August 2012 AQUA SERVICES & ENGINEERING (PTY) LTD. Aqua Services & Engineering (Pty) Ltd

Transcription

1 MILLENNIUM CHALLENGE ACCOUNT-NAMIBIA CONTRACT NO: MCAN/COM/RFP/2A02002 DESIGN AND CONTRACT SUPERVISION OF INFRASTRUCTURE EXPANSION AND IMPROVEMENT OF MANAGEMENT CENTRES & STAFF HOUSING IN THE ETOSHA NATIONAL PARK, NAMIBIA ANALYSES AND TREATMENT OF POTABLE WATER AT OKAUKUEJO August 2012 Reg. No.: 93/196 VAT No.: Directors: Windhoek, Namibia International: ( )Dr. G.E. Rencken P.O. Box Gisclon (French)

2 TITLE: AUTHORS: PROJECT NAME: ANALYSES AND TREATMENT OF POTABLE WATER AT OKAUKUEJO AQUA SERVICES, NAMIBIA (On Behalf of PDNA-Consultant) DESIGN AND CONTRACT SUPERVISION OF INFRASTRUCTURE EXPANSION AND IMPROVEMENT OF MANAGEMENT CENTRES & STAFF HOUSING IN THE ETOSHA NATIONAL PARK, NAMIBIA CLIENT REFERENCE: Contract No. MCAN/COM/RFP/2A02002, Amendment No.2 PDNA REFERENCE: By of 17 th August 2012 STATUS REPORT: SECOND ISSUE: NUMBER OF COPIES: Draft NONE One (1) Electronic Copy PDNA Holdings (Pty) Ltd, Represented by PDNA International Approved on behalf of the Consultant By Date: 17 th August 2012 S A Rashid Project Manager K Moodley Project Director MILLENNIUM CHALLENGE ACCOUNT-NAMIBIA Approved on behalf of the Client By Date: N Hibbert Project Manager Reg. No.: 93/196 VAT No.: Directors: Windhoek, Namibia International: ( )Dr. G.E. Rencken P.O. Box ase@ase.com.naa.m. Gisclon (French)

3 Contract: MCAN/COM/RFP/2A02002 ANALYSES AND TREATMENT OF POTABLE WATER AT OKAUKUEJO CONCEPTUAL DESIGN REPORT REV DATE BY COMMENTS A 15 August 2012 RPvA Draft Report for Client s comments B 16 August 2012 RPvA Final Report Report by: Dr. G. Lempert & R. Pascal van Alphen Revision: B Reg. No.: 93/196 VAT No.: Directors: Windhoek, Namibia International: ( )Dr. G.E. Rencken P.O. Box ase@ase.com.naa.m. Gisclon (French)

4 DISCLAIMER COPYRIGHT: The information and design contained in this document and all software produced from this document are licensed for use on the ANALYSES AND TREATMENT OF POTABLE WATER AT OKAUKUEJO Project only, and may not be re-used in part, or in whole, on any other site or part thereof. Reg. No.: 93/196 VAT No.: Directors: Windhoek, Namibia International: ( )Dr. G.E. Rencken P.O. Box Gisclon (French)

5 Abstract The Etosha National Park (ENP) is one of the most sought-after tourist destinations in Namibia. It is therefore of utmost importance that the quality of drinking water supplied to these tourists stemming from all over the world, be of an excellent class, viz Group A as per the Namibian Drinking Water Guidelines (Namibia Water Corporation, 1988). As such, an investigation was conducted under the Millennium Challenge Account-Namibia (MCA-N) in which the primary objectives were to assess the sustainability of the raw water sources supplying the Okaukuejo Camp with potable water as well as the quality of the water. Based on the quality analyses, a possible treatment plant could be designed and suggested. The investigation showed that Okaukuejo has three different raw water sources that contribute to its potable water usage. Water from BH 6459 and BH is pumped to the reservoir and from there distributed for potable use. Water from BH 3904 is used for gardening purposes, the water hole as well as tower by-pass. Water from the tower by-pass is used for potable use only when the reservoir is out of operation, for example when it needs to be cleaned. Records from December 2010-June 2012 revealed an average potable water demand of ca m 3 /month (ca 433 m³/d) and, based on a population of ca people, relates to an average per capita consumption of approximately 170 l/p/d. Latter figure also conforms to average per capita usages throughout Namibia for typical tourist resorts. Evaluation of the raw water quality analyses showed that the raw water has high concentrations of total hardness due to high magnesium hardness, chlorides and sodium. Although the raw water still falls within Group B (Namibia Water Corporation, 1988), this would not be acceptable for international tourists and it was therefore recommended to provide a treatment plant to treat the water to fall within Group A. Maintaining and improving current potable water quality is thus of utmost importance. i

6 To economically improve the available raw water quality at Okaukuejo from Group B to Group A would require desalination, with Reverse Osmosis (RO) membrane technology being the most economical treatment process for the envisaged application. A treatment plant was proposed to provide for the maximum daily demand of ca 600 m 3. Latter figure was based on peak daily demand as observed during the most recent peak tourism season (in April 2012 and June 2012). The total capital cost for such a RO plant and evaporation ponds will be N$ ,00 (excl. V.A.T.) and operating costs N$ 4.45 per m³ (excl. V.A.T). It is furthermore recommended that an operator be trained to operate the plant full time to ensure functionality of the plant. ii

7 Table of Contents AQUA SERVICES Abstract...i Table of Contents... iii List of Nomenclature...iv List of Figures...v List of Tables...vi 1. Introduction Methodology Results and Discussion Conclusions and Recommendations References Appendix...20 iii

8 List of Nomenclature Symbol Description Units BH ENP MCC MCA-N MET NWR PE PFD RO Borehole Etosha National Park Millennium Challenge Corporation Millennium Challenge Account-Namibia Ministry of Environment and Tourism Namibia Wildlife Resort Population Equivalent Process Flow Diagram Reverse Osmosis iv

9 List of Figures Figure 1: Schematic representation of the location of the boreholes with regards to the camp... 4 Figure 2: Raw water sources supplying potable water to the reservoir Figure 3: BH 3904 which is used for gardening, the water hole and tower by-pass Figure 4: BH XYX previously used for gardening Figure 5: Reservoir containing water from BH 6459 and BH Figure 6: BH used for washing machinery and spraying roads Figure 7: Past water demand for Okaukuejo Figure 8: Proposed Process flow diagram of R.O. Plant...24 v

10 List of Tables AQUA SERVICES Table 1: Different potable, raw water sources (approximate distances)... 3 Table 2: Quality analyses from borehole sources...10 Table 3: Constituents rendering the Okaukuejo raw water Group B...12 Table 4: Past raw water demand from Dec 2010-June Table 5: Quality analyses of BH Table 6: Quality analyses of BH Table 7: Quality analyses of BH vi

11 1. Introduction A primary aim of the Millennium Challenge Corporation (MCC) is to assist and aid developing countries in reducing poverty. This function is achieved by supporting long-term sustainable, transformative economic growth. Expanding tourism in the Etosha National Park (ENP) has been identified as an area where latter goals can be achieved, but needs additional development. To assist the Ministry of Environment and Tourism (MET) in developing a better infrastructure for the ENP, the Millennium Challenge Account-Namibia (MCA-N) was implemented. By developing a better infrastructure more tourists will visit this Park, the living conditions of employees in the ENP can be improved and this would also result in attracting and maintaining competent staff more easily. This would furthermore also result in the ENP being managed more effectively and would allow Namibia and the ENP to be more competitive in the eco-tourism market (Aurecon, 2010:i). Improving the infrastructure of the Okaukuejo Rest Camp (only resort in the south of the ENP) is one of the primary concerns for the MCA-N in the ENP as it attracts tourists from all over the world and the necessity to maintain high standards are of utmost importance. The rest camp is situated in the south zone of the ENP and is approximately 17 km from the Anderson Gate (one of three official entrances into the park). The settlement has various tourist bungalows, camping sites, shops and restaurants. Staff quarters, administrative buildings for MET and the Namibia Wildlife Resort (NWR), a research institute, staff clinic and shops are also to be found inside the rest camp. Due to the high tourist attraction Okaukuejo experiences, it is of utmost importance to ensure that high qualities and standards are maintained in every aspect. One aspect of particular concern is the potable water supply to the resort. This facilitated the need to conduct a proper investigation into the sustainability and quality of the available raw water sources. From the quality analyses, a process design and cost estimate was undertaken to propose a water treatment plant that would ensure final water conforming to Group A as per the Namibian 1

12 Drinking Water Guidelines (Namibia Water Corporation, 1988) can be provided for all consumers. 2. Methodology To obtain reliable data for the design of a potable water treatment plant needed detail knowledge of the possible contaminants in the available raw water. A two-day visit (8 to 9 August 2012) to Okaukuejo was undertaken to determine the number of raw water sources currently being used. Raw water samples were then collected from all the boreholes that were being used at Okaukuejo. Information that was collected included: Identification of the number of potable, raw water sources in use; The percentage that each raw water source contributed to the overall potable water supply; The quality analyses of all the raw water sources and Past potable water demand figures, which would be used in addition to the population estimation (2500 PE) as previously obtained (Lempert and Van Alphen, 2012). Monthly potable water demand figures were obtained from NamWater s Invoices to the Client and this was also compared with visitors figures to the Camp as given by MET. 2

13 3. Results and Discussion The potable water demand figures from Dec 2010-June 2012 can be found in Appendix A, the original quality analyses in Appendix B and the Process Flow Diagram (PFD) of the proposed treatment plant in Appendix C. 3.1 Sources of Potable Water Supply During discussions with various members from MET, maintenance teams from the NWR as well as manager of NamWater Otjiwarongo, it was concluded that there are three different raw water sources, which contribute to the potable water supply of Okaukuejo. These discussions were confirmed during a site visit. The boreholes and its distance from the entrance to the Okaukuejo resort (located at the south of the ENP) are listed in Table 1. Discussions furthermore suggested that these raw water sources have supplied Okaukuejo with potable water reliably for over 30 years, without having run dry even in the worst years of drought. Table 1: Different potable, raw water sources (approximate distances). Raw water source BH 3904 BH 6459 BH Distance from Okaukuejo Entrance 100 m m m A schematic representation of Okaukuejo and the location of each of the above boreholes relative to the Camp are shown in Figure 1 and will be described thereafter. 3

14 Wat er hole Figure 1: Schematic representation of the location of the boreholes with regards to the camp. 4

15 Raw water extracted from boreholes 6459 and (Figure 2) is pumped to the reservoir, which is located inside the Okaukuejo resort fenced-in area, near the accommodation of senior staff. (a) BH 6459 (b) BH Figure 2: Raw water sources supplying potable water to the reservoir. Water from borehole 3904 is equipped with three different distribution lines (Figure 3a and 3b): Water used for gardening; supplying water for the water hole (animals); stand-by water for tower by-pass. Latter is used only when maintenance on the reservoir has to be done, for example when it has to be cleaned. 5

16 (a) Physical layout of BH 3904 (b) Three different distribution lines Figure 3: BH 3904 which is used for gardening, the water hole and tower by-pass. Originally, there was another borehole used for gardening purposes, indicated as BH XYX on Figure 1 and shown in Figure 4 below. Figure 4: BH XYX previously used for gardening. 6

17 This borehole is located only ca 100 m from the filling station and fuel spillages resulted in the water of this borehole became contaminated with diesel and the borehole has since been taken out of commission (Figure 4). The boreholes (BH 6459 & 27933) supplying water to the reservoir (Figure 5) operate on automatic mode and alternate one another. One borehole pump fills the reservoir until it reaches a 45% level inside the reservoir, where after it switches off and the second pump then fills the reservoir from the second borehole. Figure 5: Reservoir containing water from BH 6459 and BH There is also another borehole (BH 24634), which is only used to supply water for cleaning machinery and spraying roads and is equipped with an overhead filling point (Figure 6). 7

18 Figure 6: BH used for washing machinery and spraying roads. 3.2 Potable Water Demand To determine the past and future potable water demand of Okaukuejo, invoices from NamWater to NWR Okaujuejo were obtained. These invoices clearly distinguish between the quantities of water used every month for potable consumption, gardening and/or tower by-pass. Figure 7 shows the water demand from December 2010 till June 2012 according to the different categories. It is assumed that the future water demand will remain constant at ca m 3 /month seeing as some of the staff and their families will be moved and housed in Ombika (Lempert and Van Alphen, 2012). 8

19 700 Dailiy water demand (m 3 /d) Potable supply Gardening 0 Dec-10 Jan-11 Feb-11 Mar-11 Apr-11 May-11 Jun-11 Jul-11 Aug-11 Sep-11 Oct-11 Nov-11 Dec-11 Jan-12 Feb-12 Mar-12 Apr-12 May-12 Jun-12 Months Figure 7: Past water demand for Okaukuejo. 3.3 Quality Assessment One sample from each borehole was taken and analyzed to determine the quality of each source and overall group rating of the water. A sample analyses of the reservoir water from NamWater is also included. Table 2 depicts the results from the individual sources as well as the combined sample from the reservoir and these results are compared to the General Standard for Potable Water. 9

20 Table 2: Quality analyses from borehole sources Parameter Units BH 3904 BH 6459 BH Reservoir Group A Standard ph Electrical Conductivity ms/m Turbidity NTU Total Dissolved Solids (TDS) mg/l P-Alkalinity as mg/l CaCO 3 Total Alkalinity as mg/l CaCO 3 Total Hardness mg/l as CaCO 3 Ca-Hardness as mg/l CaCO 3 Mg-Hardness as mg/l CaCO 3 Chloride as Cl - mg/l

21 Fluoride as F - mg/l Sulphate as SO 4 2- mg/l Nitrate as N mg/l Nitrite as N mg/l <0.10 <0.10 <0.10 <0.10 Sodium as Na mg/l Potassium as K mg/l Magnesium as Mg mg/l Calcium as Ca mg/l Manganese as Mn mg/l <0.01 < < Iron as Fe mg/l <0.01 < < * Highlighted figures shows non-compliance as Group A water From Table 2 it is evident that the water from all three water sources cannot be classed as Group A water but rather fall within Group B. However, as the ENP attracts high-class tourists, it would be preferable for the water to be of excellent quality (Group A). Parameters preventing the water from falling in Group A are: Electrical conductivity (high TDS), total hardness, chlorides, sodium and magnesium. The high salt concentration is to be expected as all the raw water sources are located in the endothecia salt pan of the ENP. 11

22 3.4 Treatment Plant Required Technology Before being able to choose and design a potable water treatment plant in which the raw water can be treated to an excellent quality (Group A), the parameters being responsible for the water only meeting Group B quality are summarized in Table 3 below. Table 3: Constituents rendering the Okaukuejo raw water Group B Parameter Units Measured Value Limit Group A Limit Group B BH 3904 BH 6459 BH Reservoir Conductivity ms/m Total Hardness mg/l as CaCO 3 Mg-Hardness mg/l as CaCO 3 Chloride as Cl - mg/l Sodium as Na mg/l Magnesium as Mg mg/l

23 To reduce the high sodium and chloride concentrations from the raw water will require desalination technology and Reverse Osmosis (RO membrane) technology is currently the most widely understood and economically acceptable process used throughout Namibia (Von Oertzen & Schultz, 2008) However, RO treatment will result in a final water being produced that is highly aggressive due to all the minerals being removed and will need re-mineralization for potable water purposes. This is economically done by back-mixing (blending) raw water with the final RO water in a specific ratio to obtain a Group A final water.. For the different borehole waters as shown in Table 3 a blending ratio of approximately 2 / 3 RO water with 1 / 3 raw water will result in a final water adhering to Group A. We have therefore based our calculations on a RO plant that will produce 400 m³/d of permeate and this will be blended with 200 m³/d of borehole water to give the required 600 m³/d final water, which will then conform to a Group A water Design The total number of people that will be served by this RO plant, will be approximately persons. If the average per capita consumption figure of 200 l/p/d is assumed the potable water demand will be ca m 3 /month (500 m³/d). From the past potable water demand figures, the average water demand is ca m 3 /month (433 m³/d), which translates to ca 170 l/p/d. However, due to peak demand figures for April 2012 and June 2012, the daily capacity should be increased to ca 600 m 3 /d to ensure sufficient water can be supplied for a maximum influx of tourists. 13

24 The design of an RO plant should be based on the following recommended design parameters: Membrane Plant flow rates (max): o Raw water feed in = 20 m 3 /h o Recycle = 5 m 3 /h o Permeate production = 18 m 3 /h o Brine rejection = 2 m 3 /h o Recovery = 90% o Membrane operating pressure = 10 bar Inflow water quality major parameters: o TDS 1500 mg/l o Total Hardness (Ca + Mg) 600 mg/l Blending of Raw/ Permeate water = 33/ Process Description Raw water from boreholes (BH 6459 and/ BH 27933) will be pumped into 3 off intermediate storage tanks ( L) at a rate of 22 m 3 /h. From the intermediate tanks (TS 001), the raw water will be pumped (PC 001) through a pressure sand filter (VF 001) to remove larger particles (ca > 40µ) from the water. The filter will have to be backwashed manually from time-to-time with raw water. After filtration, the water is split and 33% is bypassed to the final water storage tank. The other 67% passes through a 5µ cartridge filter (VF 002). Depending on the quality of the boreholes, the cartridge filter will need to be replaced ca once every 6 months. 14

25 From the 5µ cartridge filter, the water is pumped by a high pressure pump (PC 002) to the RO unit (MM 001). The RO unit will consist of 4 off pressure vessels, with 7 off 8-inch low-energy RO membranes (e.g. typical DOW/Filmtex LE-400). This type of membrane is chosen as it uses little energy compared to other types of membranes. The RO membranes will operate at ca 10 bar feed pressure. There should be 3 off chemical dosing stations: Anti-scalant to prevent precipitate from depositing on the membrane; Acid to lower the ph of the feed water as well as to prevent membrane scaling and liquid chlorine (NaOCl) for final water disinfection. After the water has passed through the membranes, the product water (permeate) is disinfected with liquid chlorine (NaOCl) and will be pumped (PC 003) to the existing reservoir (TS 002) where the final water will be stored. The plant will operate intermittently, viz if the final water storage tank is full, the plant will automatically switch off. The membranes will be cleaned using a 500 L CIP (cleaning-in-place) tank to perform chemical cleans from time-to-time (ca once every 6 to 8 weeks). Allowance must be made for brine disposal. At Okaukuejo, evaporation will be the most appropriate means for discarding the effluent and evaporation ponds with total surface area of m³ must be provided. 15

26 3.4.4 Costing The following estimated costs will apply: Capital Costs. The total cost for a 600 m 3 /d treatment facility in which 400 m 3 /d are treated through RO membrane technology as described above, delivered, commissioned and training for 2 operators, without maintenance contract and brine evaporation ponds totaling m 2 surface area: o Complete RO plant o Evaporation Ponds N$ ,00 (excl. V.A.T.) N$ ,00 (excl. V.A.T.) Operating costs. Unit costs for operating and maintaining this RO plant, viz for chemicals, spares, membrane replacements, disinfection, manpower and operators to operate the plant at full capacity are estimated to be: N$ 4.45 per m³ (N$2 580/d) (excl.v.a.t.) The above 400 m³/d RO final water (permeate) will be blended with 200 m³/d raw water to provide for 600 m³/d of Group A drinking water for Okaukuejo. It is recommended that should the RO plant be provided for Okaukuejo, the client insists on a service and maintenance contract to be drawn up by the provider. 16

27 4. Conclusions and Recommendations From the above results and discussions, the following conclusions and recommendations can be made with regards to Okaukuejo s potable water supply: There are three raw water sources that contribute to the total potable water supply; o Water from BH 6459 and BH is pumped to the reservoir from where it is distributed throughout the camp to be used for drinking purposes; o BH 3904 is equipped with three different discharge lines to distribute water for gardening purposes, the water hole and tower by-pass (only when reservoir is out of operation). Water from this borehole is not fed into the reservoir; o BH XYX originally used for gardening is out of commission as it has been contaminated with diesel; o BH is only used for washing (machinery) and roads. The potable water demand according to previous records (Dec 2010-Jun 2012) is ca m 3 /month. Raw water quality analyses showed that the water fails with regards to a Group A water on high electrical conductivity, magnesium hardness, sodium concentration as well as chloride concentration, but still falls within a Group B water. An RO plant to improve water quality to ensure the final water supplied to the Camp falls within a Group A water is recommended. The RO plant must be designed to produce at least 400 m³/d of permeate and latter will then be blended with 200 m³/d raw water to achieve a production rate of 600 m 3 /day. 17

28 This is done to accommodate peak flow that might occur during the main tourism season: o The budget costs for a 400 m³/d RO plant would be N$ (excl. V.A.T.); o Operation and maintenance costs would be ca N$ 4.45/m³ (excl. V.A.T) It is furthermore recommended that an operator be employed full time to operate and maintain the RO plant and ensure functionality of the plant. It is recommended that a service and maintenance contract be drawn up by the provider for the client. 18

29 5. References AURECON ENVIRONMENTAL AND SOCIAL IMPACT ASSESSMENT (ESIA) FOR THE UPGRADING OF INFRASTRUCTURE IN THE ETOSHA NATIONAL PARK-SOUTH ZONE. NAMIBIA WATER CORPORATION. APRIL GUIDELINES FOR THE EVALUATION OF DRINKING-WATER FOR HUMAN CONSUMPTION WITH REGARD TO CHEMICAL, PHYSICAL AND BACTERIOLOGICAL QUALITY. LEMPERT, G.G & PASCAL VAN ALPHEN, R. JULY OKAUKUEJO SITE INVESTIGATION FOR THE REPORT: MCA ETOSHA: TESTS AND ANALYSES OF SEWAGE AT OMBIKA AND OKAUKUEJO. VON OERTZEN, D. & SCHULTZ, R VILLAGE-SCALE AND SOLAR DESALINATION TECHNOLOGY EXPERIENCE IN NAMIBIA. 19

30 6. Appendix 6.1 Appendix A Table 4: Past raw water demand from Dec 2010-June 2012 Treated water demand Month Potable water (m³/month) Potable water (m3/d) Gardens (m³/month) Gardens (m3/d) Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Tower By-pass (m³) Nov Dec Jan Feb Mar Apr May Jun

31 & E 6.2 Appendix B Table 5: Quality analyses of BH 6459 ANALYTICAL LABORATORY SERVICES cc P.O. Box Eros, Windhoek, Namibia Tel (061) Fax (061) analab@mweb.com.na TEST REPORT To: Attn: Aqua Services & Engineering P.O.Box Windhoek Date received: 9-Aug-12 0 Date required: 0-Jan-00 0 Date completed: 13-Aug-12 Rolene 0 Your Reference: O 08/025-ANALYTICAL Lab Reference: I Sample details BH 6459 Location of sampling point Okaukuejo Description of sampling point - Date of sampling 2012/08/08 Time of sampling - Test item number I120982/1 Recommended maximum limits Human consumption Livestock Parameter Value Units Classification Group A Group B Group C watering p H 6.9 A Electrical Conductivity 212 ms/m B Turbidity 0.15 NTU A Total Dissolved Solids (calc.) 1420 mg/l 6000 P-Alkalinity as CaCO 3 0 mg/l Total Alkalinity as CaCO mg/l Total Hardness as CaCO mg/l B Ca-Hardness as CaCO mg/l A Mg-Hardness as CaCO mg/l B Chloride as Cl mg/l B Fluoride as F mg/l A Sulphate as SO mg/l A Nitrate as N 2.6 mg/l A Nitrite as N <0.1 mg/l 10 Sodium as Na 290 mg/l B Potassium as K 3.4 mg/l A Magnesium as Mg 72 mg/l B Calcium as Ca 112 mg/l A Manganese as Mn <0.01 mg/l A Iron as Fe <0.01 mg/l A Stability ph, at 25 C 6.7 Langelier Index 0.2 scaling >0=scaling, <0=corrosive, 0=stable Ryznar Index 6.5 scaling <6.5=scaling, >7,5=corrosive, >6.5 and <7.5=stable Corrosivity ratio 1.1 increasing corrosive tendency Applies to water in the ph range 7-8 Remark: which also contains dissolved oxygen ratios <0.2 no corrosive properties ratios >0.2 increasing corrosive tendency Overall classification of water, considering only constituents that have been tested for: Group B, good quality water. 21

32 & E Table 6: Quality analyses of BH ANALYTICAL LABORATORY SERVICES cc P.O. Box Eros, Windhoek, Namibia Tel (061) Fax (061) analab@mweb.com.na TEST REPORT To: Attn: Aqua Services & Engineering P.O.Box Windhoek Date received: 9-Aug-12 0 Date required: 0-Jan-00 0 Date completed: 13-Aug-12 Rolene 0 Your Reference: O 08/025-ANALYTICAL Lab Reference: I Sample details BH Location of sampling point Okaukuejo Description of sampling point - Date of sampling 2012/08/09 Time of sampling - Test item number I120982/2 Recommended maximum limits Human consumption Livestock Parameter Value Units Classification Group A Group B Group C watering p H 7.1 A Electrical Conductivity 218 ms/m B Turbidity 1.1 NTU B Total Dissolved Solids (calc.) 1461 mg/l 6000 P-Alkalinity as CaCO 3 0 mg/l Total Alkalinity as CaCO mg/l Total Hardness as CaCO mg/l B Ca-Hardness as CaCO mg/l A Mg-Hardness as CaCO mg/l A Chloride as Cl mg/l B Fluoride as F mg/l A Sulphate as SO mg/l A Nitrate as N 2.5 mg/l A Nitrite as N <0.1 mg/l 10 Sodium as Na 320 mg/l B Potassium as K 3.1 mg/l A Magnesium as Mg 69 mg/l A Calcium as Ca 114 mg/l A Manganese as Mn 0.01 mg/l A Iron as Fe 0.03 mg/l A Stability ph, at 25 C 6.7 Langelier Index 0.4 scaling >0=scaling, <0=corrosive, 0=stable Ryznar Index 6.3 scaling <6.5=scaling, >7,5=corrosive, >6.5 and <7.5=stable Corrosivity ratio 1.1 increasing corrosive tendency Applies to water in the ph range 7-8 Remark: which also contains dissolved oxygen ratios <0.2 no corrosive properties ratios >0.2 increasing corrosive tendency Overall classification of water, considering only constituents that have been tested for: Group B, good quality water. 22

33 & E Table 7: Quality analyses of BH 3904 ANALYTICAL LABORATORY SERVICES cc P.O. Box Eros, Windhoek, Namibia Tel (061) Fax (061) analab@mweb.com.na TEST REPORT To: Attn: Aqua Services & Engineering P.O.Box Windhoek Date received: 13-Jul-12 0 Date required: 0-Jan-00 0 Date completed: 26-Jul-12 Thomas 0 Your Reference: 336/LAB/16782 Lab Reference: I Sample details Etosha BH 3904 Location of sampling point Okaukuejo Description of sampling point Date of sampling 2012/07/11 Time of sampling - Test item number I120835/1 Recommended maximum limits Human consumption Livestock Parameter Value Units Classification Group A Group B Group C watering p H 7.2 A Electrical Conductivity ms/m B Turbidity 0.20 NTU A Total Dissolved Solids (calc.) 1514 mg/l 6000 P-Alkalinity as CaCO 3 0 mg/l Total Alkalinity as CaCO mg/l Total Hardness as CaCO mg/l B Ca-Hardness as CaCO mg/l A Mg-Hardness as CaCO mg/l B Chloride as Cl mg/l B Fluoride as F mg/l A Sulphate as SO mg/l A Nitrate as N 3.0 mg/l A Nitrite as N <0.1 mg/l 10 Sodium as Na 290 mg/l B Potassium as K 3.1 mg/l A Magnesium as Mg 75 mg/l B Calcium as Ca 115 mg/l A Manganese as Mn <0.01 mg/l A Iron as Fe <0.01 mg/l A Stability ph, at 25 C 6.7 Langelier Index 0.5 scaling >0=scaling, <0=corrosive, 0=stable Ryznar Index 6.2 scaling <6.5=scaling, >7,5=corrosive, >6.5 and <7.5=stable Corrosivity ratio 1.1 increasing corrosive tendency Applies to water in the ph range 7-8 Remark: which also contains dissolved oxygen ratios <0.2 no corrosive properties ratios >0.2 increasing corrosive tendency Overall classification of water, considering only constituents that have been tested for: Group B, good quality water. 23

34 6.3 Appendix C AQUA SERVICES Figure 8: Proposed Process flow diagram of R.O. Plant. 24

35 Using a simulating program, the following results were obtained with the current water quality analyses: System Design Overview Raw Water TDS mg/l % System Recovery (7/1) % Water Classification Well Water SDI < 3 Fouling Factor (Pass 1) 0.85 Feed Temperature 25.0 C Pass # Stage # Element Type Pressure Vessels per Stage Elements per Pressure Vessel Total Number of Elements Pass Average Flux Pass 1 1 LE lmh 25

36 Stage Average Flux Permeate Back Pressure Booster Pressure Chemical Dose Energy Consumption lmh 0.00 bar 0.00 bar 100% HCl 0.02 mg/l 0.59 kwh/m³ Pass 1 Stream # Flow (m³/h) Pressure (bar) TDS (mg/l) /1 % Recovery Design Warnings: -None- Solubility Warnings: CaSO4 (% Saturation) > 100% CaF2 (% Saturation) > 100% Antiscalants will be required. 26

37 System Details AQUA SERVICES Feed Flow to Stage m³/h Pass 1 Permeate Flow m³/h Osmotic Pressure: Raw Water Flow to System m³/h Pass 1 Recovery % Feed 0.90 bar Feed Pressure bar Feed Temperature 25.0 C Concentrate 7.45 bar Fouling Factor 0.85 Feed TDS mg/l Average 4.18 bar Chem. Dose (100% HCl) 0.02 mg/l Number of Elements 28 Average NDP 4.18 bar Total Active Area M² Average Pass 1 Flux lmh Power kw Water Classification: Well Water SDI < 3 Specific Energy 0.59 kwh/m³ Stage Element #PV #Ele Feed Flow (m³/h) Feed Press (bar) Recirc Flow (m³/h) Conc Flow (m³/h) Conc Press (bar) Perm Flow (m³/h) Avg Flux (lmh) Perm Press (bar) Boost Press (bar) Perm TDS (mg/l) 1 LE Pass Streams (mg/l as Ion) Name Feed Adjusted Feed Concentrate Permeate Initial After Recycles Stage 1 Stage 1 Total NH K Na Mg Ca Sr Ba CO HCO NO Cl F SO SiO Boron CO TDS ph Design Warnings -None- Solubility Warnings 27

38 CaSO4 (% Saturation) > 100% CaF2 (% Saturation) > 100% Antiscalants will be required. Stage Details Stage 1 Element Recovery Perm Flow (m³/h) Perm TDS (mg/l) Feed Flow (m³/h) Feed TDS (mg/l) Feed Press (bar) Scaling Calculations Raw Water Adjusted Feed Concentrate ph Langelier Saturation Index Stiff & Davis Stability Index Ionic Strength (Molal) TDS (mg/l) HCO CO CO CaSO4 (% Saturation) BaSO4 (% Saturation) SrSO4 (% Saturation) CaF2 (% Saturation) SiO2 (% Saturation) Mg(OH)2 (% Saturation) To balance: 0.00 mg/l Cl added to feed. 28