required by NMMM for normal service delivery?

Water used for construction (earthworks, cement concrete production, etc) and for domestic purposes Conditions may be such that all present and future demands cannot be met (normal weather conditions) Drought conditions can have a significant impact on water availability

Potential negative impact arises via water use by project overreaching local water supply infrastructure Potential negative impact arises via water use by project exceeding sustainable yield of water resources

Impact would occur if the water reserve is not sufficient to meet demands of consumers (public and industry) and ensure protection of the environment (e.g. drought conditions exist which results in an inability to meet all water demands) Impact would occur if the present spare capacity Nooitgedacht Water Treatment Works is completely utilised by new industry and future requirements by communities cannot be met (without enlarging the present water treatment works).

Will wastewater (stormwater and other runoff, domestic, etc) generated during the construction phase negatively impact the local environment (surface water, groundwater, marine)?

Release of contaminated stormwater and discharge of other runoff contaminated by, for example, chemicals, oils, fuels, sewage, solid waste, litter, etc Increased turbidity and downstream sedimentation (arising from erosion from construction areas) Release of untreated domestic sewage into the surrounding environment

Depending on the nature of the contaminants, the release of contaminated stormwater and other runoff can negatively impact the surrounding environment. (NOTE: Any wastewater discharges from the site must meet with required legislative requirements) The release of untreated domestic sewage could have an impact on environmental and community health

Impact would occur if structures to contain and treat contaminated wastewaters are not in place Impact would occur if stormwater containment structures overflow Impact would occur if contaminated wastewaters are discharged in an inappropriate manner Impact would occur if on-site sanitation services are not as required or if sanitation practices are not followed by personnel




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Table 6.4 Operations phase issues

Issue/concern identified Potential Source of Impact Potential Impact Risk Situation Will water used during the operations phase have a significant impact on water required by NMMM for normal service delivery?

Water used for various on-site processes and for domestic purposes Conditions may be such that all present and future demands cannot be met (normal weather conditions) Drought conditions can have a significant impact on water availability

AP35 technology results in the use of higher quantities of process water Potential negative impact arises via increased water use by project overreaching local water supply infrastructure Potential negative impact arises via increased water use by project exceeding sustainable yield of water resources

Impact would occur if the water reserve is not sufficient to meet demands of consumers (public and industry) and ensure protection of the environment (e.g. drought conditions exist which results in an inability to meet all water demands) Impact would occur if the present spare capacity Nooitgedacht Water Treatment Works is completely utilised by new industry and future requirements by communities cannot be met (without enlarging the present water treatment works).

Will domestic sewage negatively impact the local environment (surface water, groundwater, marine)?

Release of untreated domestic sewage into the surrounding environment

The release of untreated domestic sewage could have an impact on environmental and community health

Impact would occur if on-site sanitation services are not as required or if sanitation practices are not followed by personnel

Could untreated process wastewater be discharged into the local environment (surface water, groundwater, marine)?

Release of untreated process wastewater into the surrounding environment (e.g. accident)

AP35 technology results in the production of higher quantities of process wastewater Depending on the nature of the contaminants, the release of untreated process wastewater can negatively impact the surrounding environment. (NOTE: Any wastewater discharges from the site must meet with legislation requirements)

Impact would occur if untreated process wastewaters are discharged in an inappropriate manner




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Issue/concern identified Potential Source of Impact Potential Impact Risk Situation Will treated process wastewater negatively impact the local environment (surface water, groundwater, marine)?

Release of treated process wastewater effluent into the surrounding environment

Depending on the nature of the contaminants, the release of treated process wastewater that does not satisfy required legislative quality requirements can negatively impact the surrounding environment.

Impact would occur if treated wastewater does not meet required specifications and is still discharged to the environment Impact would occur if wastewater treatment plant fails and untreated or poorly treated process wastewaters are discharged in an inappropriate manner

Will brine and other concentrated wastes from treatment processes have a negative impact on the local environment (surface water, groundwater, marine)?

Release of brine and other concentrated wastes into the surrounding environment. (If on-site treatment is practiced, concentrated wastes will be produced. These wastes will need to be handled appropriately.)

The release of brine and other concentrated wastes can negatively impact the surrounding environment.

Impact would occur if brine and other concentrated wastes are discharged in an inappropriate manner

Will contaminated stormwater have a negative impact on the local environment (surface water, groundwater, marine)?

Release of contaminated stormwater into the surrounding environment

AP35 technology may result in a higher fluoride load to stormwater. The stormwater quality may therefore not meet current ROD requirements. The release of contaminated stormwater from the site can negatively impact the surrounding environment. (NOTE: Any contaminated stormwater discharges from the site must meet with legislation requirements)

Impact would occur if structures to contain stormwater are not in place Impact would occur if stormwater containment structures overflow




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Table 6.5 Decommissioning phase issues

Issue Potential Source of Impact Potential Impact Risk Situation Will stormwater and other runoff generated during the decommissioning phase negatively impact the local environment?

Discharge of contaminated stormwater and other runoff from the site Increased turbidity and downstream sedimentation (arising from erosion)

Depending on the nature of the contaminants, the release of contaminated stormwater and other runoff can negatively impact the surrounding environment

Impact would occur if structures to contain stormwater are not in place Impact would occur if stormwater containment structures overflow




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6.4 Interpretation and Assessment of the Original Record of Decision

In order to determine the impact of technology changes, it is necessary to understand the specific requirements of the original ROD. The following section therefore highlights conditions of authorization (conditions for approval of the proposed aluminium smelter) issued by the Department of Economic Affairs, Environment and Tourism pertaining to water use and liquid waste (ROD section 8.6) and provides brief commentary on key points. 6.4.1 ROD Section 8.6

The following points are extracted from the ROD:

8.6 Conditions pertaining to water use and liquid waste 8.6.1 Process water (cooling water blow-down) must be treated on site for re-use in the

smelter, or diverted to the foul water sewer for treatment and disposal through the municipal treatment works.

8.6.2 If process water is diverted to the foul water sewer, Aluminium Pechiney must enter

into a trade effluent agreement with the Nelson Mandela Metropolitan Municipality to dispose of the daily quantity of process water to the Municipal Water Treatment Works (at Fishwater Flats).

8.6.3 Aluminium Pechiney must also seek written approval from the NMMM to substitute

the cooling water blow-down with collected storm water, in the event of such storm water being more contaminated than the cooling water blow-down.

8.6.4 A Storm and Waste Water Management Plan to be compiled to the satisfaction of

DEAE&T, DWAF, CDC and other relevant authorities. 8.6.5 DWAF to approve the Storm and Waste Water Management Plan prior to construction

of any permanent storm water infrastructure. 8.6.6 The Storm and Waste Water Management Plan must be informed by a detailed study,

which must consider amongst others:

8.6.6.1 A comprehensive water balance; 8.6.6.2 The principles of prevent, separate, concentrate and contain; 8.6.6.3 An assessment of all appropriate management options and mitigatory

measures including waste water minimisation, treatment, and contractual aspects;

8.6.6.4 Identification of sources of fluoride and other pollutants reported to contaminate storm water;




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8.6.6.5 Mitigation measures of how such sources can be designed and engineered at source so that the potential for pollution is eliminated;

8.6.6.6 The option of total storm water containment, treatment and re-use on site. 8.6.6.7 Appropriate site selection (to be sited over an aquitard area of the shales

underlying the site) and design plans for the interceptor pond and attenuation dam.

8.6.7 The storm water management infrastructure constructed on site must reflect the

approved storm water management plan and must be fully functional prior to any process materials being brought on-site.

8.6.8 Any storm water dams/ponds that will be constructed as part of the storm water

management infrastructure must be designed to contain runoff from a 1:100 year storm event, and must be registered and licensed in terms of section 21(g) of the National Water Act, Act 36 of 1998.

8.6.9 A license in terms of condition 8.6.8 will not be issued until conditions 8.6.1, 8.6.2,

and 8.6.3 have been satisfactorily addressed. 8.6.10 Construction of the ponds contemplated in point 8.6.8 may only commence once

licensing of such has been confirmed by DWAF. 8.6.11 The interceptor pond must be designed and constructed to trap particulates. 8.6.12 Particulate matter captured in the storm water system must be stipulated in the waste

inventory and disposal thereof addressed in the Waste Management Plan. 8.6.13 The interceptor pond and attenuation dam must be lined with an appropriate

impermeable material/substance to the satisfaction of DWAF and DEAE&T. 8.6.14 Subject to conditions 8.6.1 to 8.6.6, storm water not re-used on site or diverted for

treatment may be released into the storm water reticulation of the CDC, provided that it complies with the quantity and quality requirements specified by the CDC Storm Water Management Plan and in terms of CDC’s water use license.

8.6.15 As a minimum, storm water leaving the Aluminium Pechiney site to conform (95

percentile) to the standard as set out in the table below.




Page 6-16

Table 6.6 Required stormwater quality (95 percentile) for discharge from CAS site

Constituent name Unit Stormwater concentration Total suspended solids (TSS) mg/l 9.8 F mg/l 21.3 Al µg/l 9000.0 CN free µg/l 10.0 Ag µg/l 1.0 As µg/l 50.0 Be µg/l 3.0 Cd µg/l 2.5 Cr µg/l 20.0 Cu µg/l 35.0 Fe µg/l 350.0 Hg µg/l 1.0 Ni µg/l 60.0 Pb µg/l 5.0 Sb µg/l 10.0 Se µg/l 3.0 Sn µg/l 4.0 Ti µg/l 5.0 V µg/l 3.0 Zn µg/l 180.0 Total hydrocarbons mg/l 0.4 Phenol mg/l 0.02 PAH’s: Naphthalene µg/l 1 Benzo(a)Pyrene µg/l 1

8.6.16 Storm water discharge to the port must not increase the need to dredge the port above the normal dredging requirements for port operations. If discharge of storm water containing waste results in the deposition and accumulation of contaminants, specific investigations into origins, discharge limits and pre-treatment will be necessary. Results of such investigations to be implemented to the satisfaction of the relevant authorities.

8.6.17 Aluminium Pechiney to adopt water conservation best practice including but not

limited to the following: 8.6.17.1 Implement water saving devices for domestic water use at the smelter (e.g.

dual flush toilets, automatic shut-off taps, etc.);




Page 6-17

8.6.17.2 As a general principle, potable water should not be used for irrigation purposes and landscapes must be designed to absorb rainwater run-off rather than having to carry it off-site in storm water drains;

8.6.17.3 Indigenous vegetation to be used for landscaping to minimise watering requirements;

8.6.17.4 Cleaning methods utilised for the cleaning of vehicles, floors etc. must aim to minimise water use;

8.6.17.5 Maintenance of proper pressure within fire water systems to limit water use; 8.6.17.6 Conducting of regular audits of water systems to identify and rectify any

possible water leakages; and 8.6.17.7 Implementing a system for the proper metering and measurement of water

use and wastewater discharges to enable proper performance review and management.

8.6.18 Aluminium Pechiney to undertake a geo-hydrological study to verify and supplement

existing groundwater information. 8.6.19 DWAF to be kept informed of events/incidents that could lead to water pollution within

48 hours. 8.6.20 DWAF to be involved in any mitigation/corrective measures undertaken as a result of

such events/incidents. 8.6.21 A monitoring programme for water related impacts to be compiled and implemented

to ensure that the predictions of the EIR are correct and such monitoring programme to be approved by DWAF before licenses/registrations required in terms of conditions 8.4.9 and 8.6.8 will be issued. Such a monitoring programme must amongst others consider: 8.6.21.1 The quality and quantity of process wastewater; 8.6.21.2The quality and quantity of storm water; 8.6.21.3 Continued monitoring of both local surface and ground waters upstream and

downstream of the smelter site. 8.6.21.4 Determination of both particulate and dissolved concentrations of

contaminants with separate reporting. 8.6.21.5 Monitoring of storm water (including all the contaminants identified in

condition 8.6.15) at the point where it leaves the property of Aluminium Pechiney.

The above ROD conditions of authorization are still valid for the proposed Coega Aluminium Smelter using AP35 technology.




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6.4.2 Discussion of ROD Section 8.6

The above ROD conditions of authorization clearly indicate that the project proponents are required to investigate:

Process wastewater treatment and re-use Contaminated stormwater treatment and re-use The exchange of process wastewater with stormwater in the event that stormwater is

more contaminated than the process wastewater (for the situation where process water is being sent to the sewer system).

The feasibility of these options was investigated in the study entitled Coega Aluminium Smelter: Review of Wastewater Treatment Options with Special Emphasis on Stormwater and Process Wastewater (CSIR, 2003). As part of the investigation, the decisions and required actions presented in the ROD (Section 8.6) were reviewed. A number of pertinent points noted from specific clauses are discussed in the following section. The following points should be noted:

Wrt Clause 8.6.1 This clause indicates that process water must be treated on-site for re-use in the smelter OR diverted to the sewer for treatment and disposal through the municipal treatment works. Therefore if an agreement cannot be reached with NMMM for process wastewater discharges (e.g. salinity of blowdown may negatively impact on existing sewer system through causing corrosion), then on-site treatment for re-use purposes is the only other option.

Wrt Clause 8.6.3 This clause indicates that the possibility of substituting contaminated stormwater for process wastewater must be investigated. However, such an approach is not a practically feasible solution from the outset and can only be established with time. The reasons for this are: Different constituents contaminate Process wastewater and stormwater and the relative

toxicities of these contaminants are unknown. It is therefore not possible to determine which wastewater stream is more contaminated.

Stormwater quality will vary constantly depending on rainfall patterns and onsite management of spillages. As water quality measurement is not undertaken on a continuous basis, and water quality analysis results are not immediately available, it is practically impossible to determine when stormwater is more polluted than process wastewater (not taking into account the difficulties associated with comparing the relative toxicity of waters contaminated by different constituents as described above). The technical feasibility of a sustainable solution is therefore questioned. There is therefore, at this stage, no simple way (e.g. via a model) to determine when the contaminated stormwater will be of a better quality




Page 6-19

than the process wastewater. Information will only be available from practical experiences gained during operation. Substitution would also only be possible if agreed to by NMMM, with the quantity of contaminated stormwater allowed to be discharged limited to the agreed quantity of process wastewater discharged.

In addition to the above, if treatment and re-use of process wastewater and contaminated stormwater is implemented, disposal to the municipal sewer would be avoided. The specialists therefore feel that this clause of the ROD should be revised and that the condition does not require further investigation.

Wrt Clause 8.6.6.6 and 8.6.8 These clauses indicate that the option of TOTAL stormwater containment, treatment and re-use be investigated. However, TOTAL stormwater containment, treatment and re-use is not a practically feasible solution. The reasons for this are: Only the “first flush” stormwater will be contaminated whilst subsequent rainfall can be

considered to be uncontaminated stormwater (i.e. not an industrial effluent) and can be discharged without associated negative effects to the receiving environment.

Infrastructural requirements (capital costs, operation and maintenance costs) to ensure that ALL stormwater from ALL rainfall events are contained, treated and re-used will be prohibitive (i.e. sizing water treatment equipment for an extreme rainfall event is not economically feasible).

In addition to the above, the project proponents requested the specialists to investigate the feasibility of increasing the size of the proposed interceptor pond. This would increase the volume of stormwater that could be contained on-site for re-use purposes. However, it should be acknowledged that such systems cannot be designed to contain all rainfall events, and that in extreme cases overflow of the interceptor pond will occur. However, with a large interceptor pond, the risk of discharge/overflow of contaminated stormwater off-site will be greatly reduced. Based on the above, the specialists felt that investigating the option of CONTAMINATED stormwater containment, treatment and re-use was more feasible. Dependant on the final proposed capacity of the interceptor pond, uncontaminated stormwater (following the “first flush”) should not be considered as an industrial effluent (and will therefore not require further containment, treatment and re-use).

Wrt Clause 8.6.15 This clause sets out the stormwater quality discharge requirements. Fluoride concentration requirements used in other countries are included in Table 6.7 for comparative purposes.




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Table 6.7 Required fluoride limits for effluent discharges

Country Location National Regulations Permit Requirements Water Quality Objectives Effluent Limits WHO World Bank

New aluminium smelter : 20 mg/l

EU EU states Drinking water : limit 1,5 mg/l objective 1 mg/l Fishing water : no limit Shell-fishing farming : no limit Bathing water : no limit

No limit (fluoride is not a priority substance)

Australia Tomago Drinking water : limit 1 mg/l No limit (fluoride is not a priority substance)

40 mg/l (Hunter River - estuarine)

Cameroon Edea - - No limit (Sanaga) Quebec Becancour 11 mg/l (St Laurent River - fresh)

Auzat 15 mg/l (Vicdessos river - fresh) Dunkerque 10 mg/l dry weather (North Sea)

20 mg/l any time

Lannemezan 15 mg/l (Baïse river - fresh)

France

Saint-Jean-de-M.

EU General limit : 15 mg/l New aluminium smelters : 25 mg/l

15 mg/l (Arc river - fresh)

Greece Aghios Nikolaos EU - No limit (Mediterranean Sea) The Netherlands Vlissingen EU 50 mg/l (North Sea) British Columbia New aluminium smelters : 15 mg/l -




Page 6-21

Wrt Clauses 8.6.14 and 8.6.16 These clauses state that stormwater not treated/re-used on site may be released into the storm water reticulation of the CDC (provided that it complies with the quantity and quality requirements specified in the CDC Storm Water Management Plan and CDC’s water use licence) and that stormwater discharges to the port must not increase the need to dredge the port above the normal dredging requirements for port operations. The ROD states that “stormwater leaving the site” may not exceed the specified concentrations. It is important to note that CDC stormwater quality requirements and the allowable quality of stormwater that can be discharged into the port are not directly specified in the ROD conditions, the reason being that the ROD applies directly to the applicant (i.e. Alcan) and not the managers of the stormwater system and/or port. However, combination of the stormwater from the Coega Aluminium Smelter with other stormwater runoffs may result in an acceptable blending of problematic constituents (in particular, for fluoride), resulting in a stormwater quality, which is environmentally acceptable for discharge to the port. It is suggested that the ROD could reflect the potential to manage stormwater at this broader IDZ-wide scale (NOTE: This aspect will be discussed further in Section 6.5.6).

Wrt Clause 8.6.21 This clause relates to water quality monitoring. With appropriate process wastewater and contaminated stormwater treatment and re-use in place, monitoring requirements indicated in this clause may need to be reviewed and possibly reduced. If, however, treatment is not implemented, the original monitoring requirements must be implemented. The ROD requirements will receive appropriate consideration in the following sections.

6.5 Updated Impact Assessment and Mitigation 6.5.1 Water Use During Construction

Water used for construction will be obtained from the Nooitgedacht Water Treatment Works. The treatment works has a capacity of 70 ML/day and presently has spare capacity of approximately 15 – 20% (i.e. approximately 10.5 – 14 Mℓ/day) (Raymer, D. NMMM, Personal Communication, 2005). As noted in the initial EIA, water use during this phase is a small percentage of available spare capacity. In addition, it appears as though water availability for the Coega IDZ is not problematic at this stage. The negative impact of construction water use on the available capacity is, therefore, likely still to be of low significance.




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6.5.2 Water Use During Operation

The following water uses are considered:

Domestic Water Use Domestic water is to be supplied from the NMMM. Typical consumption by the smelter has been estimated to be 84 000 m3/year (or 0,23 Mℓ/day) for the base scenario and 87 000 m3/year (or 0,24 Mℓ/day) for the upside scenario. The volume of domestic water consumption by the proposed smelter is therefore approximately 1.6 – 2.2% of the spare capacity of the Nooitgedacht Water Treatment Works for the base scenario and approximately 1.7 – 2.3% of the spare capacity of the Nooitgedacht Water Treatment Works for the upside scenario.

Process Water Use Industrial water consumption for the base scenario has been estimated at approximately 940 000 m3/year (or 2.6 Mℓ/day), while industrial water consumption for the upside scenario has been estimated at approximately 1 036 800 m3/year (or 2.8 Mℓ/day). Initially this requirement will be met by the Nooitgedacht Water Treatment Works. Process water consumption by the proposed smelter is approximately 18 – 24% of the spare supply capacity of the Nooitgedacht Water Treatment Works for the base scenario and approximately 20 – 27% of the spare supply capacity of the Nooitgedacht Water Treatment Works for the upside scenario. Total water use during operations is therefore approximately 20 – 27% of the present spare capacity of the Nooitgedacht Water Treatment Works for the base scenario and approximately 22 – 29% of the present spare capacity of the Nooitgedacht Water Treatment Works for the upside scenario. NMMM have indicated that these requirements are not presently problematic, and noted that with an increase in water demand in the industrial area, water needs will be met by the proposed reclamation works. The CDC has proposed that, in the future when water demand is high, that the bulk of the water required by the smelter would be recycled water supplied from the Fishwater Flats Reclamation Works. Although the facilities for reclaiming treated wastewater do not presently exist, a water re-use facility with a capacity of 60 Mℓ/day is envisaged. Water consumption by the proposed smelter is approximately 4.7% of the total capacity of the proposed Fishwater Flat Reclamation Works for the base scenario and approximately 5.1% of the total capacity of the proposed Fishwater Flat Reclamation Works for the upside scenario. As noted before, increased demand as a result of the proposed smelter on the regional water budget is considered to be negligible. Therefore, the significance of the negative impact of the use of during the operation of the smelter is still considered to be low.




Page 6-23

6.5.3 Wastewater Generated During Construction

The following wastewater impacts are considered:

Domestic wastewater With respect to domestic wastewater (i.e. sewage) produced during construction, the CDC has stated that it will utilise the existing municipal sewer network and the Fishwater Flats Reclamation Works for treatment of domestic wastewater produced by the IDZ. NMMM has noted that there is sufficient spare capacity to treat the quantities of effluent from the smelter (Raymer, D NMMM, Personal Communication, 2005). If sanitary facilities cannot be connected to the Coega IDZ sewage collection network, a local waste contractor will need to be appointed (e.g. provision of portable toilets). If properly managed, no impacts of environmental significance are expected.

Construction process wastewater and stormwater With respect to construction process wastewater and stormwater, contamination could result from contact with, for example, chemicals, oils, fuels, sewage, solid waste, litter. However, during construction, erosion from construction areas resulting in increased turbidity and downstream sedimentation is likely to be the main water quality concern. Management measures are proposed to ensure that the negative impacts associated with construction wastewater are of low significance. 6.5.4 Wastewater Generated During Operation

Wastewater generated as a result of the proposed project will include:

Domestic wastewater As before, the CDC plans to utilise the existing municipal sewer network and the Fishwater Flats Reclamation Works for treatment of domestic wastewater produced by activities in the IDZ. NMMM has indicated that sufficient spare capacity exists to treat the effluent from the smelter (Raymer, D NMMM, Personal Communication, 2005). No impacts of environmental significance are expected.

Process wastewater The amount of process wastewater generated has been estimated to be 470 000 m3/year (i.e. 1 288 m3/day) for the base scenario and 518 400 m3/year (i.e. 1 420 m3/day) for the upside scenario. The quantity of process wastewater is within the DWAF maximum allowable discharge of 2 000 m3/day. As discussed earlier, a number of options exist for process wastewater discharge, namely;

Discharge to stormwater system, Use for irrigation on site, Redirect to the Fish Water Flats Sewage Treatment Works, or Treatment for re-use




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The quality of process wastewater is expected to be the same for both AP50 and AP35 technology. Therefore, as noted in the initial EIA, use of process wastewater for irrigation raises concerns about the potential medium to long-term effects that fluoride in the process water could have on the soil and water chemistry of the site. In addition, although redirecting the process wastewater to a sewage treatment works has the potential benefit that this water could in future be treated and re-used, the necessary re-use facilities have not yet been established. Discharge to the stormwater system was previously assessed to have a manageable impact on the receiving environment. However, considering the ROD it was necessary to investigate treatment and re-use of process wastewater (and stormwater). This study (CSIR, 2003) found that various treatment options were available for consideration. By implementing such treatment and re-use systems, the environmental impact associated with process wastewater (and stormwater) discharge would be effectively managed and could be considered to have a negative impact of low significance.

Stormwater As noted in the initial EIA, constituents of primary concern include zinc, aluminium and fluoride. Of these, fluoride is still of greatest concern, with a change in fluoride concentration expected (due to higher fluoride emissions, lowered area of hardened surfaces and less covered areas). Considering the ROD, it is important to note that as a minimum requirement, stormwater leaving the Coega Aluminium Smelter site must have a fluoride concentration of 21.3 mg/ℓ (95 percentile). The impact of the change in technology from AP50 to AP35 on the fluoride concentration therefore needed to be revisited. (NOTE: It is expected that the concentrations of the remaining constituents of concern would be very similar to that predicted for AP50 technology.) As before, a number of scenarios were developed for both the base scenario and the upside scenario. The results of this analysis are summarised in the tables below. It is important to note that these are total cumulative concentrations and based on worst case scenarios where heavy rainfall is experienced after a dry period (i.e. 3 months). The following key assumptions were applied in calculating the predicted concentration of fluoride in stormwater:

The average atmospheric deposition rate for fluoride at the smelter site is estimated to be 195 mg/m2/month for the base scenario and 212.5 mg/m2/month for the upside scenario (previously 150 mg/m2/month)

The interceptor pond has a capacity of 14 000 m3 (previously 12 600 m3) Hardened surfaces have a surface area of approximately 42.5 ha for the base scenario

and 45 ha for the upside scenario (previously 50 ha) The mean maximum rainfall intensity for a one-hour period is 20 mm for the period 1972

to 2001 Note 1 (no change) The maximum rainfall intensity for a one-hour period for the period 1972 to 2001 is 56.5

mm Note 1 (no change) 80% mobilisation of surface fluoride occurs in the first 20 mm of rainfall (no change)

Note 1: Based on data for Port Elizabeth. No long-term data is available for Coega.




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A summary of the updated assessment is presented in the following tables.

Table 6.8 Estimated fluoride concentrations in stormwater

Source of fluoride

AP50 Estimated

total concentratio

n in discharge

mg/ℓ )

AP35 (Base

Scenario) Estimated total concentration in discharge

(mg/ℓ )

AP35 (Upside Scenario)

Estimated total concentration in discharge (mg/ℓ )

Scenario

15.3 19.9 21.7 Scenario 1: 20mm rainfall in 1 hour after 3 month dry spell

1. Deposition (“fallout”) from the smelter fluoride emissions into the atmosphere

9.7 9.7 9.9 Scenario 2: 56.5mm rainfall in 1 hour after 3 month dry spell

30 37.5 38.3 Scenario 3: 50kg of cryolite is spilt per month, in addition to the fluoride from the atmospheric deposition as described in Scenario 1

2. Atmospheric deposition plus accidental or other spillages of fluorinated materials (e.g. Cryolite)

Not previously considered

55.2 55.0 Scenario 4: 100kg of cryolite is spilt per month, in addition to the fluoride from the atmospheric deposition as described in Scenario 1

13.8 17.1 18.4 Scenario 5: Process water with 2mg/ℓ fluoride is added to the stormwater discharge for Scenario 1

3. Atmospheric deposition plus discharge of process wastewater into the stormwater system

14.2 17.7 19.0 Scenario 6: Process water with 6mg/ℓ fluoride is added to the stormwater discharge for Scenario 1

From the above, the following is noted:

Scenario 1: Due to the higher fluoride deposition rate for the AP35 technology, a higher fluoride concentration in the stormwater is expected (19.9 mg/ℓ (AP35 base scenario) and 21.7 mg/ℓ (AP35 upside scenario) vs. 15.3 mg/ℓ (AP50)). The predicted fluoride




Page 6-26

concentration for the AP35 base scenario is close to the ROD 95 percentile limit of 21.3 mg/ℓ, while the ROD 95 percentile limit is exceeded for the upside scenario.

Scenario 2: The likely fluoride concentration in an extreme rainfall event is similar for AP35 technology (9.7 mg/ℓ for base scenario and 9.9 mg/ℓ for upside scenario) and AP 50 technology (9.7 mg/ℓ).

Scenario 3: A higher fluoride concentration in the stormwater is expected (37.5 mg/ℓ for base scenario and 38.3 mg/ℓ for upside scenario vs. 30 mg/ℓ for AP50). The predicted fluoride concentration exceeds the ROD 95 percentile limit of 21.3 mg/ℓ.

Scenario 4: Increased spills of cryolite (increase from 50 kg/month to 100 kg/month) can result in very high fluoride concentrations in the stormwater. This scenario must receive careful consideration as the proposed AP35 technology will have fewer covered areas, resulting in an increased likelihood of spillages occurring. The predicted fluoride concentration (55.2 mg/ℓ for the base scenario and 55.0 mg/ℓ for the upside scenario) exceeds the ROD 95 percentile limit of 21.3 mg/ℓ.

Scenario 5 and Scenario 6: Combining the process wastewater (2 – 6 mg/ℓ fluoride) with stormwater has a minimal dilution effect. The predicted fluoride concentrations are close to the ROD 95 percentile limit of 21.3 mg/ℓ.

In addition to the above findings, the following is of importance to note:

The scenarios developed are believed to be “worst case” scenarios. By way of example, the dry period used for the calculations is three months. Although rainfall patterns will vary from year to year, review of rainfall data will give an indication of the likelihood of the length of a dry period. Review of data for Year 2000 for the Port Elizabeth area and review of data from July 2003 to present (April 2005) for the Coega IDZ is shown in Table 6.9 and Table 6.10 below.

Table 6.9 Analysis of dry periods for Year 2000 (Port Elizabeth)

Dry Period (Days) Number of Occasions Occurring in Year 2000 (Port Elizabeth)

5 – 10 15 11 – 15 3 16 – 20 1 21 – 25 3

The above table shows that for Year 2000 (i.e. 12 months) in Port Elizabeth, a dry period in excess of 10 days only occurred on 7 occasions. The longest dry period recorded in Year 2000 was 25 days.




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Table 6.10 Analysis of dry periods for July 2003 to Present (April 2005) (Coega IDZ)

Dry Period (Days) Number of Occasions Occurring in Period July 2003 to April 2005

(Coega IDZ) 5 – 10 28

11 – 15 9 16 – 20 8 21 – 25 0

> 25 1

The above table shows that for the period July 2003 to April 2005 (i.e. 22 months) in the Coega IDZ, a dry period in excess of 10 days only occurred on 18 occasions. Furthermore a dry period in excess of 20 days only occurred on one occasion. The longest dry period recorded for the period was 27 days.

Considering the above data, it is evident that the expected actual dry periods are much lower than the dry period of 90 days used in the simulations. This confirms that the simulations can be considered “worst case” scenarios.

It was previously indicated that, based on the project proponent’s experience from similar smelter operations around the world, the fluoride concentration in the combined stormwater and process water is expected to be below 20 mg/ℓ on average. However, during the study on process wastewater and stormwater treatment options, a stormwater quality composition was obtained from a “synthesis” of analyses of discharged stormwater from several aluminium smelter sites. These results indicated a fluoride concentration of 41 mg/ℓ and 25 mg/ℓ for two different smelters (Table 6.11), which exceeds the ROD condition of 21.3 mg/ℓ. It is also important to note that the ROD specifies 95 percentile limits (i.e. effectively maximum limits); whereas the synthesized concentrations in Table 6.11 are for a combination of annual averages and worst case monthly averages obtained from monitoring at aluminium smelters. [Refer to section 4.3 of the Specialist Study on Marine Discharges (Luger et al, 2002) for more detail on the synthesized concentrations].

At the time of completing the Final Environmental Impact Report (CSIR, 2002), Aluminium Pechiney and CSIR further analysed the synthesized concentrations presented in Table 6.11 in order to remove anomalous data and short-term worst case conditions. This led to a revised set of average annual concentrations being proposed, which reflect a “realistic” operating scenario. These concentrations were included in the ROD, except that they were changed from being an average to being a 95 percentile limit. (Refer to Chapter 7 of the Technology Review for more information).

In addition to fluoride, Table 6.11 shows that comparison of the synthesised stormwater concentrations and the ROD conditions indicates that many parameters may exceed




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ROD requirements. These potentially include: total suspended solids, aluminium, iron, zinc, cyanide, beryllium, cadmium, chromium, nickel and lead. Stormwater quality will therefore to be carefully managed to ensure that ROD conditions are satisfied.

Table 6.11 Contaminated stormwater composition

Parameter Synthesised Concentration (mix of annual averages and worst case monthly

averages)

ROD Conditions (95 percentile)

pH 6.5 – 8.5 Not specified Total dissolved solids (TDS) (mg/L) 90 – 530 Not specified Electrical Conductivity (mS/m) 12 – 70 Not specified Alkalinity 11 – 160 Not specified Total suspended solids (TSS) (mg/L) 42 9.8 F (mg/L) 41 (Smelter 1)

25 (Smelter 2) 21.3

Al (mg/L) 7 – 19 9 Fe (mg/L) 0.3 – 2 0.35 Zn (mg/L) 0.7 – 2 0.18 CN Free (µg/L) 50 10 Ag (µg/L) 1 1 As (µg/L) 50 50 Be (µg/L) 4 3 Cd (µg/L) 10 2.5 Cr (µg/L) 25 20 Cu (µg/L) 35 35 Hg (µg/L) 1 1 Ni (µg/L) 108 60 Pb (µg/L) 22 5 Sb (µg/L) 10 10 Se (µg/L) 3 3 Sn (µg/L) 4 4 Ti (µg/L) 5 5 V (µg/L) 3 3 Total hydrocarbons (mg/L) 0.4 0.4 Phenol (mg/L) 0.02 0.02 PAH’s: - Naphthalene (µg/L) 1 1 - Benzo(a)Pyrene (µg/L) 1 1

Furthermore, of importance to note is that poor on-site management of spillages can increase fluoride loading in the stormwater substantially (as shown in Table 6.8). Whilst the magnitude and frequency of fluorinated material spillages on the site is difficult to predict/model in a meaningful manner, experience at other South African aluminium smelters has shown that this source can contribute from 10 mg/ℓ up to 50 mg/ℓ of fluoride in stormwater. With an increase in uncovered areas, the importance of good




Page 6-29

management needs to be stressed. Alcan have indicated that it is feasible to achieve stormwater fluoride levels of 20 – 25 mg/L under normal conditions if best practise (i.e. interceptor ponds) and good housekeeping is applied.

Based on the above findings, the following is noted: Considering the worst case scenarios described in Table 6.8 and monitoring results from

existing smelters (Table 6.11), the concentration of several stormwater constituents is highly likely to exceed ROD requirements (even if process wastewater is combined with contaminated stormwater to dilute the species concentration). Discharge of such waters off the smelter site into the CDC stormwater system (and into the port) is predicted to have a negative impact of high significance because they may exceed the limits specified in the ROD. (NOTE: In this EIA, a predicted contravention of environmental legislation or guidelines having legal standing is considered to constitute a negative impact of “high” significance, as it could prevent the project from obtaining environmental authorisation).

To assist the reader in understanding the subsequent impacts associated with discharge of wastewater/stormwater to the marine environment, a brief summary is provided. The specialist study on marine discharges (Luger et al, 2002) assessed the impacts of stormwater and process wastewater of a quality shown under “synthesized concentrations” in Table 6.11 being discharged into the port. A 200m mixing zone was assumed around the point of discharge into the port and the concentration of constituents was analysed at the edge of this mixing zone. This was done for a “worst case” rainfall situation (i.e. a situation were the concentration of constituents in the process water and stormwater would be at a maximum). It was found that:

i.) The concentrations in the water column (dissolved phase) would be within the South African Marine Water Quality Guidelines (except for three constituents, which had a supporting explanation) and the resulting negative impact was predicted to be of low significance (with mitigation); and

ii.) The concentrations in the sediment (particulate phase) would be within the London Convention (except for three constituents, which had a supporting explanation) and the resulting negative impact was predicted to be of low significance (with mitigation).

The above section highlights that although stormwater and process wastewater discharges to the marine environment potentially do not have a impact of high significance, a legal risk exists that the specified ROD conditions will not be met. In order to further reduce impacts associated with process wastewater and stormwater discharges and fulfil the ROD requirements, treatment and re-use of these wastewaters was considered in a follow-up study (CSIR, 2003).




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6.5.5 Process Wastewater and Stormwater Treatment Considerations

The environmental impact assessment in the previous section showed that stormwater from the Coega Aluminium Smelter potentially has a negative impact of high significance. Considering the above and based on the findings from the study of process wastewater and stormwater treatment options, the following important points are noted:

The total quantity of liquid wastes (process wastewater and stormwater) produced for AP35 technology is higher than that for AP50 technology (i.e. ~682 500 m3/yr for the AP35 base scenario and ~743 400 m3/yr for the AP35 upside scenario vs. ~550 000 m3/yr for AP50, with process wastewater increasing from ~300 000 m3/yr to ~470 000 m3/yr, and average stormwater volume decreasing from ~250 000 m3/yr to ~212 500 m3/yr for the base scenario and with process wastewater increasing from ~300 000 m3/yr to ~518 400 m3/yr, and average stormwater volume decreasing from ~250 000 m3/yr to ~225 000 m3/yr for the upside scenario). If a treatment solution is implemented, the design will need to consider the required increase in capacity.

A membrane-based treatment solution was found to be appropriate for treating the process wastewater and stormwater (single treatment system to treat both waters). The proposed treatment chain considered chemical precipitation, clarification, filtration and reverse osmosis (RO). It is expected that the treatment chain would be the same for both AP50 and AP35 technologies.

The proposed treatment solutions would produce a number of waste streams which would need to be disposed in an appropriate manner. It is expected that the quantity and quality of wastes produced would be very similar for both AP50 and AP35 technologies.

Wastes produced could include:

○ Sludge from precipitation and clarification processes, i.e. pre-treatment prior to RO. (Note: This sludge is expected to contain the majority of the constituents of concern and will need to be disposed of appropriately. The details of the pre-treatment process and expected efficiencies would need to be clarified during the detailed process engineering design.)

○ Washwater from filter backwashing (normally recycled to start of treatment process)

○ Brine from RO, which is expected to be of a quality very similar to seawater. As RO membranes are sensitive to fouling, pre-treatment of problematic wastewaters is

normally required. Pre-treatment would normally include coagulation, precipitation and clarification processes which capture and remove fouling constituents prior to RO treatment. Therefore, if careful pre-treatment is performed; the majority of problematic constituents should be removed as a waste sludge. This sludge would need to be thickened and conditioned on-site, and disposed of at an appropriate hazardous waste site. These wastes will need to be captured and reported in the required Waste Classification Report.




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If the project proponents wish to operate the smelter as a Zero Industrial Effluent Discharge facility, this sludge would need to be conditioned to the solid state (so that it would be considered a solid) prior to disposal to the hazardous waste site.

If careful pre-treatment is followed, the brine from RO is expected to have a quality very similar to seawater. (NOTE: The final quality of brine will only be determined through detailed process design and on-site pilot testing).

If appropriate disposal techniques are followed, the impact associated with brine will be effectively managed. Of the available techniques, the following methods should be considered:

○ Regulated discharge to the marine environment This is generally the most economical method of brine disposal. However, concentrated waste can affect marine ecology, and appropriate studies will be required. However, as the brine is expected to have a quality similar to seawater, discharge of concentrated brine into the marine environment is expected to have a low negative impact. This should be via a dedicated pipeline and would require a special authorisation from DWAF.

○ Discharge to municipal sewers Although conventional wastewater treatment unit processes do not remove dissolved minerals from water, dilution of the brine by domestic sewage, could neutralise the brine. Brine, however, can interfere with wastewater settling, inhibit biological processes and aggravate plant equipment and piping corrosion. However, considering the low quantity of brine produced, the biggest concern to conventional wastewater operations would the increased likelihood of corrosion and the need for specialised construction materials (e.g. stainless steel).

○ Disposal via evaporation ponds Generally used if evaporation rates are high, precipitation is minimal, and land costs are low. In most localities, precautions must be taken to ensure that brine ponds do not overflow or leak into the ground water (inclusion of an appropriate lining). Considering the large difference between the average precipitation rate (613.7 mm/year) and the average evaporation rate (1750 mm/year) in the Port Elizabeth area, evaporation ponds appear feasible for ultimate brine disposal. Evaporation ponds are, however, likely to require a large surface area and possibly have a negative visual impact.

○ Concentration of brine via evaporator/concentrator/crystallization treatment steps The brine stream is further concentrated, whilst the recovered water can be recycled for re-use. This treatment process generally results in a very small final brine stream or a crystallised product. High capital and operating/maintenance costs can be expected for this brine disposal method.

If the project proponents wish to operate as a Zero Industrial Effluent Discharge facility, the most appropriate brine management disposal and techniques appear to be discharge to evaporation ponds and/or mechanical/thermal brine concentration.




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If operation of a Zero Industrial Effluent Discharge facility is not economically feasible and if, for example, brine needs to be discharged to the port, further studies will be needed to determine the significance of such discharges (i.e. is there any impact on the marine environment). However, considering the expected quality of the brine (close to seawater), the environmental impact associated with discharges of brine to the marine is expected to be low.

A further option that can be considered is off-site treatment of process wastewater and stormwater. This could be a central treatment facility for wastewaters from all industries within the Coega IDZ. Wastewaters should be treated to a quality which would allow subsequent reuse at the Coega Aluminium Smelter and other industries. This option would be beneficial to all industries within the Coega IDZ and will ensure that the Coega IDZ is operated in an environmentally sustainable manner. Through combination of wastewaters, dilution of problematic constituents could result. Of importance to consider is the need for a flexible and robust treatment solution. This treatment system should also preferably be modular in nature to easily allow an increase in the capacity of the system when more industries are located in the Coega IDZ. A membrane based treatment system could be considered.

The above discussion has shown that: Implementation of a Zero Industrial Effluent Discharge facility should reduce the

significance of the predicted negative impact of process wastewater and stormwater discharge from high to low. It is recommended that this option be seen as the ideal solution. This solution may, however, at this stage not be considered an urgent requirement from an environmental impact point of view.

Implementation of on-site process wastewater and stormwater treatment with disposal of brine to the marine environment is also likely reduce the significance of the predicted negative impact of process wastewater and stormwater discharge from high to low. However, the predicted impact will be highly dependant on the final quality of brine that would be discharged to the marine environment. This will be largely dependant on the treatment solution implemented and management thereof.

The sludge produced by RO pre-treatment will need to be conditioned and disposed of at an appropriate hazardous waste site. Based on available information, it is predicted that the sludge disposal will result in a negative impact of low significance, due to the volumes being low. This assessment rating has a low confidence level, as the volumes and constituency of the sludge are not defined at this stage, and can only be defined when more detailed process engineering studies have been undertaken.

Off-site treatment of process wastewater and stormwater (e.g. at a CDC operated facility) and subsequent reuse of these treated wastewaters at the Coega Aluminium Smelter and other industries is also likely reduce the significance of the predicted negative impact of process wastewater and stormwater discharge from high to low.




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6.5.6 Integrated Stormwater Management Options

The previous section has shown that the stormwater from the CAS site is predicted to contain fluoride concentrations near or in excess of current ROD requirements. However, of importance to note is that as one moves away from the smelter site, the deposition of fluoride reduces exponentially. In the initial EIA (2002), there was insufficient information available on the CDC stormwater system design. A precautionary approach was therefore assumed with the smelter stormwater being managed in "isolation" from wider stormwater management in the IDZ (i.e. this lead to the assumption that whatever stormwater left the site arrived in the port, without any mixing with other streams). CDC are in the process of implementing stormwater containment and transport structures for the Coega IDZ. In brief, the stormwater system will incorporate both attenuation ponds and litter traps within the Coega IDZ. In particular, downstream of the CAS site, an attenuation pond and associated litter traps have been proposed. Considering the above, the option of integrating the stormwater management for the CAS site with stormwater management for surrounding areas of the IDZ can now be considered. It is possible that a mixing of fluoride concentrations could occur if stormwater from the CAS site is combined with “cleaner” stormwater from other zones within the IDZ. The resultant impact of combined stormwater discharge to the port could therefore be potentially decreased. The following stormwater catchment areas feed into the CDC stormwater system (with eventual discharge to the port) as shown in Figure 6.1:

• CAS site, located in non-ferrous metals cluster (Zone 5) of the IDZ (consists of both hardened surfaces and non-hardened surfaces)

• Remainder of Zone 5 (excluding CAS site) • Neptune Road to Butterfly Valley • Zone 2 to Butterfly Valley • Zone 1 to Butterfly Valley • Zone 1 to adjacent valley

The following sections will aim to predict the fluoride concentration in stormwater from the above catchment areas and the combined fluoride concentration of all stormwater as it would enter the port. (NOTE: As noted previously, at this stage the fluoride concentration in the stormwater resulting from the CAS site air emissions is of primary concern. Combination of stormwater should also result in a blending of concentrations for other less problematic parameters. This would need to be revisited when additional industries enter the Coega IDZ.) Considering the above, the area of the above catchments, predicted fluoride deposition and average rainfall runoff is indicated in the following table.




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Figure 6.1 Stormwater catchments

included in the integrated

stormwater analysis for the

CAS site

Remainder of Zone 5: 366ha @ 65%

Zone 1 to Butterfly Valley: 32ha @ 60%

Zone 1 to adjacent Valley: 46ha @ 60%

Zone 1 to NPA land: 26ha @ 60%

CAS Site: 120ha @ 42%


Neptune Road to Butterfly Valley: 53ha @ 65%

Remainder of Zone 5: 366ha @ 65%


Zone 1 to adjacent Valley: 46ha @ 60%

Zone 1 to NPA land: 26ha @ 60%

CAS Site: 120ha @ 42%


Neptune Road to Butterfly Valley: 53ha @ 65%




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Table 6.12 List of relevant stormwater catchment areas that feed into the CDC

stormwater system leading to the port

Area (hectares) of stormwater catchments

% runoff Predicted fluoride deposition (mg

F/m2/month) (Base Scenario)

Predicted fluoride deposition (mg

F/m2/month) (Upside Scenario)

CAS site, located in non-ferrous metals cluster (Zone 5) of the IDZ (hardened surfaces)

42.5 ha (base) 45 ha (upside)

80% 195 212.5

CAS site, located in non-ferrous metals cluster (Zone 5) of the IDZ (non-hardened surfaces)

77.5 ha (base) 75 (upside)

35% 195 212.5

Remainder of Zone 5 (excluding CAS site)

366 ha 67% 90.4 98.5

Neptune Road to Butterfly Valley

53 ha 65% 52.0 56.7

Zone 2 to Butterfly Valley 79 ha 45% 5.82 6.34

Zone 1 to Butterfly Valley 32 ha 60% 16.65 18.15

Zone 1 to adjacent valley 46 ha 60% 3.7 4.03

Zone 1 to NPA land 26 ha 60% 1.78 1.94

As per previous stormwater calculations, the following key assumptions were applied in calculating the predicted concentration of fluoride in stormwater:

The average atmospheric deposition rate for fluoride at the smelter site is estimated to be 195 mg/m2/month for the base scenario and 212 mg/m2/month for the upside scenario

The interceptor pond has a capacity of 14 000 m3 The mean maximum rainfall intensity for a one-hour period is 20 mm for the period 1972

to 2001 80% mobilisation of surface fluoride occurs in the first 20 mm of rainfall




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In addition to the above assumptions, the following three “worst case” scenarios were revisited: • Scenario 1: 20mm rainfall in 1 hour after 3 month dry spell • Scenario 3: 50kg of cryolite is spilt per month, in addition to the fluoride from the

atmospheric deposition as described in Scenario 1 • Scenario 4: 100kg of cryolite is spilt per month, in addition to the fluoride from the

atmospheric deposition as described in Scenario 1 A summary of the updated assessment is presented in the following tables.


(Scenario 1: 20 mm rain in 1 hour after 3 month dry spell)

AP35 (Base Scenario) Estimated total

concentration in discharge (mg/ℓ )




19.9 21.7


45.5 49.5


11.0 12.0

Neptune Road to Butterfly Valley 6.5 7.1

Zone 2 to Butterfly Valley 1.1 1.1


Zone 1 to adjacent valley 0.5 0.5

Zone 1 to NPA land 0.2 0.3

Combined stormwater to Port 11.2 12.2


Although the stormwater leaving the CAS site is close to or exceeds ROD fluoride requirements of 21.3 mg/ℓ (19.9 mg/ℓ for the AP35 base scenario and 21.7 mg/ℓ for the




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AP35 upside scenario), from an integrated stormwater management approach the predicted fluoride concentration of combined stormwater entering the port would be 11.2 mg/ℓ for the AP35 base scenario and 12.2 mg/ℓ for the AP35 upside scenario. Previous marine discharge modelling has shown that discharge of such waters would have a low negative impact.


(Scenario 3: As per Scenario 1 with spillage of additional 50 kg of fluoride per month)






37.5 38.3


45.5 49.5


11.0 12.0








With on-site spillage and subsequent poor management (spillage of 50 kg of cryolite), modelling shows that the stormwater leaving the CAS site is likely to exceed ROD fluoride requirements of 21.3 mg/ℓ (37.5 mg/ℓ for the AP35 base scenario and 38.3 mg/ℓ for the AP35 upside scenario). However, when considering an integrated stormwater management approach the predicted fluoride concentration of combined stormwater




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entering the port would be 12.6 mg/ℓ for the AP35 base scenario and 13.6 mg/ℓ for the AP35 upside scenario. Previous marine discharge modelling has shown that discharge of such waters would have a low negative impact.


(Scenario 4: As per Scenario 1 with spillage of additional 100 kg of fluoride per month)






55.2 55.0


45.5 49.5


11.0 12.0










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With excessive on-site spillage and subsequent very poor management (spillage of 100 kg of cryolite), modelling shows that the stormwater leaving the CAS site is likely to exceed ROD fluoride requirements of 21.3 mg/ℓ (55.2 mg/ℓ for the AP35 base scenario and 55.0 mg/ℓ for the AP35 upside scenario). However, when considering an integrated stormwater management approach the predicted fluoride concentration of combined stormwater entering the port would be 14.0 mg/ℓ for the AP35 base scenario and 14.9 mg/ℓ for the AP35 upside scenario. Previous marine discharge modelling has shown that discharge of such waters would have a low negative impact.

Fluoride concentrations for the combined stormwaters are summarised in the table below.

Table 6.16 Estimated fluoride concentrations in combined stormwater to port





Scenario 1: 20mm rainfall in 1 hour after 3 month dry spell

11.2 12.2

Scenario 3: 50kg of cryolite is spilt per month, in addition to the fluoride from the atmospheric deposition as described in Scenario 1

12.6 13.6

Scenario 4: 100kg of cryolite is spilt per month, in addition to the fluoride from the atmospheric deposition as described in Scenario 1

14.0 14.9

As part of the original EIA (2002), the CSIR developed stormwater release limits which would ensure that the marine standards would be met at 200m within the harbour areas. The provisional limits proposed for stormwater releases are shown in the following table.




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Table 6.17 Limits that could apply to stormwater releases from the Coega IDZ to the

harbour

Parameter CSIR derived standards for release

to harbour Total suspended solids (TSS) (mg/L) 9.8 F (mg/L) 21 Al (mg/L) 9 Fe (mg/L) 0.35 Zn (mg/L) 0.18 CN Free (µg/L) 10 Ag (µg/L) 1 As (µg/L) 50 Be (µg/L) 3 Cd (µg/L) 2.5 Cr (µg/L) 20 Cu (µg/L) 35 Hg (µg/L) 1 Ni (µg/L) 60 Pb (µg/L) 5 Sb (µg/L) 10 Se (µg/L) 3 Sn (µg/L) 4 Ti (µg/L) 5 V (µg/L) 3 Total hydrocarbons (mg/L) 0.4 Phenol (mg/L) 0.02 PAH’s: - Naphthalene (µg/L) 1 - Benzo(a)Pyrene (µg/L) 1

Comparison of the CSIR developed stormwater release limits with the predicted fluoride concentrations for the combined stormwater scenarios show that the fluoride concentrations for all integrated stormwater management scenarios evaluated are below the CSIR derived standard for fluoride. An important aspect which could, however, require revisiting would be the effect of the total load into the marine environment. The previous sections have shown that an integrated stormwater management approach for the Coega IDZ is predicted to result in a significant dilution effect at the point where stormwater enters the port. This is likely to reduce the significance of the predicted negative impact of stormwater discharge from high to low. If this option is considered for implementation the following important points should be noted:




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• A suitable stormwater quality monitoring and management programme must be established. Monitoring should at least be conducted at all major stormwater intersection points, as this will allow tracing of problematic areas and required management interventions. It would therefore be necessary to have appropriate emergency procedures in place to deal with abnormal conditions.

• To ensure environmental sustainability for the Coega IDZ, it is recommended that a suitable treatment facility for wastewaters (process wastewater and contaminated stormwater) from industries within the Coega IDZ be investigated and designed, for implementation when a critical mass of IDZ tenants renders the project financially viable and sustainable.

• In the unlikely event that monitoring shows an unacceptable environmental impact, implementation of a wastewater treatment facility should be fast tracked.

6.5.7 Summary of Process Wastewater and Stormwater Management Options

The previous sections have shown that a number of options can be considered for management of process wastewater and contaminated stormwater from the CAS site. The various options considered, and relative advantages and disadvantages of each option are shown in the following table.




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Table 6.18 Coega Aluminium Smelter options considered for management of contaminated stormwater and process

wastewater

Process Wastewater

Discharge to

Municipal Sewer System

Discharge to CDC Stormwater System

(i.e. to marine environment)

On-site Treatment and Reuse (with

discharge of sludge to hazardous waste

site and brine to marine environment)

On-site Treatment and Reuse

(ZLD option)

Off-site Treatment and Reuse (e.g.

central treatment facility for Coega

IDZ)

Discharge to Municipal Sewer System

Discharge to CDC Stormwater System (i.e. to marine environment)

On-site Treatment and Reuse (with discharge of sludge to hazardous waste site and brine to marine environment)

On-site Treatment and Reuse (ZLD option)

Stor

mw

ater

Off-site Treatment and Reuse (e.g. central treatment facility for Coega IDZ)




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Advantages and disadvantages of each of the options are noted in the following table:

Table 6.19 Advantages and disadvantages of contaminated stormwater and process wastewater management options

Advantages Disadvantages

Discharge to Municipal Sewer System

1) Mixing of problematic constituents (e.g. fluoride)

2) Utilise existing Wastewater Treatment Works (WWTW) infrastructure and trained operators

3) Treatment to legislated requirements

1) Need for new pipe infrastructure (capital costs, environmental impact, etc)

2) Potential negative impact on wastewater treatment operations

3) Water conservation, recycle and reuse principles not followed (unless reuse is introduced at the WWTW) sets precedent for other industries entering Coega IDZ

Discharge to CDC Stormwater System (i.e. to marine environment)

1) Blending of problematic constituents (e.g. fluoride)

2) Appropriate infrastructure is being implemented by CDC

1) Water conservation, recycle and reuse principles not followed sets precedent for other industries entering Coega IDZ

On-site Treatment and Reuse (with discharge of sludge to hazardous waste site and brine to marine environment)

1) Treatment of problematic constituents (e.g. fluoride)

2) Treated wastewater can be reused within smelter (i.e. water conservation, recycle and reuse principles followed environmental sustainability)

1) Capital and operating costs may be prohibitive

2) Sludge (and to a lesser extent brine) needs careful management and disposal

On-site Treatment and Reuse (ZLD option)


2) Treated wastewater can be reused within smelter (i.e. water conservation, recycle and reuse principles followed environmental sustainability)

1) Capital and operating costs may be prohibitive

2) Visual impact of evaporation ponds (if employed instead of high cost crystallisers)

Off-site Treatment and Reuse (e.g. central treatment facility for Coega IDZ)


2) Dilution of problematic constituents through combination of wastewaters from other industries

3) A centralised treatment facility is generally more cost effective than multiple smaller facilities

4) Treated wastewater can be reused within the smelter and other industries (i.e. water conservation, recycle and reuse principles followed

environmental sustainability)

1) Infrastructure does not currently exist (plant, pipelines from industries, etc)

2) Process needs to be flexible and robust to accommodate a range of problematic wastewaters

3) Need experienced operators or private company to operate treatment plant

The above aspects should be noted when considering the appropriate way forward.




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6.5.8 Impact Summary

Based on the available information, it has been predicted in the study that there is no real difference in environmental impact between AP50 and AP35 technologies (for both the base scenario and upside scenario). In addition to the above, the following is of importance:

Water Use (Construction and Operations) Increased water use for industrial purposes using AP35 technology will have a low negative impact. This is because of the already existing spare capacity and planned facilities for future water supply.

Domestic wastewater discharge (Construction and Operations) Domestic wastewater discharge has not changed for using AP35 technology and will still have a low negative impact. This is because domestic wastewater would be discharged to the existing sewer facilities.

Wastewater/Stormwater discharge (Construction) Although the expected environmental impact is rated as low, it must be noted that the assessment was made based on expected general management practises to be followed on-site during the construction period. A number of practical on-site management measures were previously recommended in the initial EIA for AP50 technology. If these measures are followed, environmental impacts related to construction activities will be minimised.

Wastewater/stormwater discharge (Operations) As per the AP50 technology study, wastewater/stormwater discharge utilising AP35 technology will have a high negative impact if discharged to a surface freshwater or river environment (eg. Coega River), due to exceedance of South African water quality guidelines. In the Final EIR (CSIR, 2002) and in this review, discharge to a surface water/river environment is not considered a feasible option. The AP35 proposal results in an increase in fluoride concentration in stormwater, which results in a high likelihood that the concentration of many stormwater parameters (and in particular fluoride) will exceed the 95 percentile limits specified in the ROD. Under present ROD conditions, it is conceivable that for extended periods of time, stormwater will not be able to leave the Coega Aluminium Smelter site as it will not comply with the ROD conditions (NOTE: The likelihood of this occurring will be determined by actual rainfall, length of dry periods and on-site management practises). Therefore, the impact of this discharge is assessed to be of high significance, due to the frequent potential contravention of the ROD. Considering the above, various options were investigated for managing process wastewater and stormwater from the site. The following points are therefore of importance.




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• Discharge to municipal sewer system Although discharges to the municipal sewer system should not affect conventional wastewater treatment unit processes, conventional wastewater treatment operations do not remove fluoride. Fluoride concentrations will therefore largely be reduced through mixing with waste waters of low fluoride concentrations. Operation in this fashion would require the following:

o Modification of the present ROD conditions to allow discharges of all process wastewater and stormwater to the municipal sewer system.

o An agreement between Alcan and Nelson Mandela Metropolitan Municipality with regards to acceptable discharges (quality/quantity).

o Modification to the existing municipal infrastructure (piping system, possible increase in capacity, etc)

o Evaluation of environmental impacts associated with new infrastructure requirements and confirmation that mixed wastewaters would meet required water quality specifications.

• Discharge to CDC stormwater system (i.e. discharge to marine environment)

The marine discharges specialist study (Luger et al, 2002) predicted that the impact of discharging process wastewater and stormwater from the CAS site (of a quality shown under “synthesised concentration” in Table 6.8) directly into the marine environment is of low significance (with mitigation), when compared against relevant guidelines and conventions. In addition to the above, further modelling predicted that an integrated stormwater management approach (i.e. combination of stormwater from the CAS site with stormwaters from the other zones in the Coega IDZ) would result in a significant lowering of fluoride concentrations in the stormwater discharged to the port. Comparison of the CSIR developed stormwater release limits with the predicted fluoride concentrations for the combined stormwater scenarios show that the fluoride concentrations for all integrated stormwater management scenarios evaluated are below the CSIR derived standard for fluoride. The impact of this combined stormwater discharge into the marine environment is therefore considered to be of low significance. Implementation of the option would require the following:

o Modification of the existing ROD, as the current 95 percentile limits for stormwater leaving the CAS site specified in the ROD are likely to be exceeded. (NOTE: The ROD only considers the quality of stormwater leaving the Coega Aluminium Smelter site, and does not clearly specify the stormwater quality that is allowed to be discharged to the port.

o Possible modification of the ROD to allow discharges of process wastewater to the port (NOTE: This would result in a constant discharge of process wastewater into the port – even in times when no stormwater flow).




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o Transport of process wastewater and stormwater must ensure low environmental impact. The CDC’s stormwater system (including attenuation ponds, litter traps and lined canals) is deemed appropriate for transport of these wastewaters to the port.

• On-site treatment and re-use Another option is on-site treatment and re-use of both stormwater and process wastewater via a single treatment system. Treatment of such waters is likely to produce other wastes, which require appropriate management. Disposal of sludge produced by RO pre-treatment at an appropriate hazardous waste site is expected to result in a negative impact of low significance. Discharge of concentrated brine into the marine environment via a dedicated pipe (would require a special authorisation from DWAF) is expected to have a low negative impact. The option with the lowest environmental impact is likely to be operation of a Zero Industrial Effluent Discharge facility.

o Off-site treatment and re-use

A further option that can be considered is off-site treatment of process wastewater and stormwater. This could be a central treatment facility for wastewaters from all industries within the Coega IDZ. Wastewaters should be treated to a quality which would allow subsequent reuse at the Coega Aluminium Smelter and other industries. This option would be beneficial to all industries within the Coega IDZ and will ensure that the Coega IDZ is operated in an environmentally sustainable manner. This option is also likely to result in a negative impact of low significance.

In addition to the above, the impact of wastewater on the groundwater is potentially of medium significance (unchanged from section 9.7.5 of the Final Environmental Impact Report, CSIR, 2002). This is a precautionary assessment and further investigation is required to fully understand groundwater characteristics of the site. The impact assessment for issues related to water use and liquid waste generation and management are summarised in Table 6.18 for the base scenario and Table 6.19 for the upside scenario. (NOTE: Analysis reveals that the environmental impact of the upside scenario is not significantly different from the environmental impact of the base scenario. Nevertheless, the impact summary tables are repeated for completeness).




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Table 6.20 Base scenario: summary of impacts of the proposed AP35 Coega Aluminium Smelter

Impact Status Extent Duration Intensity Probability of occurrence Confidence

Significance (without mitigation)

Significance (with mitigation)

Construction Increased water use during construction Negative Local Short term Low Definite High Low Low

Construction wastewater and stormwater discharge during construction

Negative Local Short term Medium Probable Medium Low Low

Operations Increased water used during operation Negative Local Long term Low Definite High Medium Low

Domestic effluent discharge into sewer Negative Local Long Term High Low High Low Low

Process wastewater and stormwater discharge into environment not meeting ROD requirements

Negative Local Permanent High Definite High High N/A

Process wastewater and stormwater discharge to port via CDC stormwater system

Negative Local Long term Low Definite Medium Low Low

On-site treatment of process wastewater and stormwater with disposal of sludge at a hazardous waste site

Negative Local Long Term Low Definite Medium Low Low

On-site treatment of process wastewater and stormwater treatment with discharge of





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concentrated brine to port via CDC stormwater system On-site treatment of process wastewater and stormwater with operation as a Zero Liquid Effluent Discharge facility

Negative Local Long Term Low Definite High Low Low

Off-site treatment of process wastewater and stormwater (e.g. Coega IDZ facility)


Influence of wastewater practices on groundwater Negative Local Long term Medium Probable Medium Medium Low

Table 6.21 Upside scenario: summary of impacts of the proposed AP35 Coega Aluminium Smelter




Construction Increased water use during construction Negative Local Short term Low Definite High Low Low

Construction wastewater and stormwater discharge during construction

Negative Local Short term Medium Probable Medium Low Low

Operations




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Increased water used during operation Negative Local Long term Low Definite High Medium Low

Domestic effluent discharge into sewer Negative Local Long Term High Low High Low Low

Process wastewater and stormwater discharge into environment not meeting ROD requirements

Negative Local Permanent High Definite High High N/A

Process wastewater and stormwater discharge to port via CDC stormwater system

Negative Local Long term Low Definite Medium Low Low

On-site treatment of process wastewater and stormwater with disposal of sludge at a hazardous waste site


On-site treatment of process wastewater and stormwater treatment with discharge of concentrated brine to port via CDC stormwater system


On-site treatment of process wastewater and stormwater with operation as a Zero Liquid Effluent Discharge facility

Negative Local Long Term Low Definite High Low Low

Off-site treatment of process wastewater and stormwater (e.g. Coega IDZ facility)


Influence of wastewater practices on groundwater Negative Local Long term Medium Probable Medium Medium Low




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6.6 Re-Consideration of the Best Practicable Environmental Option (BPEO)

In order to reduce the concentration of fluoride in stormwater, it is essential that previously identified principle applications of BAT and BPEO be implemented for the proposed smelter using AP35 technology. This includes the following design and management principles:

Dry scrubbing air emission controls for primary collection and treatment of gaseous and particulate fluorides from the electrolysis cells (pots) and operation with fully hooded pots.

BAT materials handling systems, featuring enclosed conveyors, fully sealed pneumatic transport, dust filters at all transfer points, crushing systems under negative pressure, covered production workshops and internal transfer routes.

Enhanced integrated plant layout minimising transport distances of raw materials and intermediate products.

Extensive spillage control and housekeeping procedures, featuring bunded areas, regular sweeping of roadways and work areas, reporting systems, rigorous training and awareness programs.

Lined interceptor pond on-site to capture the “first flush” of rainfall events and trap sediments, oils and litter.

A lined (or otherwise isolated from groundwater resources) attenuation dam to allow controlled release of stormwater.

Regular monitoring of water quality.

Of importance to note is that as a result of fewer covered areas, the potential for materials spillages is increased, which could result in a high negative impact on stormwater quality. In order to minimise the fluoride concentration in stormwater resulting from on-site spillages, extensive spillage control and house-keeping measures must be applied during operation. In addition to the above, Clause 8.6.17 of the ROD specifies a number of water conservation best practise that must be adopted. This is especially important as a significant increase in process water use is noted for AP35 technology.

6.7 Review of Implications for the Record of Decision Considering Section 4, the following possible modifications to the ROD are noted:

Clause 8.6.3 (regarding substitution of contaminated stormwater and process wastewater) should be reworded to allow the option to be considered practically feasible.

Clause 8.6.6.6 (relating to TOTAL stormwater containment) and Clause 8.6.8 (relating to design for 1:100 year stormwater run-off) should be modified to only require containment of contaminated stormwater.




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Clause 8.6.15 (that specifies stormwater quality requirements leaving the CAS site) could be modified to consider the actual quality required for stormwater leaving the CAS site to achieve quality requirements in the port.

Clause 8.6.21 (that specifies water quality monitoring requirements) could be modified, and requirements possibly reduced, if treatment and re-use of liquid wastes is implemented.

Considering the findings of the previous sections, there is a high likelihood that the stormwater quality leaving the CAS site will not meet the present ROD requirements. At present, stormwater exceeding ROD quality requirements would not be allowed to be discharged from the CAS site. Furthermore, the ROD specifies that process wastewater must either be treated on-site or discharged to the municipal sewer. Mixing of stormwater with process wastewater is therefore not presently acceptable (modeling has also showed that in all likelihood the concentration of such a blended water would still be close to or exceed ROD requirements). Considering the above, the following options exist for managing and avoiding the potential negative impacts arising from the discharge of wastewaters (i.e. stormwater and process water) from the smelter site: Option to change the limits in the ROD:

Change the limits in the ROD so that they reflect the actual quality requirements for stormwater leaving the CAS site to achieve quality requirements in the port. Observations from industry confirm that it is feasible to achieve fluoride levels of 20 – 25 mg/L under normal conditions if best practice (e.g. interceptor ponds) and good housekeeping is applied.

Options for discharge and/or disposal of wastewater and associated sludge/brine:

Change the ROD to allow wastewaters with higher concentrations of problematic parameters to be discharged to the municipal sewer system via an appropriate pipeline (if discharge to the sewer is acceptable by NMMM and is predicted to have a low negative impact).

Change the ROD to allow wastewaters with higher concentrations of problematic parameters to be combined with other stormwater from the Coega IDZ and discharged to the port via the CDC stormwater system. Comparison of modelling results for the combined stormwater with previously developed CSIR stormwater release limits indicates a low negative impact.

Change the ROD to state that in the unlikely event that monitoring shows an unacceptable environmental impact, implementation of a wastewater treatment facility must be fast tracked.

Wastewaters are treated on-site for re-use purposes:




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○ With disposal of sludge to an appropriate hazardous waste site and discharge of brine to the port via a dedicated pipeline (with special authorisation from DWAF and if the discharge to the port is proven to have low environmental impact) OR

○ With operation of a Zero Industrial Effluent Discharge facility with disposal of sludge as a solid to an appropriate hazardous waste site and brine discharged to evaporation ponds or via brine concentration and disposal.

Change the ROD to allow wastewaters to be transported and treated off-site for re-use

purposes (e.g. at a central facility in the Coega IDZ).

The advantages and disadvantages of the above options should be noted when considering the appropriate way forward.

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