SEDIIBENG REGIIONAL SANIITATIION SCHEME
A STUDY OF CURRENT AND EXPECTED FUTURE SEWER FLOWRATES TO DETERMIINE THE WASTEWATER TREATMENT CAPACITY REQUIREMENTS OF THE REGIION UP TO 2025
FINAL DRAFT
NOVEMBER 2008
A STUDY OF CURRENT AND EXPECTED FUTURE SEWER FLOWRATES TO DETERMINE THE WASTEWATER TREATMENT CAPACITY REQUIREMENTS OF THE REGION UP TO 2025
CONTENTS
Chapter Description Page
1 INTRODUCTION AND BACKGROUND 1
1.1 Background to the Study Area 1
1.2 Scope of the Study 1
1.3 Overview of the Existing Wastewater Treatment in the Region 3
2 AN EVALUATION OF FACTORS AND TRENDS INFLUENCING CURRENT AND FUTURE SEWER FLOWRATES 5
2.1 Current Demographics and Service Levels 5 2.1.1 Emfuleni Local Municipality 5 2.1.2 Midvaal Local Municipality 7
2.2 Population Growth Projections – Emfuleni and Midvaal 9
2.3 Future Land Use and Residential Developments 10 2.3.1 Emfuleni Local Municipality 10 2.3.2 Midvaal Local Municipality 11
2.4 Anticipated Improvements in Sanitation Levels of Service 12 2.4.1 Emfuleni Local Municipality 12 2.4.2 Midvaal Local Municipality 13
3 CALCULATIONS OF CURRENT AND FUTURE SEWER FLOW RATES 14
3.1 Calculation of Current Sewer Flows 14 3.1.1 Emfuleni Local Municipality 14 3.1.2 Midvaal Local Municipality 15
3.2 Calculation of Future Sewage Flow Rates 16 3.2.1 Emfuleni Local Municipality 16 3.2.2 Midvaal Local Municipality 17 3.2.3 Consolidated Future Sewage Flow Rates 18
4 CONCLUSIONS 20
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Figures
Figure 2.1 Emfuleni population distribution per settlement type ...... 6 Figure 2.2 Midvaal household distribution per settlement type...... 7 Figure 2.3 Emfuleni Population Growth ...... 9 Figure 2.4 Midvaal Population Growth...... 9
Tables
Table 1.1 Overview of Treatment Works in the Study Area ...... 3 Table 3.1 2008 Sewer Flows for Emfuleni ...... 14 Table 3.2 Current Sewer Flows for Midvaal...... 15 Table 3.3 Projected Future Flows for Emfuleni (AADF – Ml/day) ...... 16 Table 3.4 Projected Future Flows for Midvaal (AADF – Ml/day)...... 17 Table 3.5 Consolidated Future Flows for the study area...... 18 Table 3.6 Sebokeng Catchment Sewer Flows ...... 18 Table 3.7 Consolidated Future ADWWF Flows (Excluding Sebokeng and Johannesburg)...19
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1 INTRODUCTION AND BACKGROUND
1.1 Background to the Study Area
Emfuleni Local Municipality (Emfuleni) and Midvaal Local Municipality (Midvaal) are located along the southern boundary of Gauteng Province in an area known commonly as the Vaal Triangle. These municipalities fall within the Sedibeng District Municipality (Sedibeng), a large district extending along the southern region of Gauteng Province between the adjacent provinces of Mpumalanga and North West. The Vaal River forms the southern boundary of Sedibeng, and also serves as the boundary with the Free State Province.
Emfuleni covers an area of just under 990 square kilometres with its main economic and commercial nodes being Vanderbijlpark and Vereeniging. Vanderbijlpark was originally established to house the workers of the Mittal (previously ISCOR) steel company. Evaton, Sharpville and Sebokeng are predominantly residential areas within Emfuleni and also linked to the Mittal steel factory.
Midvaal on the other hand, is the largest municipality (by area) in Gauteng Province - covering an area of 2000 square kilometres. Urban areas are located in the towns of Meyerton and Vaal Marina, which are developed around a Central Business District. Residential densities decline from the Central Business District outwards with low- income residential areas being situated on the outer edges of the towns.
Lesser-urbanised towns are also found at De-deur, Daleside, Walkerville, Henley on Klip, Riversdale, Risiville, Ohenimuri, Klipwater, Kliprivier, Highbury, Riversdale and Rothdene.
Appendix A illustrates a map of the study area.
1.2 Scope of the Study
This sewer flow estimation study is a component of the overall larger project entitled “Sedibeng Regional Sanitation Scheme” jointly undertaken by Sedibeng, Emfuleni and Midvaal Municipalities, and implemented by Arcus GIBB and its partners.
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The primary goal of the overall project is to eliminate polluted discharges into the Vaal Barrage and its catchments. It was generally accepted that a 2 phased approach is required to address the problem of discharges, as follows:
PHASE 1 – dubbed short term, was to rectify the most serious shortcomings at the pump stations and at the Rietspruit and Leeukuil works. PHASE 2 – the long-term solution, concentrates on reducing the number of pumpstations to a bare minimum and also rationalising the treatment aspect.
The project by Arcus GIBB is geared to Phase 2 – ie. to enable the Sedibeng Regional WWTW to become operational as soon as possible in order to limit non- compliant effluent discharges into the Vaal Barrage.
The objective of the project is to carry out a feasibility study into the site selection, and design parameters to construct a Regional WWTW, which will cater for the future requirements of the entire Region up to year 2025.
The envisaged benefits of a Regional sanitation scheme will be:
Elimination of problematic sewage pump stations as much as possible Scale of economics with regard to the proposed Regional WWTW Improved effluent quality – and hence reduced environmental pollution Reduced operational and maintenance costs Growth and development of the Region –job creation, skills development, and SMME development
The objective of this “flows” estimation study is to predict the current and future wastewater generation and hence treatment requirements up to year 2025. This information will inform the site selection and conceptual design components of the Regional WWTW and outfall sewer route selection. In estimating the future wastewater generation this study factors in, amongst other information,
the available population figures, census results, growth forecasts, planning information from the spatial development frameworks, water services development plans, information from Housing departments integrated development plans.
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The above information guided the study team as to where future residential and other developments were likely to take place in the Region. This will have a direct impact on the future demand for wastewater treatment services.
Finally, the current and future wastewater flows from areas outside the study area, which contributes to the Sedibeng Region (such as Johannesburg), were analysed.
1.3 Overview of the Existing Wastewater Treatment in the Region
The Sedibeng Region is currently being serviced by six sewage WWTW - with three works located in Emfuleni and Midvaal respectively. The diagram in Appendix B points out the geographic location of the treatment works as well as the catchment areas associated with each treatment works. Table 1.1below summarises the design, location and feeder catchments of the six existing treatment works.
Table 1.1 Overview of Treatment Works in the Study Area
Name of Treatment Treatment Municipality Catchment Comments Works Capacity Areas Evaton, 100Ml/day Sebokeng 100Ml/day Emfuleni Sebokeng, South BNR of Johannesburg, 11Ml/day Rietspruit 25Ml/day Emfuleni Vanderbijlpark, BNR Vereeniging, 20Ml/day Leeukuil 35Ml/day Emfuleni Sharpville, Three BNR Rivers Meyerton, Henley Meyerton 8Ml/day Midvaal 8Ml/day BNR on Klip
Package Ohinimuri 1Ml/day Midvaal Ohinimuri Plant
Package Vaal Marina 1Ml/day Midvaal Vaal Marina Plant
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Discussions with Municipal officials indicate a preference for Ohinimuri WWTW to be closed. Also, as per the Client’s instruction, the Vaal Marina WWTW is not analysed in the scope of this study. Hence the Sedibeng region has a total sewage treatment capacity of 168Ml/day (combined Biological Nutrient Removal (BNR) plus Trickling Filters). It is generally accepted that BNR treatment plants are required to meet the DWAF discharge standards. The combined BNR treatment capacity of Sedibeng is 139Ml/day (and 39Ml/day if one excludes Sebokeng).
The Sebokeng WWTW is able to meet the DWAF effluent discharge standards. It is also important to note that the Sebokeng WWTW has part of its catchments located across the Emfuleni borders, notably south of Johannesburg and parts of Midvaal.
Leeukuil WWTW also receives part of its inflow sewer from Risiville, Duncanville Extension 3, Mackay and Uitgvilt which are areas in Midvaal.
Meyerton WWTW receives sewer from Rustervaal and Roshnee, which are areas located in Emfuleni. These inter-municipality flows of sewer are supported by inter- municipality agreements entered into by the respective municipalities.
As illustrated in the diagram in Appendix B the area to the west of the N1 in Emfuleni receives no wastewater services. This is because the area is predominantly farmland. Similarly the diagram also illustrates that the majority of Midvaal receives no wastewater services because it is covered by agricultural holdings and farmland.
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2 AN EVALUATION OF FACTORS AND TRENDS INFLUENCING CURRENT AND FUTURE SEWER FLOWRATES
2.1 Current Demographics and Service Levels
2.1.1 Emfuleni Local Municipality
(a) Population Density and Growth
Population figures for the study area were obtained from three inter-related sources namely
The Emfuleni Local Municipality’s Integrated Development Plan (IDP) The Water Services Development Plan for Emfuleni (WSDP) The 2001 National Census
The 2001 population census places the population of Emfuleni at 665 027 whilst the Demarcation Board of 2002 indicates a population of 1 309 846.
The Town Planning Department of Emfuleni places the population at 1 200 110 based on the number of households located within the municipality.
The Emfuleni WSDP on the other hand places the population at 1 191 000 based on water usage figures. The WSDP also estimates the population growth rate to be 2.6%.
This study uses the WSDP population density figure of the base year 2007 (1 191 000 inhabitants) with an assumed population growth of 2.6% per anum. The reason for this is that the data is fairly recent and correlates well with the figures of the Town Planning Department. Figure 2.1 below illustrates the population distribution of Emfuleni by type of dwelling.
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Figure 2.1 Emfuleni population distribution per settlement type
372 1204
1622
15915
Formal Informal Traditional Other
(b) Dwelling Types and Levels of Service
Currently it is estimated that there are 224 000 households in Emfuleni split as follows:
139 000 formal dwellings - access to full waterborne sanitation services 14 600 informal dwellings located in informal settlements - using pit latrines 64 900 informal dwellings located in backyard shacks - so called “Evaton backyard dwellers” residing in backyards of some erven in Evaton using pit latrines 5 500 informal dwellings located on agricultural holdings and farmlands - make use of onsite sanitation either in the form of pit latrines or septic tanks
The above implies that the sewer flows received at the WWTW are from 139 000 households representing 62% of the total households in Emfuleni. It is highly probable that the 79 500 households currently located in informal settlements and backyard shacks will be connected to the municipality’s sewer system into the future - through township upgrades of these settlements. Additionally, the anticipated growth of 2,6% per anum will place more burden on the demand for waterborne sewer services. However, households located on agricultural holdings and farmland are unlikely to be connected to the municipality’s sewer system into the future because they are so sparsely populated that it would be too costly install the necessary infrastructure to
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service them with waterborne sewage. The future demand is covered in more detail in Chapter 2.2.
2.1.2 Midvaal Local Municipality
(a) Population Density and Growth
Population figures for this study were taken from the following sources:
The Midvaal Integrated Development Plan (IDP) The Midvaal Water Services Development Plan (WSDP)
Analysis of the above sources reveals that the population of Midvaal is estimated to be 95 033 inhabitants - residing in 19 113 households. Of these 15 915 are formal houses receiving a high level of wastewater service (waterborne sewage and formalised VIP’s).
The annual population growth for Midvaal is estimated to be 6.7% per anum - which is much higher than that of Emfuleni (2,6% per anum).
Figure 2.2 below illustrates the household distribution per settlement type in Midvaal.
Figure 2.2 Midvaal household distribution per settlement type
1204 372
1622
15915
Formal Informal Traditional Other
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(b) Dwelling Types and Levels of Service
Midvaal comprises predominantly agricultural holdings and farmland. “Traditional houses” are typically built in these areas. According to the WSDP about 49% of the households in Midvaal have full waterborne sewer systems. The following areas are serviced with full waterborne sewer:
Meyerton Randvaal Walkerville Blue Saddle Ranches Henley on Klip Vaal Marina
The rest of the municipality uses pit latrines and septic tanks. Appendix B shows that only a small area in Midvaal is serviced while the bulk of the municipality does not have sewer services. This is due to the fact that most of Midvaal is Agricultural land and sparsely populated. It would therefore be very costly to service the areas.
Midvaal is poised rapid development and growth as indicated by the aggressive projected growth rate of 6,7% per annum over the coming years. Also, discussions with municipal officials reveal that major developments are proposed west of the R59 into the future.
Informal settlements are presently located adjacent to urban areas and water service levels in these areas are generally very poor. Midvaal municipality is planning to formalise these settlements through upgrade programmes. Planning phases for upgrading settlements such as Mamello, Bantu Bonke and Sicelo are already underway.
Therefore the combined result of new developments, plus upgrading of existing developments will place significant demand for higher levels of services and hence waterborne sewer into the future. The future demand is covered in more detail in Chapter 2.2.
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2.2 Population Growth Projections – Emfuleni and Midvaal
A growth rate of 2.6% is assumed for Emfuleni as suggested by the WSDP, and 6.7% for Midvaal. Figure 2.3 below illustrates the current and projected population figures for the two Municipalities. The growth in population will result in an increased demand for sanitation services and hence an increased load on the existing sanitation system.
Figure 2.3 Emfuleni Population Growth
2,000,000 1,750,339 1,800,000 1,662,752 1,600,000 1,462,482 1,400,000 1,286,334 1,221,966 1,200,000 1,000,000 800,000 Population 600,000 400,000 200,000 0 2008 2010 2015 2020 2025 Year
Figure 2.4 Midvaal Population Growth
350000
300000 286,200
250000 206,940 200000 149,640 150000
Population 108,190 95,030 100000
50000
0 2008 2010 2015 2020 2025 Year
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Currently, the population of Midvaal is about 7.2% of the total population of the study area and this is expected to increase to 14% in the year 2025 because of the higher growth rate for the area.
2.3 Future Land Use and Residential Developments
2.3.1 Emfuleni Local Municipality
Numerous developments have been planned for in Emfuleni with the majority of these to occur towards the eastern part of the Municipality. The region towards the west of the N1 has mostly been designated as agricultural areas. The following section discusses the planned developments within the different catchments.
(a) Sebokeng Catchment
As discussed in Chapter 1, this catchment also covers the areas to the south of Johannesburg, and includes Poortjie, Lenasia and Ennerdale. A large number of developments are currently being implemented in this area in the form of low-cost housing. Johannesburg Water figures of expected future flows and hence contribution to the treatment works is shown in Appendix E.
Several developments are expected in the areas to the north of Emfuleni, which drains into the Sebokeng catchment. Information from the Planning Department indicates that about 36 455 erven will be developed in the next 7 years. Appendix D lists the expected developments in the area. In addition to these, Doornkuil, a housing development located in Midvaal forms part of this catchment. 18500 erven have been planned for in Doornkuil and construction will begin in 2009.
(b) Rietspruit Catchment
This area is largely the southwestern region of Emfuleni. This catchment area has a number of regions that are vacant and the Planning Department has indicated that there are plans to fill these gaps with mostly residential development. It is planned that around 27 550 residential erven will be
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developed in the next 7 years. Details of these are also provided in Appendix E.
According to the Spatial Development Framework (Appendix C) it is expected that future growth in Emfuleni will take place towards the southwestern parts of the Municipality - with areas around the Vaal Barrage targeted for numerous developments. Currently there are no indications as to the number and type of developments that are expected in the area.
(C) Leeukuil Catchment
As per the rest of Emfuleni, a number of areas have been earmarked for infilling with residential developments. It is expected that some 22 922 residential units will be developed in this region. Details of these developments are listed in Appendix D. Some industrial developments are also expected in the Duncanville, Powerville and Sonderland areas.
It is further envisaged that a number of dedicated student housing developments will be constructed in the future to relieve houses in the area that are overpopulated due to large numbers of students sharing. The spatial development framework for the Municipality indicates areas that have been earmarked for infilling and industrial developments.
2.3.2 Midvaal Local Municipality
According to the Midvaal IDP, several development nodes have been identified in this catchment. Appendix D shows the spatial development framework of the municipality and the different areas to be developed. The municipality has taken a stand to promote appropriate mixed land usage along the R59 and R82 corridors.
Since most of the developments in Midvaal are expected to occur in areas that are currently not serviced, it was decided to weight the future sewer demand calculations in terms of the areas to be developed. Majority of these developments are discussed in the Sewer Master Plan for the R59 corridor.
Appendix E lists the various expected developments in Midvaal. About 18 500 stands are to be constructed in Doornkuil. This area drains to the Sebokeng catchment and
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as a result it has been included on the discussion for the Sebokeng catchment under Emfuleni.
The R59 corridor has been identified as a major development node and as such a number of industrial developments are expected in the area. A summary of the developments in Midvaal is as follows:
4200 residential stands to be developed in Uitvlucht
2400 residential plots to be developed in Risiville and Mackay (These two developments drain to Leeukuil Treatment Works in Emfuleni)
Residential and Industrial developments in Eye of Africa
Developments in Vaal Marina
1000 residential stands in Sicelo
1000 residential stands in Blue Saddles Ranch.
2.4 Anticipated Improvements in Sanitation Levels of Service
2.4.1 Emfuleni Local Municipality
The WSDP prepared by Emfuleni indicates that there are plans to upgrade the sewer infrastructure in urban areas. Currently there are 65 000 backyard dwellers in Evaton who are not connected to the sewer system. Plans are afoot to connect these to the sewer system via the Evaton Renewal Programme – as initiated by the Gauteng Housing Department. It is envisaged that this programme will be completed by 2010.
The Municipality has an undertaking to upgrade sanitation service levels for those that are still using pit latrines to water borne sanitation. Currently, there are no plans to upgrade sewer systems in existing informal settlements to full water borne sewer. These residents will be relocated to low-income housing developments in due course. As a result, these will not be factored into this study.
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2.4.2 Midvaal Local Municipality
According to Midvaal Municipality, informal settlements will be the focal point for the provision of sewer and water services. This will be done by formalising and upgrading informal settlements to include waterborne sewage. Processes are already underway for the townships of Sicelo, Mamello and Lakeside, and other informal settlements are expected to follow - although no detailed time frames have been indicated for the roll- out.
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3 CALCULATIONS OF CURRENT AND FUTURE SEWER FLOW RATES
3.1 Calculation of Current Sewer Flows
3.1.1 Emfuleni Local Municipality
The current sewer flows were calculated based on the number of existing connections into the sewer system. Billing Information for the year 2007 was received from Metsi- a-Lekoa. This data was used together with information from the GLS Consulting report (Computer Analysis & Master Planning of Sewer distribution Network, Emfuleni). The year 2007 was used as a base year for calculating the current flows since all the IDP, WSDP and billing information received were for the year 2007.
Table 2.1 below lists the calculated sewer flows for Emfuleni. It contains the annual average daily flow (AADF) for Emfuleni, (which is the expected sewer flow including ingress of ground water into the sewer system at a rate of 15% as recommended by the Guidelines for Human Settlement Planning and Design).
Table 3.1 2008 Sewer Flows for Emfuleni
Calculated Current Actual Measured WWTW Treatment Catchment (2008) Flows (Ml/day) Flows (Ml/day) Capacity (Ml/day) AADF (July 2007)
Sebokeng 93 115* 100
Rietspruit 31 20.7 25
Leeukuil 44 33.9 35
Total 168 165.6 160 * 2008 Measured flow into Sebokeng Treatment Works
As indicated in Table 1.1, the Sebokeng WWTW also receives flows from areas in the south of Johannesburg. Appendix E confirms that the current flows from Johannesburg into Emfuleni is 40 Ml/day, which constitutes about 50% of the ADDWF flows into the Sebokeng treatment works.
When one compares these calculated flow figures to actual measured flows into the treatment works, it is found that the calculated wet weather flows are lower than those actually measured at the works by approximately 22Ml/day. It is important to note that these flow measurements were taken during the dry period when both groundwater
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ingress and general water usage was low. ILIFA consulting conducted a study in October 2007, after a rainy period, which showed that the sewage was actually diluted by up to 50% thus suggesting that there was a large amount of water ingress into the sewer system. Further investigations will have to be carried out to ascertain the extent of water ingress as well as that of inefficient usage of water by residents.
Current (2008) flow calculations for the other two catchments were found to be higher than the July 2007 actual flow measurements. It should be noted that the increase in flows is higher than the expected population growth rate of 2.6%. This then could mean that the Red Book sewer generation guidelines may be slightly above the actual generation in the two catchments.
3.1.2 Midvaal Local Municipality
Information on the number of stands connected to the sewer system in Midvaal was deduced from the IDP and the WSDP. Each catchment was looked at separately and the results are as shown in Table 3.2.
Table 3.2 Current Sewer Flows for Midvaal
Calculated Current Flow WWTW Treatment Catchment (Ml/day) AADF Capacity (Ml/day)
Meyerton 9.6 8
Ohinimuri 0.86 1
Vaal Marina 0.6 1
Total 11.06 10
Currently only Meyerton treatment works is receiving flows above its design capacity. Ohinimuri and Vaal marina treatment works are operating at below their design capacity - even when factoring in stormwater ingress.
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3.2 Calculation of Future Sewage Flow Rates
Given the planned developments as well as the expected future population growth, it is envisaged that both Municipalities will experience a significant increase in sewage flow in the years ahead.
3.2.1 Emfuleni Local Municipality
Table 3.1 below illustrates the calculated future sewage flows to the 3 catchments up to year 2025.
Table 3.3 Projected Future Flows for Emfuleni (AADF – Ml/day) WWTW Calculated Flows Treatment Current Catchments 2010 2015 2020 2025 Capacity Inflows (Ml/day) (Ml/day) (Ml/day) (Ml/day) (Ml/day) (Ml/day) Sebokeng 100
Emfuleni North 47 60 74 95 108 Johannesburg 46 61 88 95 109 Total 92 121 162 190 217
Rietspruit 25 31 37 51 63 72
Leeuwkuil 35 44 46 53 64 72
TOTAL 160 168 204 266 317 361
The Sebokeng catchment is expected to experience the highest increase in future flows (40% increase) especially between years 2008 and 2015. This is primarily due to the wastewater services backlogs eradication and new developments in the area.
WWTW works in Emfuleni are currently operating above their hydraulic design capacities and it is therefore inevitable that more capacity needs to be built to meet the future demand.
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3.2.2 Midvaal Local Municipality
Flows in Midvaal are expected to increase substantially into the future due to planned developments (discussed earlier) in the region. As shown in Appendix B, most of the areas in Midvaal are currently not serviced with waterborne sewage.
Table 3.4 below illustrates the expected future flows for the different areas in Midvaal. Discussions with the Midvaal Engineering department reveals that many of the new developments will be drained to the ERWAT treatment works located in the west. These developments include the Eye of Africa, Tedderfield and Blue Rose, Klipriver, Waterval, Blue Saddle, Drumblade and Graceview. The sewer volumes for these areas will therefore not be considered in the calculations for this report.
Additionally, Vaal Marina is being dealt with under a different study and will also not be included.
These areas were not classified according to catchment areas since most of them are not yet reticulated and a decision will have to be made as to where they will drain.
Table 3.4 Projected Future Flows for Midvaal (AADF – Ml/day)
WWTW Treatment Catchment Capacity Current 2010 2015 2020 2025 (Ml/day) (Ml/day) (Ml/day) (Ml/day) (Ml/day) (Ml/day) Meyerton Catchment 8 (not Witkopen, Daleside connected) 2.3 2.9 3.5 4.3 Henley on Klip up to Rothdene 7.8 8.7 17.3 19 21
Rustervaal 1.8 2.2 2.5 2.8 3.2 Ohinimuri Catchment 1 Ohenimuri 0.86 0.9 1.2 1.7 2.3
Total 10.5 14 23 27 31
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3.2.3 Consolidated Future Sewage Flow Rates
a) Combined Total Sewer Flows for the Study area
Table 3.5 shows the total current and future estimated flows for the study area.
Table 3.5 Consolidated Future Flows for the study area
Municipality Current 2010 2015 2020 2025 (Ml/day) (Ml/day) (Ml/day) (Ml/day) (Ml/day) Emfuleni 168 204 266 317 361 Midvaal 10.5 14 23 27 31 Total 178.5 218 289 344 392
The current total sewer flows for the study area is 177.5Ml/day whilst the total treatment capacity for the area is 168Ml/day. This confirms the present status that the WWTW in the region cannot cope with the current flows and will definitely not cope with future increase in flows. At the study horizon of year 2025 the treatment capacity for the Region as a whole must increase from 168Ml/day to 392Ml/day
b) Sebokeng Catchment
The Sebokeng WWTW (100Ml/day) is able to meet the DWAF effluent discharge standards and utilises a BNR treatment process. Hence this works will not be made redundant even when a new Regional WWTW is commissioned.
Table 3.6 below indicates the total current and future ADWWF flows for the Sebokeng catchment.
Table 3.6 Sebokeng Catchment Sewer Flows Current 2010 2015 2020 2025 (Ml/day) (Ml/day) (Ml/day) (Ml/day) (Ml/day) Emfuleni North 47 60 74 95 108 Johannesburg 46 61 88 95 109 Total 93 121 162 190 217
The sewer flows into the Sebokeng WWTW at year 2025 is calculated to be 217Ml/day. This then means that the catchment area requires the capacity of the Sebokeng works to be increased by at least 100Ml/day from the present 100Ml/day.
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As indicated above Johannesburg will contribute approximately 50% of the total future flows. Discussions are therefore needed between Emfuleni LM and Johannesburg Water to plan the future upgrades (minimum another 100ML/day) to the Sebokeng WWTW.
b) Future New Regional Treatment Works
Given the discussion above, the Sebokeng catchment needs to be excluded from the flow estimates to the new Regional WWTW.
Table 3.7 indicates the future flows from Midvaal and the south of Emfuleni (representing the remaining flows in the Region is one excludes the Sebokeng catchment).
Table 3.7 Consolidated Future ADWWF Flows (Excluding Sebokeng and Johannesburg) Current 2010 2015 2020 2025 (Ml/day) (Ml/day) (Ml/day) (Ml/day) (Ml/day) Emfuleni 75 83 104 127 144 Midvaal 10.5 14 23 27 31
Total 85.5 97 127 154 175
These flows are currently being treated at Leeuwkuil, Rietspruit and Meyerton WWTW. If it is estimated that these 3 WWTW will operate for another 7 years to 2015, then a new Regional WWTW of 127Ml/day treatment capacity needs to be operational by 2016. At year 2025 a 175Ml/d WWTW needs to be operational.
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4 CONCLUSIONS
The investigation into the current and future sewer flows for the Sedibeng Region indicates that there is a need to construct more wastewater treatment capacity in the Region due largely to the combined effect of the sanitation backlog eradication programmes, growth in the Region, and the construction of new planned developments. It is estimated that 20Ml/day infiltration into Sebokeng WWTW is currently taking place. This needs to be addressed in the short-term to free up much needed hydraulic treatment capacity. Flows into Sebokeng WWTW will increase dramatically into the future. Johannesburg will contribute 50% of the flows. The Sebokeng plant needs to be upgraded by another 100Ml/day to cater for predicted flows by 2025. The Midvaal and Emfuleni south regions will generate approximately 180Ml/day of sewer by year 2025. The existing WWTW in Leeukuil, Rietspruit and Meyerton should be “nursed” to operate for the next 7 years (at least), to allow for a new 175Ml/day plant and collector sewers to be built by 2015.
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DOCUMENT CONTROL SHEET (FORM IP180/B)
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Approved By Reviewed By Prepared By REVISION NAME NAME NAME
DATE SIGNATURE SIGNATURE SIGNATURE
This report, and information or advice, which it contains, is provided by ARCUS GIBB solely for internal use and reliance by its Client in performance of ARCUS GIBB duties and liabilities under its contract with the Client. Any advice, opinions, or recommendations within this report should be read and relied upon only in the context of the report as a whole. The advice and opinions in this report are based upon the information made available to ARCUS GIBB at the date of this report and on current SA standards, codes, technology and construction practices as at the date of this report. Following final delivery of this report to the Client, ARCUS GIBB will have no further obligations or duty to advise the Client on any matters, including development affecting the information or advice provided in this report. This report has been prepared by ARCUS GIBB in their professional capacity as Consulting Engineers. The contents of the report do not, in any way, purport to include any manner of legal advice or opinion. This report is prepared in accordance with the terms and conditions of the ARCUS GIBB contract with the Client. Regard should be had to those terms and conditions when considering and/or placing any reliance on this report. Should the Client wish to release this report to a Third Party for that party's reliance, ARCUS GIBB may, at its discretion, agree to such release provided that: (a) ARCUS GIBB written agreement is obtained prior to such release, and (b) By release of the report to the Third Party, that Third Party does not acquire any rights, contractual or otherwise, whatsoever against ARCUS GIBB and ARCUS GIBB, accordingly, assume no duties, liabilities or obligations to that Third Party, and (c) ARCUS GIBB accepts no responsibility for any loss or damage incurred by the Client or for any conflict of ARCUS GIBB interests arising out of the Client's release of this report to the Third Party.
ARCUS GIBB (Pty) Ltd Website : www.arcusgibb.co.za Postal Address : PO BOX 2700, RIVONIA Physical Address : 1410 EGLIN RD Contact Person : R MOTOMA Email Address : [email protected] Telephone No. : 011 519 4600 Fax No : 011 807 5670
Rev 3 / March 2008
REVIEW STATEMENT (FORM IP180A) Applicable for Proposals, Technical Reports, Progress Reports, Tender Docs, Tender Adjudication Reports, etc – NOT FOR DESIGN REVIEW
Project / Proposal No...... Project / Proposal Name: ......
1. Preparer to enter the details of the project and document to which this form applies, and to sign and date the form. (*PL to enter source details where document was prepared externally e.g. sub/co-consultants.)
Preparer / (Source*): ...... Date Required: ......
Document Title Document No / Version Document Purpose
2. Use the following checklist as guidance to assist in a systematic appraisal of the document. (V1, V2, V3 denotes the versions reviewed – mark with a [if correct] or X [if incorrect]).
TECHNICAL REVIEW V1 V2 V3 BRIEF COMMENT
Constituent documents, drawings & calcs reviewed. Adequacy and appropriateness of references (Regulations, Codes, Standards etc.).
Accuracy of results and recommendations.
Adequacy of assumptions.
Adequacy of argument or analysis.
Appropriateness of recommendations.
Health, Safety and Environmental
impact.
Financial, multiplier.
Contractual, Commercial, Risk.
EDITORIAL REVIEW
Project title, number and Workcode.
Table of Contents, Pagination.
Appendices, Cross-references.
Document number and version
identifier.
ARCUS GIBB report template and
front cover
Tables, Figures and Diagrams.
3. Reviewer must decide whether the document is fit for delivery in its current form or whether corrections/deletions/additions or other alterations are required. Mark required changes in the text of the document. Return the document to the preparer, together with the Review Statement or proceed to step 4.
4. Reviewer please sign and date the statement when satisfied with the quality of the document.
I/We have reviewed this document against the requirements of the task specification. My/Our review comments and reservations have been resolved to my/our satisfaction. This document is presentable and technically fit for delivery. (delete as appropriate)
Reviewer ...... Date: ......
Comments : ......
......
File original in relevant section in the Quality File. Rev 2 / March 2008