Fresh from the sea

WATER WORRIES India has over 100 small and large desal plants. Seen here is the Chennai Water Desalination Ltd plant at Kattupalli in Minjur. Photo: V. Ganesan   | Photo Credit: V. Ganesan

With increasing demand for good water and all other water sources depleting, the desalination sector has been growing rapidly in the last decade. About 97.2 per cent of earth’s water resources are in the sea. And 39 per cent of the world’s population (2.4 billion people) lives within 100 km of the sea. As per a study, of the 70 cities in the world with no direct access to additional fresh water source, 42 are in coastal areas.

Currently, desalination plants provide approximately 1 per cent of the world’s drinking water supply and this number is increasing every year. Estimating the global market value for desalination is extremely difficult as it is composed of a few large projects. However, the global market is roughly $12 billion per year, about $6 billion per year in capital expenditure and about $6 billion per year in operating expenditure.

According to the International Desalination Association (IDA), the past five years have seen a 57 per cent increase in the capacity of desalination plants on line. The installed base of desalination plants around the world now has a capacity of 78.4 million cu meters per day compared to 47.6 million cu meters per day at the end of 2008, according to the latest edition of the IDA/GWI Worldwide Desalting Plant Inventory.

Desalination capacity is expected to increase from about 0. 40 billion cubic metres per day (bcm/day) to about 0.975 bcm/day by 2015. Most of this growth will come from the US, Israel, Spain, Australia, China and the Mediterranean area (Algeria, Libya). Traditionally, the Middle East has been the biggest market and they are expected to continue to add capacity till 2015. With increasing capacity, operating expenditure is also expected to increase from the current $6 billion to about $14.8 billion by 2015.

Historically, large-scale desalination has mainly been built in the Middle East where there is no alternative for public water supply. Countries in the Gulf and Southern Europe have invested heavily on building huge desalination plants to meet the drinking and industrial water requirements of their population. A number of islands and coastal areas have also successfully explored this option. But the growth of lower cost membrane desalination and increased water scarcity means that big desalination plants are now being built outside the Gulf. The largest membrane desalination plant in the world — the 444mld Victoria Desalination Plant in Melbourne, Australia — was commissioned earlier this year. This will be soon surpassed by the 500mld Magtaa plant in Algeria, and the 510mld Soreq plant in Israel.

Desalination in India

India has a long coastline of 7,600 km. Coastal areas such as Tamil Nadu, Gujarat and Andhra Pradesh have a huge problem of water scarcity due to poor river water availability, low ground water levels and high demand. Interestingly, these states also have high industrial penetration and demand from industrial users with readiness to pay high prices for reliable water supply. Large industries such as refineries, petrochemical complexes and power plants come up near the coast, and need huge volumes of water. Thus, desalination is a relevant and economically feasible solution to water problems in coastal areas. Many industries in Maharashtra, Gujarat and Tamil Nadu are already paying more than Rs. 60 per cubic metres for their water supply costs.

Over 100 small and large desalination plants are running across the country. A 100 mld desalination plant is being built in Nemmeli, Chennai for Chennai Metro by VA Tech Wabag.

Big industries in coastal areas have also been seriously exploring sea water. Industries like Nirma, Gujarat Heavy Chemicals Ltd, Indian Rayon and Chennai Petroleum Corporation Ltd. have been some of the pioneers in this area. However, as technology costs reduce and there is a higher level of market acceptability, one can expect desalination plants to come up along the coasts of Gujarat, Tamil Nadu and Andhra Pradesh.

Chief concerns

As more countries and communities consider desalination a viable option, a number of new socio-political issues are getting discussed. These include environmental concerns, energy requirements, greenhouse gas production issues, impact on local communities, water distribution to competing sectors and privatisation issues. Even issues related to the quality and taste of the desalinated seawater are of concern.

Energy costs are worrying, and solutions such as water conservation, reuse and recycling are proposed as preferable solutions. Environmental concerns also persist, related to disposal of the concentrate and the impact on marine life. While there have been attempts to allay these concerns, environmental groups and NGOs continue to protest against desalination projects.

Economic sustainability is a concern, with many commentators saying that desalination may be okay for the rich nations of the Middle-East, Europe and North America, but that it is impractical for developing countries. However, plants in Africa and Asia have been successful so far.

What does the future hold?

According to Patricia A. Burke, secretary general, IDA, “Growth in desalination is not linear, and it is tied to many other factors including the cost of oil, prices of certain commodities, and availability of financing. However, the underlying factors that have driven the growth of desalination remain in place, including population growth, industrial development, pollution of traditional water resources, and climate change. At the same time, the desalination industry has done much to lower the cost of desalination by developing technologies that lower energy requirements, implementing practices that achieve greater operational efficiency, and adopting measures to enhance environmental stewardship.”

Desalination technologies have evolved over the last few years and a number of changes implemented. Traditionally, thermal desalination was preferred, particularly where excess steam was easily available. Advancements in membrane technology have made reverse osmosis an equally viable option in many cases. The approach in some of the latest desalination plants like Fujairah in UAE has been to go for hybrid technology which uses both thermal and membrane approaches.

The development of newer membrane material, pump models and other engineering equipment has been continuously reducing plant costs. Newer materials of construction like titanium alloys and plastics also ensure longer life and reliability. All these developments mean that desalination systems are more economical and more reliable than before. Indian research organisations such as National Institute of Ocean Technology and Central Salt and Marine Chemicals Research Institute have also been developing indigenous concepts for Indian conditions.

India is one of the big upcoming global markets for desalination. About 30 new desalination plants are expected to come up in the next three-five years. As India begins to look increasingly at this solution, the globalised nature of desalination is here to stay.

The writer is COO, EA Water Pvt. Ltd.

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Printable version | Jan 29, 2022 5:12:18 PM |

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