environmental impact assessment for the proposed aluminium

Environmental Impact Assessment for the proposed Aluminium Pechiney smelter within the Coega Industrial Zone, Port Elizabeth, South Africa

SPECIALIST STUDY:

WATER USE AND LIQUID WASTE

September 2002

Prepared by

Philip de Souza and Grant Mackintosh Cape Water Programme

CSIR, Stellenbosch P. O. Box 320

7599 STELLENBOSCH SOUTH AFRICA

Prepared for CSIR Environmentek

Stellenbosch

CSIR Report reference: ENV-S-C 2002-092(B)

Specialist Study on Water Use and Liquid Waste

Aluminium Pechiney Coega EIA page i

SUMMARY

WATER USE AND LIQUID WASTE STUDY OF THE ENVIRONMENTAL IMPACT ASSESSMENT FOR THE PROPOSED

PAS 2005 SMELTER AT COEGA INDUSTRIAL DEVELOPMENT ZONE

ALUMINIUM PECHINEY has identified the Coega Industrial Development Zone (IDZ), located north east of Port Elizabeth, Eastern Cape Province as a potential site for construction and operation of an aluminium smelter. The proposed smelter will produce approximately 485 000 tonnes per year of primary aluminium using AP’s latest AP50 reduction technology. Aluminium Pechiney state that the recently developed AP50 smelting technology represents significant capital and operating cost advantages over older smelting technologies. The smelter project will generate impacts on regional and local water resources in terms of: • Water usage • Domestic wastewater, construction

wastewater, process wastewater and stormwater discharge

The general approach used in this study was to gather all information and data available to be able to address the Terms of Reference. Thereafter, the environmental significance of possible impacts of wate r use, domestic wastewater discharge, construction wastewater discharge, process wastewater discharge and contaminated stormwater discharge of the proposed aluminium smelter were considered. As the nature of the study is such that not all

information and data ideally required is necessarily available, a number of representative scenario’s were explored which enabled a quantitative analysis of the compliance of the proposed stormwater management system with appropriate water quality guidelines. These identified “worst case” environmental scenarios were then used to determine the environmental significance of impact. A key issue related to water discharges from the smelter site is the assessment of impacts on the receiving environment including Butterfly Va lley, the Coega River, and the marine environment. This specialist study considers the impacts on the first two environments whereas the Specialist Study of Discharges to the Marine Environment addresses impacts on the marine environment. The Water Study has assessed the environmental significance of: • Water use • Domestic wastewater discharge • Construction wastewater discharge • Process wastewater and stormwater

discharge on the surface water environment

• Process wastewater and stormwater practices on the groundwater environment


Aluminium Pechiney Coega EIA page ii

Water Use Increased water use for both domestic and industrial purposes was shown to have a low negative impact. This was because of the already existing or planned facilities for water supply. Domestic wastewater discharge Domestic wastewater discharge was shown to have a low negative impact. This was because domestic wastewater would be discharged to the existing sewer facilities. Construction wastewater discharge Although the expected environmental impact was 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 have been recommended, which, if followed, will minimise environmental impacts related to construction activities. Wastewater/stormwater discharge on the surface water environment Wastewater/stormwater discharge was found to have a high negative impact on the surface water environment. This results from the high likelihood that process wastewater and stormwater fluoride levels will fail the required DWAF General Limit Values and DWAF Water Quality Guidelines for Aquatic Ecosystems. It is recommended that only marine discharge of fluoride enriched process wastewater and stormwater be considered. Findings of the marine discharges specialist study suggest that discharge of process wastewater and stormwater into the marine environment is not problematic (for further details refer to the report entitled: “Specialist Study on Discharges to the Marine Environment,

Luger et al, 2002). Considering marine discharge, the transport of process wastewater and stormwater from the western edge of the saltworks to the port has yet to be finalized. Assessment revealed that a lined canal or enclosed pipeline would have the lowest environmental impact. However, considering the present degraded state of the lower reach of the Coega River, the debate surrounding the nature of river within this reach (marine or surface water environment), and the possible expansion of the port in the future, the capital expenditure required to construct these systems may not be justified. Satisfaction of impact mitigation measures will reduce the environmental impact from high negative impact to low negative impact. In particular, the management of spills is very important. Wastewater/stormwater practises on the groundwater environment Wastewater/stormwater practises were found to have a medium negative impact on the groundwater environment. Although the proposed smelter is to be located on the Adolphspoort shale, which is an aquitard with no aquifer potential, insufficient information was at hand to rule out all impacts. It is thus recommended that a groundwater survey of the site and surrounding area be conducted. In the interim, precautionary planning is recommended. In conclusion, this study has identified that there are a number of aspects of concern relating to stormwater management. Satisfaction of the suggested impact mitigation measures will reduce the environmental impact thereof to acceptable levels.


Aluminium Pechiney Coega EIA page iii

CONTENTS SUMMARY OF KEY ASPECTS ________________________________ ___________ i

1. INTRODUCTION ________________________________________________1

2. APPROACH TO THE WATER STUDY _______________________________3 2.1 Terms of Reference ________________________________ _____________3 2.2 General Approach ________________________________ _____________4

3. LOCAL WATER ENVIRONMENT ___________________________________4 3.1 Surface Water Environment_______________________________________4 3.2 Groundwater Environment _______________________________________8

4. REGULATIONS REGARDING WATER USE AND QUALITY______________9 4.1 Introduction ________________________________ __________________9 4.2 Registration of Water Use ________________________________ ________9 4.3 Water Use Licensing/Authorisation ________________________________10 4.4 Other Applicable Water Quality Guidelines___________________________12 4.5 Pollution Mitigation ___________________________________________13 4.6 Other Regulatory Considerations__________________________________14

5. WATER USE AND LIQUID WASTE GENERATED BY THE PROPOSED PAS 2005 PROJECT ________________________________________________14

5.1 Water Use __________________________________________________14 5.2 Liquid Waste ________________________________________________15

5.2.1 Domestic wastewater ______________________________________________________ 15 5.2.2 Process wastewater _______________________________________________________ 16 5.2.3 Stormwater ______________________________________________________________ 17

6. ENVIRONMENTAL IMPACT ASSESSMENT METHODOLOGY___________20

7. ASSESSMENT OF IMPACTS BY THE PROPOSED ALUMINIUM SMELTER ON THE WATER ENVIRONMENT__________________________________22

7.1 Environmental Significance of Increased Water Use ____________________22 7.1.1 Construction Phase _______________________________________________________ 23 7.1.2 Operational Phase ________________________________________________________ 23

7.2 Environmental Significance of Wastewater Discharge ___________________27 7.2.1 Wastewater Generated during Construction ___________________________________ 27 7.2.2 Operation Wastewater _____________________________________________________ 30

7.3 Environmental Significance of Wastewaters on Groundwater ______________46 7.3.1 Geohydrology ____________________________________________________________ 46

8. WATER CONSERVATION/BEST PRACTICE_________________________51

9. CONCLUSIONS AND RECOMMENDATIONS_________________________52

10. REFERENCES _________________________________________________55


Aluminium Pechiney Coega EIA page iv

List of Appendices

Appendix A Rainfall Data: Port Elizabeth Appendix B Interceptor Pond: Sizing Considerations Appendix C Extreme Rainfall Events and Return Periods for Coega Area

List of Tables

Table 1: Classification of rivers according to the present ecological state ________________________ 5

Table 2: Overall class index for the different reaches of the Coega River ________________________ 6

Table 3: Wastewater limit values applicable to discharge of wastewater into a water res ource _____ 11

Table 4: South African Water Quality Guidelines for aquatic ecosystems (DWAF, 1996) __________ 13

Table 5: Water supply – volumes and quality required ______________________________________ 15

Table 6: Domestic wastewater volumes __________________________________________________ 15

Table 7: Typical composition of untreated domestic wastewater ______________________________ 16

Table 8: Typical process wastewater composition__________________________________________ 16

Table 9: An assessment of the potential impact of increased water use during constructio n _______ 25

Table 10: An assessment of the potential impact of increased water use during operation _________ 26

Table 11: An assessment of the potential impact of construction wastewater and stormwater discharge during construction phase ____________________________________________________ 28

Table 12: Estimation of the potential fluoride concentrations in the stormwater discharge from the interceptor pond (12 600 m3) __________________________________________________ 32

Table 13: Estimation of the potential fluoride concentrations in the stormwater discharge from the interceptor pond (30 000 m3) __________________________________________________ 34

Table 14: Average monthly rainfall (mm) for Port Elizabeth (1980 -1996) _______________________ 35

Table 15: Estimation of the effect of poor on-site management on the fluoride concentration in the stormwater_________________________________________________________________ 37

Table 16: Effect of combining process wastewater and stormwater____________________________ 38

Table 17: An assessment of the potential impact of process wastewater/stormwater discharge on an environmentally sensitive ecosystem ___________________________________________ 40

Table 18: An assessment of the potential impact of process wastewater/stormwater discharge from the western edge of the saltworks to the port via an earth/natural channel ________________ 42

Table 19: An assessment of the potential impact of process wastewater/stormwater discharge from the western edge of the saltworks to the port via an engineered canal or a pipeline ________ 43

Table 20: An assessment of the potential impact of wastewater practises on groundwater _________ 48

Table 21: Summary impact assessment of the proposed aluminium smelter ____________________ 50


Aluminium Pechiney Coega EIA page v

List of Figures

Figure 1: Aerial view of the proposed Aluminium Pechiney smelter within the Coega IDZ __________ 1

Figure 2: Aerial view of the IDZ showing the location of the proposed PAS 2005 smelter ___________ 2

Figure 3: Flow of Coega River (2000 – 2001) (SRK, 2001)____________________________________ 7

Figure 4: Coega River fluoride concentrations (2000 – 2001) (SRK, 2001) _______________________ 7

Figure 5: IDZ groundwater fluoride concentrations (2000 – 2001) (SRK, 2001) ___________________ 9

Figure 6: Proposed PAS 2005 Project stormwater system ___________________________________ 20

Figure 7: Port Elizabeth monthly rainfall: year 2000_________________________________________ 35

Figure 8: Port Elizabeth Daily and Cumulative Rainfall: year 2000 _____________________________ 36

Figure 9: Rainfall Intensity (mm): Port Elizabeth 1972 – 2001 (60 min) _________________________ 36

Figure 10: Map of the Coega Industrial Development Zone showing the geological formations and the location of the proposed PAS 2005 smelter______________________________________ 46

This report is to be cited as follows:

de Souza P and Mackintosh G. 2002. Specialist study: Water Use and Liquid Waste. In: Environmental Impact Assessment for the proposed Aluminium Pechiney smelter within the Coega Industrial Zone, Port Elizabeth, South Africa. Specialist Studies Report. CSIR Report No. ENV-S-C 2002-092B, Stellenbosch, South Africa.


Aluminium Pechiney Coega EIA page v i

Glossary

Acute effect value The concentration at and above which statistically significant acute adverse effects are expected to occur.

Aquifer A geological formation that has structures or textures that hold water or permit appreciable water movement through them.

Aquitard A formation or group of geological formations with low permeability which retard the flow of groundwater.

Attenuation dam Dam downstream of the interceptor pond to allow additional detention capacity and sedimentation of suspended material.

Blowdown To prevent the formation of precipitates within the cooling circuit, a portion of the concentrated cooling water is bled off and replaced with low salt make-up water to maintain a proper salt balance. The highly saline water that is bled off from the cooling system is called blowdown.

Chronic effect value The concentration limit that is safe for all or most populations even during continuous exposure.

Complex Industrial Wastewater

Wastewater arising from industrial activities and premises that contains a complex mixture of substances that are difficult or impractical to chemically chara cterise and quantify, or one or more substances, for which limit values have not been specified, and which may be harmful or potentially harmful to human health, or to the water resource wastewater

Domestic water Water used for survival (drinking and food preparation), for personal hygiene (washing clothes, bathing and sewage removal) and for gardening.

Domestic wastewater/sewage Wastewater produced because of domestic activities and includes both liquid and solid waste.

Fallout Deposition of materials because of gaseous emissions.

“First flush” The first hour of rainfall (stormwater) runoff from the site.

Interceptor pond Pond to allow containment of the “first flush” of stormwater.

Pinch technology This is a systematic technique for analysing heat fl ows or mass transfer through industrial processes and can be used to decrease energy consumption or water use/wastewater generation.

Process water/industrial water

That water which can be used in a number of processes in the manufacture of a product, but is not part of the product.

Process wastewater Wastewater produced because of industrial activities.

Receiving water quality objective

This approach focuses on the quality of the receiving water, instead of the quality of the emissions from a source, in decisions concerning pollution control.

Stormwater Runoff resulting from rainfall and snowmelt.

Target water quality range For each quality constituent of concern a range of water quality can be defined over which there would be no impairment of a particular water use or of the natural aquatic environment.

Total dissolved solids (TDS) The total dissolved solids concentration is a measure of the quantity of various inorganic salts dissolved in water.


Aluminium Pechiney Coega EIA page 1

ALUMINIUM PECHINEY

WATER USE AND LIQUID WASTE STUDY OF THE ENVIRONMENTAL IMPACT ASSESSMENT FOR THE

PROPOSED PAS 2005 SMELTER AT COEGA INDUSTRIAL DEVELOPMENT ZONE

1. INTRODUCTION ALUMINIUM PECHINEY (AP) has identified the Coega Industrial Development Zone (IDZ), located north east of Port Elizabeth, Eastern Cape Province as a potential site for construction and operation of an aluminium smelter. The proposed smelter will produce approximately 485 000 tonnes per annum of primary aluminium using AP’s latest AP50 reduction technology. Aluminium Pechiney state that the recently developed AP50 smelting technology represents significant capital and operating cost advantages over older smelting technologies. An aerial view of the proposed smelter site at Coega is shown in Figure 1.

Figure 1: Aerial view of the proposed Aluminium Pechiney smelter within the Coega IDZ



The location of Coega IDZ and the proposed AP smelter site is shown in Figure 2, in which can also be seen the general locality of the coast line (bottom right hand corner), the Coega River and the associated salt pans (to the east of the proposed smelter site).

Figure 2: Aerial view of the IDZ showing the location of the proposed PAS 2005 smelter

The smelter project will comprise a single potline of 336 electrolysis cells together with associated facilities for carbon anode production, aluminium casting, materials handling and storage, and port loading and unloading. The Aluminium Pechiney area has been estimated at approximately 80 hectares, of which approximately 50 hectares will be terraced (i.e. paved areas/buildings, etc). The water usage for the plant during operations is approximately 600,000 m3/year (includes both industrial and domestic water requirements). Key issues related to water utilization are the availability of water, the optimisation of on-site water use and the prevention of pollution of aquatic ecosystems. During the construction period, 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. Be that as it may, during construction increased turbidity and downstream sedimentation (arising from erosion from construction areas) is likely to be the main water quality concern.



During operation, the three main liquid discharges from the site will be domestic sewage, process wastewater and stormwater. A key issue related to water discharges from the smelter site is the risk of pollutants reaching any environmentally sensitive areas (e.g. Butterfly Valley). In particular, the “first flush” (i.e. first rain run-off after a dry period) carries a higher concentration of potential pollutants (most notably fluoride).

2. APPROACH TO THE WATER STUDY The primary objective of the water study is to identify the significance of possible environmental impacts of water use (during construction and operation), domestic sewage discharge, process wastewater discharge and contaminated stormwater discharge from the proposed aluminium smelter site. 2.1 Terms of Reference The Water Use and Liquid Waste Management Study addresses a range of factors associated with water use and the handling of liquid waste generated on-site. The study includes confirmation and assessment of available water sources, pre -treatment requirements, liquid wastewater characterization (in terms of both volumes and quality) and the management of all liquid wastes generated on -site for discharge from the smelter site. Consideration of water recycling and re -use within the system is also included. The study includes the following: Water Use:

• Confirmation of water sources • Confirmation of quantities of water required • Recycle/re-use options

Liquid Waste and Stormwater:

• Effluent discharge water quality requirements in terms of local/national regulations including National Water Act (Act 36 of 1998) and other legislation identified as pertinent.

• Qualification and quantification of effluent including: o Location, identification and confirmation of sources of impact on water quality

[on-site wastewater production and effect of discharge on receiving water quality (both surface and groundwater), atmospheric fallout, effects of non-point sources (run -off) and seepage from stormwater retention dam]

o Identification of constituents of concern in effluent o Effect of effluent water quality on future water uses and the natural aquatic

environment, in particular the Coega River. o Identification of effluent water treatment/remediation requirements or

opportunities and other management considerations.



2.2 General Approach The general approach used in this study was to gather all information and data available to be able to address the Terms of Reference. Thereafter, the significance of possible environmental impacts of water use, domestic wastewater discharge, process wastewater discharge and contaminated stormwater discharge of the proposed aluminium smelter were considered. As the nature of the study is such that not all information and data ideally required is necessarily available, a number of representative scenario’s were explored which enabled a quantitative analysis of the compliance of the proposed stormwater management system with appropriate water quality guidelines. These identified “worst case” environmental scenarios were then used to determine the environmental significance of impact. Based on the determined environmental significances, recommendations have been made regarding:

• The adoption of impact mitigation measures to reduce the level of environmental impact,

• The on-site environmental management required, • The monitoring programme required to ensure compliance with water quality

guidelines or other site specific criteria. 3. LOCAL WATER ENVIRONMENT 3.1 Surface Water Environment Butterfly Valley, a natural watercourse located between the proposed smelter and the saltworks/Coega River has been identified as “Environmentally Sensitive” with regards to slope, vegetation and fauna in both the Strategic Environmental Assessment (CSIR, 1997) and the Coega Rezoning EIA (Coastal and Environmental Services, 2000). It is therefore important that no waste of undesirable quality is discharged into Butterfly Valley, a seasonal watercourse south of the smelter site on the seaward side of the N2 highway. Water flowing through Butterfly Valley discharges into the lower reaches (flood plain) of the Coega River. The Coega River is a relatively small sand-bed river in the Coega Industrial Development Zone (IDZ) and is the most significant surface water feature associated with the proposed smelter development. The Coega River is diverted into a trapezoidal earth channel about 3.3 km upstream of the river mouth. A commercial saltworks is located within the flood plain of the Coega River downstream of the N2 highway bridge. During flood events, floodwaters will overtop the west bank of the channel and spread over the total area of the saltworks. Part of the eastern fringes of these saltworks will be lost to infrastructural requirements if the IDZ is further developed. In general, rivers are classified using a system that assigns a particular class to a river based on its present ecological state. The following table provides an overview of river classification guidelines used to determine the ecological state of the Coega River.



Table 1: Classification of rivers according to the present ecological state

Present

ecological state Description of perceived conditions

Within desired range A Unmodified, or approximates natural condition; the natural abiotic template

should not be modified. The characteristics of the resource should be determined by unmodified natural disturbance regimes. There should be no human induced risks to the abiotic and biotic maintenance of the resource. The supply capacity of the resource will not be used.

B Largely natural with few modifications; only a small risk of modifying the natural abiotic template and exceeding the resource based should be allowed. Although the risk to the well-being and survival of especially intolerant biota (depending on the nature of the disturbance) at a very limited number of localities may be slightly higher than expected under natural conditions, the resilience and adaptability of biota must not be compromised. The impact of acute disturbances must be totally mitigated by the presence of sufficient refuge areas.

C Moderately modified; a moderate risk of modifying the abiotic template and exceeding the resource base may be allowed. Risks to the well- being and survival of intolerant biota (depending on the nature of the disturbance) may generally be increased with some reduction of resilience and adaptability at a small number of localities. However, the impact of local and acute disturbances must at least partly be mitigated by the presence of sufficient refuge areas.

D Largely modified; large risk of modifying the abiotic template and exceeding the resource base may be allowed. Risk to the well-being and survival of intolerant biota depending on (the nature of the disturbance) may be allowed to generally increase substantially with resulting low abundance and frequency of occurrence, and a reduction of resilience and adaptability at a large number of localities. However, the associated increase in the abundance of tolerant species must not be allowed to assume pest proportions. The impact of local and acute disturbances must at least to some extent be mitigated by refuge areas.

Outside desired range E Seriously modified. The losses of natural habitats and basic ecosystem

functions are extensive. F Critically modified. Modifications have reached a critical level and the system

has been modified completely with an almost complete loss of natural habitat.



Using the above river classification guidelines, the Coega River management class was determined (Gibb, 1999). In this assessment, the river was divided into four reaches:

• Reach 1 This region is in the upper reaches of the catchment. The river and the direct surroundings are not pristine, but also not in a serious degraded or disturbed state.

• Reach 2 Middle reaches of the catchment. In this reach, the riverbed appears more disturbed than in the upper reaches, but is still not badly degraded.

• Reach 3 Incorporates the top reaches of the Coega IDZ. The influence of human activities is more evident in the area than in the upper or middle reaches.

• Reach 4 Area to the south -east of the N2 highway (i.e. downstream) and includes the river and the estuary. The saltworks is included in this reach.

From the study, the class indices shown in Table 2 were assigned to the various reaches. Table 2: Overall class index for the different reaches of the Coega River

Reach Overall class index 1 C 2 C 3 D 4 F

Considering the proposed location of the aluminium smelter, it is clear that the reach that could possibly be affected by liquid waste discharges from the smelter site is Reach 4 (the topography of the area is such that the main run-off from the proposed smelter site is towards this area). From the above table it is clear that the present ecological state of the Coega River in this reach is already critically modified and environmentally degraded. An almost complete absence of natural habitat exists. The salinity levels in this reach suggest this may warrant reclassification as a marine (or salt water) environment. Linked to the above, and in order for the Coega Development Corporation to monitor the environmental performance by industries in the future, an independent surface water quality monitoring system has been established in the Coega IDZ. The results of preliminary monitoring of the flow conditions and fluoride concentrations of the Coega River are presented in the figures below (SRK, 2001).



Flow of Coega River

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

22/03/2000 11/05/2000 30/06/2000 19/08/2000 08/10/2000 27/11/2000

Date

Flo

w (

m3/

s)

SW-DS SW-1 SW-2 SW-3 SW-4 SW-US

Figure 3: Flow of Coega River (2000 – 2001) (SRK, 2001)

Surface Water Fluoride Concentrations

0

5

10

15

20

25

30

35

40

22/03/2000 11/05/2000 30/06/2000 19/08/2000 08/10/2000 27/11/2000

Date

F (m

g/L)

SW-DS SW-1 SW-2 SW-3 SW-4 SW-US DWAF General Limit

Figure 4: Coega River fluoride concentrations (2000 – 2001) (SRK, 2001)



Although the Coega River is described as a perennial river, Figure 3 shows that during the assessment period, periods of low/no flow have been recorded. In Figure 4 it is shown that during these periods of low/no flow, the fluoride concentrations recorded were higher than both the DWAF freshwater and marine water quality guidelines (refer to section 4) at most sample points. This could probably be attributed to concentration effects because of evaporation. NOTE: The sampling points shown in the graphs above monitor flow and water quality at upstream (SW-US), downstream (SW-DS) and intermediate (SW-1, SW -2, SW-3, SW-4) locations within the IDZ. 3.2 Groundwater Environment The proposed smelter site is underlain by Adolphspoort shale. This formation is part of the Traka subgroup of the Bokkeveld shale. The Adolphspoort shale is expected to act as an aquitard on site (i.e. rainfall infiltration is limited), with no aquifer potential. 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.

Although no direct geohydrological or groundwater data is available for the Aluminium Pechiney site itself, some information is known about groundwater in similar aquifers in the surrounding area (SRK, 1998, Colvin et al 1996, Meyer 1998). Typically, groundwater gradients mirror the topography and it is expected that any groundwater flow from the site would be approximately towards the coast and locally towards Butterfly Valley. The only evident potential receptors for groundwater impacts are the Butterfly Valley, the coastal environment and the Coega estuary. These environments may rely on groundwater inputs to control salinity or provide nutrients or trace elements. Limited groundwater quality data is available for the Coega IDZ. As per surface water, a groundwater quality monitoring system was established by the Coega Development Corporation. The results of preliminary monitoring have indicated that the groundwater quality in the area is generally poor (SRK, 2001). By way of example, the fluoride concentration as recorded at groundwater sampling points are shown in Figure 5. The figure shows that fluoride concentrations measured are generally high, regularly failing SABS 241-2001 Maximum Allowable Limits of 1.5 mg/L for drinking-water. In particular, fluoride concentrations at sampling point CM-1 and CM-2, which are upriver of the N2 highway and near the Coega hamlet, are consistently in excess of SABS 241-2001 specifications (water abstracted from groundwater for domestic purposes should satisfy SABS 241-2001 specifications).



Groundwater Fluoride Concentrations

0

2

4

6

8

10

12

14

16

25/01/2000 15/03/2000 04/05/2000 23/06/2000 12/08/2000 01/10/2000 20/11/2000 09/01/2001 28/02/2001

Date

F (m

g/L)

CM-1 CM-2 CM-4 SABS241 - Acceptable SABS241 - Max Allow.

Figure 5: IDZ groundwater fluoride concentrations (2000 – 2001) (SRK, 2001) The previous sections have highlighted the current status of both surface- and groundwater in the Coega IDZ. In particular, attention is brought to the respective high fluoride concentrations recorded.

4. REGULATIONS REGARDING WATER USE AND QUALITY 4.1 Introduction Water use is controlled by the National Water Act 36 of 1998, which protects all water resources countrywide (both surface and ground waters). The enforcing authority is the Department of Water Affairs and Forestry (DWAF). Of the water uses listed in the National Water Act, the following are relevant to the PAS 2005 project:

• Taking water from a water resource; • Discharging waste or water containing waste into a water resource through a

pipe, canal, sewer or other conduit; • Disposing of waste in a manner, which may be detrimental on the water

resource. 4.2 Registration of Water Use It is the statuary obligation for all water users to register for their water use. There are strict penalties prescribed in the Act (National Water Act 1998) for those who do not comply. Water users who must register include those who use water for inter alia:

• Industrial use • Irrigation



• Discharges of waste or water containing waste. However, if the aforementioned water use is part of the services provided by a water services provider (e.g. Water Board, local municipality), the individual water users need not register. In this case, the water services provider will need to register the water use with DWAF. 4.3 Water Use Licensing/Authorisation A person may only use water (National Water Act 1998):

• Without a licence o If that water use is permissible under Schedule 1 of the Act o If that water use is permissible as a continuation of an existing water use; or o If that water use is permissible in terms of general authorisation issued under

section 39 of the Act • If the water use is authorised by a licence under the Act • If the responsible authority has dispensed with a licence requirement

General Authorisation Issued under Section 39 Licenses are not required (Section 22) where the use is permissible under a General Authorisation, or where a responsible authority has waived the need for a licence (because it is satisfied that the purpose of the Act will be served by an authorisation under any other law). The authorisation permitted replaces the need for a water user to apply for a licence in terms of the National Water Act if the water use is within the limits and conditions set out in the authorisation. The intention of the General Authorisation is to allow water use of small or insignificant impacts on a water resource to take place without a licence. The Director-General of DWAF has issued General Authorisation in respect of four water uses, where need for a licence is not required:

• Taking of water from a water resource and storage of water. • Engaging in a controlled activity, identified as such in section 37(1), namely

irrigation of any land with waste or water containing waste generated through any industrial activity or by waterworks.

• Discharging of waste or water containing waste into a water resource through a pipe, canal, sewer, or other conduit or discharging water from an industrial or power generation process.

• Disposing of waste in a manner that may detrimentally impact on a water resource.

The General Authorisation provides information regarding discharge of wastewater into a water resource. Wastewater limit values applicable to discharge of wastewater into a water resource are shown in Table 3.



Table 3: Wastewater limit values applicable to discharge of wastewater into a water reso urce

Parameter General Limit Special Limit Faecal coliforms (per 100 mL) 1000 0 Chemical Oxygen Demand (mg/L) (after removal of algae)

75 30

pH 5.5 – 9.5 5.5 – 7.5 Ammonia as N (mg/L) 3 2 Nitrate/Nitrite as N (mg/L) 15 1.5 Chlorine as free chlorine (mg/l) 0.25 0 Suspended solids (mg/L) 25 10 Electrical conductivity (mS/m) 70 mS/m above intake to

a max. of 150 mS/m 50 mS/m above intake to

a max. of 100 mS/m Ortho-phosphate as phosphorous (mg/L) 10 1 (median) and

2.5 (max.) Fluoride (mg/L) 1 1 Soap, oil or grease (mg/L) 2.5 0 Arsenic (dissolved) (mg/l) 0.02 0.01 Cadmium (dissolved) (mg/L) 0.005 0.001 Chromium VI (dissolved) (mg/L) 0.05 0.02 Copper (dissolved) (mg/L) 0.01 0.002 Cyanide (dissolved) (mg/L) 0.02 0.01 Iron (dissolved) (mg/L) 0.3 0.3 Lead (dissolved) (mg/L) 0.01 0.006 Manganese (dissolved) (mg/L) 0.1 0.1 Mercury and its compounds (mg/l) 0.005 0.001 Selenium (dissolved) (mg/L) 0.02 0.02 Zinc (dissolved) (mg/L) 0.1 0.04 Boron (mg/L) 1 0.5 Under the general authorisation, the proposed aluminium smelter would be allowed to:

• Discharge up to 2000 m3 of wastewater on any given day into a water resource that is not a listed water resource 1 provided the:

o Discharge complies with the General Limit Values as set out above. o The discharge does not alter the natural ambient water temperature of the

receiving water resource by more than 3 ºC. o The discharge is not a Complex Industrial Wastewater.

• Discharge up to 2000 m3 of wastewater on any given day into a listed water

resource provided the:

o Discharge complies with the Special Limit Values as set out above. o The discharge does not alter the natural ambient water temperature of the

receiving water resource by more than 2 ºC. o The discharge is not a Complex Industrial Wastewater.

1 In the National Water Act, a water resource is defined as including a watercourse, surface water, estuary or aquifer.



• Discharge stormwater runoff from the premises, not containing waste or wastewater emanating from industrial activities and premises, into a water resource.

Based on the above requirements, the following should be noted:

• The Coega River is not a listed water resource , and therefore General Limit Values are applicable. Wastewater discharged from the smelter site into a water resource must therefore satisfy General Limit Values.

• Process wastewater from the proposed smelter is not considered a Complex Industrial Wastewater.

• As air emissions from the smelter and general on-site activities (spillages, etc) are likely to result in contamination of stormwater runoff from the smelter site, discharge of this stormwater does not fall under the General Authorisation. Stormwater must therefore be regarded as a wastewater.

4.4 Other Applicable Water Quality Guidelines In addition to satisfaction of the water quality requirements specified under the General Authorisation, the following guidelines are applicable to the smelter.

• South African Water Quality Guidelines – Aquatic Ecosystems • Marine Water Quality Guidelines

South African Water Quality Guidelines – Aquatic Ecosystems These guidelines are used by DWAF as a decision support tool for management and protection of aquatic ecosystems. The different water quality criteria and objectives provided in the guidelines are typically used in the following ways:

• Target Water Quality Range (TWQR) is a management objective that is used to specify the desired or ideal concentration range and/or water quality requirements for a particular constituent.

• The Chronic Effect Value (CEV) is a criterion that is used, in certain special cases where the TWQR is exceeded. The setting of water quality requirements or objectives at the CEV protects aquatic ecosystems from acute toxicity effects.

• The Acute Effect value (AEV) is a criterion used to identify those cases requiring urgent management attention because the aquatic environment is threatened, even if the situation persists only for a brief period. The AEV may also be used to identify those cases in need of urgent mitigationary action. However, the AEV should not be used for setting water quality requirements for aquatic ecosystems.

Table 4 below shows the guidelines applicable to the smelter to ensure protection of aquatic ecosystems.



Table 4: South African Water Quality Guidelines for aquatic ecosystems (DWAF, 1996) Parameter Target Water Quality Range (TWQR) Chronic

Effect Value (CEV)

Acute Effect Value (AEV)

pH pH vales should not be allowed to vary by > 0.5 of a pH unit, or by > 5% (use more conservative estimate)

- -

Aluminium as Al (mg/L)

< 0.005 (pH < 6.5) < 0.01 (pH > 6.5)

0.01 (pH < 6.5) 0.02 (pH > 6.5)

0.1 (pH < 6.5) 0.15 (pH > 6.5)

Total Suspended Solids (TSS) (mg/L)

Any increase in TSS concentrations must be limited to < 10% of the background TSS concentrations at a specific site and time

- -

Total Dissolved Solids (TDS) (mg/L)

TDS concentrations should not be changed by > 15% (from normal water body cycles), and amplitude/frequency of natural cycles in TDS concentrations should not be changed

- -

Fluoride (mg/L) < 0.75 1.5 2.54 Soap, oil or grease (mg/L)

No guidelines

Zinc (dissolved) (mg/L)

< 0.002 0.0036 0.036

Marine Water Quality Guidelines If process wastewater and contaminated stormwater are discharged from the smelter site to the sea, the necessary Marine Discharge Guidelines will be applicable. The impact of process wastewater and contaminated stormwater discharges on the marine environment forms the focus of the report entitled: “Specialist Study on Discharges to the Marine Environment”. 4.5 Pollution Mitigation Under Chapter 3 of the National Water Act (Act 36 of 1998) (Section 19) any person who owns, controls, occupies or uses land is deemed responsible for taking measures to prevent pollution of water resources. If these measures are not taken, the responsible authority may do whatever is necessary to prevent the pollution or remedy its effects and to recover all reasonable costs from the responsible person. Non-compliance with this provision constitutes a criminal offence. The measures referred to may include measures to :

• Cease, modify or control any act or process causing the pollution; • Comply with any prescribed waste standard or management practice; • Contain or prevent the movement of pollutants; • Eliminate any source of the pollution; • Remedy the effects of the pollution; and • Remedy the effects of any disturbance to the bed and banks of a watercourse.



4.6 Other Regulatory Considerations The Water Services Act (108 of 1997) This Act regulates rights of access to basic water supply and sanitation necessary to secure sufficient water and environment not harmful to human health or well-being. In the case of the abstraction of water for industrial purposes or the disposal of process wastewater the provisions of section 7 of this Act must be met. In particular:

• Industrial water must be sourced from the distribution system of the water services provider nominated by the water services authority having jurisdiction in the area in question (unless approval is granted by the Water Services Authority not to do so).

• Wastewater produced by the industry must be disposed in a manner approved by the water services provider nominated by the water services authority having jurisdiction in the area in question.

CDC By-Laws Relating To the Discharge of Domestic Wastewater, Process Wastewater and Other Substances Any By-Laws generated will be administered by the CDC and will regulate:

• The quality and quantity of wastewater that might have an impact on aquatic systems, and

• The quality and quantity of wastewater that may be discharged into municipal sewers.

The By-Laws will prohibit the discharge of specified substances and allow the CDC to impose stricter conditions on any permission granted to discharge industrial wastewater into a sewer where circumstances require it. 5. WATER USE AND LIQUID WASTE GENERATED BY THE

PROPOSED PAS 2005 PROJECT 5.1 Water Use Two distinct stages can be identified for the proposed PAS 2005 Project, namely:

• Construction • Operation

The following table shows the expected water use for the various stages of the proposed smelter project.



Table 5: Water supply – volumes and quality required

Phase Water Volume Requirement Water Quality Requirement Preliminary earthworks 2 L/s Drinking-water standards Smelter construction 144 000 m 3/yr Drinking-water standards required for

construction personnel Quality required for concrete, compaction, dust control not specified

Smelter construction (for cathode sealing)

Min. emergency flow of 10 m3/hr pH 7 – 8 Hardness < 150 mg/L as CaCO3 Alkalinity < 60 mg/L as CaCO3 Conductivity < 1000 µS/cm Chloride < 100 mg/L

Smelter operation – drinking water

80 000 m3/yr Drinking-water standards

Smelter operation – process water

500 000 m 3/yr pH 7 – 8 Hardness < 150 mg/L as CaCO3 Alkalinity < 60 mg/L as CaCO3 Conductivity < 1000 µS/cm Chloride < 100 mg/L

Fire fighting water 400 m3/hr during 1 hour Not specified NOTE: The quantity of process water presented in the table above is “fresh” water required for the smelter cooling circuit (i.e. process water is primarily used in cooling circuits as make -up water for evaporation and blowdown losses). The majority of water used in the smelter cooling circuits is therefore recycled. 5.2 Liquid Waste 5.2.1 Domestic wastewater As per water use, expected quantities of domestic wastewater produced will vary during construction and operation. The following table shows the expected domestic wastewater volumes for the various stages of the proposed smelter project. Table 6: Domestic wastewater volumes

Phase No. of People Rate

(L/person/day) Daily Volume

(m3) Preliminary earthworks 115 (peak) 100 11.5 Smelter construction 5 800 (12 month peak) 100 580 Smelter construction 3 200 (14 month average) 100 320 Smelter operation 460 peak per shift + contractors

= 1 150 in 24 hours 100 115

NOTE: Smelter construction as sumes a 26-month construction period with a 12-month peak in the middle of the construction period. The typical composition of untreated domestic wastewater is shown in Table 7 (Metcalf and Eddy, 1991).



Table 7: Typical composition of untreated domestic wastewater

Parameter Concentration Total solids (mg/L) 720 Settleable solids (mg/L) 10 Biochemical oxygen demand (BOD) (mg/L) 220 Total organic carbon (TOC) (mg/L) 160 Chemical oxygen demand (COD) (mg/L) 500 Total nitrogen (mg/L) 40 Total phosphorous (mg/L) 8 Chlorides (mg/L) 50 Sulphate (mg/L) 30 Alkalinity as CaCO3 (mg/L) 100 Grease (mg/L) 100 Total coliform (no./100 mL) 107 - 108 Volatile organic compounds (VOC’s) (µg/L) 100 – 400

It is proposed that domestic wastewater generated will be discharged into the municipal sewer network for treatment at the municipal wastewater treatment plant. Initially CDC plan to discharge into the Fish Water Flats treatment works; and later (when volumes from the IDZ increase) into a new treatment works intended for the IDZ. 5.2.2 Process wastewater Most of the process wastewater originates from cooling water used throughout the plant for the cooling of cast products. Wastewater from these circuits is generated to maintain a constant dissolved minerals content (water hardness), by balancing the concentrating effects caused by water evaporation losses through addition of an excess of fresh water above evaporation makeup demand. In effect, a constant minerals concentration cycle is established and maintained in the cooling water circuits through adjustment of this discharge (termed “blowdown” or “purge”), within technical specifications. A small proportion of the cooling water is therefore drawn off, resulting in a process wastewater which Aluminium Pechiney has noted has the characteristics as shown in the table below (from “PAS 2005” Project, Preliminary Information documents). Table 8: Typical process wastewater composition

Parameter Concentration Fluoride (mg/L) 2 – 6 pH 6.5 – 9.5 Oil and grease (mg/L) < 10 Suspended solids (mg/L) < 30

Consideration of data relating to other South African aluminium smelters, indicates that the above mentioned process wastewater characteristics are reasonable. It is also worth noting that:

• Process wastewater is expected to have high concentration of total dissolved solids (TDS) (as a result of concentration brought about by evaporation within



the cooling circuit). • Although the fluoride content is generally expected to be less than 6 mg/L, higher

fluoride concentrations (~ 18 mg/L) have been noted in other smelter operations. These higher fluoride concentrations are generally attributed to poor operation and maintenance practices.

The amount of process wastewater generated has been estimated at 300 000 m3/year (i.e. within the DWAF maximum allowable discharge of 2000 m3/day). It is proposed to discharge this process wastewater into the site stormwater system. The quality of this wastewater will be controlled within acceptable discharge parameters (pH, suspended solids, metals) by way of specification of the commercial water treatment programs employed for corrosion and biological control in the circuits. The wastewater will be discharged into the stormwater system (most likely the attenuation dam) on a semi-continuous basis, likely resulting in small dry weather base flows from the smelter site. However, potential exists for this water source to be recycled for site landscaping irrigation purposes (depending on water quality and DWAF requirements) or for treatment and re-use in the smelter process. 5.2.3 Stormwater Stormwater contamination can be expected to arise from:

• Deposition (“fallout”) from the smelter fluoride emissions into the atmosphere. • Accidental or other spillages of fluorinated materials, oils, litter, etc. • Discharge of process wastewater into the stormwater system.

Aluminium Pechiney were able to provide data regarding expected stormwater quality in the form of a “synthesis” of wastewater analysis from several Pechiney smelter sites (Aluminium Pechiney, 2002). A review thereof reveals that constituents of primary concern included zinc, aluminium and fluoride.

• Zinc. An average zinc concentration of 0.66 mg/L (total) is noted. This is of concern considering the DWAF General Limit of 0.1 mg/L (dissolved). It is not easy to identify the origin of the zinc. It can be postulated that the zinc originates from the corrosion of galvanized structures, and not from the aluminium smelter process itself. It is worth noting that other aluminium smelters in South Africa that use Pechiney technology have not recorded raised zinc levels.

• Aluminium. An average aluminium concentration of 9 mg/L is noted. This is a

concern considering the South African Water Quality Guidelines (DWAF, 1996) Aquatic Eco-system Acute Effect Value (AEV) of 0.1 mg/L (pH < 6.5) and 0.15 mg/L (pH > 6.5). The reported aluminium levels are difficult to understand. Whilst there is no shortage of aluminium onsite, aluminium is of low solubility in the pH range of terrestrial waters (usually pH 6 to pH 7) and can be expected to have a solubility of between 0.1 mg/L to, at most, 0.5 mg/L (depending on localised aquatic chemistry circumstance). It has been confirmed by Aluminium Pechiney that the aluminium data reflects Total Concentrations (i.e. the sum of both dissolved and particulate aluminium). The latter will have no environmental



impact, whilst the former has environmental significance. It is worth noting that other aluminium smelters in South Africa that use Pechiney technology have not recorded raised aluminium levels, except on a few unusual occasions.

• Fluoride. An average fluoride concentration of 21.3 mg/L is noted. Such

fluoride concentrations are problematic as they by far exceed both the DWAF General Limit Value of 1.0 mg/L (for discharging of wastewater to a water resource) and the South African Water Quality Guidelines (DWAF, 1996) Aquatic Ecosystem Target Water Quality Range (TWQR) of 0.75 mg/L, the Chronic Effect Value (CEV) of 1.5 mg/L and the Acute Effect Value (AEV) of 2.54 mg /L.

Considering the significance of the gap between target fluoride levels and stated average fluoride concentrations, the fluoride issue will be the main wastewater issue considered further in this report. The following section describes the stormwater management plan proposed by Aluminium Pechiney (Brooks, Aluminium Pechiney, 2002) There are several principles that guide the design and operation of the PAS 2005 smelter stormwater system. The system for the Coega site has to account for specifications on both discharge quality and discharge flow rate.

Principle 1 – Sediment Capture Initial control of water quality collected from the site network requires collection of gross sediments, oils and floating debris. A sedimentation basin designed to separate gross particulates is required at the site network collection point immediately prior to the site interceptor pond. Trap mechanisms are also to be installed in this basin for oils and other floating contaminants. Recovery and disposal methods for those materials collected by the traps should also be provided. The design should facilitate pumping of sediments from the basin to an evaporation pond to assist final disposal.

Principle 2 – “First Flush” Collection An interceptor pond is constructed to provide control of the “first flush” of stormwater from any rain event. This first flush principle aims to collect up to (nominally) the first 20 mm of rainfall from the paved, roofed and sealed areas of the smelter site. Sizing of the pond is simply calculated by multiplying the total sealed collection area of the site by the level of rainfall to be collected (in this case 20 mm). In the case of Coega Stage 1, the total sealed area is estimated to be 50 hectares, which gives rise to a calculated required Inte rceptor Pond capacity of 10,000 m3. This volume has been supplemented at Stage 1 for future provision of Stage 2 surface areas by construction of an Interceptor Pond with a proposed volume of 12 600 m3. The design of the Interceptor Pond allows a filled pond to be emptied in two days (i.e. discharge of 6 300 m3/day).

In principle, the first flush of stormwater contains the highest level of dissolved fluorides rapidly leached from dusts deposited on rooftops, roads and other sealed areas between each rain event. The first flush collection also acts as an important interception control for accidental spillages on site of materials such as oils or chemicals and for water from fire fighting.



In practice, this first flush principle may be compromised by poor housekeeping procedures, which can introduce an additional fluoride load to the stormwater collection network. Excess spillages of fluoride based production materials, such as bath (cryolite), can contribute to the overall fluoride load if exposed to the rain. Strict operational housekeeping controls are therefore required to minimise these effects.

Following the cessation of a rain event, water stored in the first flush interceptor pond can be discharged as a “controlled” flow via the normal offsite network (possibly via the second flowrate controlling Attenuation Dam). A controlled rate of release ensures the total mass of fluoride collected in the first flush is discharged over an extended time to meet final dispersion targets in the receiving waters (river, sea, etc). Limits of fluoride concentration to be released from the pond will be controlled by a permit/licence issued by the relevant authority.

After the pond is drained, it is subsequently maintained in an almost empty state in readiness for the next rain event.

Continuous monitoring devices for flowrate, volume and quality (soluble fluoride, pH) should be installed. The base of the pond should also be lined with an impervious material to prevent seepage into local groundwater reserves. Principle 3 – Discharge Flowrate Attenuation Once the first flush Interceptor Pond is full, all further stormwater flow during a rain event bypasses the Interceptor Pond by way of a series of different height weirs. The discharge rate of this bypass flow from the smelter site to the IDZ network is subsequently controlled by an additional Attenuation Dam, designed to meet the flowrate limits set by permits/licenses or by agreements between relevant parties. CDC has indicated that the release flowrate from the attenuation dam into the stormwater system is designed to equal to a one in two year peak rainfall event (K Byrnes, CDC, pers comm.).

The calculated volume of this Attenuation Dam is determined from historic rainfall data. The maximum volume generated from a one in 100 year rain event (the worst case) must be captured and the discharge flowrate from the smelter site constrained to an overall discharge limit set by the relevant authority (DWAF or CDC) – in this case the flowrate equivalent to a one in two year peak rain event. Similar to calculation of the first flush Interceptor Pond volume, the sealed surface area of the smelter site is multiplied by the predicted maximum level of rainfall (one in 100 year event) to calculate the volumes to be collected. The calculation may discount the volume provided independently by the first flush Interceptor Pond. The required capacity of the Attenuation Dam has been estimated to be 30 000 m3. Rainfall associated with the one in two year event is used to calculate the allowable rate of discharge from the site, which is presently understood to be 23 m3/s.

An automatic volume control device (V–weir, orifice, auto adjusting valve) should be fitted to the discharge point to ensure simple but constant rates of discharge to the IDZ network not exceeding the calculated limit.



Principle 4 – Process Wastewater Discharge As outlined in 5.2.2 , it is proposed to discharge process wastewater from the recirculating process cooling water circuits into the site stormwater system. Valves allow a range of operational configurations as required by specific circumstance.

The following figure describes the proposed stormwater system. Figure 6: Proposed PAS 2005 Project stormwater system

The potential environmental impacts of water use and liquid discharges by the PAS 2005 Project will be discussed in the following sections. 6. ENVIRONMENTAL IMPACT ASSESSMENT METHODOLOGY The following methodology was applied in the water study to determine the potential impacts of water use, domestic wastewater, process wastewater and stormwater discharge on the biophysical environment. The significance of potential impact is described as follows:

Dirt trap

Interceptor pond

Attenuation dam

Stormwater Process wastewater

Final discharge

Overflow weir



Low Where the impact will not have an influence on the decision or require to be significantly accommodated in the project design

Medium Where it could have an influence on the environment that will require modification of the project design or alternative mitigation;

High Where it could have a ‘no-go’ implication for the project regardless of any possible mitigation.

The assessment of impact significance is based on the following convention:

Nature of impact This reviews the type of effect that a proposed activity will have on the environment and should include “what will be affected and how?” Extent This should indicate whether the impact will be local and limited to the immediate area of development (the site or the servitude corridor); limited to within 5km of the development; or whether the impact may be realised regionally, nationally or even internationally.

Duration This should review the lifetime of the impact, as being short term (0 - 5 years), medium (5 - 15 years), long term (>15 years but where the impacts will cease after the operation of the site), or permanent.

Intensity Here it should be established whether the impact is destructive or innocuous and should be described as low (where no environmental functions and processes are affected), medium (where the environment continues to function but in a modified manner) or high (where environmental functions and processes are altered such that they temporarily or permanently cease).

Probability This considers the likelihood of the impact occurring and should be described as improbable (low likelihood), probable (distinct possibility), highly probable (most likely) or definite (impact will occur regardless of prevention measures).

The status of the impacts and degree of confidence with respect to the assessment of the significance, is stated as follows:

Status of the impact A description as to whether the impact will be positive (a benefit), negative (a cost), or neutral.



Degree of confidence in predictions The degree of confidence in the predictions, based on the availability of information and specialist knowledge. • Impacts are described both before and after the proposed mitigation and

management measures have been implemented. • All impacts are evaluated for the full-lifecycle of the proposed development,

including construction, operation and decommissioning. • The impact evaluation takes into consideration the cumulative effects associated

with this and other facilities that are either developed or in the process of being developed in the region.

• Attempts are made to quantify the magnitude of potential impacts (direct and cumulative effects) and outline the rationale used. Where appropriate, national standards are used as a measure of the level of impact.

Mitigation and Monitoring • Where negative impacts are identified, mitigation objectives (i.e. ways of

reducing negative impacts), and recommend attainable mitigation actions have been proposed. Where no mitigation is feasible, this is stated and the reasons given. Where positive impacts are identified actions to enhance the benefit are also recommended.

• Quantifiable standards are set for measuring the effectiveness of mitigation and enhancement. In addition, monitoring and review programmes to assess the effectiveness of mitigation are described.

Use of ISO 14001 Based Approach In order to quantify the relative significance of different potential environmental impacts, an ISO 14001 based scoring process was used (National Quality Assurance, 2000). This has two objectives, firstly to ensure that the most environmentally hazardous issues are clearly prioritised and addressed. Secondly, it enables organisations to identify and evaluate current control mechanisms and decide what further steps may be needed to deal with significant potential causes of impact.

7. ASSESSMENT OF IMPACTS BY THE PROPOSED ALUMINIUM SMELTER ON THE WATER ENVIRONMENT

In this section, the potential impacts of increased water use, domestic wastewater discharge, construction wastewater discharge, process wastewater discharge and stormwater discharge on the environment will be discussed. 7.1 Environmental Significance of Increased Water Use The Water Services Development Plan for the Nelson Mandela Metropolitan Municipality (Metro), which incorporates the former Port Elizabeth, Despatch and Uitenhage Municipalities, is currently being prepared and is therefore not yet available. Nevertheless, via interaction with the Metro, relevant available information was obtained. Aluminium Pechiney provided information relating to on-site water use requirements (as discussed in section 5.1).



7.1.1 Construction Phase Preliminary Earthworks and Construction Water Use During construction, water will be used for both construction and domestic purposes. Water used for preliminary earthworks has been estimated at 0.2 ML/day, whilst water used during construction has been estimated at 230 000 m3/year (or 0.6 ML/day). This water will be supplied by the Metro, the quality of which will be as per minimum standards of the Metro (i.e. drinking -water quality). Due to the apparent short time frames (construction has been estimated to begin January 2003), it is highly unlikely that the proposed water-reuse facilities at Fishwater Flats Reclamation Works will be available. It is therefore envisioned that water used for construction will be obtained from the Nooitgedagt Water Treatment Works. Water from the Nooitgedagt Water Treatment Works originates from the Gariep Dam on the Orange River. The Nooitgedagt Water Treatment Works is located at Sunland some 40 km north of the IDZ. The works has a capacity of 70 ML per day and the current output is an average of 42 ML per day (i.e. Nooitgedagt Water Treatment Works has spare capacity of approximately 28 ML/day). Treated water is pumped to the Grassridge Reservoir which then supplies the Coegakop Break Pressure Tank (2 ML) in the IDZ. A large diameter pipeline has been installed to Coegakop and a delivery pipeline has been installed from Coegakop to the edge of the Coega IDZ to the N2 road. Numerous tee-off points have been allowed for the internal pipelines of the Coega IDZ. The bulk water supply is therefore ready to be supplied to the smelter or any other development. It is planned that once the water demand in the IDZ requires it, an additional service reservoir with a capacity of 17 ML will be constructed adjacent to the Coegakop Break Pressure Tank. From the above description, water consumption during preliminary earthworks of the proposed smelter is approximately 1.4% of the spare capacity of the Nooitgedagt Water Treatment Works, while water consumption during the construction phase of the proposed smelter is approximately 2.2% of the spare capacity of the Nooitgedagt Water Treatment Works. 7.1.2 Operational Phase Domestic Water Use As described in section 7.1.1, domestic water supply (for consumption, toilets, kitchens, cleaning, etc) is to be supplied from the Nelson Mandela Metropolitan Municipality (Metro). Typical consumption by the smelter has been estimated at 80 000 m3/year (or 0.2 ML/day). Water quality will be as per minimum standard s of the Metro (i.e. drinking-water quality). The domestic water consumption by the proposed smelter is approximately 0.8% of the spare capacity of the Nooitgedagt Water Treatment Works. Process Water Use As described in section 5.1 , industrial water consumption has been estimated at approximately 500 000 m3/year (or 1.4 ML/day). Initially this requirement will be met by the Nooitgedagt Water Treatment Works.



It is envisioned that in the future the bulk of the process water required would be reclaimed water supplied from the Fishwater Flat Reclamation Works near the Swartkops River mouth. The facilities for reclaiming treated wastewater do not presently exist, but are planned (depending on future demand). It is envisioned that proposed water re-use facilities with a capacity of 60 ML/day will be constructed. Infrastructural requirements include additional treatment facilities, pump station, rising main and a service reservoir. These facilities will need to be able to produce the water quality required by the smelter. From the above, process water consumption by the proposed smelter would be approximately 2.3% of the total capacity of the proposed Fishwater Flat Reclamation Works facilities. However, as it is unlikely that the Fishwater Flat Reclamation Works will be available at the start of smelter operation, the process water will need to be sourced from the Nooitgedagt Water Treatment Works. Process water consumption by the proposed smelter is approximately 5% of the spare capacity of the Nooitgedagt Water Treatment Works. In summary, although the Water Services Development Plan for the Metro is currently being finalised and is therefore not yet available, the Metro has noted that the additional water demands from the smelter are insignificant relative to present demand and existing capacities (Raymer, D., 2002). The existing infrastructure and water sources of Metro have sufficient capacity to meet the water demands of Aluminium Pechiney without the planned water-reuse facilities at Fishwater Flat Reclamation Works. Furthermore, Metro has noted that the water consumed by the smelter will have no impact on rates and negligible impact on the water tariff of other users (Raymer, D., 2002). Tables 9 and 10 show the methodology followed to assess the environmental significance of increased water use because of smelter construction and operation.



Table 9: An assessment of the potential impact of increased water use during construction

Nature and Status of Potential Impact

• Potential negative impact arises via water use by smelter overreaching local water supply infrastructure

• Potential negative impact arises via water use by smelter exceeding sustainable yield of water resources

Sources of Potential Impact • Construction of smelter Significance of Environmental Impact Extent • Is not likely to affect regional water supply/demand Duration • Short term – construction phase is 26 months

Intensity • Low – water use is low compared to capacity of the facilities (i.e. excess capacity currently exists)

Probability/Likelihood • Low likelihood of impact on the environment SIGNIFICANCE OF ENVIRONMENTAL IMPACT Score Total

3 (High)

2 (Medium)

1 (Low)

A. Extent a 1

4

(Permanent)

3 (Long-term >15 years)

2 (Medium term 5-15

years)

1 (Short -term 0-

5 years)

B. Duration a 1

3

(High) 2

(Medium) 1

(Low)

C. Intensity a 1 SIGNIFICANCE OF IMPACT SCORE (A + B + C) = 3 PROBABILITY OR LIKELIHOOD OF ACCIDENT OR ABNORMAL CONDITIONS Score (4=high, 1 = low) Total

4

(Definite)

3 (Highly

probable)

2 (Probable)

1 (Improbable)

Likelihood a PROBABILITY OR LIKELIHOOD OF OCCURRENCE SCORE = 1

TOTAL SCORE (Significance of impact x Likelihood of occurrence) = 3

Score Rating: LOW < 10

MEDIUM 11 – 20 HIGH > 20 Score: 3 Rating: LOW Negative Impact Degree of Confidence: High: The Nelson Mandela Metropolitan Municipality and

Aluminium Pechiney provided the data.



Table 10: An assessment of the potential impact of increased water use during operation

Nature and Status of Potential Impact

• Negative Impact arises via water use by smelter overreaching local water supply infrastructure

• Negative Impact arises via water use by smelter exceeding sustainable yield of water resources

Sources of Potential Impact • Operation of smelter Significance of Environmental Impact Extent • Is not likely to affect regional water supply/demand Duration • Long term (> 15 years) – for the life of the smelter

Intensity • Low – water use is low compared to capacity of the facilities (i.e. excess capacity currently exists )

Probability/Likelihood • Low likelihood of impact on the environment SIGNIFICANCE OF ENVIRONMENTAL IMPACT Score Total

3

(High) 2

(Medium) 1

(Low)

A. Extent a 1

4

(Permanent)


2 (Medium term 5-15

years)

1 (Short -term 0-

5 years)

B. Duration a 3

3

(High) 2

(Medium) 1

(Low)

C. Intensity a 1 SIGNIFICANCE OF IMPACT SCORE (A + B + C) = 5

PROBABILITY OR LIKELIHOOD OF ACCIDENT OR ABNORMAL CONDITIONS Score (4=high, 1 = low) Total

4

(Definite)

3 (Highly

probable)

2 (Probable)

1 (Improbable)

Likelihood a PROBABILITY OR LIKELIHOOD OF OCCURRENCE SCORE = 1

TOTAL SCORE (Significance of impact x Likelihood of occurrence) = 5

Score Rating: LOW 1 – 10

MEDIUM 11 – 20 HIGH > 20 Score: 5 Rating: LOW Negative Impact Degree of Confidence: High: The Nelson Mandela Metropolitan Municipality and

Aluminium Pechiney provided the data.



Impact Mitigation against the Environmental Significance of Increased Water Use As the significance of impacts has been rated as LOW, no specific impact mitigation is required. However, although it is noted that the proposed smelter recycles the majority of process water used, it must be further recognized that South Africa is a water scarce country, and that every effort should therefore be made to limit/reduce water use on the site. In this regard, it is recommended that in the future:

• The planned water-reuse facilities at Fishwater Flat Reclamation Works should be implemented.

• If the above option is not implemented, reuse of process water should be investigated.

• Pinch technology for optimum cooling water use should be investigated. Furthermore, appropriate water conservation measures could be introduced (see section 8). 7.2 Environmental Significance of Wastewater Discharge 7.2.1 Wastewater Generated during Construction During construction, wastewater generated will include:

• Domestic wastewater • Construction wastewater • Stormwater runoff

With regards to domestic wastewater produced during construction, the Coega Development Corporation has stated that they will utilise the existing municipal sewer network and Fishwater Flats Reclamation Works for treatment of domestic wastewater arising from the IDZ. The Metro has noted that the Fishwater Flats Reclamation Works has sufficient spare capacity to meet the effluent from the smelter (Raymer, D., 2002). 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. With regards to construction wastewater and stormwater, contamination could result from contact with, for example, chemicals, oils, fuels, sewage, solid waste, litter, etc. However, during construction, erosion from construction areas resulting in increased turbidity and downstream sedimentation is likely to be the main water quality concern. The potential impacts of construction wastewater and stormwater discharges during the construction phase are assessed in the following table.



Table 11: An assessment of the potential impact of construction wastewater and stormwater discharge during construction phase

Nature and Status of Potential Impact • Negative Impact arises via uncontrolled discharge of

potentially contaminated waters with increased turbidity to surface water or groundwater environments

Sources of Potential Impact • Uncontrolled discharge of contaminated construction wastewater and stormwater during construction phase

Significance of Environmental Impact Extent • Limited to within 5 km of development Duration • Short term

Intensity

• Medium – Although increased turbidity in rivers after rainfall events is a natural occurrence, there is a possibility of contaminants occurring in the construction wastewater/stormwater

Probability/Likelihood • Probability is linked to management practises followed SIGNIFICANCE OF ENVIRONMENTAL IMPACT Score Total

3 (High)

2 (Medium)

1 (Low)

A. Extent a 2

4

(Permanent)


2 (Medium term 5 -15

years)

1 (Short -term 0-

5 years)

B. Duration a 1

3

(High) 2

(Medium) 1

(Low)


4 (Definite)

3 (Highly

probable)

2 (Probable)

1 (Improbable)

Likelihood a 2 PROBABILITY OR LIKELIHOOD OF OCCURRENCE SCORE = 2 TOTAL SCORE (Significance of impact x Likelihood of occurrence) = 10 Score Rating: LOW 1 – 10

MEDIUM 11 – 20 HIGH > 20 Score: 10 Rating: LOW Negative Impact Degree of Confidence: Medium: Assessment was made based on expected general

management practises to be followed on-site during the construction period. The exact nature of practises to be employed on site, and the control thereof, is unknown.



Although the environmental impact has been rated as low, the exact management practises that will be followed during the construction phase are unknown. For this reason a number of practical mitigation/environmental management measures that should be implemented are highlighted. Impact Mitigation against the Environmental Significance of Uncontrolled Discharge of Construction Wastewater and Stormwater during Construction In order to minimise potential environmental impacts, the following measures must be implemented: • Erosion and sedimentation because of construction activities must be limited. In

particular: o The boundaries of the site must be clearly demarcated in order to restrict

construction activities to the site. o Permanent or temporary fences must be erected and maintained to ensure

that activities are conducted within a limited area, and thus limit impact on the environment.

o “No-go” areas (e.g. environmentally sensitive areas) should be clearly marked. No persons, machinery, equipment or materials should enter these areas.

o Suppliers/contractors should ensure that all vehicles utilize dedicated routes for construction vehicles.

• All material storage areas should be designated to reduce risk of spillages. All materials should be covered during transport to prevent them from spilling. If risk of stormwater contamination occurs, material stockpiles should be covered/kept out of the rain.

• Information posters describing environmental specifications requirements, and aimed at all levels of construction personnel should be erected and maintained.

• Transport, use and disposal of hazardous material must comply with relevant legislation (dispose at a permitted hazardous waste site). Of importance in this regard is required training and education of personnel, and road safety when transporting these materials.

• Contaminated stormwater and other run-off from the construction site must be contained. Construction of the dirt trap, Interceptor Pond and the Attenuation Dam must therefore commence at the start of the construction phase.

• Workshops, washing areas, etc must contain bunded areas. • Tanks containing fuels should have lids and must remain shut. Fuel tanks must be

contained in bunded areas, and any wastewater or spilled fuel collected within the bund must be disposed of as a hazardous waste. Oils collected in grease traps must be collected by the appointed waste contractor.

• Emergency procedures should be developed and communicated to all construction personnel such that all personnel are aware of the procedures to be followed for dealing with spills and leaks. The procedures developed should include identification of responsible personnel, contact details of emergency services, etc. The necessary materials and equipment for dealing with spills and leaks must be available at all times.



7.2.2 Operation Wastewater As described in section 5.2 , wastewater generated during smelter operation will include:

• Domestic wastewater • Process wastewater (mostly cooling water blowdown) • Stormwater runoff

With regards to domestic wastewater, the Coega Development Corporation has stated that they will utilise the existing municipal sewer network and Fishwater Flats Reclamation Works for treatment of domestic wastewater arising from the IDZ. The Metro has noted that the Fishwater Flats Reclamation Works has sufficient spare capacity to meet the effluent from the smelter (Raymer, D., 2002). No impacts of environmental significance are expected. Therefore, the focus of this study is process wastewater and stormwater discharges. With regards to both these are the characteristics of the respective discharge, and the nature of the receiving environment. Given that a number of aspects relating to the wastewater management in the Coega IDZ have yet to be finalised, we have approached the matter as follows:

• Considering a number of stormwater disposal options • Reviewing a number of stormwater and process wastewater quality scenarios • Determining the significance of the potential impact of expected stormwater and

process wastewater quality as discharged via the various disposal options With regards to liquid waste disposal, the following alternatives exist:

• Discharge from the Attenuation Dam via a pipeline under the N2 highway, to a river course (e.g. to Butterfly Valley or the smaller side valley to the north -east of Butterfly Valley)

• Discharge from the Attenuation Dam via a pipeline under the N2 highway into a conduit (eg. culvert or pipeline) running through the Butterfly Valley area to the western edge of the saltworks, and further discharge to the coast via either:

o Earth or natural channel to port o Engineered (lined) canal to port o Pipeline to port

• Removal from site by tanker truck to wastewater treatment works

With regards to reviewing stormwater and process wastewater quality scenarios , the objective is to determine the possible range of fluoride concentrations in the liquid waste being discharged offsite. During dry periods, fluoride material will accumulate on the site due to atmospheric fallout from the smelter and from on -site spillages (e.g. cryolite). In addition, it should be noted that stormwater could potentially have significant fluoride levels if poor spillage management procedures are followed. Whilst 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 up to 50 mg/L of fluoride to stormwater. What needs to be more fully explored is the contribution related to fluorinated atmospheric fallout and in particular with regards to:

• The contribution of atmospheric fallout to the fluoride loading in the stormwater of the smelter site.

• The ability of the on-site stormwater system to manage the concentration of fluoride discharge to acceptable levels.

In order to assess the above, and the potential environmental significance thereof, a number of scenarios have been have been considered. These include:

• Scenario 1 and Scenario 2: effect of varying rainfall intensity on potential fluoride concentrations in the stormwater discharge from the Interceptor Pond (12 600 m3).

• Scenario 3: effect of enlarging Interceptor Pond to 30 000 m3.

• Additional considerations related to Scenario 1, 2 and 3 include:

o Risk of Interceptor Pond overflow. o Removal of wastewater via tanker truck.

• Scenario 4: effect of poor on-site management of spillages on fluoride loading in the stormwater.

Scenario 1 and 2: Potential Fluoride Concentrations in the Stormwater Discharge In order to quantify the potential impacts on the environment, two case studies were investigated. The case studies considered:

• Scenario 1 o Dry period: 3 months (extreme) o Rainfall intensity: 20 mm/hr o Fluoride mobilisation: 80% in first 20 mm of rain o Duration: 1 hour

• Scenario 2

o Dry period: 3 months (extreme) o Rainfall intensity: 56.5 mm/hr o Fluoride mobilisation: 80% in first 20 mm of rain, remaining 20%

equally mobilised over subsequent 36.5 mm of rain

o Duration: 1 hour In the above case studies, an extreme dry period of three months is considered, with fluoride fallout determined from the air quality study (Zunckel et al, 2002). Rainfall intensity data indicating the highest rainfall for a one -hour period was obtained from Port Elizabeth for the period 1972 – 2001, as no detailed data from the Coega area exists. The mean of the



maximum rainfall intensity for a one-hour period is 20.25 mm and the maximum rainfall intensity for a one-hour period for the period 1972 – 2001 is 56.5 mm. The “first flush” was considered to be the first hour of runoff from the site, assuming 80% mobilisation of fluoride in the first 20 mm. The following table shows the results obtained from estimating the potential fluoride concentrations in the stormwater discharge from the interceptor pond. Table 12: Estimation of the potential fluoride concentrations in the stormwater discharge from the interceptor pond (12 600 m 3)

Parameter Scenario 1 Scenario 2 Average fluoride fallout expected over smelter site 150 mg/m 2/month 150 mg/m2/month Percentage of average fluoride fallout that is water soluble 68% 68% Effective atmospheric fallout rate (68% x 150 mg/m2/month) 102 mg/m 2/month 102 mg/m2/month

Area over which fallout occurs/runoff is generated 50 ha i.e. 500 000 m 2

50 ha i.e. 500 000 m2

Total fallout rate of water soluble fluoride expected over the whole site

51.0 kg/month 51.0 kg/month

Length of dry period/period of accumulation prior to rainfall event

3 months 3 months

Total fallout of water soluble fluoride over the whole site over a 3 month period

153.0 kg 153.0 kg

Percentage of fluoride removed from site by rainfall event 80% 80% Total mass of fluoride washed into interceptor pond 122.4 kg 122.4 kg Duration of rainfall event 60 min 60 min Rainfall intensity 20 mm/hr 56.5 mm/hr Rainfall runoff factor 80% 80% Rain runoff (mm) 16 mm 45.2 mm Total volume of rainfall runoff from site 8 000 m 3 22 600 m3 Volume of interceptor pond 12 600 m3 12 600 m3 Total available spare capacity of interceptor pond 4 600 m 3 0 m3 Total volume of rainfall that enters the attenuation dam 0 10 000 m3 Fluoride concentration in interceptor pond after rainfall event (i.e. assume that 80% of fluoride is mobilised in first 20 mm of rain) 15.3 mg/L 9.7 mg/L Fluoride concentration in bypass to attenuation dam (i.e. assume remaining fluoride is mobilised in subsequent rainfall) - 3.1 mg/L Table 12 shows that if only atmospheric fallout of fluoride emissions are taken into account, and assuming a dry period of 3 months, a fluoride concentration of approximately 15.3 mg/L can be expected in the Interceptor Pond after a rainfall event of 20 mm with a duration of one hour (assuming 80% mobilisation of fluoride in the first 20 mm). In this case, the Interceptor Pond does not fill (spare capacity of approximately 4 600 m3). Subsequent runoff should therefore be allowed to enter the Interceptor Pond until it has filled (to 12 600 m3). Following this, subsequent runoff must be diverted from the Interceptor Pond and into the stormwater Attenuation Dam. However, of concern is if sufficient dilution will be attained to reach the DWAF General Limit Value of 1 mg/L:

• Presuming that no further fluoride enters the system and the Interceptor Pond is

filled with “fluoride free water” (i.e. addition of 4 600 m3 of “fluoride free water” to the Interceptor Pond), this dilution will still result in fluoride concentration being reduced from 15.3 mg/L to about 9.7 mg/L.



• Further presuming that fluoride loading is further diluted with ”fluoride free water“ in the Attenuation Dam (i.e. Attenuation Dam is filled to 30 000 m3 with 12 600 m3 from the Interceptor Pond and a further 17 400 m3 of “fluoride free water”), this dilution will result in fluoride concentration of about 4.1 mg/L.

These calculations show that neither the DWAF General Limit Value nor the DWAF guidelines for the protection of aquatic ecosystems will be met. NOTE: Aluminium Pechiney have indicated that the expected fluoride concentration of the combined process wastewater/stormwater should be below 20 mg/L on average; this is significantly above the DWAF General Limit Value of 1 mg/L and DWAF Aquatic Ecosystem Guideline values.

In the extreme rainfall event of 56.5 mm with a duration of one hour, the Interceptor Pond of 12 600 m3 would fill. In this case, if we assume 80% mobilisation of fluoride in the first 20 mm of rain (with the subsequent 20% of fluoride mobilised evenly throughout the remaining 36.5 mm of rain), the fluoride concentration within the Interceptor Pond would be about 9.7 mg/L. The remaining runoff (once the pond is full) is then diverted to the stormwater Attenuation Dam, which would then be discharged off site. The fluoride concentration of this discharge has been estimated at 3.1 mg/L. This concentration does not satisfy the DWAF General Limit Value of 1 mg/L or DWAF Aquatic Ecosystem Guideline values. (NOTE: The above Scenario 1 and 2 calculations do not include any fluoride as a result of spillages or process wastewater discharge, i.e. calculations are only based on mobilisation of airborne depositions by rainfall). Scenario 3: Potential Fluoride Concentrations in the Stormwater Discharge if the Interceptor Pond is Enlarged

It is useful to consider a circumstance where the Interceptor Pond is enlarged to 30 000 m3, and consider the maximum rainfall intensity for a one hour period for the period 1972 – 2001 of 56.5 mm. The following situation will then arise.



Table 13: Estimation of the potential fluoride concentrations in the stormwater discharge from an enlarged interceptor pond (30 000 m3)

Parameter Scenario 3

Enlarged Interceptor Pond (30 000 m3)

Average fluoride fallout expected over smelter site 150 mg/m2/month Percentage of average fluoride fallout that is water soluble 68% Effective atmospheric fallout rate (68% x 150 mg/m 2/month) 102 mg/m2/month

Area over which fallout occurs 50 ha 500 000 m2

Total fallout rate of water soluble fluoride expected over the whole site 51.0 kg/month Length of dry period/period of accumulation prior to rainfall event 3 months Total fallout of water soluble fluoride over the whole site over a 3 month period 153 kg Percentage of fluoride removed from site by rainfall event 80% Total mass of fluoride washed into interceptor pond 122.4 kg Duration of rainfall event 60 min Rainfall intensity 56.5 mm/hr Rainfall runoff factor 80% Rain runoff (mm) 45.2 mm Total volume of rainfall runoff from site 22 600 m3 Volume of interceptor pond 30 000 m3 Total available spare capacity of interceptor pond 7400 m 3 Total volume of rainfall that enters the attenuation dam 0 m3 Fluoride concentration in interceptor pond after rainfall event (i.e. assume that 80% of fluoride is mobilised in first 20 mm of rain)

5.4 mg/L

Fluoride concentration in bypass to attenuation dam (i.e. assume remaining fluoride is mobilised in subsequent rainfall)

-

In the case of the 30 000 m3 Interceptor Pond, the full 1-hour rainfall event will be captured in the Interceptor Pond and will have fluoride concentration of the stormwater would be approximately 5.4 mg/L (i.e. does not satisfy the DWAF General Limit Value of 1 mg/L or DWAF Aquatic Ecosystem Guideline values). This indicates that increasing the capacity of the Interceptor Pond still does not result in satisfaction of required fluoride concentration standards.

(NOTE: The above calculations do not include any fluoride as a result of spillages or process wastewater discharge; i.e. calculations are only based on mobilisation of airborne depositions by rainfall.) In the following section, two additional considerations are investigated, namely:

• Risk of Interceptor Pond and Attenuation Dam overflow, and • Removal of process wastewater via tanker truck

Risk of Interceptor Pond and Attenuation Dam Overflow In order to determine the risk of overflow from the Interceptor Pond during the first hour’s rainfall (the first hour being nominally regarded as the “first flush” period), rainfall data for the area is required. Unfortunately, to date, extensive rainfall data has not been captured for the



Coega area. Rainfall data from Port Elizabeth has therefore been used in determining the risk of Interceptor Pond/Attenuation Dam overflow. The Port Elizabeth area has a bimodal rainfall pattern, with peaks in Spring and Autumn. Rainfall ranges from 400 – 800 mm per year in the region. Rainfall in the Coega area, however, has been found to be at the low end of the range, averaging approximately 400 mm per year. The average monthly rainfalls for Po rt Elizabeth are listed in Table 14. Table 14: Average monthly rainfall (mm) for Port Elizabeth (1980-1996)

Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Mm 36.5 33.4 47.7 40.7 62.9 65.1 50.0 60.3 59.9 57.2 58.7 41.3 Based on the above, the average rainfall in the area Port Elizabeth area equates to 613.7 mm/year. Average evaporation rates for the area have been estimated at 1750 mm/year. Rainfall intensity data for the Port Elizabeth area for year 1972 – 2001 is shown in APPENDIX A, with othe r related information shown in APPENDICES B and C. Furthermore, detailed rainfall data from the Port Elizabeth Metropolitan sampling station for year 2000 is shown graphically in Figures 7 and 8.

Figure 7: Port Elizabeth monthly rainfall: year 2000

0

20

40

60

80

100

120

140

160

Jan-00 Feb-00 Mar-00 Apr-00 May-00 Jun-00 Jul-00 Aug-00 Sep-00 Oct-00 Nov-00 Dec-00

Month

Rai

nfal

l (m

m)



Figure 8: Port Elizabeth Daily and Cumulative Rainfall: year 2000

The above Figures 7 and 8 indicate that a total of 724.4 mm of rain fell in year 2000. The peak rainfall in a single day was 50.2 mm with a peak hourly rainfall of 17.2 mm (recorded on 21/02/2000). Based on year 2000 data, the Interceptor Pond would have been able to catch the “first flush”. Analysis of the peak one hour rainfall intensities for the period 1972 – 2001 (Figure 9 below) indicates that the 12 600 m3 Interceptor Pond would have been able to retain all but eight of the last 30 years peak one hour rainfall events. Of importance to note is that no rainfall events in the last 30 years would have filled both the Interceptor Pond and the Attenuation Dam.

Figure 9: Rainfall Intensity (mm): Port Elizabeth 1972 – 2001 (60 min)

Max. Rainfall at PE Airport

0

10

20

30

40

50

60

1972

1974

1976

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

Year

mm

60 min

0

5

10

15

20

25

30

35

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45

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55

01/01/2000 01/03/2000 30/04/2000 29/06/2000 28/08/2000 27/10/2000 26/12/2000

Date

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nfal

l (m

m)

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Cum

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Rai

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Daily Rainfall Cumulative Rainfall



Removal of Process Wastewater via Tanker Truck Here we consider the practicality of removing fluoride rich process wastewater from the smelter site via tanker truck. This preliminary calculation considers process wastewater only (i.e. excludes stormwater). Aluminium Pechiney have stated that total process wastewater will amount to 300 000 m3/year. Ignoring evaporation effects, and assuming a tanker truck capacity of 30 000 L, approximately 10 000 tanker trucks would be required per year to remove process wastewater alone (i.e. 27 tanker trucks per day). This simplified description shows that removal of wastewater from site by any means other than a controlled discharge off the site is not feasible. Scenario 4: Effect of Poor On-site Management of Spillages on Fluoride Loading in Stormwater To-date, the scenarios described did not consider the influence of on-site spillages and poor site management on the stormwater fluoride concentration. Table 15 below shows that assuming spillage of only 50 kg of fluorinated material per month (with no subsequent clean-up), the stormwater fluoride concentration (as a result of air emissions and on-site spillages) after a three-month dry period could be as high as 30.3 mg/L. This simple scenario highlights that it is crucial that effective on -site spillage management is practised. Table 15: Estimation of the effect of poor on-site management on the fluoride concentration in the stormwater Parameter Scenario 4 Average fluoride fallout expected over smelter site 150 mg/m2/month Percentage of average fluoride fallout that is water soluble 68% Effective atmospheric fallout rate (68% x 150 mg/m 2/month) 102 mg/m2/month

Area over which fallout occurs 50 ha 500 000 m2

Total fallout rate of water soluble fluoride expected over the whole site 51 kg/month Additional fluoride on site due to spillages not effectively contained/controlled 50 kg/month Total fluoride over whole site due to air emissions and spillages 101 kg/month Length of dry period/period of accumulation prior to rainfall event 3 months Total fallout of water soluble fluoride over the whole site over a 3 month period 303 kg Percentage of fluoride removed from site by rainfall event 80% Total mass of fluoride washed into interceptor pond 242.4 kg Duration of rainfall event 60 min Rainfall intensity 20 mm/hr Rainfall runoff factor 80% Rain runoff (mm) 16 mm Total volume of rainfall runoff from site 8 000 m3 Volume of interceptor pond 12 600 m3 Total available capacity of interceptor pond 4 600 m3 Total volume of rainfall that enters the attenuation dam 0 m3 Fluoride concentration in interceptor pond after rainfall event (i.e. assume that 80% of fluoride is mobilised in first 20 mm of rain)

30.3 mg/L

Fluoride concentration in bypass to attenuation dam (i.e. assume remaining fluoride is mobilised in subsequent rainfall)

-



Disposal of Combined Process Wastewater and Stormwater In the above scenarios, it has been shown that stormwater could potentially have high fluoride concentrations (e.g. In Scenario 1 stormwater had a fluoride concentration of 15.3 mg/L). Process wastewaters, however, are expected to have much lower fluoride concentrations, with Aluminium Pechiney expecting to meet target levels of 2 – 6 mg/L. The possibility therefore arises to blend process wastewater with stormwater, and in so doing, diluting the fluoride concentration of the combined stream. This assumption forms the basis for the following scenario. Scenario 5 and 6: Effect of Combining Process Wastewater and Stormwater on Fluoride Concentrations in the Final Stormwater Discharge In this scenario, it is assumed that the Interceptor Pond is filled with stormwater (i.e. 12 600 m3) with a fluoride concentration of 15.3 mg/L. As described earlier, the design of the Interceptor Pond allows a filled pond to be emptied in two days (i.e. discharge of 6 300 m3/day). Aluminium Pechiney have stated that the volume of process wastewater is approximately 300 000 m3/year or 822 m3/day. In Scenario 5 a process wastewater fluoride concentration of 2 mg/L is assessed, while in Scenario 6 a process wastewater fluoride concentration of 6 mg/L is assessed (typical range of process wastewater fluoride concentrations as supplied by Aluminium Pechiney). Table 16 below shows that due to the small daily quantities of process wastewater discharged, the dilution effects are not substantial, and final wastewater discharged still fails the DWAF General Limit Value of 1 mg/L and DWAF Aquatic Ecosystem Guideline values. Table 16: Effect of combining process wastewater and stormwater

Parameter Scenario 1 Scenario 2 Volume of stormwater in interceptor pond 12 600 m3 12 600 m 3 Fluoride concentration in interceptor pond (from Scenario 1) 15.3 mg/L 15.3 mg/L Stormwater discharge per day 6 300 m3 6 300 m3 Total fluoride in stormwater discharged per day 96.39 kg/day 96.39 kg/day Process wastewater 300 000 m 3/year 300 000 m3/year 821.92 m 3/day 821.92 m 3/day Fluoride concentration in process wastewater 2 mg/L 6 mg/L Therefore total fluoride in process water 1.64 kg/day 4.93 kg/day Total fluoride into attenuation dam 98.03 kg/day 101.32 kg/day Fluoride concentration of water in attenuation dam 13.8 mg/L 14.2 mg/L Discussion Regarding Operation Wastewater Discharges The above scenarios analyses have shown that:

• No impacts of environmental significance are expected with regards to domestic wastewater.

• Construction wastewater has a low negative impact. This impact can be further reduced by effective on-site management practices.

• Elevated fluoride concentrations in excess of the DWAF General Limit Value and DWAF Aquatic Ecosystem Guideline values will most likely be recorded in



process wastewater and stormwater discharges (HIGH probability).

• In the absence of site -specific bio -toxicity tests to show the contrary, it is presumed that these elevated fluoride concentrations will negatively impact on the surface water environment, and pose a potential toxic threat to flora and fauna (HIGH impact).

• It is not feasible to consider removing captured high fluoride concentration wastewater by way of tanker truck to off-site disposal/treatment.

Impact Assessment of Wastewater Discharge to an Environmentally Sensitive Ecosystem (e.g. Butterfly Valley) Table 17 shows the ISO 14001-based methodology followed to assess the environmental significance of process wastewater/stormwater discharge on an environmentally sensitive ecosystem such as Butterfly Valley. In this scenario, it is assumed that combined process water and stormwater is discharged into a dry watercourse (eg. Butterfly Valley) in the absence of any of stormwater management structures (eg. concrete lining).

Table 17 continues…



Table 17: An assessment of the potentia l impact of process wastewater/stormwater discharge on an environmentally sensitive ecosystem

Nature and Status of Potential Impact • Negative Impact arises via toxic effect of discharged stormwater on flora and fauna

Sources of Potential Impact • Discharge from the stormwater/process wastewater Interceptor Pond/Attenuation Dam

Significance of Environmental Impact Extent • Limited to within 5 km of development Duration • Could have a permanent impact on the environment Intensity • High – Affects health of aquatic ecosystem

Probability/Likelihood • Based on case studies, distinct possibility of negative impact occurring

SIGNIFICANCE OF ENVIRONMENTAL IMPACT Score Total

3

(High) 2

(Medium) 1

(Low)

A. Extent a 2

4

(Permanent)



years)

1 (Short -term 0-

5 years)

B. Duration a 4

3 (High)

2 (Medium)

1 (Low)


4 (Definite)

3 (Highly

probable)

2 (Probable)

1 (Improbable)


MEDIUM 11 – 20 HIGH > 20 Score: 36 Rating: HIGH Negative Impact Degree of Confidence: Aluminium Pechiney have indicated that the fluoride

concentration of the combined process wastewater/stormwater is expected to be below 20 mg/L. The data is supported by results/findings obtained from other aluminium smelter operations.



The above table clearly indicates that process wastewater/stormwater should not be discharged into an environmentally sensitive ecosystem such as Butterfly Valley. Wastewater Discharge to the Marine Environment The impact assessment of Table 17 clearly shows that liquid waste cannot be discharged to an environmentally sensitive area. Findings of the marine discharges specialist study suggest that discharge of process wastewater/stormwater into the marine environment is not problematic as dilution of contaminants (including fluoride) to acceptable levels is readily achieved (for further details refer to the report entitled: “Specialist Study on Discharges to the Marine Environment”). Therefore, the ultimate discharge of process wastewater/stormwater to the marine environment is the only viable option that should be considered. However, of concern to this study is the method of process wastewater/stormwater transport from the smelter site to the sea. It is understood that the following approach is to be implemented for transport of process wastewater/stormwater from the Attenuation Dam to the western edge of the saltworks (Meeting between involved parties on 5 th August 2002):

• From the Attenuation Dam to the N2 highway, a fully enclosed pipe will be used. • From the N2 highway to the western edge of the saltworks, an engineered canal

will be used (canal to be constructed in the valley to the north -east of Butterfly Valley).

These transport methods should adequately retain process wastewater and stormwater and therefore no impacts of environmental significance are expected. Transport of process wastewater/stormwater from the western edge of the saltworks to the port has yet to be finalised. The following approaches have been suggested by involved parties (Meeting of 5th August 2002 with National Port Authority, CDC, Aluminium Pechiney and engineering consultants to NPA and CDC):

• Discharge via a earth/natural channel to the port • Discharge via an engineered canal (lined) to the port • Discharge via pipeline to the port.

When considering the various alternatives, the following points should be noted:

• As described in section 3.1, the saltworks falls within the flood basin of the Coega River. Based on the ecological state of the river, this reach (Reach 4) has been classified as Class F. This implies that the river in this reach is already critically modified and that the area is not a pristine environment.

• Currently the classification of the bo ttom reach (Reach 4) of the Coega River as a surface water or a marine environment is being debated.

• A possibility exists that the port will be extended northwards into the lower reaches of the Coega River, with the result that the present saltworks will be lost and the area will be a fully marine environment.

Considering the fact that no final decisions had been reached by the parties involved, a brief assessment of the environmental impact of wastewater discharged via each of these suggested solutions was conducted. NOTE: The engineering, economic or other feasibility issues surrounding these options were not assessed.



The following section will utilise the ISO 14001-based methodology followed earlier to assess the environmental significance of these a lternatives. Table 18: An assessment of the potential impact of process wastewater/stormwater discharge from the western edge of the saltworks to the port via an earth/natural channel

Nature and Status of Potential Impact • Negative Impact arises via toxic effect of discharged stormwater on flora and fauna and aquatic ecosystems

Sources of Potential Impact • Discharge from the stormwater/process wastewater

Interceptor Pond/Attenuation Dam to the coast via an earth/natural channel

Significance of Environmental Impact Extent • Limited to within 5 km of development

Duration • Long-term (port is envisaged and area is already degraded)

Intensity • Low given the degraded nature of river and naturally occurring high fluoride levels

Probability/Likelihood • Probable due to not being lined SIGNIFICANCE OF ENVIRONMENTAL IMPACT Score Total

3

(High) 2

(Medium) 1

(Low)

A. Extent a 2

4

(Permanent)



years)

1 (Short -term 0-

5 years)

B. Duration a 3

3 (High)

2 (Medium)

1 (Low)


4 (Definite)

3 (Highly

probable)

2 (Probable)

1 (Improbable)


MEDIUM 11 – 20 HIGH > 20 Score: 12 Rating: MEDIUM Negative Impact Degree of Confidence: Medium: Specific design details are not yet finalised. However,

the current degraded state of the aquatic ecosystem into which the proposed discharge will occur, the debate surrounding the nature of the river in this reach, and the possible future expansion of the port, must be taken into account.



As the environmental impacts associated with using a lined engineered canal or a pipeline for discharge of process wastewater/stormwater are similar, a single assessment was conducted (Table 19). Table 19: An assessment of the potential impact of process wastewater/stormwater discharge from the western edge of the saltworks to the port via an engineered canal or pipeline

Nature and Status of Potential Impact • Negative Impact arises via toxic effect of discharged stormwater on flora and fauna and aquatic ecosystems

Sources of Potential Impact • Discharge of stormwater/process wastewater from the

Interceptor Pond/Attenuation Dam to the coast engineered canal or pipeline

Significance of Environmental Impact Extent • Limited to within 5 km of development Duration • Long-term (port is envisaged/area is already degraded)

Intensity • Low given the degraded nature of river and naturally occurring high fluoride levels

Probability/Likelihood • Improbable due to use of lined canal or fully enclosed pipeline

SIGNIFICANCE OF ENVIRONMENTAL IMPACT Score Total

3 (High)

2 (Medium)

1 (Low)

A. Extent a 2

4

(Permanent)



years)

1 (Short -term 0-

5 years)

B. Duration a 3

3

(High) 2

(Medium) 1

(Low)


4

(Definite)

3 (Highly

probable)

2 (Probable)

1 (Improbable)


MEDIUM 11 – 20 HIGH > 20 Score: 6 Rating: LOW Negative Impact Degree of Confidence: Medium: Specific design details are not yet finalised. However,

the current degraded state of the aquatic ecosystem into which



the proposed discharge will occur, the debate surrounding the nature of the river in this reach, and the possible future expansion of the port, must be taken into account.

Based on the above findings, it appears as though the use of a lined canal or an enclosed pipeline will have the lowest environmental impact. However, considering the present degraded state of the aquatic ecosystem into which the proposed wastewater will be discharged, the debate surrounding the nature of the river in this reach (surface water or marine environment), and considering the possible expansion of the port in the future, the capital expenditure required to construct these systems may not be justified. Impact Mitigation against the Environmental Significance of Process Wastewater and Stormwater Discharges The above findings indicate the importance of effective process wastewater and stormwater management. It is thus recommended that:

• As planned, the plant terrace is elevated above the natural surface topography to ensure

that drainage from the plant terrace and the surrounding plant area within the plant boundary is separate from each other. Furthermore, locating the Interceptor Pond and Attenuation Dam at the lowest possible point on the smelter site will aid drainage to the pond/dam. The Interceptor Pond should be lined to minimize possible groundwater seepage. Aluminium Pechiney has confirmed that the pond will be concrete lined (Warren Brooks, Aluminium Pechiney, pers comm.).

• As planned, the “first flush” (high fluoride and other contaminant concentrations) must be

captured within the Interceptor Pond. Thereafter, the piping configuration of the stormwater system will allow for stormwater bypass from the Interceptor Pond to the Attenuation Dam.

• As planned, the Interceptor Pond must be operated at a minimum level to ensure

sufficient capacity for runoff from subsequent rain events. If lined with a geofabric or plastic membrane (and not concrete lined), then the lining might be sensitive to UV exposure and care must be taken to ensure that a layer of water is retained to cover the lining. In addition, annual sludge cleanout/maintenance of the Interceptor Pond will reduce the amount of fluoride accumulated within the pond, and thus reduce fluoride concentrations in the waters discharged.

• The quality and quantity of process wastewater and stormwater must be

monitored/recorded. Furthermore, continued monitoring of both local surface water and groundwater upstream and downstream of the smelter site is recommended. It is important that both particulate and dissolved concentrations of contaminants are determined and reported separately.

• Only marine discharge of fluoride enriched process wastewaters and stormwater should

be considered (refer to the report entitled: “Specialist Study on Discharges to the Marine Environment”). This is because of fluoride concentrations in both the process wastewater and stormwater exceeding the DWAF General Limit Value and DWAF Aquatic Ecosystem Guideline values. Discharge or spillage of this water into a watercourse (i.e. Butterfly Valley area) will exceed the DWAF limit values for water



discharge to a water resource (Table 3). The wastewater could therefore have detrimental impacts on both flora and fauna.

• The exact nature of the Coega River in Reach 4, in terms of the degraded nature of the

site, and the applicability of DWAF General Limit Values and DWAF Aquatic Ecosystem Guideline values should be clarified. Furthermore, the influence of possible reclassification from a surface water to a marine environment must be clarified.

• The Interceptor Pond should be sited over an aquitard area of the shales underlying the

site. Potentially more vulnerable areas over the Bluewater Bay gravels should be avoided as pond or wetland sites.

• As the fluoride concentrations of the process wastewater are expected to be

considerably less than the stormwater (say, 6 mg/L vs. 15 mg/L), the piping arrangement must be such that process wastewater can be discharged separately to stormwater. This would facilitate possible future re-use or recycling of this water.

• Stormwater quality can be improved by effective management of on -site spills. It is thus

recommended that plant-wide spillage audits be conducted. The introduction of such audits will identify areas contributing to the elevated contaminant levels in the Interceptor Pond. Responsible departments would be required to ensure prevention of reoccurrences of problems experienced. Proper education and awareness training will encourage employees (and contractors) to minimize spillages, timeously report incidents of spillage and follow good cleaning practices.

Upon occurrence of a spillage, the offending department must immediately contact the site environmental specialist. The environmental specialist must photograph the incident and identify the events leading up to the spillage. Thereafter, the environmental specialist must collate the in formation and generate a spillage audit report (the report should include photographs of the incident and a brief description of events). A non-conformance report must also be completed by the environmental specialist. Progress must be tracked in management meetings against agreed upon target dates for completion of required actions. This system will aid identification of problem areas that require focused management or specifically engineered solutions. Sensitive areas identified should contain bunded areas and dirt/oil traps to ensure that spillages do not enter the stormwater system. Appointment of a cleaning contractor to manage the cleaning of all spillages on site should also be considered.

• With regards to improvement in the quality of the process wastewater a number of

measures could be investigated including regular cleaning of hot and cold wells, and improved monitoring, including installation of TDS monitors to control the recycle rate and thereby improve the quality of process wastewater, and installation of on-line fluoride monitors.

• Although it is noted that Aluminium Pechiney recycle the majority of process water used

within the smelter, re-use of process wastewater and stormwater as a direct replacement for the drinking-water used in various processes would be ideal. This approach would in-line with the principles of water conservation and would minimise any environmental impacts associated with discharge of fluorinated water. This matter should receive



further attention via the implementation of the proposed Fishwater Flats Reclamation Works.

Implementation of these measures will reduce the environmental impacts associated with process wastewater and stormwater discharge from HIGH to LOW. NOTE: The means of transportation of wastewater from the western edge of the saltworks to the port is influenced by unknowns relating to both, (i) engineering considerations (technical and financial), and (ii) ecological considerations (review of the classification of Reach 4 of the river, and the applicability of DWAF water quality requirements). It is recommended that clarity be attained from the appropriate experts and authorities regarding points (i) and (ii). 7.3 Environmental Significance of Wastewaters on Groundwater 7.3.1 Geohydrology The proposed metallurgical plant site is underlain by Adolphspoort shale. This formation is part of the Traka subgroup of the Bokkeveld shale. It is expected to act as an aquitard (formations with low permeability which retard the flow of groundwater) on site, with no aquifer potential.

Figure 10: Map of the Coega Industrial Development Zone showing the geological formations and the location of the proposed PAS 2005 smelter



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.

Typically, groundwater gradients mirror the topography and it is expected that any groundwater flow in site would be approximately towards the coast and locally towards Butterfly Valley. No direct groundwater data are available for the site itself. Some information is known about groundwater in similar aquifers in the surrounding area (SRK, 1998, Colvin et al 1996, Meyer 1998). The only evident potential receptors for groundwater impacts are the Butterfly Valley, the coastal environment and the Coega estuary. These environments may rely on groundwater inputs to control salinity or provide nutrients or trace elements. The Adolphspoort shale does not form a significant aquifer. No groundwater is known to be abstracted down gradient of the site and, due to its low permeability and naturally poor quality, it is not expected to deliver significant quantities of water to receiving environments, if any. The depth to the water table on the site is not known. Bluewater Bay gravels occur to the north and east of the site next to a Cambrian granite outcrop. Whilst no site-specific data are available for this formation, these gravels are likely to host a local aquifer of limited importance. The hydraulic conductivity of gravels is typically high at up to 100m/day, and as these deposits are typically only several meters thick, the water table is likely to be shallow. These factors, combined with the low attenuation potential of most gravel aquifers means that this aquifer is highly vulnerable to contamination from surface and would rapidly conduct contaminants towards Butterfly Valley. Figure 2 indicates that this deposit does not intersect either the coast or sea and therefore may not act as a pathway to marine environments, however, its connectivity with the neighbouring granite and arenite would need to be understood to confirm this. In summary, the gravels are a potential pathway for migration of contaminated groundwater, towards Butterfly Valley. The gravels occur off-site but potential impacts of atmospheric emissions should be considered. Construction in and around the site may impact natural groundwater recharge to the gravels and reduce groundwater fed base flow or spring flow in the Valley. Site construction could be seen as a stream flow reduction activity if this occurred.



Table 20: An assessment of the potential impact of wastewater practises on groundwater Nature and Status of Potential Impact Groundwater pollution as a result of smelter operations

Sources of Potential Impact

Negative impact arises via: • Runoff and infiltration from storm events • Irrigation with stormwater/process water • Discharge and spillage from the stormwater/process

water impoundment dam Significance of Environmental Impact Extent • Locally, therefore low

Duration • Aquifers would be affected for tens to hundreds of years depending on the permeability of the aquifers.

Intensity • Medium if aquatic environments receive significant concentrations via groundwater

Probability/Likelihood • Limited potential for groundwater pathway SIGNIFICANCE OF ENVIRONMENTAL IMPACT Score Total

3 (High)

2 (Medium)

1 (Low)

A. Extent a 1

4

(Permanent)



years)

1 (Short-term 0-5 years)

B. Duration a 3

3

(High) 2

(Medium) 1

(Low)

C. Intensity a 2 SIGNIFICANCE OF IMPACT SCORE (A + B + C) = 6

PROBABILITY OR LIKELIHOOD OF ACCIDENT OR ABNORMAL CONDITIONS Score (4=high, 1 = low) Total

4

(Definite)

3 (Highly

probable)

2 (Probable)

1 (Improbable)

Likelihood a 2 PROBABILITY OR LIKELIHOOD OF OCCURRENCE SCORE = 2

TOTAL SCO RE (Significance of impact x Likelihood of occurrence) = 12 Score Rating: LOW 1 – 10

MEDIUM 11 – 20 HIGH > 20 Score: 12 Rating: MEDIUM Negative Impact Degree of Confidence: Medium: Degree of confidence is not high as desirable as no

on-site tests confirming local geology are available.



Impact Mitigation against the Environmental Significance of Wastewater on Groundwater It is recommended that a groundwater survey of the site and surrounding area be conducted, including drilling a limited number of shallow test boreholes, to determine:

• Does groundwater underlie the site and in which aquifer units (the extent)? • Do these units connect with potentially vulnerable receiving environments such

as aquatic ecosystems and riparian zones? • How vulnerable is groundwater underlying and surrounding the site (depth to

water table, permeability of unsaturated zone, transmissivity, natural recharge and expected recharge under construction)?

• If groundwater feeds either aquatic or riparian ecosystems in the area, what are the key attributes of groundwater discharge that should be protected to maintain ecosystem functioning (e.g. – outflow volumes, salinity, etc)? These attributes may be defined as Resource Quality Objectives.

If aquifers are found to underlie the site and the neighbouring area, monitoring boreholes should be established. A trained hydrogeologist should implement a monitoring programme. Sampling may take place on a bi-monthly basis for key potential contaminants with additional sampling runs tracking the ‘first flush effect’ immediately after significant rains that may have induced recharge. Meanwhile, precautionary planning is recommended. This should ensure that higher risk activities such as retention dams are not sited on the Bluewater Bay formation. It is also recommended that, in the longer term, the environmental manager for the site participates in setting the Class and Resource Quality Objectives for groundwater in the area as required under the National Water Act (Act 36 of 1998). If groundwater is found to significantly contribute to the estuary then a groundwater component of the Reserve may also be specified. Implementation of these will reduce the environmental impacts from MEDIUM to LOW. The table on the following page provides a summary of the environmental impacts associated with the proposed smelter.



Table 21: Summary impact assessment of the proposed aluminium smelter

Assessment of impact

Impact Extent Duration Intensity

Probability of occurrence Status Confidence

Significance (without

mitigation)

Significance (with

mitigation) Increased water use during construction

Local Short term Low Improbable Negative High Low Low

Increased water use during operation

Local Long term Low Improbable Negative High Low Low

Construction wastewater and stormwater discharge during construction phase

Local Short term Medium Probable Negative Medium Low Low

Process wastewater & stormwater discharge on environmentally sensitive ecosystems

Local Permanent High

Definite Negative High High

Not applicable, as mitigation action is to avoid releasing into a watercourse

Process wastewater & stormwater discharge along western edge of the saltworks to the port/coast via an earth/natural channel

Local Long term Low

Probable Negative Medium Medium Low

Process wastewater & stormwater discharge along western edge of the saltworks to the port/coast via a lined channel/pipeline

Local Long term Low

Improbable Negative Medium Low Low

Influence of wastewater practises on groundwater

Local Long term Medium Probable Negative Medium Medium Low

Extent - this indicates whether the impact will be local and limited to the immediate area of development (the site or the servitude corridor); limited to within 5km of the development; or whether the impact may be realised regionally, nationally or even internationally. Duration - this reviews the lifetime of the impact, as being short term (0 - 5 years), medium (5 - 15 years), long term (>15 years but where the impacts will cease after the operation of the site), or permanent. Intensity – this establishes whether the impact is destructive or innocuous and is described as low (where no environmental functions and processes are affected), medium (where the environment continues to function but in a modified manner) or high (where environmental functions and processes are altered such that they temporarily or permanently cease). Probability - this considers the likelihood of the impact occurring and is described as improbable (low likelihood), probable (distinct possibility), highly probable (most likely) or definite (impact will occur regardless of prevention measures). Status of the impact - a description as to whether the impact will be positive (a benefit), negative (a cost), or neutral. Degree of confidence in predictions - the degree of confidence in the predictions, based on the availability of information and specialist knowledge.



8. WATER CONSERVATION/BEST PRACTICE Cooling water used in the proposed smelter is largely recycled. This practise is in line with DWAF’s National Water Conservation and Water Demand Management Strategy. Although this practise is commended, the following additional water conservation techniques should be considered:

• Domestic Implement water saving devices (Dual flush toilets, automatic shut-off taps, etc).

• Irrigation

As far as possible, potable water should not be used for irrigation purposes. However, untreated process wastewater or stormwater is most likely not suitable for irrigation purposes due to high fluoride and TDS levels. Ideally, landscapes should be designed to absorb rainwater runoff (stormwater) rather than having to carry it off-site in stormwater sewers.

Furthermore, the following should be noted: o Proper irrigation scheduling will limit evaporation losses. o Indigenous plants generally require less water than alien species. o Gardens should be structured as to minimise surface run-off.

• Cleaning

Cleaning methods utilised for cleaning vehicles, floors, etc should aim to minimise water use.

• Fire fighting

Proper pressure management within fire water systems will limit water use.

• Elimination of leakage Regular audits of water systems should be conducted to identify possible water leakages.

• Metering and measurement

Proper metering and measurement of water use and wastewater discharges will enable proper performance review and management.

• Education and awareness

Awareness campaigns focussing on spillages and the effects thereof on stormwater quality and the environment should be launched in all departments. These campaigns must be aimed at all levels of the organisation (including contractors). Furthermore, water system operating personnel need to have extensive knowledge of the various water control systems, to allow for optimum operation thereof.



9. CONCLUSIONS AND RECOMMENDATIONS Water Use No shortcomings with regards to the supply of domestic water, process water or construction water by the smelter were identified. The predicted increase in water use by the smelter has already been approved by the Nelson Mandela Metropolitan Municipality and will have no impact on the regional water supply. However, although it is noted that the proposed smelter recycles the majority of process water used, it must be further recognized that South Africa is a water scarce country, and that every effort should therefore be made to limit/reduce water use on the site. In this regard, a number of water conservation measures have been recommended. Domestic Wastewater The Coega Development Corporation has stated that they will utilise the existing municipal sewer network and Fishwater Flats Reclamation Works for treatment of domestic wastewater arising from the IDZ. The Nelson Mandela Metropolitan Council has noted that the Fishwater Flats Reclamation Works has sufficient spare capacity to meet the effluent from the smelter. No impacts of environmental significance are expected. Construction Phase: Construction Wastewater and Stormwater Although contamination could result from contact with for example, chemicals, oils, etc during construction, erosion from construction areas resulting in increased turbidity and downstream sedimentation is likely to be the main water quality concern. Although the expected environmental impact was 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 have been recommended. These practises should be followed to minimise environmental impacts related to construction activities. Process Wastewater and Stormwater Discharge Process wastewaters from smelters generally indicate high TDS (cooling water blowdown) while fluoride concentrations are generally expected to be less than 6 mg/L (higher fluoride concentrations have been noted in smelter operations where poor operation and maintenance practises are followed). Aluminium Pechiney have proposed that process wastewater (300 000 m3/year) be discharged into the stormwater system. Stormwater drainage from the terraced area is routed by means of a stormwater collection network to an Interceptor Pond with a proposed capacity of 12 600 m3 (containment of “first flush”) followed by an and an Attenuation Dam with a proposed capacity of 30 000 m3. Analysis indicates that the stormwater will be primarily contaminated with fluoride.



In order to assess the environmental impact of process wastewater/stormwater a number of scenarios were considered. The following points highlight the main findings: • It is highly unlikely that either process wastewaters or stormwater will satisfy the DWAF

General Limit Value or DWAF Aquatic Ecosystem Guidelines. • Increasing the capacity of the Interceptor Pond still does not result in the satisfaction of

the required fluoride concentration standards/guidelines. • Risk of Interceptor Pond/Attenuation Dam overflow because of site runoff is minimal. • Removal of either process wastewater or stormwater form site via tanker truck is not

feasible. • Poor on -site management of spillages can substantially increase fluoride loading in the

stormwater. • Combining process wastewater and stormwater has minimal dilution effects, and still

does not result in the satisfaction of the required fluoride concentration standards/guidelines.

Based on the above findings, discharge or spillage of process wastewater/stormwater into the surface water environment (e.g. Butterfly Valley) will have detrimental impacts on both flora and fauna. It is thus recommended that only marine discharge of fluoride enriched process wastewaters and stormwater be considered. Findings of the marine discharges specialist study suggest that discharge of process wastewater/stormwater into the marine environment is not problematic (for further details refer to the report entitled: “Specialist Study on Discharges to the Marine Environment”). Considering marine discharge, the transport of process wastewater/stormwater from the western edge of the saltworks to the port has yet to be finalized. Assessment revealed that a lined canal or enclosed pipeline would have the lowest environmental impact. However, considering the present degraded state of the lower reach of the Coega River, the debate surrounding the nature of river within this reach (marine or surface water environment), and the possible expansion of the port in the future, the capital expenditure required to construct these systems does not appear justified. In addition to the above, the following points should be noted: • The quality and quantity of process wastewa ter and stormwater must be

monitored/recorded. Furthermore, continued monitoring of both local surface water and groundwater upstream and downstream of the smelter site is recommended.

• Stormwater quality can be improved by effective management of on -site spills. It is thus recommended that plant-wide spillage audits be conducted.

• With regards to improvement in the quality of the process wastewater a number of measures could be investigated including regular cleaning of hot and cold wells, and improved monitoring including installation of TDS monitors to control the recycle rate and thereby improve the quality of process wastewater, and installation of an on -line fluoride monitors.

• Although it is noted that Aluminium Pechiney recycle the majority of process water used within the smelter, wastewater re-use as a direct replacement for the drinking -water used in various processes would be ideal. This approach would in-line with the principles of water conservation and would minimize any environmental impacts associated with



discharge of fluorinated water. This matter should receive further via the implementation of the proposed Fishwater Flats Reclamation Works.

Effect of Wastewater Practises on Groundwater Although the environmental impact was rated as low, limited data for the site is available. It is thus recommended that a groundwater survey of the site and surrounding area be conducted. In the interim, precautionary planning is recommended. This should ensure that higher risk activities such as ponds/dams are not sited on potentially vulnerable formations.



10. REFERENCES Aluminium Pechiney (2002) Preliminary Information based on AP50 Reduction Technology

South Africa – Coega Site. Aluminium Pechiney (2002) Draft 2 PAS 2005 Stormwater Management Plan Aluminium Pechiney (2002) Synthesis of Waste Water Analyses – Aluminium Pechiney

Smelters Brooks, Warren (2002), Aluminium Pechiney, Personal communication Coastal and Environmental Services (2000) Coega Rezoning EIA – Environmental Impact

Report. Coega Development Corporation. Coega Development Corporation (2002) Environmental Management System Legal Register. Coega Development Corporation. Standard Environmental and re -vegetation Specifications Colvin, C, Eekhout, S, Taljaard, S and Botes, W.A.M. (1996) Proposed Eastern Cape Zinc

and Phosphoric Acid Project. Final Impact Assessment Report: Water Quality. Report number ENVS – C96049/C

CSIR (January 2000) A Model-based assessment of management strategies for fluoride-

contaminated storm water discharges from the Mozal Smelter site into the Matola River Estuary, Mozambique.

CSIR (September 2000) Water Management Plan for Hillside Aluminium Degremont (1999), Water Treatment Handbook, Volume 1 and 2, 6th Edition, Lovoisier

Publishing, ISBN 2.9503984.1.3. Department of Water Affairs and Forestry (1996). South Africa Water Quality Guidelines,

Volume 7, First edition Department of Water Affairs and Forestry (1997) Water Services Act (Act 108 of 1997) Department of Water Affairs and Forestry (1998) National Water Act (Act 36 of 1998) Department of Water Affairs and Forestry (1999) Government Notice No. 1191, Government

Gazette No. 20526. Gibb. 1999. Preliminary catchment management guidelines for the Coega River (including

the Coega Development Zone) in the Port Elizabeth region. Gibb Africa. Luger S, Monteiro P, van Ballegooyen R, Taljaard S and Probyn T. 2002. Specialist study:

Water Discharges to the Marine Environment. In: Environmental Impact Assessment for the proposed Aluminium Pechiney smelter within the Coega Industrial Zone, Port



Elizabeth, South Africa. Specialist Studies Report. CSIR Report No. ENV-S-C 2002-092(B), Stellenbosch, South Africa.

Mbalo B. (2001) Overview of South African National Environmental Legislation and

Regulations Report No. 363636, SRK Consulting Pty Ltd. Metcalf and Eddy (1991) Wastewater Engineering Treatment, Disposal and Reuse , 3rd

Edition, McGraw-Hill, Inc ISBN 0-07-100824-1. Pechiney (2002) www.pechiney.com Raymer, David. (2002) Nelson Mandela Metropolitan Municipality: Acting City Engineer, Personal communication. Schmidt, EJ and Schulze, RE (1987) Flood Volume and Peak Discharge from Small

Catchments in Southern Africa, Based on the SCS Technique: Appendices. Water Research Commission Report No. TT 31/87.

Van Duuren, F.A. (1997) Water Purification Works Design . Water Research Commission,

ISBN 1 86845 345 6. van Hooydonck, J.J., Libala, M., Maclear, L.G.A and Rosewarne, P.N. (2001) Coega Water

Quality Monitoring Final Report: 2000 – 2001 Period . Coega Development Corporation.

Wates, Meiring and Barnard (August 2000) Water Study for the Environmental Impact

Assessment Related to the Proposed Expansion at Hillside Aluminium – DRAFT, Report No. 4472/2240/1/W.

Zunckel, M., Haffejee, R., Hong, Y. & Oosthuizen, R. 2002. Specialist study: Air quality. In:

Environmental Impact Assessment for the proposed Aluminium Pechiney smelter within the Coega Industrial Development Zone, Port Elizabeth, South Africa. Specialist Studies Report. CSIR Report No. ENV-S-D-2002-092(B), Stellenbosch.

environmental impact assessment for the proposed aluminium

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