India is faced with the alarming prospect of becoming water scarce by 2025. Close to 200 million from 1.2 billion will not have access to clean water. In his reply to a question in Lok Sabha, Minister of State for Water Resources Sanwar Lal Jat on Thursday said that consulting firm ‘Everything About Water’ (EA Water) has concluded that India’s demand for water is expected to exceed all current sources of supply and the country is set to become water scarce by the year 2025.
India is not alone in this predicament – according to Population Action International, based upon the UN Medium Population Projections of 1998, more than 2.8 billion people in 48 countries will face water stress, or scarcity conditions by 2025.
The possible solution to prevent an exacerbation of this situation is utilizing the current sources correctly i.e. sustainable management of existing water supply.
One country which stands ahead of the crowd in water management solutions is the state of Israel. Israel is a country that is just 67 years old, was born the same time as India and has an extremely harsh topography. They have just three sources of natural water – Sea of Galilee, underground aquifers and rainwater runoff (rainfall is restricted to two weeks in a year). Because rain falls only in the winter, and largely in the northern part of the country, irrigation and water engineering are considered vital to the country’s economic survival and growth. Additionally, Israel has had to contend with continuous years of drought, with a concurrent increase in population and water consumption.
These combined factors made the government of Israel undertake water management as early as 1955. Today, the country has not only achieved sufficiency, Israel government exports excess water to countries in the region.
Shafdan Water Plant
Shafdan waste water plant is Israel’s largest wastewater treatment facility – it treats and reclaims water for 2 million people in Tel Aviv and 22 cities and towns throughout central Israel. Mekorot, the national water company, is responsible for administering and carrying out the purification process.
Completed in 1969 the Shafdan wastewater treatment plant is spread over 125 acres of land. Located to the south of Tel Aviv, Shafdan has the capacity to treat approximately 130 million cubic meters of wastewater per year. Shafdan spokesman Meir Ben-Noon lays out the reason, “Because sewage is 99.8 percent water, the potential to reuse it is huge. The objective of the Shafdan plant is to exploit that potential,” otherwise, he says, “sewage just goes to contaminate the rivers, lakes and the sea.”
On a daily basis, the Shafdan plant treats close to 100 million U.S. fluid gallons of wastewater, received through pipes which are located more than 80 feet below ground. The pipes are 6.5 feet in diameter and the network stretches over a 100 kilometres. Once the sewage reaches Shafdan, the multi-stage purification process begins with pretreatment. Bar screens, vertical steel bars spaced between 1 to 3 inches apart, remove large objects – bags, diapers and cell phones (and in rare cases – bicycles) are removed.
Following the initial filtering process, basins separate the remaining grit, oils and fat. Grit sinks to the bottom and is pumped into four sand separators. Oil and fats float to the surface and are transported to an adjacent plant that recycles them for industrial use.
Next comes biological purification, whereby microorganisms digest organic materials in the sewage. Special ventilators generate oxygen-saturated areas to accelerate the digestion process. Whatever settles to the bottom is sludge, and what remains on top is treated wastewater that is transferred to large sand fields used to filter the water to potable levels.
The fields, managed by Mekorot, Israel’s national water company, are the final treatment phase. They are flooded with wastewater that eventually sinks through nearly 100 feet of sand, a filtration process that takes 400 days. At the end of the complex procedure, the water is pumped out
Recently the company began to develop advanced methods of purifying the sewage before recharging it into the sand. This became necessary as despite the benefits of the current purification process, it was discovered that when the wastewater is recharged into the ground after undergoing primary purification, it damages the soil that it reaches before it hits the sand. As a result of that damage, experts looked at new ways to purify the wastewater, which are not easy to find in densely populated areas.
Today the purified water from Shafdan is almost equal in quality to drinking water, and is used for irrigation in the Negev. The plant is also energy self-sufficient.
Sorek Desalination plant
Until, 2004 Israel relied entirely on groundwater and rain, but today it has four seawater desalination plants running; Sorek being the largest. Desalination plants account for 40 percent of Israel’s water supply.
Located 15 kilometres from Tel Aviv, the Sorek desalination plant, built by IDE Technologies in 2013 for the Israeli government is the country’s largest desalination facility. At full capacity, the Sorek plant produces 627,000 cubic meters of water of desalinated water on a daily basis. Sorek uses the conventional reverse osmosis technology for desalination but due to engineering and materials advances, it produces clean water from the sea cheaply and at a scale never before achieved.
The plant is fitted with pressure tubes that are 16 inches in diameter rather than eight inches. This allows more capacity, needs only a fourth as much piping and other hardware, slashing costs.
The plant also has highly efficient pumps and energy recovery devices. “This is indeed the latest technology and allows one of the cheapest methods of potable water generation from seawater desalination in the world”, explains Udi Tirosh, the business development director at IDE Technologies.