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Monday, April 30, 2018

Desalination is unaffordable and destructive of the environment & livelihoods

According to the International Desalination Association (IDA), there are around 18,426 desalination plants spread across 150 countries, benefitting as many as 300 million people.

55 % of Israel’s domestic water consumption is manufactured and many countries, especially in the arid regions of Northern Africa and the Middle East, find desalination a relatively cheaper option compared to other alternatives.


India’s average annual rainfall is about 1,200 mm. In contrast, middle eastern countries such as Saudi Arabia, UAE and Qatar get much less than 100 mm a year. Many developed countries in Europe and even the US, get much less rain than India (715 mm 
yearly for the latter). 


Rain at Plant / Prabas007 / CC-BY-SA 4.0
Desalination as a “solution” for Tamil Nadu’s water problem is what social activists disparagingly refer to as a ‘technofix’. Technofixes and their proponents are dangerous because they aggravate the problem that they claim to address by lulling society into a false sense of complacency. Their actions highlight dubious benefits even as it exacts a heavy price on the environment and invisible and marginalised sections of society.

A new mission on desalination is in the works in India, according to union minister of earth sciences, Harsh Vardhan. Despite the reliance on desalination, countries like Israel have invested heavily in securing their water sources and recycling used water. For example, Israel treats close to 85 percent of its wastewater which it then uses for irrigation, gardening and industrial purposes. In fact in 2005less than seven percent of Israel’s total water needs was met through desalination plants.
Another country that is often on the cutting edge of technology and practicality is Singapore. It is working to ramp up the recycling of treated sewage as well as construct more desalination plants. The plan is to increase water supply from the former source from 30 % to 50 % and the latter from 10 % to 30 %.


Singapore River / Formulax / CC-BY-SA 2.0.
In 2002, Singapore reclaimed water from a sewage treatment plant at an additional cost of 30 cents per thousand litres using advanced membranes, filtration and disinfection. Desalinated water is more expensive by two and a half times at 78 cents per thousand litre, and Singapore is resorting to it only as it has little land to store rainwater.

With the ongoing awareness programmes, Singapore's National Water Agency aims to reduce per capita domestic water use to less than 150 ltrs by 2020. Compare that to over 400 ltrs per day use by US residents and 550 ltrs per day by UAE residents, when living standards of Singapore residents are not thought to be poorer compared to USA and UAE. So responsible planning and use need to go hand and in hand with planning for new water sources. 

Critics decry the high cost and high energy consumption of desalination, which can have a negative impact on the environment and on our oceans. Desalinating 1 cubic meter (1000 litres) of water requires 3.5 units of electricity per 1000 litres. In comparison, the average daily electricity consumption of an Indian household is about 3 units of electricity.


Kanchipuram, India / McKay Savage / CC-BY-SA 2.0
Thus, an average family of five consuming 675 ltrs for domestic use at the rate of 135 ltrs per capita (the norm suggested by the Central Public Health and Environmental Engineering Organisation for cities with piped water supply where sewerage system is existing/ contemplated) will increase its electricity usage per day by nearly 80 % (an addition of about 2.3 units of electricity) simply to use desalinated water - even if the desalinated water production cost is subsidized by the State. 

Together, the two desalination plants in Chennai are estimated to consume between 500,000 to 700,000 units of electricity each day if they run at full capacity– enough to power 2 lakh households for a day. The electricity required to run the desalination plants will come from power plants, which have their own negative impacts on the environment, climate change and human health. 

The end-user price for water manufactured at the newer, lower-cost Nemmeli desalination plant located in Chennai is about Rs 50 per 1000 litres or Rs. 34 for 675 ltrs a day for a family of five. A month's usage thus translates to more than Rs. 1000 for such a family. 


Arizona Cap Canal / US Govt.
In contrast, the average cost of production of the conventional piped supply of water is almost one fourth the cost of production in desalination plants. For example, Chennai Metrowater buys water from the Minjur desalination plant at 54 per kilolitre (Kl). On the other hand, conventional sources cost 13/Kl. Thus the water supply for an average family would cost about Rs. 9 a day or about Rs. 260 a month if the water was sourced from conventional sources. 

Even in Israel which is tom-tommed to have the most cost efficient technologies for desalination, the price of desalinated water is ILS 2.50 per cubic meter (ILS - Israeli New Shekel), while brackish water pumped up from underground acquifers, costs only ILS 1.00 per cubic meter. Israel’s Sorek plant, which is the largest in the world, can produce a thousand litres of drinking water for 58 cents which is still nearly double the cost of recycling wastewater in Singapore. 

According to the Department of Atomic Energy, Government of India, on an average, the cost of conversion of sea water into desalinated water is about 10 paise per litre of water produced. That would imply a Rs. 100 cost per 1000 ltrs of water produced !

And as to proponents of using desalinated water for agriculture - just the water costs of producing a kilo of rice using desalinated water will be about Rs 100 in Tamil Nadu.


Palm Tree Farm in Israel/ Tiia Monto / CC-BY-SA 3.0
The glowing articles in the media about the transformation of Israeli agriculture due to desalination, fail to highlight the costs and contexts within which such a transformation can be justified. Israel’s water needs are paltry compared to India's. Israeli agro-climatic conditions are vastly different. The arid regions of Israel do not receive the kind of rainfall that many regions of India get. And Israel grows vegetable and fruit crops suited to its arid lands, unlike much of India focusing on water intensive crops. 

Beyond the links to climate problems, marine biologists warn that widespread desalinisation could take a heavy toll on ocean biodiversity; as such facilities’ intake pipes essentially vacuum up and inadvertently kill, millions of plankton, fish eggs, fish larvae and other microbial organisms that constitute the base layer of the marine food chain. Marine fisheries, which are an important source of inexpensive protein and livelihood for lakhs of fishworkers, will be harmed.

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