Even as Union Finance Minister Arun Jaitley announced an ambitious Rs. 2037-crore ‘Namami Ganga’ project in his maiden budget to kick-start the process of cleaning up the holy river, a noted water expert has said the model adopted to rejuvenate the Thames in London could be “ideal” for freeing the Ganga from pollution.
In the mid-19 century, the Thames river or the ‘Great Stink’, as it was then called, was so bad that even sittings in the House of Commons had to be put off. But in subsequent years, as part of an ‘ongoing restoration plan’, a systematic application of scientific methods of wastewater treatment helped to turn around the “once dead Thames”. The river has now been “fully rejuvenated,” says P.M. Natarajan, a member of the working group of the State Planning Commission.
Sharing his thoughts on this issue with The Hindu , in the backdrop of the Prime Minister Narendra Modi having announced a new Ganga river restoration plan, Mr. Natarajan pointed out that the best way to do it could be the four-fold strategy adopted for the Thames.
The steps for wastewater treatment are adoption of source control and sustainable urban drainage; separation of foul and surface drainage and local storage; screening or treatment at the point of discharge to the river; and in-river treatment. Among the potential strategies, “the screening or treatment at the point of discharge would fully meet the objectives,” Mr. Natarajan claimed.
Mr. Natarajan said the Ganga basin constitutes 26 per cent of India’s land mass. Major cities in the basin — including Delhi, Agra, Meerut, Kanpur, Lucknow, Varanasi, Allahabad, Patna and Calcutta — generate and discharge huge quantities of wastewater into the river. There are 29 cities with a population of above one lakh in the basin, 23 smaller cities with a population between 50,000 and one lakh, and 48 towns with fewer than 50,000 inhabitants each.
Citing data from the Central Pollution Control Board, he said a large number of industries (over 250 units) situated in this zone, from Uttar Pradesh to West Bengal, discharged “toxic substances” into effluent flows “with BOD (biochemical oxygen demand) concentrations of more than 100 mg per litre. Each unit generated “over one million litres of wastewater a day.”
The first and second phases of the Ganga Action Plan, launched during the mid-1980s, did not serve the purpose, Dr. Natarajan said. Not only was the programme delayed by problems in land acquisition and litigation, the “infrastructure installed failed to close the gap on the sewage generated in the Ganga basin,” he noted. More importantly, the treatment plants, already beset with erratic power supply, suffered from “erroneous positioning, mostly on the peripheries,” he said. The total expenditure incurred so far by the Centre has been about Rs.950 crore.
Given the current “total pollution load” of the Ganga basin at 50,500 million litres per day (MLD), it would be ideal to have treatment plants of 20 MLD capacity each, and “villages have to be connected so as to reach the capacity of each treatment plant,” Dr. Natarajan said. Specific treatment facilities for each type of industrial effluent were also needed.
While numerous technologies were used to recycle wastewater, he said, it was not advisable to “start treating the wastewater and leave it halfway” as it was done in the first two Ganga action plans in the past 30 years. The biogas extracted from the processing of wastewater could be used for cooking and generating some electricity. The ‘bio sludge’ was another important by-product that could be used as manure, he said, advocating a multi-pronged approach. “Ganga, the holy river, can thus be made permanently holy without foul smell,” he added.
