There are many types of salt found around the world, but, the term ‘salt’ commonly refers to edible table salt – Sodium Chloride (NaCl). This type of salt is typically produced in salterns through the solar evaporation of seawater (brine).
Ideal conditions for establishing salterns include coastal areas with clay-rich soil, low rainfall, strong winds, low humidity, and flat, open land. Sri Lanka, a developing country, is naturally endowed with these favourable conditions. Salterns in Sri Lanka are located in several coastal regions, including Elephant Pass, Mannar, Puttalam, Hambantota, and Trincomalee.
In ancient times, salt was naturally formed without human intervention. During the high tide, seawater or lagoon water would flow into low-lying areas and become trapped. Over time, the water would evaporate under the sun's heat, leaving behind a white salt deposit. This naturally occurring salt, known as ‘self-formed salt’ is not suitable for human consumption, as it contains a mixture of various other salts and impurities present in the brine.
The production of pure, edible common salt began in 1920 with the establishment of systematic salterns. From that time, these salterns came under the management of the Salt Department in Sri Lanka. Later, all salterns were brought under the Sri Lanka National Salt Corporation to accelerate development efforts. As a result, salt production significantly increased, and the country became self-sufficient in common salt for nearly a century.
During this period, several salterns across the country – including in Elephant Pass and Chemmani in the North; Puttalam, Palavi, Kalpitiya and Karaithivu in the West; and Hambantota, Bundala and Palatupana in the South – produced significant quantities of high-quality salt. These operations made a valuable financial contribution to the national economy. In 1980, salt production reached its peak with a total output of 180,000 metric tonnes (MT): 80,000 MT from the Northern region, 62,000 MT from the Western region, and 38,000 MT from the Southern region.
Regarding the salt production and export in 1980, here are some statistics: Sri Lankan population in 1980 – 15 million, human consumption per person per year – 5-6 kg, the annual requirement for edible purpose – 90,000 MT, supplied to the Paranthan Chemicals Corporation as raw material to produce Caustic Soda (NaOH) and Chromone (Cl2) – 8,000 MT, other industrial purposes - 22,000 MT, the total annual country requirement – 120,000 MT, the total annual production – 180,000 MT and the balance excess quantity - 60,000 MT.
The accumulated surplus salt from 1977 was exported through the Kankesanthurai (KKS) Harbour to countries such as the Maldives, Kenya, Bangladesh, Uganda, and others. These exports generated a substantial amount of foreign exchange for the country.
Production process of common salt
A typical medium-sized saltern covers approximately 500 acres, with about 50 acres dedicated to crystallisers (salt production areas), maintaining a 10:one ratio. Under favourable weather conditions, the average annual salt production ranges from 18,000 MT to 20,000 MT.
Sea water contains several types of salts, primarily in ionic form. The following are the most important salts present: Calcium Carbonate (CaCO3), Calcium Sulphate (CaSO4), NaCl, Magnesium Chloride (MgCl2), and Magnesium Sulphate (MgSO4).
In Sri Lanka, pure common salt is produced in salterns using a scientifically-managed process. This process involves several well-defined stages, with different types of ponds constructed in proportionate sizes. It begins in the reservoir, where the initial brine is stored and partially evaporated. The brine is further concentrated through evaporation and circulation across multiple condenser ponds. Once it reaches a saturated, high-density state, it is transferred to the forebasin, also known as the pickling pond. From there, the brine is directed to the crystallisers, where salt is formed. Most of the brine is circulated under gravitational floor, ensuring the efficient and energy-saving movement of brine between the stages.
Evaporation throughout the process is driven entirely by solar energy and enhanced by strong wind conditions. As the brine passes through the different ponds, various types of salts crystallise separately, based on their solubility levels – a process known as fractional crystallisation. Pure common salt containing 97-98% NaCl is produced without contamination from other salts present in sea brine. This common salt is then further processed through washing and crushing, and refined into iodised crystal salt and table salt, making it suitable for human consumption and ready for market distribution.
Production and shortage in 2024
The following stats are useful in this regard: Sri Lankan population last year (in 2024) - 22 million, the required quantity of salt per person per year – 5-6 kg, total human consumption per year for 22 million (22 million multiplied by six kg) – 132,000 MT, industrial and other purposes per year – 48,000 MT, total country requirement for the said year – 180,000 MT, total salt production for the said year – 130,000 MT, the shortage of salt – 50,000 MT, and the imported quantity of salt in January of this year (2025) – 25,000 MT. Furthermore, salt imports continued throughout last month (June) as well.
Over the past three years, unusually heavy rainfall has severely impacted salt production in Sri Lanka. The annual rainfall in the saltern areas significantly exceeded the average of 1,000 millimetres (mm), with recorded levels of 1,073 mm in 2022, 1,500 mm in 2023, and 1,895 mm in 2024. This excessive rainfall led to a substantial reduction in the salinity of lagoon brine, resulting in diluted brine density throughout the salt production system – including the reservoirs, condenser ponds, and forebasins. The most critical impact was observed in the crystallisers, where the reduced brine concentration caused already-formed salt to dissolve before it could be harvested.
As a result of the unfavourable weather conditions, annual salt production across all salterns in Sri Lanka dropped significantly, reaching only about 40% of the expected output. This severe shortfall led to the necessity of importing salt from India to meet the country's demand.
As of June, no salt has been produced in any of the salterns due to continuous and unusual rainfall over the past five months, with rain occurring almost every month. This persistent weather pattern has once again disrupted the salt production cycle: January – 175 mm, February – 81 mm, March – 114 mm, April – 141 mm, May – 124 mm, and June – 20 mm.
A continuous dry period of at least 80 days without rain is necessary to complete one full cycle of salt harvesting in a saltern.
If the current unfavourable weather patterns persist in the coming years, it will be necessary to explore alternative methods using modern technology - such as an integrated facility combining a desalination plant, a chemical treatment plant, and a pure vacuum-dried salt (PVD) production plant.
Salt’s presence often goes unnoticed but its absence leaves everything tasteless.
(The writer is a consultant in the salt industry)
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The views and opinions expressed in this article are those of the author, and do not necessarily reflect those of this publication