TAMIL NADU

Ganga clean-up project can emulate Thames model, says expert

Major cities in the Ganga basin discharge huge quantities of wastewater into the river. A scene at Sangam in Allahabad after the Kumbh Mela held last year.— FILE PHOTO: AFP  

: 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{+t}{+h}century, the Thames river or the ‘Great Stink’, as it was then called, was so bad that even sittings at 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 has helped to turn around a “once dead Thames river”. The waterbody 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 in the case of the Thames.

The wastewater treatment steps involved the following: ‘adoption of source control and sustainable urban drainage, separation of foul and surface drainage and local storage, screening or treatment at the discharge point to the river and fourthly, in-river treatment’. Among the potential strategies, “the screening or treatment at the point of discharge would fully meet the objectives,” Mr. Natarajan claimed.

Stating that the Ganga basin constitutes 26 per cent of India’s land mass, Mr. Natarajan said 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 Ganga basin, 23 smaller cities with a population between 50,000 and one lakh and 48 towns with less than 50,000 inhabitants each.

Citing Central Pollution Control Board data, 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 per 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 land acquisition and litigation problems, 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 by erratic power supply, suffered from “erroneous positioning, mostly at 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 are 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 got from processing wastewater could be used for cooking and generating some electricity. The ‘bio sludge’ is 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.