Desalination & Drought Mitigation in Developing Countries - - PowerPoint PPT Presentation

desalination: a promise for the future

Desalination & Drought Mitigation in Developing Countries

Maria ria Kenned nnedy, y, PhD Professor fessor of Water ter Treatm atment ent Techn chnol

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desalination: a promise for the future

Sources: FAO Aquastat (2013) World Bank (2013)

Water scarcity in 2050?

By 2050, 78 countries (mainly developing countries) and almost 4.5 billion people affected……

Dealing with water scarcity?

Saving water: Increasing productivity in agriculture & industry Reducing leakages in public water supply Progressive tariffs Water transport: Large distances!! Aquifer storage: River water during high flow Water reuse: Increasing reuse/recycling in industry & domestic wastewater in agriculture Desalination Brackish water Waste water Sea water

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Can desalination alleviate water scarcity in developing countries?

• Desalination is considered as a drought-proof

water source, which does not depend on river flows, reservoir levels or climate change…

• Desalination maybe an option to alleviate scarcity

in industry and coastal cities..

Desalination – an option for coastal cities?

World: 80 Mm3/day Africa: 7.5 Mm3/day

Desalination capacity in Africa today?

Desalination in China India & Algeria

Algeria (2.7 Mm3/day)

Municipal, 93 % Industrial, 6 % Others, <1 %

User category

In Algeria, >90% of desalinated water is used by municipalities

Membrane, 93 % Thermal, 7 % Others, <1 %

Technology Source: DesalData (2017)

India (2.6 Mm3/day)

In India, >75% of the desalinated water is used by industry

Municipal, 25 % Industrial, 75 % Others, 0 %

User Category Source: DesalData (2017)

Membrane, 81 % Thermal, 19 % Others, 0 %

Technology

China (4.5 Mm3/day)

In China, >80% of the desalinated water is used by industry

Municipal, 18 % Industrial, 79 % Others, 3 %

User category Source: DesalData (2017

Membrane, 78 % Thermal, 6 % Others, 17 %

Technology

What are the key challenges to implement desalination in developing countries…

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POTENTIAL ENVIRONMENTAL IMPACTS: – Concentrate and chemical discharges – Energy and GHG emissions

Disperse concentrate through multiport diffuser in a suitable marine site Use of subsurface

• r submerged

intakes with low intake velocities Treatment of all backwashing and cleaning wastes to reduce marine pollution Improve recyclability and reuse of materials

Is energy demand significant in desalination?

• depends on a society's values, economic potentials,

politics, and existing environmental regulations…

How much energy is required to desalinate water in Africa today (current capacity ≈7.5 Mm3/day)?

• Assume: total installed capacity realized with SWRO ( ≈3 kWh/m3)
• Total energy requirment for desalination in Africa today:

Capacity x 3 kWh/m3 = 7.5 106 m3 /day x 3 kWh/m3 = 22.5 106 kWh = 0.02 109 kWh

0.3 % of the electrical power consumption in Africa today!

Energy - a key issue due to global warming!

Q: How much energy is used in Africa today ? A: Primary energy use is ≈ 8,000 TWh/year by 1 billion people. Q: How much water can be desalted with that much energy? A: Assume: SWRO (3 kWh/m3); conversion factor from primary to electrical energy (30%); Pop. of Africa: 1 billion people

= 800 m3 / capita per year.

Domestic use: requires ≈ 100 L per capita/day or 40 m3 per capita/year

5% of Africa’s current energy consumption would be required to meet their domestic water demand by desalination

Desalination using renewable energy?

• No large desalination plant driven by RE!
• Compensation measures only (all Australian projects)
• Small, stand-alone desalination systems

ED MD MSF MED- TVC MED- MVC RO

Solar energy

Wind / Tides Heat (collector) Radiation (PV cell)

Non-concentrating collectors

• solar pond
• flat plate or tube collectors

(e.g., for domestic purposes) Concentrating collectors

• parabolic design (trough, dish)
• flat mirrors, e.g. Fresnel
• power tower (>1000°C)

Electricity

Turbine

Mechanical Solar stills

Concluding remarks

• By 2050, we may have 4.5 billion people suffering from water

scarcity/stress/vulnerability on the planet, and > 95% of these people may live in developing countries...

• Desalination is technically feasible on a large scale and can be applied to

solve water scarcity in coastal cities.

• Industry already has turned to desalination to meet their water needs

(India & China) – this strategy may be applied to other developed and developing countries...

• ENERGY is a key issue and will remain a challenge because of the high cost
• f renewable energy.......
• Capacity development and training........

Desalination costs

Cost breakdown for SWRO

Capital recovery 41% Power 19% Membranes 16% O&M 14% Chemicals 6% Spares 4%

Source: Ghaffour et al. 2013

Cost indication Euro/m3 Seawater reverse osmosis 0.50 – 1.00 Brackish water reverse osmosis 0.25 – 0.50 Electrodialysis 0.25 – 0.50 Nanofiltration 0.15 – 0.25 Ultra/microfiltration 0.05 – 0.10

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Can water reuse solve water scarcity in developing countries?

• Desalination is considered as a drought-proof

water source, which does not depend on river flows, reservoir levels or climate change…

• Desalination maybe an option to alleviate scarcity

in industry and coastal cities..