Agreeing with the view that the rejected water in the process of purification by Reverse Osmosis (RO) systems further percolates down to the ground water, thereby contaminating it, the National Green Tribunal (NGT) has constituted an expert committee to devise ways of re-filtration or secondary use of such water.
The tribunal, while dealing with an application filed by an NGO, Friends, has set up a panel comprising representatives of Ministry of Environment, Forests and Climate Change (MOEFFCC), Central Pollution Control Board (CPCB), Bureau of Indian Standards (BIS), Indian Institute of Technology, Delhi and the National Environmental Engineering Research Institute (NEERI), Delhi, to look into ways of making re-filtration or the secondary use of the rejected waste water from RO systems viable.
The committee, to be coordinated by the CPCB, has also been asked to explore whether deficiencies in the filtered treated water could be made up and whether the purified water needs to be remineralized in order to compensate for the minerals lost during the RO purification process, besides suggesting ways of utilizing the waste water.
The panel would also go into the question of whether different approaches are required in different parts of the country having their own specific problems of ground water contamination, requiring customized solutions.
The expert group, which has to furnish its report with the tribunal by April 30, 2019, has further been directed to review the prescriptions of standards for drinking water.
The petitioner, in the matter, contended by Advocate Rahul Choudhary, said that the RO purification processes led to huge wastage of large quantities of fresh water.
The petitioner claimed that in a given RO purification system, around 80 per cent of the water fed to it is wasted, which “otherwise could be used by the middle class and lower class people of the country”, while only 20 per cent of the water gets purified which is “used by a limited class of the society thus depriving a large number of common people of the country who cannot buy and maintain such very expensive filters from having potable water”.
“For each litre of filtered water, domestic filter dumps some 3-4 litres of wastewater. If it is assumed that there is a colony of 400 households and assume each household is using RO system for consuming 100 litres water per day, the daily wastage will be to the tune of 1,20,000 litre that too in the case where the waste from each RO filter is considered to be around 70%,” the application, citing several newspaper articles, claimed.
“…in the absence of any regulatory restrictions, manufacturers are encashing consumer sentiments by making tall claims like turning drain water into pristine potable water. RO systems, being generally used by a well-off class, generate contaminated waste water in excess that further contaminates other sources of water,” raised the petition that sought directions to the manufacturers to stop sale of RO machines or improve them to recycle water wastage during the RO process.
The petition filed on April 29, 2015, also sought directions to Ministry of Water Resources to provide an effective centralized water purification mechanism in urban as well as rural areas to bring down the popularity of RO systems and eventually phase it out in due course of time.
Sharad Tiwari, general secretary of the petitioner organization, said, “We brought before the court that apart from the domestic RO users, the industrial and commercial users wasted huge quantities of water laden with impurities. We had asked that such rejected water from industrial and commercial users should be treated as an effluent within the meaning under Section 2(k) of the Water (Prevention and Control of Pollution) Act, 1974.”
“Further, the BIS has only laid some standards for the RO systems but have fallen short of making it mandatory. As a result, no manufacturer is producing RO machines with ISI certification. Even in areas receiving treated or Ganga-like pure water from supply agencies which have no TDS (Total Dissolved Solids) content, households are using RO machines when they are meant only for removing the latter. We would place these facts before the committee, as well,” said Tiwari.
The Water Quality India Association (WQIA), representing the water treatment industries stated, in its response, that 98 districts in 13 states were affected by high arsenic contamination in groundwater. High TDS was common which could adversely affect the health. Thus RO system was helpful in the situation. The residue of purified water is not water wasted but water consumed in the same way as the water is left over after washing clothes or after bathing.
The CPCB had admitted that the waste water from RO was laden with pollutants, which is then thrown away and gets mixed with ground water.
“There is no denying the fact that while purification may help public health by avoiding adverse effect of heavy metals or other contaminators, the fact remains that the rejected water remaining major part which goes to the ground water and again contaminates even the pure ground water,” observed a bench of Chairperson Justice Adarsh Kumar Goel, Judicial Members Justices S.P. Wangdi and R. Ramakrishnan and Expert Member Dr. Nagin Nanda.
“There is undoubtedly scarcity of drinking water. While purity of drinking water is a priority, the process pf purification should not result in contamination of the remaining available water,” the NGT observed while asking the expert committee constituted to explore the upgrade of the available technology in line with the latest advancements.
Read the Order Here