Environmental Impact Assessment ______For Jebel Ali Power and Desalination Station M
April 1, 2009
Prepared for:
Prepared By:
Environmental International ConsultanConsultantstststs
Office: P.O. Box 123401, Dubai, UAE Tel: 04-3357044, Fax: 04-335733 http://www.eicon.ae
Confidentiality Clause: This is a confidential document expressly prepared for the client’s evaluation of EIC’s technical report with regard to the above referenced project. Unauthorized copying, duplication, and transmittal of this document in whole or in part for other projects or to a third party is prohibited. We do not hold responsibility or any legal liability for the consequences arising from the results or interpretations made therein.
Table of Contents
EXECUTIVE SUMMARY CHAPTER 1 INTRODUCTION 1.1 Preamble 1-1 1.2 Objective of the study 1-2 1.3 Objective of the Project 1-2 1.4 Location and Accessibility 1-3 1.5 Methodology of EIA study 1-7 1.6 Approach of the EIA study 1-7 1.7 Structure of Report 1-8
CHAPTER 2 POLICY AND LEGAL FRAMEWORK 2.1 Preamble 2-1 2.2 Guidelines 2-1 2.3 Standards 2-3 2.3.1 Ambient Air Quality Standards 2-3 2.3.2 Ambient Noise Level 2-4 2.3.3 Wastewater Discharge Limits 2-5 2.3.4 Solid Waste 2-8 2.4 ISO 14000 2-10
CHAPTER 3 PROJECT DETAILS 3.0 Project Characteristics 3-1 3.1 Outline and Rationale of the Project 3-1 3.2 Plant Layout and Land Requirement 3-1 3.3 Project Description – Power Plant (2000 MW) 3-2 3.3.1 Main Systems / Components 3-3 3.3.2 Modes of Operation 3-4 3.3.3 Abnormal Operating modes 3-5
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3.4 Project Description – Desalination plant 3-6 3.4.1 Details of Proposed Desalination Plant 3-9 3.5 Operational Features of the Project 3-11 3.5.1 Fuel 3-11 3.5.2 Chemicals 3-14 3.6 Water System 3-15 3.7 Wastewater Treatment System 3-16 3.7.1 The Treatment for the Oily Wastewater 3-18 3.7.2 Treatment for Chemical Wastewater 3-19 3.8 Details of Sewage Water Treatment System 3-23 3.9 Sources of Pollution 3-25 3.9.1 Air Environment 3-26 3.9.2 Water Environment 3-27 3.9.3 Solid waste 3-27 3.9.4 Noise Levels 3-28
CHAPTER 4 BASELINE ENVIRONMENTAL STATUS 4.1 Preamble 4-1 4.2 Climatology and Meteorology 4-1 4.2.1 General 4-1 4.2.2 Temperature 4-2 4.2.3 Relative Humidity 4-2 4.2.4 Atmospheric Pressure 4-3 4.2.5 Rainfall 4-3 4.2.6 Annual Wind Pattern 4-4 4.3 Sea Surface Water Treatment 4-6 4.4 Landuse 4-7 4.5 Regional Geology 4-8 4.6 Existing Baseline Air Quality 4-8 4.7 Biological Features 4-11 2
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4.7.1 General 4-11 4.7.2 Birds 4-12 4.7.3 Fauna, Wildlife 4-12 4.8 Soil, Geology and Geomorphology 4-13 4.8.1 General 4-13 4.8.2 Regional geology and Hydrogeology 4-13 4.9 Shoreline, Water Courses and Discharges 4-14 4.10 Cultural Heritage 4-15 4.11 Lanscape and Topography 4-15 4.12 Surrounding Recreational Land uses 4-15 4.13 Population 4-16 4.14 Water Quality 4-16 4.14.1 General Characteristics of the Arabian Gulf 4-17 4.14.2 Water Quality of the Gulf 4-18 4.14.3 Environmental threats of the Gulf 4-18 4.14.4 Water Quality off DEWA Station M 4-18 4.14.5 Results and Discussion 4-20 4.15 Marine Ecology 4-23 4.15.1 The Arabian Gulf Marine Environment 4-25 4.15.2 Objective of the Marine Study 4-26 4.15.3 Data Collection and Monitoring Stations 4-26 4.15.4 Strategy of Selecting Biological Variables 4-27 4.15.5 Methodology of Sampling and Analysis 4-30 4.15.6 Phytoplankton 4-31 4.15.7 Macro – Benthos 4-33 4.15.8 Conclusion 4-34 4.16 Terrestrial Ecology 4-37
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CHAPTER 5 ENVIRONMENTAL IMPACT ASSESSMENT 5.1 Preamble 5-1 5.2 Impacts during Construction Phase 5-4 5.2.1 Impact on Air Quality 5-4 5.2.2 Impact on Water Quality 5-5 5.2.3 Impact on Noise Level 5-6 5.2.4 Impact on Landuse 5-7 5.2.5 Assessment of Works, Health and Safety 5-7 5.3 Impacts during Operation Phase 5-8 5.3.1 Impact on Ambient Air Quality 5-8 5.3.2 Impact on Water Quality 5-12 5.3.3 Impact of Brine from Desalination Plant 5-14 5.3.4 Impact on Noise Levels 5-18 5.3.5 Impact on Social Life 5-20 5.3.6 Impact on Cultural Heritage 5-21 5.3.7 Impact on Terrestrial Ecology 5-21 5.3.8 Solid Waste 5-21
CHAPTER 6 PROPOSED MITIGATION MEASURES 6.1 Preamble 6-1 6.2 Mitigation Measures during Design and Construction 6-1 6.2.1 Dust Emissions 6-1 6.2.2 Noise Emissions 6-3 6.2.3 Flora and Fauna 6-3 6.2.4 Traffic and Transport 6-4 6.2.5 Socio – economic effects 6-4 6.2.6 Archaeology 6-5 6.2.7 Solid wastes during Construction 6-5 6.2.8 Occupational Health and Safety 6-6 6.3 Mitigation Measures during Operation 6-7 4
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6.3.1 Introduction 6-7 6.3.2 Air Quality during operation 6-8 6.3.3 Noise Emissions during Operation 6-8 6.3.4 Flora and Fauna during Operation 6-9 6.3.5 Visual Impact during Operation 6-9 6.3.6 Solid Waste Impacts during Operation 6-9 6.3.7 Health and Safety during Operation 6-10 6.4 Environment Monitoring Program 6-11 6.5 Hazard Protective Measures 6-15
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LIST OF TABLES Table 2.1 Ambient Air Quality Standards 2-3 Table 2.2 Standards For Ambient Noise Levels 2-4 Table 2.3 Limits for Discharges into the Marine Environment 2-5 Table 2.4 Dubai Municipality Wastewater Discharge Standards 2-6 Table 2.5 Limits of Trace Metals in Sludge intended for Disposal on Land 2-8 Table 2.6 Land Contamination Indicator Levels 2-9 Table 3.1 Parameters for the Calculation of Emissions 3-2 Table 3.2 Natural Gas Analysis 3-11 Table 3.3 The Typical Diesel Oil Analysis 3-12 Table 3.4 Quality of the Wastewater Prior to the Treatment 3-17 Table 3.5 Details of Stack and Gaseous Emission 3-25 Table 4.1 Climatological Data – Dubai International Airport – 2008 4-3 Table 4.2 Monthly Sea Temperature Variation for the Year 2007 4-6 Table 4.3 Jebel Ali Village Air Quality Monitoring 4-10 Table 4.4 Background Heavy Metals in Soil in Dubai 4-14 Table 4.5 Selected Water Quality Parameters and Their Test Methods 4-19 Table 4.6 Distribution of Phytoplankton Cell Counts (NO/L) Along 4-35 Different Stations Table 4.7 Distribution of Macro-Benthos Biomass (gm/m 2) and Population 4-36 (no/m 2) Table 5.1 Impact Rating Assessment Matrix 5-2 Table 5.2 Impact Rating Assessment Matrix 5-3 Table 5.3 Source Data of the proposed ‘M’ Station Desalination Plant 5-10 Table 5.4 Predicted 24-Hourly short term Incremental Concentrations of 5-11 NOx Table 5.5 Quality of Wastewater 5-13 Table 5.6 Predicted Noise Levels Plant Boundary 5-19 Table 6.1 Role and Responsibilities of the Project Proponent 6-2 Table 6.2 Responsibilities of Environmental Team during Operational 6-7 6
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Phase Table 6.3 Environmental Monitoring During Construction Period 6-12 Table 6.4 Environmental Monitoring During Operation Period 6-13
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LIST OF FIGURES Figure 1.1 Proposed Project site 1-4 Figure 3.1 Process Flow Diagram of MSF with Brine Circulation 3-7 Figure 4.1 Annual Windrose of Dubai International Airport – 2008 4-5 Figure 4.2 Monthly Sea Water Temperature 4-7 Figure 4.3 Marine Water Quality Monitoring 4-20 Figure 4.4 Monitoring Stations Along Coastal Environment of DEWA 4-27 Figure 4.5 Marine Environment of DEWA showing outfall Locations 4-29 Figure 4.6 Distribution of Macro-Benthos Biomass (gm/m2 ) and 4-37 Population (no/m2) Figure 5.1 Noise Dispersion Contours 5-20
LIST OF APPENDICES Appendix 1 Layout Plan of the Desalination plan Appendix 2 Main Stack and Bypass Stack Appendix 3 Wastwater Treatment P & I Diagram Appendix 4 Sewage Treatment Plan
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EIA study for the proposed Jebel Ali Power and Desalination Station M
Executive Summary
M/s Fisia Italimpianti, Gruppo Impregilo & M/s Doosan are the main contractor for the execution of the project, retained M/s. Environmental International Consultants, Dubai to carry out the Environmental Impact Assessment (EIA).
The EIA has been carried out as per the ETG 53 prescribed by Dubai Municipality for getting environment clearance. EIA report has been prepared in accordance with the Guidelines of Local Order 61 of 1991 published by Dubai Municipality (DM). The environmental impacts of the proposed project for the activities during construction as well as operation phase. As far as possible, these evaluations are quantitative and based on comparisons with relevant available standards specified by Dubai Municipality and International Organizations (WHO, World Health Organization, World Bank).
Location of the project:
Proposed project is located in Dubai, U.A.E and is about 0.5 km from west of the Dubai-Abu Dhabi highway and adjacent to Jebel Ali Free Zone. The proposed site is at the existing Jebel Ali Power Station Complex. The project location is already owned by DEWA. The project site is located along the shore of the Arabian Gulf and adjacent to existing Jebel Ali ‘L’ power station. The new desalination plant will be part of the Jebel Ali Power Station.
Project description:
The project consists of gas-based power plant to generate 2000 MW of electricity and desalination plant of 140 MIGD capacities to produce potable water.
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Executive Summary
The seawater desalination plant shall consist of eight desalination units having capacity of 17.5 MIGD each. This will result in total desalination plant capacity of 140 MIGD.
1 Power Plant
To meet the continuously growing requirement for power in the emirate of Dubai, UAE, the Dubai Electricity and Water Authority (DEWA) has planned to install 2000 MW power plant.
The power plant of Jebel Ali ‘M’ station extension includes a total of six Gas Turbines (GTs), equipped with Heat Recovery Steam Generators (HRSG) comprising duct burners for supplementary firing, 3 condensing extraction Steam Turbines (STs), and 2 Auxiliary Boilers (ABs). All considerations in the present Report are based on this configuration.
In order to achieve a gross output of 2000 MW, six gas turbines will be
installed in ‘M’ station. The GTs will be equipped with dry low NO 2 combustion chambers for natural gas and Diesel oil fuel operation. No injection water or
steam injection facilities will be foreseen for NO 2 reduction in case of Diesel oil operation (only emergency cases).
2 Desalination Plant
The proposed desalination plant will be operated on Multi Stage Flash (MSF) process.
Each distiller unit consists on a multistage flash evaporator chamber with its auxiliary and ancillary equipment.
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Executive Summary
The evaporator is a Multi Stage Flash type (MSF) with brine recirculation and of cross tube single tier design. An anti scale system is used to treat the recirculating brine in the whole temperature operating range of the evaporator. The distillate produced by the eight desalination units is sent to the product water system and blending plant. Each Unit can be subdivided from the functional point of view in the following sections:
• Brine Heater Section; • Heat Recovery Section; and • Heat Reject Section.
Sources of Pollution:
1 Air emission:
In the proposed project the air emissions will be from the six stacks of power plant and two stacks of auxiliary boilers in desalination plant. Since the power plant and boilers will be fired on natural gas, the gaseous emissions will comprise of NOx. These power units will be provided with stacks of adequate height for the wider and quicker dispersion of the gaseous emissions.
3 The maximum incremental concentrations of NO X will be 8.6 µg/m and occurring at a distance of about 3.0 km in southeast direction from the plant, which are well within the stipulated standards of Dubai Municipality.
2 Wastewater
The wastewater generated in the project consists of;
• Oily Wastewater from service area of the power plant;
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• Chemical dosing area of power plant;
• Condensate discharge from the steam generator;
• Closed cooling water system;
• Brine from desalination plant; and
• Sewage from the restrooms.
The wastewater generated in the power plant shall be treated in the Effluent Treatment Plant before sending it to desalination plant. The quality of the discharge shall comply with Dubai Municipality regulation applicable for the discharge into sea. The quality of condensate and discharge from closed cooling water system will be similar to sea water quality except for the higher temperature. These wastewater discharges shall be mixed with brine before discharging into sea through out fall point.
The domestic wastewater shall be treated in the Sewage Treatment Plant and treated wastewater shall be utilized in the landscaping.
3 Noise
The major noise generating equipment in the proposed facility will be pumps used in pumping of seawater and brine. These pumps will be designed for noise levels <85 dB (A) at 1 m from the equipment. These pumps will be provided with pump house with adequate acoustic to attenuate the noise levels. The noise levels shall fall below 70 dB (A) outside the pump house.
4 Solid waste
The solid waste shall be generated at the screening unit, where the debris from the seawater will be screened out. The solid waste will be sent to the E-4
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Executive Summary
solid waste shall be non-hazardous in nature and disposed off as per Dubai Municipality guidelines.
5 Salinity
Salt concentrations of the final effluent are above those of the receiving waters, and will be consistently between 1 and 2.5 ppt above the existing seawater background levels. In normal and minimal conditions, the salinity of the effluent at the exit of the outfall (end-of-pipe) will be less than a 5% increase above background seawater salinity. It is expected that at the edge of the mixing zone, the Dubai Municipality (DM) Marine Standard (no more than 5% in background concentration) would be respected at all conditions.
6 Chlorine
A chlorine generating system will produce the 0.1 to 0.15% sodium hypochlorite solution from seawater feed. This solution will be injected into the cooling tower and MED makeup streams on a continuous basis for a chlorine residual of 0.5 ppm in these flows.
7 Oxygen
The DEWA effluent will be aerated in a way that the dissolved oxygen (DO) concentration at the exit of the aeration basin would be at least 3 mg/l and at the edge of the mixing zone, the dissolved oxygen levels should be close to the background dissolved oxygen levels. The DO concentrations in the effluent should not cause any mortality and should not affect the marine organisms.
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8 Anti-scaling and antifoaming agents
Use of anti-scaling agents may lead to formation of orthophosphates from hydrolysis of polyphosphates. Orthophosphates are a macronutrient that may enhance biological growth (e.g. red and green algae). Polymeric additives based on polyacrylate or polycarboxylic acids prevent this problem, and are biodegradable and certified non-toxic .
Similarly, antifoaming agents are also degradable and non-toxic. Therefore anti-scaling and antifoaming agents will be selected to avoid polyphosphate formation and their impact on the marine environment will be considered negligible.
9 Heavy Metals
Discharged brine contains low concentrations of metal ions resulting from corrosion, namely copper, nickel, chromium and iron. These concentrations are profoundly increased with acid cleaning of the plants, which occurs once or twice per year.
Bioaccumulation of heavy metals in benthic fauna around the outfall could, in theory, occur. Nevertheless, heavy metal concentrations at the outfall would be very low due to the cooling water dilution, and below DM regulations. These metals are also normal constituents of the sea (even if in low concentrations) and are not of great concern except in extreme occurrences. If bioaccumulation would occur, it would be locally.
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10 Thermal Impacts
The use of seawater will result in a discharge seawater temperature will comply DM Standards. This small change in seawater temperature should not be of concern for the marine environment, keeping in mind the choice of the outfall location and design for the initial dilution
11 Socio economic
The new power plant will create new employment opportunities for approximately 200 qualified employees, who will most likely be living in downtown Dubai. Therefore the corresponding effect on population around the project area will not be significant.
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CHAPTER 1
Introduction
1.1 Preamble
The demand of power and water is rapidly increasing in Dubai Emirates due to growing industrial activities in the region. To meet the growing demand of waster and power, Dubai Electricity and Water Authority (DEWA) is proposing the Jebel Ali Power and Desalination Station ‘M’ in addition to the existing power project located adjacent to the project site. The project consists of power plant with capacity of 2000 MW, 140 MIGD desalination plant and 400 kV substation.
The Environmental Impact Assessment is carried out for the proposed project consisting of power having capacity of 2000 MW and 140 MIGD capacity desalination plant. The desalination plant shall cater the requirement of power plant and fulfill the water demand of Dubai city.
The power plant will be planned and built by M/s Doosan Heavy Industries & Construction Company. The Desalination plant shall be designed and constructed by M/s Fisia Italimpianti, Gruppo Impregilo. Both these companies retained M/s. Environmental International Consultants, Dubai to carry out the Environmental Impact Assessment (EIA).
The EIA shall be carried out as per the ETG 53 prescribed by Dubai Municipality for getting environment clearance. EIA report has been prepared in accordance with the Guidelines of Local Order 61 of 1991 published by Dubai Municipality (DM). The environmental impacts of the proposed project for the activities during construction as well as operation phase. As far as possible, these evaluations are quantitative and based on comparisons with relevant available standards specified by Dubai Municipality and International Organizations (WHO, World Health Organization, World Bank).
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1.2 Objective of the Study
EIA is a tool to assess the sustainability of the project with respect to benefits of the project and environmental issues. The objective of EIA is to improve the decision making process and to ensure that the project options under consideration are environmentally sound and sustainable. EIA identifies the ways to minimize the adverse impacts and identify the ways to improve the environment.
The advantages of an EIA are:
• It allows project designers and implementing agencies to address environmental issues in a timely and cost effective manner; • Reduces the need for the project conditionality since appropriate steps can be taken in advance or incorporated into project design or alternatives to the proposed project can be considered; and • Helps to avoid costs and delays in implementation due to unanticipated environmental problems.
The basic objective of conducting an EIA study for the proposed project is to rationalize the procedure for an effective environmental management plan, leading to an improvement in environmental quality as a result of constructing this power station.
1.3 Objective of the Project
Desalination capacities offered by the project are of basic importance for the future water supply needs of the Dubai. Therefore, type, size and location of the plant as well as the fuel to be used have been determined to meet necessary development in energy supply as well as the limitation or environmental impacts resulting from the plant.
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To meet the continuously growing requirement for water in Dubai, UAE, the Dubai Electricity and Water Authority (DEWA) is planning to extend the existing Jebel Ali Power and Desalination unit to have an additional installed capacity of 2000 MW power with 140 MIGD desalination plant.
1.4 Location and Accessibility
Proposed project is located in Dubai, U.A.E and is about 0.5 km from west of the Dubai-Abu Dhabi highway and adjacent to Jebel Ali Free Zone. The present location of the proposed project is shown in Figure 1.1 .
The proposed site is at the existing Jebel Ali Power Station Complex. The project location is already owned by DEWA.
The project site is located along the shore of the Arabian Gulf and adjacent to existing Jebel Ali ‘L’ power station. The new desalination plant will be part of the Jebel Ali Power Station.
Jebel Ali Power complex consist of the following operating units:
• Station ‘D’ Phase I , was built between 1976 and 1980. The plant consist of five steam turbine generators each of 68 MW capacity and five desalination plants producing in total 14.38 MIGD of water. During the years 1982 and 1983, two gas turbines each with a summer site rating capacity of 42.50 MW were added.
• Station ‘D’ Phase II , was built between 1981 and 1984. It consists of three steam turbine generators each of 75 mw capacity and three desalination plants producing in total 17.16 MIGD of water.
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FIGURE 1.1 PROPOSED PROJECT SITE
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• Station ‘E’ , consisting of three gas turbine generating plants each of 84 MW capacity (gross) at 50o C and four desalination plants producing 24 MIGD, was commissioned between 1989 and 1991. The station was extended by two gas turbine generators with a total site summer output of around 180 MW (gross). These two units were commissioned in 1992. The extension part was converted to combined cycle operation by adding heat recovery systems and a steam turbine generator of around 112 MW (gross) capacity, these being finally commissioned in 1996
• Station ‘G’ , consisting of four gas turbine generators having a total capacity of 457 MW (gross) and eight desalination plants producing 60 MIGD of water, was commissioned between 1993 and 1994.
• Station ‘G’ extension consists of one gas turbine generator and one WHRB of the same type as for Station ‘G’. The gas turbine generator has a capacity during summer of 121 MW (gross). In addition, the station possess two backpressure steam turbines each with a capacity of 71 MW and a further backpressure steam turbine with a capacity of around 58 MW located at E station. The units were commissioned between 1996 and 1997.
• Station ‘K’ Phase I plant was awarded at the beginning of 1999 and has two desalination units (10 MIGD each) associated with blending plant, potable water reservoir, and potable water pumps etc. The steam supply for these two desalination units was sourced from existing auxiliary boilers at ‘G’ Station until the new power plant ‘K’ Station Phase II took over the steam supply for the desalination units of Phase I & II.
• Repowering of ‘D’ Station Phase II was awarded in 1999 and comprises self contained gas turbine generator units (GT) having a total capacity of approximately 400 MW at 50o C ambient temperature net of all auxiliary power demands and losses, exporting to the existing Dubai grid and
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equipped with Waste Heat Recovery Boilers (WHRB) to generate steam by utilising all the waste heat available in Gas Turbine exhaust gas and supply steam to the existing three 75 MW steam turbines and three 5.75 MIGD desalination plants of Station ‘D’ Phase II plant.
• Station ‘K’ Phase II , was built between 2000 and 2003 and consists of three gas turbine generators with WHRB, two pressure steam turbines having a total capacity of 835 MW (gross) as well as three desalination plants producing 40 MIGD of water. The combined cycle power plant also supply low pressure steam for Station ‘K’ Phase I.
• Station ‘H’, Phase I , consisting of six simple cycle Gas Turbines suitable for quick starting & Peak shaving operations having a total capacity of 607 MW at 50 ° C ambient temperature, was commissioned between 1998 and 1999.
• Phase II , consisting of three simple cycle Gas Turbines suitable for quick starting & Peak shaving operations having a total capacity of 800 MW, to be commissioned between May 2006 and June 2006.
• Phase III , consisting of four simple cycle Gas Turbines suitable for quick starting & Peak shaving operations having a total capacity of 800 MW, to be commissioned by April 2008.
• Station ‘L’, Phase I , consisting of three Gas Turbines, three Waste Heat recovery Boilers, two Auxiliary Boilers, two Back Pressure Steam turbines and three Desalination Plants with a total capacity of 850 MW and 70 MIGD of water, to be commissioned between December 2005 and February 2006.
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• Station ‘L’, Phase II , consisting of four Gas Turbines, four Waste Heat Recovery Boilers. Two Auxiliary Boilers, two Condensing Steam Turbines and four Desalination Plants with a total capacity of 1200 MW and 55 MIGD of water to be commissioned between April 2007 and April 2008.
In total the Jebel Ali Power and Desalination Station has at the moment without the installation for ‘M’ Station a total installed capacity of 3833 MW power generation plus 188 MIGD water productions. Layout plan of the proposed Desalination plant is shown in Appendix 1 .
1.5 Methodology of EIA study
The proposed Desalination project is designated to be developed under the Local Order 61/1991 of Environmental Protection and Safety Section, which is guided by Technical Guideline 53 for Environmental Impact Assessment Procedure by Dubai Municipality.
This report presents the results of the EIA process, which is intended to:
• Establish and review existing conditions pertaining to the plant site and surrounding areas; • Identify and assess the environmental impacts during construction phase and subsequently during operation phase; and • Advise and assist in identifying appropriate measures to mitigate adverse impacts to be adopted under Environment Management Plan (EMP) for all specified significant environmental impacts likely to emerge.
1.6 Approach of the EIA study
EIC has adopted stepwise screening procedures for environmental impacts identification and assessment. This report on EIA is based on the observations made by the EIC team during visits to the study area and
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collection of available environmental data from secondary sources. Literature has also been reviewed and relevant information has been collected for environmental and social baseline. Reconnaissance surveys have been conducted to identify the major environmental and safety issues from the proposed project.
EIC has followed the standard EIA methodology and technique during the entire study and whenever necessary it has used its own judgment based on its own experience and knowledge. During the entire study appropriate quality checks have been taken into consideration and best management practices have been followed for a quality output.
Impacts are identified based on the actual and foreseeable events, including operational events and typical events of the proposed expansion. Processes that may create risks to the natural environment are considered in terms of key potential environmental impacts. Mitigation measures to be adopted under Mitigation Management Plan for all specified significant environmental impacts likely to result during the construction and subsequently during operation, is also a part of the EIA report. The likely impacts identified and recommended mitigation measures are based on the following:
• Project information provided by project proponent; • Baseline information and reconnaissance survey of the study area; • EIC ’s past experience on similar projects; and • Standard National/International environmental management guidelines/ practices.
1.7 Structure of Report
This report is structured based on the table of contents suggested in ETG 53 by Dubai Municipality. A brief description of each chapter is presented below;
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Executive Summary Presents significant findings and recommended actions. Chapter 1 Introduction Presents, an introduction along with scope and objective of this EIA study. Chapter 2 Policy and Legal Presents, Policy, legal, and administrative Framework framework applicable to the proposed project. Chapter 3 Project Presents, project details with regards to the Description proposed project. Chapter 4 Baseline Study Presents, description of existing environment based on monitoring / collection and evaluation of baseline data. Chapter 5 Environment Presents, the significant environment Impact impacts of proposed project with respect to Assessment air, water, soil, noise, solid waste and Terrestrial and Marine ecological environment. Chapter 6 Mitigation Presents, the followings: Measures • Mitigation Management Plan during construction and operation of the proposed project. • Environmental Monitoring Plan Appendices
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Policy and Legal Framework
2.1 Preamble
The proposed power plant and desalination plant is designated to be developed under the Local Order 61/1991 of Environmental Protection and Safety Section.
The environmental health and safety department, Dubai Municipality has developed environmental control rules, standards and guidelines for air, water pollution management, dangerous/hazardous materials, solid wastes, noise control for environmental management. These requirements are finalized in close coordination with Federal Environmental Agency or Federal Environmental law would be dealt with penalties as per EHS rules.
These guidelines give the authority to:
Issue environmental permits to the entity responsible for undertaking any enterprise;
• Issue permits for discharge of trade waste/hazardous waste water, domestic and hazardous solid waste; • Request information as the authority thinks fit; • Request Environmental Impact Assessment report containing relevant information; • Request information on pollution control activities; • Issue an annually renewable Operation Fitness Certificate (OFC);and • Revoke or suspend permits.
2.2 Guidelines
The owner of a works shall use the Best Practicable Environmental Option (BPEO) for preventing the discharge of noxious or offensive substances into
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Policy and Legal Framework
environment from the premises and for rendering harmless and inoffensive such substances as may be so discharged. Whether or not a substance is noxious or offensive shall be in the judgement of the authority and shall include gases, vapours, smoke, grit, fume, noise, solid and liquid wastes etc.
The EHS department, Dubai Municipality has prepared Environmental Technical Guidelines (ETGs) for specific facilities and concerns which need to be addressed. The following EHS guidelines shall be applicable for the proposed facility during operation:
• ETG 53, Environmental Impact Assessment Procedure by Dubai Municipality; • ETG 1, Application for waste discharge permits to sewer, land and marine environment by Dubai Municipality; • ETG 3, Guidelines for safety audit report by Dubai Municipality; • ETG 7, Heat Stress at Work by Dubai Municipality; • ETG 8, Entry into Confined Space by Dubai Municipality; • ETG 10, Guarding of Dangerous Machinery by Dubai Municipality; • ETG 13, Industrial Wastewater Disposal by Dubai Municipality; • ETG 14 - 21, Personal Protective Equipments by Dubai Municipality; • ETG 25, First aid requirements by Dubai Municipality; • ETG 26, Application for approval of disposal of hazardous wastes by Dubai Municipality; • ETG 27, Annual approval for hazardous waste disposal by Dubai Municipality; • ETG 28, Waste minimization by Dubai Municipality; • ETG 29, Requirements for the Discharge of Waste Gases, Fumes and Dusts to the Atmosphere by Dubai Municipality; • ETG 34, Requirement for the use of Waste Oil in Boilers and Furnaces;
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Policy and Legal Framework
• ETG 37, Transport of Non-hazardous wastewater by tanker vehicles by Dubai Municipality; • ETG 40, Examination and Certification of Boilers and Pressure Vessels; • ETG 44, Requirement for Reduction of Construction/demolition noise; • ETG 45 , Requirements for the Control of Entertainment Noise by Dubai Municipality; • ETG 49, Hazardous waste exemption policy by Dubai Municipality; • ETG 50, Requirements for transport of hazardous waste by Dubai Municipality;
2.3 Standards
The following EHS standards are / shall be applicable during the construction and operation of proposed desalination plant project:
• Environmental Standard and Allowable Limits of Pollutants on Land, Water and Air environment (May, 2003) by Dubai Municipality; and • Final Air Pollution Law, 2006 by FEA.
2.3.1 Ambient Air Quality Standards
The ambient air quality standards are given in Table-2.1. TABLE-2.1 AMBIENT AIR QUALITY STANDARDS
Allowable Limit (max.) Sn Pollutant Average Time µg/m 3 ppm 350 0.13 1 hour
1 Sulphur Dioxide (SO 2) 150 0.06 24 hours 50 0.02 1 year 23000 20 1 hour 2 Carbon Monoxide (CO) 10000 7 8 hours
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Allowable Limit (max.) Sn Pollutant Average Time µg/m 3 ppm 290 0.15 1 hour 3 Nitrogen Dioxide (NO 2) 110 0.06 24 hours 160 0.08 1 hour 4 Ozone (O 3) 120 0.06 8 hours 230 - 1 hour 5 TSPM 90 - 24 hours 300 - 1 hour
6 PM 10 150 - 24 hours 0.5 600 3 months Prescribed by FEA.
2.3.2 Ambient Noise Level The standards are presented in Table- 2.2.
TABLE-2.2 STANDARDS FOR AMBIENT NOISE LEVELS
Allowable Limits for Noise Level dBA* Sn Area Day Night 7 a.m-8 p.m 8 p.m-7 a.m 1 Residential areas with light traffic 40-50 30-40 2 Residential areas in downtown 45-55 35-45 Residential areas which includes some workshops & commercial 3 50-60 40-50 business or residential areas near highways 4 Commercial areas & Downtown 55-65 45-55 Industrial Areas Fence lines (Heavy 5 60-70 50-60 industry) *Prescribed by FEA.
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2.3.3 Wastewater Discharge Limits
Permissible limits for aqueous discharges to land and into the sea are listed in Table-2.3 and Table-2.4 respectively .
TABLE 2.3 LIMITS FOR DISCHARGES INTO THE MARINE ENVIRONMENT
Permissible Emission Limit to Parameter Units Marine Environment pH - 6 – 9 Suspended Solids mg/l 25 Turbidity NTU 75 B.O.D. mg/l 20 C.O.D. mg/l 125 Oil and Grease mg/l 10 Phenols mg/l 0.1 Ammonia as N mg/l 2.0 Total Organic Carbon mg/l 75 Sulphides as S mg/l 0.1 Cyanides as CN mg/l 0.1 Residual Chlorine mg/l 1.0 Cadmium (Cd) mg/l 0.05 Chromium (Cr) mg/l 0.50 Copper (Cu) mg/l 0.50 Iron (Fe) mg/l 2.0 Lead (Pb) mg/l 0.10 Mercury (Hg) mg/l 0.001 Nickel (Ni) mg/l 0.10 Selenium (Se) mg/l 0.02 Silver (Ag) mg/l 0.005 Zinc (Zn) mg/l 0.10
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Permissible Emission Limit to Parameter Units Marine Environment Faecal Coliforms MPN/ 100 ml 1000 Source : Federal Regulation of Law No. 24, 1999.
TABLE 2.4 DUBAI MUNICIPALITY WASTEWATER DISCHARGE STANDARDS
Maximum Allowable Limits Discharged to Sr. Parameters Unit Land as for No. Sewerage Irrigation System Drip Spray Physical-Chemical Biochemical Oxygen 1 Mg/l 1000 20 10 Demand Chemical Oxygen 2 Mg/l 3,000 100 50 Demand 3 Chlorides Mg/l - 500 350 Not less than 0.5 mg/l 4 Chlorine – residual Mg/l 10 after 30 min contact time 5 Cyanides as CN Mg/l 1 0.05 0.05 6 Detergents Mg/l 30 - - 7 Fluorides mg/l - 1 1 8 Nitrogen, ammoniacal Mg/l 40 5 1 Nitrogen, organic 9 Mg/l - 10 5 (Kjeldhal) 10 Nitrogen, total Mg/l - 50 30 11 Oil & Grease – Emulsified Mg/l 150 - - 12 Oil & Grease – Free oil Mg/l 50 5 5 13 pH (range) units 6 – 10 6.0–8.0 6.0–8.0 Pesticides, non- 14 Mg/l 5 - - chlorinated
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Maximum Allowable Limits Discharged to Sr. Parameters Unit Land as for No. Sewerage Irrigation System Drip Spray 15 Phenols Mg/l 50 0.1 0.1 16 Phosphorous (P) Mg/l 30 20 20 17 Sulfates, total Mg/l 500 200 200 18 Sulfides as S Mg/l 10 0.05 0.05 19 Surfactants Mg/l - - - 20 Suspended Solids (SS) Mg/l 500 50 10 45 or > 5 of 21 Temperature 0 C - - ambient 22 Total Dissolved Solids Mg/l 3,000 1,500 1,000 Metals 23 Total Metals Mg/l 10 - - 24 Aluminum (Al) Mg/l - 2 2 25 Arsenic (As) Mg/l 0.50 0.05 0.05 26 Barium (Ba) Mg/l - 1 1 27 Beryllium (Be) Mg/l - 0.1 0.1 28 Boron (B) Mg/l 2.0 2.0 2.0 29 Cadmium (Cd) Mg/l 0.3 0.01 0.01 30 Chromium (Cr) Mg/l 1.0 0.1 0.1 31 Cobalt Mg/l - 0.1 0.1 32 Copper (Cu) Mg/l 1.0 0.2 0.2 33 Iron (Fe) Mg/l - 2.0 2.0 34 Lead (Pb) Mg/l 1.0 0.5 0.5 35 Magnesium (mg) Mg/l - 100 100 36 Manganese (Mn) Mg/l 1.0 0.2 0.2 37 Mercury (Hg) Mg/l 0.01 0.001 0.001 38 Molybdenum (Mo) Mg/l - 0.01 0.01 39 Nickel (Ni) Mg/l 1.0 0.2 0.2 40 Selenium (Se) Mg/l - 0.02 0.02
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Maximum Allowable Limits Discharged to Sr. Parameters Unit Land as for No. Sewerage Irrigation System Drip Spray 41 Silver (Ag) Mg/l 1.0 - - 42 Sodium (Na) Mg/l - 500 200 43 Zinc (Zn) Mg/l 2.0 0.5 0.2 Bacteriological MPN/100 44 Fecal Coliforms 500 20 - ml.
2.3.4 Solid Waste
The standards are applicable for different usages of solid wastes (hazardous and non-hazardous) are given in Table 2.5.
TABLE 2.5 LIMITS OF TRACE METALS IN SLUDGE INTENDED FOR DISPOSAL ON LAND
10 year cumulative Maximum Limit Sn Contaminant loading on land (mg/kg) (kg/hectare) 1 Cadmium 30 20 2 Chromium 1,000 200 3 Cobalt 100 30 4 Copper 1,000 50 5 Lead 1,000 125 6 Mercury 10 5 7 Molybdenum 20 5
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10 year cumulative Maximum Limit Sn Contaminant loading on land (mg/kg) (kg/hectare) 8 Nickel 200 100 9 Zinc 1,000 250 Note * Where disposal is for the purpose of soil conditioning as in the use of compost or fertilizer for agricultural activity. In any case, disposal to land must have prior written approval from EPSS.
The indicator levels are adopted as the objectives for contaminants not to exceed for the land environment due to impact of human activities are given in Table 2.6.
TABLE 2.6 LAND CONTAMINATION INDICATOR LEVELS Sn. Parameter Acceptable Level (mg/kg) 1 Arsenic 50 2 Barium 400 3 Cadmium 5 4 Chromium 250 5 Copper 100 6 Lead 200 7 Manganese 700 8 Mercury 2 9 Selenium 2 10 Zinc 500 11 Cyanide 10 12 Fluoride 500 13 Phenols 1 14 Benzene 1 15 Chlorinated Hydrocarbons 1
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16 Pesticides (Total) 2 17 Polychlorinated Biphenyls (PCBs) 0.5 Total Petroleum Hydrocarbons 18
2.4 ISO 14000
DEWA, the owner and operator of Jebel Ali Power Station, is an ISO 14001 certified company (Environmental Management System). Further, proposed project shall also comply with the ISO 14001 requirements.
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3.0 Project Characteristics
3.1 Outline and Rationale of the Project
The proposed Power plant of 2000 MW and Desalination plant of 140 MIGD capacity is of basic importance to meet the increased demand of power and drinking water requirement of UAE. Therefore, type, size and location of the plant have been determined to meet both, the necessary development in public water and energy supply as well as the limitation or environmental impacts resulting from the plant.
3.2 Plant Layout and Land Requirement
The proposed desalination plant is located along the shore and power plant is located adjacent to the desalination plant.
The total land required for the project is about 218250 m 2. The water supply pipelines and brine discharge pipelines are laid along the length of the plant boundary parallel to sea shore.
The desalination plant is part of the Power Station ‘M’, therefore it is located near the power station and no alternate site was identified.
All considerations made in this report regarding environmental impact are based on the power plant of 2000 MW capacity and desalination plant of 140 MIGD capacity.
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3.3 Project Description – Power Plant (2000 MW)
The power plant of Jebel Ali ‘M’ extension includes three modules and each module consist of two gas turbines, two heat recovery steam generators (HRSG) and one steam turbine. All considerations in the present report are based on this configuration.
The gas turbines can be operated with supplementary firing into the HRSG for additional steam production. For supplementary firing, solely natural gas will be used.
The gas turbines will also be operated with natural gas supplied by gas pipeline connection. In emergency cases and for the unlikely event of a natural gas shortage, the gas turbines can also be operated with Diesel oil.
Table 3.1 presents the reference parameters for the calculation of emissions represent the worst case normal operation scenario at full plant load firing natural gas in summer (ambient Temperature 50° C) with full supplementary firing.
TABLE 3.1 PARAMETERS FOR THE CALCULATION OF EMISSIONS
S. Parameters for the Operation Condition No. Calculation of Emissions Exhaust gas mass flow related to each gas 1 608.33 kg/s turbine Exhaust gas emission temperature after 2 118.4°C HRSGs 3 Residual oxygen concentration in exhaust gas 11.5 vol %
Guaranteed NO X emission level in gas turbine 4 25 ppm, dry, at 15 % O 2 exhaust gas
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S. Parameters for the Operation Condition No. Calculation of Emissions Guaranteed CO emission level in gas turbine 5 15 ppm, dry, at 15 % O 2 exhaust gas 6 Particulates (ash) content of natural gas fuel Negligible 7 Exhaust gas density 0.9 kg/m 3 8 Exhaust gas velocity at stack mouth 17.5 m/s
Diesel oil will only be used as backup fuel in emergency cases, during temporary failure of the natural gas supply. Therefore operation on diesel oil is not considered as normal operation and the detailed investigation of environmental impacts will focus on operation with natural gas fuel. Due to new gas supply agreements recently made with suppliers from outside UAE, a failure of the gas supply in the future is considered very unlikely.
The operation of the plant on Diesel oil will be minimized and restricted to
emergency cases, considering the fact that higher emissions of NO X and SO X are present in this case. However, in view of change in diesel fuel specifications by the UAE government restricting the sulphur content to a maximum of 0.05% the sulphur emission is expected to comply with DM regulations on stack emissions.
3.3.1 Main Systems / Components
In order to achieve a net Output of approximately 2000 MW, six gas turbines
will be installed in M station. The GTs will be equipped with dry low NO 2 combustion chambers for natural gas and Diesel oil fuel operation. No
injection water or steam injection facilities will be foreseen for NO 2 reduction in case of diesel oil operation (only emergency cases).
The auxiliary boilers and the supplementary firing facilities will be also
equipped with low NO 2 combustion facilities .
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Each of the gas turbines (GTs) will be equipped with an individual Heat Recovery Steam Generator (HRSG) adequately sized for the related GT, so that identical HRSGs, will be installed. The GTs will be provided with bypass stacks to allow GT operation independent from the operation of the HRSG in emergency cases.
All gas turbines have to be equipped with air inlet cooling system. The plant/unit capacity at 50 o C shall be achieved at normal GT Turbine Inlet Temperature (TIT) and not of increased TIT (peak load operation). The heat of the exhaust gases shall be utilized in the respective heat recovery steam generators.
The heat of the exhaust gases will be utilized in the respective heat recovery steam generators. The HRSGs will be of two pressure type with supplementary firing and shall be designed for an optimum utilization of the exhaust heat. The summary of operating conditions at main stack and bypass stack is attached as Appendix 2.
3.3.2 Modes of Operation
The plant shall be designed to ensure flexibility of operation, a high level of fault tolerance and ease of maintenance. It shall meet the following operational and design requirements.
• Each gas turbine generator shall be capable of operating in open cycle independent of the steam generation plant;
• Each HRSG shall be capable of being started up as the first and subsequent steam generator from any condition of GT loading within predetermined thermal stress margins an a run up time to full load agreed as being operationally acceptable;
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• Each GT/HRSG unit shall be capable of being operated at part load in conjunction with other units operating at full or near full load continuously without detriment to plant life expectancy;
• Each HRSG or GT/HRSG unit shall be capable of independent shut down;
• Each steam turbine shall be capable of operating from minimum load up to maximum load. In the event of a steam turbine trip, the unit is to transfer to steam turbine by-pass mode automatically without loss of water production;
• The duct burners shall cut in automatically in case of steam generated in the HRSG from waste heat in the gas turbine exhaust is not sufficient to maintain steam turbine output.
3.3.3 Abnormal operating modes
The plant will be designed to operate satisfactorily under automatic control without undo perturbation of the steam temperature and pressure under all normal operational transients arising, for example, from the bringing into or out of service of a gas turbine, HRSG unit or a steam turbine. Furthermore, the Station shall satisfactorily run under automatic control and without direct operator intervention during such fault conditions which be reasonably anticipated, including the following:
• A trip of one power plant block from full or part load; • A gas turbine generator trip from full or part load when either operating in open or closed cycle; • A HRSG trip any load with or without auxiliary firing; • When auxiliary firing is tripped and HRSG is still in service; • A steam turbine trip from full or partial load;
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• The loss of the normal fuel gas supply to the Station and transfer to the diesel oil stand-by system; • In the event of full or partial load rejection of single GT unit, that unit shall continue to operate at synchronous speed, feeding its own auxiliaries. The unit shall be capable of resynchronized and reloaded to MCR at the maximum loading rate.
In the event of a trip of a gas turbine and/or a HRSG, the associated steam turbine shall continue to operate at reduced output. If applicable (for example only one GT/HRSG was in operation) trip of the steam turbine shall be delayed as much as possible after the GT trip. The steam turbine shall be restarted using steam generated once the required steam conditions have been established.
The impact on plant operation of any other major fault conditions shall be minimized and the control strategy of the plant shall ensure an orderly and effective recovery from such conditions.
3.4 Project Description – Desalination Plant
The seawater desalination plant shall consist of eight desalination units having capacity of 17.5 MIGD each. This will result in total desalination plant capacity of 140 MIGD.
The proposed desalination plant will be operated on Multi Stage Flash (MSF) process. In this process, two types of operations are available i.e.
1 Multi Stage Flash Once through desalination process; and 2 Multi Stage Flash process with brine recirculation.
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The proposed plant will be operated on Multi Stage Flash with brine circulation process.
Multi Stage Flash Process with Brine Circulation
In Multi Stage Flash process, an evaporator consists of several consecutive stages (evaporating chambers) maintained at decreasing pressures from the first stage (hot) to the last stage (cold). Sea-water flows through the tubes of the heat exchangers where it is warmed by condensation of the vapour produced in each stage. Its temperature increases from sea temperature to inlet temperature of the brine heater. The sea water then flows through the brine heater where it receives the heat necessary for the process (generally by condensing steam). At the outlet of the brine heater, when entering the first cell, sea water is overheated compared to the temperature and pressure of stage 1. Thus it will immediately "flash" i.e. release heat, and thus vapour, to reach equilibrium with stage conditions. The produced vapour is condensed into fresh water on the tubular exchanger at the top of the stage. The process takes place again when the water is introduced into the following stage, and so on until the last and coldest stage. The cumulated fresh water builds up the distillate production which is extracted from the coldest stage. Sea water slightly concentrates from stage to stage and builds up the brine flow which is extracted from the last stage. The typical drawing process flow diagram of MSF is given in Figure-3.1.
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FIGURE 3.1 PROCESS FLOW DIAGRAM OF MSF WITH BRINE CIRCULATION
The desalination units shall be of the Multi Stage Flash type with brine recirculation of cross tube and single deck design.
The once-through flash type evaporator uses the sea-water flow both for purposes of cooling (sea-water is introduced into the evaporator at the sea temperature and is rejected at the brine temperature) and production of distillate (by flashing from the outlet temperature of the brine heater to the brine extraction temperature). This has two consequences on plant design:
• The whole sea water flow being heated to high temperature, it has to be treated with anti-scale which increases operating costs. • As the sea water flow cannot be decreased below values allowing safe working conditions, the stages must be designed for winter operation, leading to an increased evaporator volume and thus increased investment costs.
These two points have led to the separation of the two functions (cooling and production).
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The cooling sea-water flows through the condensers of the two (or generally three) last stages, named "heat reject section". Upon leaving the evaporator, part of the warmed water is rejected to sea; part is used as the make-up for the plant. Only this part of the water is treated instead of the whole cooling water. The production is insured by the brine recycling flow that is drawn from the last stage towards the condensers of the other stages, named "heat gain section", and then to the brine heater.
The warmed water leaving the heat reject section may be used in winter to warm up the cooling sea-water, thus enabling the evaporator volume to be designed for a reasonably high temperature.
MSF plants with brine recycling are widely used all over the world. Once- through desalination plant should only be used for small plants (when the cost of the chemicals is not of great importance) and in areas where the temperature of the sea-water remains approximately constant throughout the year.
3.4.1 Details of Proposed Desalination Plant
Each distiller unit consists on a multistage flash evaporator chamber with its auxiliary and ancillary equipment.
The evaporator is a Multi Stage Flash type (MSF) with brine recirculation and of cross tube single tier design. An anti scale system is used to treat the recirculating brine in the whole temperature operating range of the evaporator. The distillate produced by the eight desalination units is sent to the product water system and Blending Plant. Each Unit can be subdivided from the functional point of view in the following sections: • Brine Heater Section; • Heat Recovery Section; and • Heat Reject Section
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The process is based on the recycle of the brine in the recovery section where the latent heat of condensing vapour is recovered by increasing the temperature of the brine recirculating in the condensers tubes. The heat input to the system is supplied by the low pressure steam coming from the Power Station (Package P) and the Auxiliary Boilers System to the Brine Heater in which the brine flowing in the tube side is heated up to Top Brine Temperature. One evaporation unit will be operated on steam procured from existing Power Station ‘L’. The heated brine then passes through all the stages where it flashes because of the higher temperature in respect of the brine flowing inside the tube bundle.
This “flashed off” vapour rises through the tube bundle and condenses on the tubes surface. The condensed water, called distillate, falls into a dedicate tray and it is collected together with distillate coming from the other stages and then sent to the distillate extraction pumping system.
The salt concentration of the recirculating brine is kept at the required value by a continuous blow down of the concentrated brine and a congruent feed of make-up sea water, which is deareted and treated with antifoam additive prior entering the evaporator. Sodium Sulphate is also used as oxygen scavenger in brine recycle line to recovery section. Most of the evaporator chambers operate under vacuum; in order to maintain the vacuum condition, leakages and non-condensable gases released from feed sea water are purged to atmosphere by a dedicated vacuum system (ejectors and condensers system).
• Discharge System
The discharge system includes one barometric pit system and one drain pit for each distiller and the outfall system with provisions for the eight units of M Station and all Power Plant discharges. For each unit, the relevant barometric pit collects all condensate discharges and drains from the three exchangers of 3-10 EIA study for the proposed Jebel Ali Power and Desalination Station M CHAPTER 3
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the vacuum system and it is equipped with of two sump pumps one on duty and one in stand by mode to send the vacuum system discharges to drain pit. The drain pit collects the discharges from the distiller and the M. P. steam condensate from the steam trap on the vacuum system steam supply line. The discharges of two units are collected together and sent to outfall.
3.5 Operational Features of the Project
3.5.1 Fuel
At present DEWA utilizes Natural Gas (NG) as primary fuel and Diesel Oil (DO) as secondary fuel. The natural Gas fuel is arranged by Dubai Supply Authority (DUSUP) from different sources. For the Jebel Ali ‘M’ project natural gas shall be used as primary fuel and diesel oil shall serve as back up fuel. The gas turbines and the heat recovery steam generators will be operated with natural gas as a main fuel. The gas turbines and the auxiliary boilers will be able to use Diesel oil if required while the duct burners of the HRSG’s (for supplementary firing) will be designed for natural gas operation only.
The gas supply system will be designed to handle the fuel demand when the gas turbine and the supplementary burning system are operating at maximum consumption.
The Diesel oil storage tank capacity will be sufficient for 8 days continuous operation of the plant considering full load of the gas turbines with condensing steam turbine at design conditions. When the supplementary firing is out of service, the auxiliary boilers will be operated to produce the additional steam flow required for 100% water production. As the auxiliary boilers are also
equipped with low NO X combustion facilities, the specific pollutant emission rates at auxiliary boiler operation will be similar as with supplementary firing.
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The Characteristics of Natural Gas and Diesel is given in Table-3.2 and Table-3.3.
TABLE 3.2 NATURAL GAS ANALYSIS
S.No Component Unit Value
1 Nitrogen Mole % 0.408
2 Methane Mole % 90.09
3 Carbon di oxide Mole % 4.257
4 Ethane Mole % 3.669
5 Propane Mole % 1.186
6 I – Butane Mole % 0.211
7 N – Butane Mole % 0.249
8 I – Butane Mole % 0.054
9 N – Butane Mole % 0.038 H2S content (maximum 10 ppm 135 250 ppm) 11 Ideal relative density (air 1) Kg/m 3 0.63394 Ideal Gas Density @ 12 Ib/ft 3 0.04838 14.696 Psia & 60 o F Ideal Net Calorific Value at 13 BTU/ft 3 921.15 14.696 Psia & 60 o F Ideal Total Calorific Value 14 BTU/ft 3 1020.92 at 14.696 Psia & 60 o F
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TABLE 3.3 THE TYPICAL DIESEL OIL ANALYSIS
Description Unit Specification Typical Low Heating Value (LHV) MJ/kg min 42.3 42.7 High Heating Value (HHV) MJ/kg min 45.0 45.7 Specific gravity at 60°F - 0.83 – 0.8 0.85 API gravity deg min 30 35.5 Flash point °C min 65 69 Pour point °C max -3 - Kinematic Viscosity at 50° C cSt 2.0 – 5.5 2.8 Kinematic Viscosity at 37.8°C cSt 3.2 - 5.8 3.8 Distillation • I.B.P. °C - 155 • 10% evaporated °C - 231 • 20% °C - 264 • 50% °C - 292 • 90% °C - 338 • FBP °C - 369 • Residue % - 1.0 • Loss % - <0.5 Water wt% max 0.05 < 0.05 Sediment wt% max 0.01 0.005 Sulphur, Total wt% max 0.25 0.25 Mercapatan sulphur ppm - 25 Aromatics vol% - 18 Olefins vol% - Nil Asphaltene wt% Nil <0.05 Carbon residue on 10% residue wt% max 0.1 0.035 Diesel index - min 55 - Cetane index - min 50 - Copper strip corrosion (3 h.v. at - - No. 1 100°C) Ash ppm max 100 25
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Description Unit Specification Typical Calcium ppm - 1 Lead ppm - Nil Sodium & Potassium ppm max 1.0 - Vanadium ppm max 0.5 - Total carbon wt% - 85.85 Hydrogen wt% - 13.25
3.5.2 Chemicals
Small amounts of dosing and treatment chemicals will be stored in the chemical stores for operation of the power facilities. Dosing quantities are manually regulated as per results of the water sample analyses.
Trisodiumphosphate (Na 3PO 4) solution will be dosed into the boiler drums to prevent the precipitation of carbonate hardness traces within the boiler water and for pH adjustment.
Ammonia (NH3) will be dosed into the boiler feed water as volatile alkalizing agent for pH adjustment and corrosion inhibition. The pH of the process water will be adjusted to 8.5 – 9.0 which will prevent corrosion within the water/steam cycle.
A corrosion inhibitor (e.g. NaOH) will be dosed into the closed cooling system to ensure an adequate pH value in the system water which prevents material corrosion.
All dosing devices will be placed in the turbine house building and will comprise chemical unloading facilities, chemical storage tanks, transfer and dosing pumps, dosing pipelines, injection facilities and control equipment.
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A suitable amount of all chemicals needed for the operation of the Jebel Ali ‘M’ CCPP will be stored inside a separate storage building at site (chemical storage building) Ammonia and Hydrazine will be stored as aqueous solutions with a chemical content of approx. 25 % wt.
3.6 Water System
The project consists of many units which are discussed in subsequent sections:
1 Seawater Screening System
The seawater received from transition bay from the intake channel shall be passed through screening trains installed in the screening and pumping station to remove all kinds of debris having particle size larger than 2 mm. Each screening train shall be divided into two sections;
• Bar Screen with revolving rake; • Traveling band screen with spray water system. The debris collected in the screening plant shall be transported with spray water via a conveyor through and special sluice gates to trash containers equipped with dewatering sieve. The wastewater collected from the containers shall be pumped back to sea via the discharge culverts/outfall structure. The debris collected shall be transported to disposal area.
The clear seawater shall be treated by hypochlorite solution to control organic substances and the growth of mussels, barnacles etc. Dosing shall take place continuous (0.5 to 1.0 ppm) and shock dosing (5 ppm) behind the bar screens and in the seawater pumped streamlines to the individual plants.
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2 Seawater Filtration and Chlorination
The seawater from the screen unit shall be passed through gravel filters of 2 x 100% for automatic operation and backwash.
The filtered water shall be treated with chlorine to disinfect before routing it to desalination plant.
3 Water Intake
The total water requirement of the desalination plant shall be 310,000 m 3/hr and same shall be met from the sea. The water intake point is about 500 m from the plant and water shall be transported through channel. The existing water intake structure of Package L shall be augmented for the purpose of proposed desalination plant by adding water channel, pumping system and screening unit etc.
4 Outfall unit
The total expected brine generation shall be 197,392m3/hr from the desalination plant i.e. 24674 m3/hr from each 17.5 MIGD unit. The brine shall be transported through pipeline to outfall point, which is located in SW of the project.
3.7 Wastewater Treatment System
The wastewater originating from the power plant only, can be classified into two categories such as oily wastewater and chemical wastewater.
The oily wastewater will be collected from the following location.
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• Oily water from oily wastewater disposal system - About 15 m 3/hr of wastewater will be generated in the power plant.
The chemical wastewater will be collected from the following locations of the power plant area.
• Chemical wastewater from chemical waste water disposal system. • Chemical wastewater from fire water collection basin.
The total chemical wastewater generation in the proposed power plant will be 20 m 3/hr.
The treated oily wastewater and chemical wastewater will be routed to the waste water collecting and monitoring basin for the final discharge. The quality of the wastewater prior to the treatment is given in Table- 3.4.
TABLE 3.4 QUALITY OF THE WASTEWATER PRIOR TO THE TREATMENT Sr. No. Parameters Oily wastewater Chemical wastewater 1 Flow 15 m 3/hr 20 m 3/hr 2 pH 6 – 8 2 – 12 3 COD 100 100 4 Oil 100 100 5 Suspended Solids 100 200
The proposed wastewater treatment P & I diagram is attached as Appendix- 3.
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3.7.1 The Treatment for the Oily Wastewater.
1 Portable Oil Skimmer
The initial suspended oil will be drawn by rotating high adhesive nitrite belt equipped in oil skimmer that is located on the oily water collecting basin.
The skimmed oil gravitates to the skimmed oil tank while the separated excess water drop back to oily water collecting basin, flow quantity is controlled by the oil dam equipped in oil skimmer.
Once oil skimmer is started, it always works except for the case of shut down.
2 Oil Water Separator
The oily water transfer pump shift the composite homogenized oil-water emulsion to the oil water separator at the constant rate, so as to separate the residual tiny oil in the water that is not removed with oil skimmer.
The oily water flows into the EPS oil water separator that consist of number of corrugated plate mounted parallel to each other at a space. When the raw waste water containing the oil passes between the plates (laminar flow is mandatory for the proper functioning of the operation) in the course of passing from EPS pack inlet to EPS pack outlet, the oil float upwards into the top of EPS pack and rise up the incline of the plates to the surface of the system where it can be removed by pipe oil separator.
The treated water will be overflowed to the waste water collecting and monitoring basin by gravity after the oil content is reduced to less than 5ppm. The skimmed oil shall be collected in the skimmed oil tank for disposal by truck. The oil sludge is displaced to the oil sludge tank periodically by the operator. 3-18 EIA study for the proposed Jebel Ali Power and Desalination Station M CHAPTER 3
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3.7.2 Treatment for Chemical Wastewater
1 Chemical Wastewater Buffer Basin
The chemical wastewater from acid dosing, NaOH dosing, alum dosing and polymer dosing units will be collected in the buffer basin. This basin is to collect and store chemical wastewater from chemical wastewater disposal system and fire water collecting basin. The first operation is to provide adequate flow to compensate the daily fluctuation of chemical wastewater from the various sources.
By means of air blower, scour air keep steering the liquid to prevent settling of denser material inside the basin. Also, scour air also helps in removing the volatile substance present in wastewater.
By means of two numbers of chemical w/w transfer pump that are controlled by the level transmitter, chemical wastewater is transferred to reaction basin. This contain following functions: • To provide adequate flow to compensate the daily fluctuation of chemical wastewater from the sources. • To homogenize chemical wastewater from the sources.
2 Reaction Basin and Flocculation Basin
This is main equipment in wastewater treatment system. The debris and dense material is removed by means of chemical cohesion. The pumped raw chemical wastewater initially enters a reaction basin at the constant rate where it is mixed with the injected chemicals from chemical dosing equipment by mix on the basin.
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Because zeta potential is reduced and cohesion is increased by chemicals, colloidal pollutions are cohered rapidly. Commonly alum is used and the reaction of cohesion is as following:
· Al 2 (SO 4)3 18 H 2O + 3 Ca (HCO 3)2 → 2Al (OH) 3↓ + 3CaSO 4 + 6CO 2 + 18H 2O
The formed floc in the reaction basin overflows to flocculation basin where it grows big and heavy by reacting with the polymer from polymer dosing equipment. The function of flocculation basin is to remove colloidal pollutions by means of chemical cohesion.
3 Sedimentation Basin
The mixed liquor is now flow to sedimentation basin, the velocity is reduced and the activated sludge is separated from the secondary effluent.
The secondary effluent discharge from the sedimentation basin via an over flow weir into the waste water collecting and monitoring basin.
The sludge is settled and stored up in the centre of hopper by means of rotating scraper, from where it is shifted by gravity to sludge thickening basin. The function of sedimentation basin is to separate water and sludge by means of the difference of specific gravity.
4 Sludge Thickening Basin
The collected sludge is disposed in the sludge storage tank. When it is filled, the sludge is discharged by means of thickened sludge pumps. Scour air keep steering the liquid to prevent settling of denser materials inside the tank. The function of the sludge thickening basin is to store and thicken the sludge.
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5 Wastewater Collecting and Monitoring Basin
The final treated water from sedimentation basin, cooling water, final filter for sewage treatment system, neutralisation tank of demineralisation plant and boiler blowdown overflows to waste water collecting and monitoring basin.
By means of analyser, the value of pH and temperature shell be constantly monitored.
6 Hydrochloric Acid (HCL) Dosing System
HCL dosing system consists of following main components: • One number HCl dosing vessel of a capacity of 2 ㎥ • Two numbers HCl dosing pumps. • One number level transmitter (Ultrasonic Type). • One number calibration column. • Four numbers pressure gauges in suction line and discharge line • Piping system Operation: It is charged from demineralisation plant to HCl dosing vessel by means of unloading pump. 33% hydrochloric acid is used to wastewater treatment system. HCl dosing pump feed to reaction basin at the preset value, to keep the pH level in the basic region.
7 NaOH Dosing System
NaOH dosing system consists of following main components: • One number NaOH dosing vessel of a capacity of 2 ㎥ • Two numbers NaOH dosing pumps • One number level transmitter (Ultrasonic Type). • One number calibration column. • Four numbers pressure gauges in suction line and discharge line
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• Piping system Operation: It is charged from demineralisation plant to NaOH dosing vessel by means of unloading pump. 50% caustic soda is used to wastewater treatment system. NaOH dosing pump feed to reaction basin at the preset value, to keep the pH level in the basic region.
8 Alum Dosing System
Alum dosing system consists of following main components: • One number alum dosing vessel of a capacity of 5 ㎥. • Two numbers alum dosing pumps. • One number level transmitter (Ultrasonic Type). • One number calibration column. • Four numbers pressure gauges in suction line and discharge line. • One number drum pump to charge alum. • Piping system.
Operation: It is charged from alum drum to alum dosing vessel by means of drum pump. About 10% alum is used in wastewater treatment system. In charging, operator keeps a watch level gauge to prevent over flow. Alum dosing pump feed to flocculation basin at the preset value, to get the best cohesion in the basic region.
9 Polymer Dosing System
Polymer dosing system consists of following main components: • One number polymer auto dissolving unit of a capacity of 1 ㎥ • Two numbers polymer dosing pumps. • One number calibration column. • Four numbers pressure gauges in suction line and discharge line. • Piping system.
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Operation: The system feed water from service water source and by solid polymer from Vinyl pack. The polymer auto dissolving unit is equipment for inserting good quality solution after complete dilution of polymer at fixed degree of density continuously in order to supply fully maturated cohesion material and needs to be charged carefully. Polymer dosing pump feed to flocculation basin at the preset value, to get the best cohesion in the basic region.
3.8 Details of Sewage Water Treatment System
The sewage wastewater of 75 m 3/day will be generated in the plant from the rest rooms will be treated in Sewage Treatment Plant. The quality of the untreated sewage wastewater will be:
BOD : 300 mg/l SS : 300 mg/l pH : 6.5 ~ 7.5
The proposed sewage P & I diagram is attached as Appendix 4. The sewage treatment plant will consist the following units:
1 Screen Tank
In the preliminary treatment, the suspended debris and coarse material will be removed in the screen tank. The sewage wastewater will be passed through screen tank in which auto bar screens are installed to remove coarse material. In addition, parallel separate channel will be provided with manual bar screens, which will be operated in case of maintenance of auto screen tank. 2 Grit Chamber
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The grit is accumulated at the bottom of chamber and the collected grit is removed by operator manually & on demand.
3 Equalization Basin
This under ground Equalization Basin takes all the sewage that is free from debris and grit. In equalization tank, the submersible mixer keep steering the liquid inside the tank to prevent settling of denser material.
4 Aeration Tank
The pumped raw sewage water initially enters an aeration tank for the removal of BOD. The tank requires sufficient contact time between the wastewater and heterotrophic micro organisms, and sufficient oxygen and nutrients.
In aerobic oxidation, the conversion of organic matter is carried out by mixed bacterial cultures in general accordance with the stoichiometry shown below.
- Oxidation and synthesis: Bacteria
COHNS + O2 + Nutrients CO2 + NH3 + C5H7NO2 + (Other end-products) Organic Matter New cells
- Endogenous respiration: Bacteria
C5 H7 NO2 + 5O2 5CO2 + 2H2O + NH3 + (Energy)
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For carbonaceous removal, pH in the range of 6.0 to 9.0 is tolerable, while optimal performance occurs near a neutral pH. The dissolved concentration 0.2 mg/l is commonly maintained in the aeration tank.
5 Clarifier Tank
After aeration, the liquor is sent to clarifier tank, for settling of the sludge. In the clarifier, velocity is reduced to give sufficient time for settlement of sludge.
Then the effluent will be discharged from the settlement tank via an over flow weir into the disinfection tank, where the NaOCl is added at the preset value for the disinfection of the system. The sludge is collected from the bottom (Hopper) of clarifier tank, where the two Sludge Transfer Pumps operate to shift the sludge in two parts:
• Return activated sludge to aeration tank via V- notch for the improvement of the system biology. • Excess sludge to Sludge Holding & Thickening Basin for its further shifting to sludge tank for the final disposal.
6 Sludge Holding & Thickening Basin
Excess sludge shall be sent to sludge holding & thickening basin. The basin will be equipped with baffles at the inlet point to reduce the velocity of the flow. This will provide sufficient time for the settlement of sludge.
3.9 Sources of Pollution
While designing the proposed project, number of measures have been incorporated to minimize the adverse impacts on the surroundings. In order to achieve this, lot of process based precautions have been integrated in the
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basic design itself as described earlier. An attempt has been made here to identify and quantify the sources of final emissions/discharges/solid wastes etc. based on the process design.
3.9.1 Air Environment
The gaseous emissions form the project will be from six stacks of Power plant and two stacks of auxiliary boilers of desalination plant. The turbines and boilers shall be operated on the clean fuel i.e. natural gas. The details of the stacks and emissions are given in Table-3.5.
TABLE-3.5 DETAILS OF STACK AND GASEOUS EMISSION
Sr. Parameters Unit Details No. Power Power Desalination Station M Station L Plant 1 Stack height m 60 60 75 2 Number of Stacks M 6 7 2 3 Stack diameter m 7 7 3.4 4 Flue Gas velocity m/s 17.5 17.5 18 5 Exit flue gas °C 118.4 118.4 204 Temperature 6 Volumetric flow Nm 3/s 512 512 102.1 7 Emission rate of NOx mg/Nm 3 51 51 51 from each stack gm/s 26 26 5.2
The adequate stacks will provided for wider and quicker dispersion of the gaseous emissions. The turbines and boilers shall be provided with low NOx burners to control the NOx emissions.
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3.9.2 Water Environment
The wastewater generated in the power plant shall be treated in oil water separator, effluent treatment plant. The domestic wastewater shall be treated in the Sewage Treatment Plant.
The treated domestic wastewater shall be utilized in landscaping and the excess quantity shall be supplied to Dubai Municipality.
The trade wastewater of power plant along with hot water shall be mixed with brine generated in desalination plant. The brine shall be discharged in sea through outfall point located about 0.5 km away from the site.
The wastewater generated from the desalination plant is called Brine, which is a high in salt concentration and alkaline in nature. The quality of the brine is almost like sea water.
The domestic wastewater generated in the restroom and canteen will be about 20m 3/day. This wastewater shall be sent to Dubai Municipality for the disposal.
3.9.3 Solid waste
The solid waste shall be generated at the screening unit, where the debris from the seawater will be screened out. The solid waste will be sent to the solid waste shall be non-hazardous in nature and disposed off as per Dubai Municipality guidelines.
The sludge from the settling tank of potable water treatment plant shall be sent to sludge drying bed located within the plant facility.
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3.9.4 Noise Levels
The major noise generating equipment in the proposed facility will be pumps used in pumping of seawater and brine. These pumps will be designed for noise levels <85 dB (A) at 1 m from the equipment. These pumps will be provided with pump house with adequate acoustic to attenuate the noise levels. The noise levels shall fall below 70 dB (A) outside the pump house.
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4.1 Preamble
This chapter describes in detail the current/existing environmental conditions at the proposed project site. Jebel Ali desalination plant is located 25 km southwest of the city centre of Dubai and 7 km Northeast of Jebel Ali Port. Southwest of the site is a wide intertidal area with a variety of productive biotopes such as fringing strips of mangrove etc. Northeast of the site up to the Dubai Creek is a 25 km long beach shoreline (small sand dunes) which represents a wide intertidal area and are intensively used for tourism and recreational purposes.
4.2 Climatology and Meteorology
The meteorological data is necessary for the proper interpretation of baseline information of ambient air quality and other environmental attributes. It is important to understand the meteorological conditions of the study area for the evaluation of impacts of the proposed project. Historical data on meteorological parameters also plays an important role in identifying the synoptic meteorological regime of the region.
4.2.1 General
Dubai climate is an arid subtropical climate due to Dubai being located within the Northern desert belt. The skies over Dubai are generally blue with little cloud cover. Dubai has a typical desert climate with very hot summers and warm winters. The low precipitation falls almost exclusively between December and April. Despite of the missing rainfall humidity of the air is relatively high, due to its proximity to the Arabian Gulf. Especially in the summer months the humidity is often very high.
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Strong Northwesterly ‘Shamals’ can occur quite suddenly and associated with squalls caused by cold front pressure troughs. In summer, these Shamals are associated with dry air, cloudless skies and dust haze.
Dust haze is common in the summer months with visibility being generally restricted to less than 10 km. Sandstorms occur occasionally, when strong south easterly winds transport sand from the interior to the coastal region. These sandstorms lead to a build up of sand on highways and alongside buildings. They also significantly affect visibility.
The local climate is broadly characterized by two seasons. There are distinct summer and winter weather patterns, with spring and autumn as transitional periods lasting approx. one month.
4.2.2 Temperature
January is the coolest month of the year 2008 with the maximum temperature around 28.9°C and minimum of 11.6°C. The period from March to May is the "spring" months in Dubai when the temperature begins its steady climb towards the summer peaks.
During summer season the maximum temperature (July) is observed to be 45.6 °C with the minimum temperature of 25.5°C (September). During autumn season the maximum temperature (October) is observed to be 38.9°C with the minimum temperature of 13.8°C (December). The monthly variations of temperatures are presented in Table-4.1
4.2.3 Relative Humidity
The air is generally very humid in the region, the maximum relative humidity is observed to be around 83 and minimum 26%. The monthly mean variations in relative humidity are presented in Table-4.1
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4.2.4 Atmospheric Pressure
The atmospheric pressure observed is in the range of 995.6 to 1019.3 mb, with the maximum pressure (1019.3 mb) occurring during the winter season, in the month of December and January. The monthly variations in the pressure levels are presented in Table-4.1
TABLE - 4.1 CLIMATOLOGICAL DATA - DUBAI INTERNATIONAL AIRPORT - 2008 Relative
Atmospheric 0 Temperature ( C) Humidity Rainfall Month Pressure (%) (mm) (Mb) Max. Mean. Min. Max. Min.
January 1019.3 28.9 18.2 11.6 83.0 44.0 15.6 February 1012.5 31.7 21.3 13.8 83.0 41.0 25.0 March 1012.5 36.7 24.7 15.0 82.0 37.0 21.0 April 1009.1 40.0 29.3 16.6 76.4 30.1 7.0 May 1005.8 42.8 33.5 23.8 72.5 26.0 0.4 June 995.6 45.0 35.3 28.8 79.0 28.3 0.0 July 995.6 45.6 35.1 28.8 76.0 30.3 0.8 August 999.0 45.0 36.3 30.5 75.0 30.0 0.0 September 1002.4 43.9 34.7 25.5 80.6 30.4 0.0 October 1012.5 38.9 30.6 21.6 81.3 33.1 1.2 November 1015.9 33.9 25.2 17.7 80.0 38.0 2.7 December 1019.3 30.0 22.4 13.8 82.6 43.7 14.9
4.2.5 Rainfall
Short and irregular rainfalls occurred in 2008. Most of the rainfall occurs between December and March. The total rainfall observed in year 2008 is 88.6 mm. Annual and monthly variations in the rainfall are given in Table-4.1
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4.2.6 Annual Wind Pattern
A review of the wind rose diagram shows that predominant winds are mostly from W and WNW directions followed by S direction (Figure-4.1).
Predominant winds from W direction were observed for 11.2% of the total time, with wind speeds (% frequencies) in the range of 5.1-11.0 kmph (0.6), 11.1-19.0 kmph (5.1%) and >19.01 kmph (5.5%). In the S direction winds were observed for 10.9% of the total time, with wind speeds (% frequencies) in the range 5.1-11.0 kmph (4.1%), 11.1-19.0 kmph (5.8 %) and >19.01 kmph (0.9%). Whereas for WNW direction the winds were observed for 10.1% of the total time with wind speeds and frequencies in the range of 1.0-5.0 kmph (0.2%), 5.1-11.0 kmph (0.9%), 11.1-19.0 kmph (4.8 %) and >19.01 kmph (4.3%).
In other directions, the percentage frequencies observed were N (4.9%), NNE (3.0%), NE (4.4%), ENE (6.1%), E (9.3%), ESE (3.5%), SE (3.5%), SSE (5.5%), SSW (3.1%), SW (2.1%), WSW (4.1%), NW (9.4%), and NNW (6.5%). Calm conditions prevailed for 2.21% of the total time.
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FIGURE - 4.1 ANNUAL WINDROSE OF DUBAI INTERNATIONAL AIRPORT – 2008
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4.3 Sea Surface Water Temperatures
The maximum, minimum and mean seawater temperatures recorded at Jebel Ali Port of the year 2007 recorded to be 34.6 oC (August), 17.7 oC (February) and 26.5 oC respectively. The monthly variations in sea temperatures are given in Table-4.2 . This is in contrary to the normal year where in minimum occurs in winter and maximum in summer.
The monthly-recorded seawater temperatures of the year 2007 at Jebel Ali are shown in Figure 4.2. The ground water table corresponds with the sea water and is established at an average elevation of approx. +1.6 m, which is approx. 4.4 m below the ground level of the existing stations. The ground water table is subject to seasonal variation and dewatering in the site vicinity.
TABLE – 4.2 MONTHLY SEA TEMPERATURE VARIATION FOR THE YEAR 2007 Sea Temperature Month Mean Max Min
January 20.9 23.0 19.0 February 20.7 23.0 17.7 March 22.3 24.3 18.0 April 25.0 29.0 24.0 May 28.5 32.0 24.0 June 31.2 32.0 22.0 July 32.2 34.0 30.0 August 32.9 34.6 25.0 September 31.9 32.0 28.0 October 29.9 32.0 27.0 November 27.0 29.0 26.0 December 23.4 27.0 24.0
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DUBAI INTERNATIONAL AIRPORT Monthly Mean 2007 SEA TEMPERATURE – JEBEL ALI PORT 2007 Monthly Max 2007
Monthly Min 2007 40 35 30 C) 0 25 20 15 DEGREE( 10 5 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec MONTH OF THE YEAR
FIGURE 4.2 MONTHLY SEA WATER TEMPERATURE
4.4 Landuse
The proposed project site is currently undeveloped desert land. The area comprises low-lying, sandy, extensive flat, stony and gravel plains. The topography is mainly gently undulating sandy slopes, with occasional Sabkha flats. The height of ground varies from 33.0m to 62.0 m above sea level. The surrounding area is in the process of large-scale development for a variety of uses.
The nature of surrounding land use will therefore change significantly in the future, as large-scale infrastructure projects, including the new Jebel Ali Airport City, Techno Park and Dubai Waterfront, Dubai Industrial city, develop in the next few years. The proposed project will change the present undeveloped desert land to industrial land use.
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4.5 Regional Geology
The general geology of the UAE has been substantially influenced by the deposition of marine deposits associated with the continuous sea level changes during the relatively recent geological time. Moreover, with the existing mountainous geology across the UAE the country is considered to be of relatively low-laying area.
The geological conditions in Dubai essentially consist in general of a linear coastline dissected by creeks. Superficial deposits consisting of beach dune sands with marine sands and silts. Furthermore, erosion, capillary rise phenomena as well as evaporations have led to extensive silt deposits in some areas especially near to the creeks. These superficial underlined by altering layers of calcarenite, carbonate sandstone, sand as well as cemented sand layers.
4.6 Existing Baseline Air Quality
Apart from the existing power production facilities at Jebel Ali Power Station the nearest major point source of atmospheric pollutants to the project site is the Dubal Aluminum Factory adjacent to the southwestern border of the Jebel Ali Site. At Dubal, several power plants are installed for the production of electricity which is required for the electrolytic aluminum smelting process. The ambient air impacts of the existing industrial facilities in the vicinity of the project site are reflected, by the results of regular ambient air quality measurements, which are available from DM environment department for the locations Jebel Ali Village and Jebel Ali Port.
In accordance with the requirement of the Environmental Protection and Safety Section of the Dubai Municipality (E.P.S.S.), the air quality impact assessment in this report focuses on the additional impact of the new project which has to be added to the existing ambient air pollutant levels which are 4-8 EIA study for the proposed Jebel Ali Power and Desalination Station M CHAPTER 4
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measured regularly at two monitoring stations in Jebel Ali Village and at Jebel Ali Port.
The E.P.S.S carries out hourly measurements of NO 2 and SO 2 and Ozone
(O 3) at Jebel Ali Village. At Jebel Ali Port hourly measurements of SO 2 and Ozone at four monitoring stations. The closest station to the project site is 2 km south-south-east in Jebel Ali Village. The station is influenced by traffic on the Sheikh Zayed Road, which runs between the project site and Jebel Ali Village.
The second measuring station is located approx. 4 km southwest of the project site at Jebel Ali Port. This location is also influenced by the Sheikh Zayed Road and by the installations at Dubal.
The air quality monitoring results from these sites are summarized in the Table 4.3 for the period 2008.
At all sites the highest 1 hour and 24 hour Nitrogen Dioxide concentrations are well below the corresponding Dubai, World Bank and WHO air quality standards.
At all sites the highest 1 hour and 24 hour Nitrogen Dioxide concentrations are well below the corresponding Dubai, World Bank and WHO air quality standards.
The highest 1 hour average concentrations measured for SO 2 are well below the Standards of Dubai, World Bank, and WHO (350 µg/m³) considerably.
A similar situation is present for Ozone At all sites the highest 1 hour and 24
hour O3 concentrations are well below the corresponding Dubai, World Bank and WHO air quality standards.
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Ozone levels are of interest for this project because the NO X emitted by the
plant is a precursor of Ozone in the atmospheric chemistry involving NO, NO 2, Hydrocarbons, and solar irradiation, where the nitrogen oxides act as a catalyst of Ozone formation in the troposphere
Besides from the existing power plant of the Jebel Ali Power Station the main ambient air pollution source in the area is Dubai Aluminum factory adjacent to the south-western border of the Jebel Ali Site.
The only air pollutants to be considered with plant operation on natural gas
are NO X and CO. Due to the fact, that only very small traces of sulphur and
particulates are contained in the natural gas, the corresponding SO 2 and particulate matter emissions are negligible. Consequently only emissions of
NO X and CO are considered in detail.
The background NOx and SO 2 concentrations were taken from the online recording done by Dubai Municipality. The monitoring location located at Jebel Ali village which is the nearest monitoring station to the proposed power project site. The recorded concentrations are hourly concentrations of NOx
and SO 2 collected for the period of two months from March and April 2008. The 24 hourly concentrations were calculated based on these hourly values.
TABLE 4.3 JEBEL ALI VILLAGE AIR QUALITY MONITORING RESULTS 2008 Monitoring Site Maximum Minimum Nitrogen Oxide Concentration 1 Hourly (Limit – 290 µg/m 3) 121.0 74.6 24 hourly (Limit – 110 µg/m 3) 46.6 28.7 Sulphur dioxide Concentration 1 Hourly (Limit – 350 µg/m 3) 5.3 3.0 24 hourly (Limit – 150 µg/m 3) 2.0 1.2
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The gas turbine emission concentrations of CO are in the same order of
magnitude as those of NO X. However, the toxicity of NO X exceeds the toxicity of CO by a factor of more than 100, which corresponds in the much higher emission limits set for CO. Therefore, the only air pollutant of significance with
regard to air quality impact is NO X.
Consequently the only air pollutant which was considered in the air dispersion
calculation and in the assessment of ambient air quality is NO X.
4.7 Biological Features
4.7.1 General
Due to the desert climate there is only very few natural vegetation in the project area. However the coastal region is heavily irrigated using water from desalination plants and re-used treated wastewater. The main vegetation growing in the irrigated area land are palm trees, grass and shrubs.
The Gulf coasts of the Arabian countries do not vary grossly in their geomorphologic structures. Nevertheless, there is a rich diversity of biotopes, some of international nature protection interest. Sensitive marine Gulf-specific biotopes are e.g. shallow bays, coral reefs, seaweed meadows, intertidal sand- and mudflats. Sensitive coastal biotopes are mangrove areas, saltmarshes, rocky shores, bird islands, coastal sabkhas, cyanobacterial mats, sand beaches and beachrock flats. Accompanying this variety of biotopes is a rich diversity of species.
Use of natural marine resources belongs to the biological context. The Gulf is a productive sea and a rich source of fish and shrimps. Even if fishery is negligible within the gross domestic product, it is present all along the Gulf coast and supplies the food of high quality and variety. The number of people engaged in traditional and modern fishery should not be underestimated. 4-11 EIA study for the proposed Jebel Ali Power and Desalination Station M CHAPTER 4
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Conflicts between interests of desalination industry and fishery can be expected wherever desalination plants are erected or enlarged. Productive fishery is a good indicator for a healthy marine ecosystem.
4.7.2 Birds
The UAE Golf coast is rich of `Important Bird Areas (IBA's)'. In general, the UAE Golf coast has functions for birds such as:
Flyways: For waders and other species from Eurasia / West Asia to Africa and vice versa, mainly during April/May and July/November. Probably more than 250,000 waders are recorded `at any one time' during the migration period. At the same time the Gulf coast works as a Resting/Feeding Place: Several million shore birds are dependent on the nutritious intertidal mudflats all year.
Wintering: For instance, the Crab Plover' and Great Knot' are dependent on places such as Khor al Beidah.
Breeding; Up till now, there are various bird Priority Species' (Aspinall, 1996) such as the Socotra Cormorant' (Endemic to Arabia), `Western Reef Heron' the `Crab Plover and Kentish Plover (throughout UAE) recorded, ussing parts of the shoreline as a breeding site.
In general, among others, 61 species of water birds alone were counted along the Golf shoreline of the UAE.
4.7.3 Fauna, Wildlife
The most frequent animals in Dubai are camels and goats. Indigenous fauna includes the Arabian Leopard and the Ibex, but sightings of them are
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extremely rare. Other desert life includes the sand cat, sand fox and desert hare, plus gerbils, hedgehogs, snakes and geckos.
No wildlife is present at the selected project location which is situated in a fenced industrial area
4.8 Soil, Geology and Geomorphology
4.8.1 General
Borings performed in previous projects at the project site showed non homogeneous surface layers of loose to medium sand with a variable concentration of seashell fragments. Approx 10 meters below the unconsolidated soil strata, layers of weak, fine to medium grained calcareous sandstone (occasionally with layers of limestone and conglomerate) were encountered.
4.8.2 Regional geology and Hydrogeology
Geologically, the UAE occupies a corner of the Arabian Platform, a body of continental rock that has remained relatively stable since the Cambrian Period-more than 500 million years ago. Ancient sediments over time, accumulated on the coast of UAE including Dubai and continental shelf that was to become the UAE. The geology in Dubai and environs is essentially unconsolidated desert plain deposits of sandy silt to fine sand followed by bedrock. Locally Dubai is built on two major geological and geo- morphological units. • Desert plain deposits consisting of sand and silt, form low flying flat or gently undulating surface with isolated dunes • Coastal Sabkah: calcareous silt, muddy sand with considerable salt content, salt crusts flooded by storm
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Regionally ground water flow from South East to North West. Ground water quality along the coast of Dubai is brackish to saline and shallow water level conditions (water level is 3.0 to 12 meters below ground level depending on ground elevation).
A study on the background heavy metals data in Dubai was conducted in 1995 by Dubai Municipality EPSS section and following are the soil background concentrations observed in Dubai as shown in Table 4.4
TABLE 4.4 BACKGROUND HEAVY METALS IN SOIL IN DUBAI
Parameter Mean value(µg/g or mg/kg) Ranges (µg/g or mg/kg) Copper 10 5 -24 Zinc 23 7-129 Cadmium 2 0.2 to 8 Lead 22 5 to 23 Nickel 27 2 to 62 Chromium 27 5 to 50 Manganese 165 33 to 253
4.9 Shoreline, Water Courses and Discharges
Dubai has an almost linear coastline to the Arabian Gulf, which is interrupted by the Dubai Creek and some other bays. Presently there are several projects which will change the natural coastline. In the vicinity of the project area a marina is constructed for which an artificial creek was created by excavation of land. Furthermore two artificial Palm Island projects are being built close to the shoreline.
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Dubai is lacking of natural freshwater resources which is overcome by use of desalination plants. The desalination installations at Jebel Ali are the largest in Dubai. By the evaporation process utilized in the desalination plants large amounts of sea water are taken from the gulf and discharged again with increased temperature and salinity. The natural cooling down of the discharge water by mixing with colder sea water from the open sea will be considerably hindered by the construction of the two palm islands.
The ground water table corresponds with the sea water and is established at an average elevation of approximately + 1.6 m, which is approx. 4.4 m below the ground level of the existing stations.
The ground water table is subject to seasonal variation and dewatering in the site vicinity
4.10 Cultural Heritage
The project area is assigned for industrial use. No items of special cultural heritage are present within a radius of 10 Km around the projected plant.
4.11 Landscape and Topography
The topography in the region consists of flat, barren coastal plain merging into rolling sand dunes of vast desert land in the south.
4.12 Surrounding Recreational Land uses
The coastline east of the project area is strongly utilized for recreational and tourist purposes and will be more extended by future developments, such as the two very large `Palm Islands Projects'.
4-15 EIA study for the proposed Jebel Ali Power and Desalination Station M CHAPTER 4
Baseline Environmental Status
4.13 Population
The total population of the UAE was estimated in 2001 to be 2,407,460. The population of Dubai was 1,241, 000 in the year 2006. Of the total population, 73 per cent or 911,000 are male and 27 per cent or 330,000 are female.
Within a radius of 10 km around the plant area, which has been defined as area of investigation for the atmospheric dispersion calculations, there are several locations of considerable population density.
Situated approx. 5 km south of the Project Site (minimum distance) are Jebel Ali Industrial Village and Dubai Inves