Collected sewage often flows untreated into the Ganges, and decentralized treatment has been proposed as a solution
The Ganges, or Ganga, is not only officially India’s national river, it also is considered its most sacred. The Ganges River dolphin is the national aquatic animal, and Varanasi, the City of Temples, one of the oldest continuously inhabited cities in the world, is situated on its banks. During the Kumbh Mela religious festival that lasts 55 days, 120 million Hindus have been known to bathe in the river waters to wash away the cycle of rebirth. But the purifying Ganges is also paradoxically India’s most polluted river.
India Taking Sanitation Seriously
In recognition of the river’s significance, Indian president Narendra Modi said on his last visit, “I feel Maa Ganga has called me. I feel like a child who has returned to his mother’s lap.” His government has spent over half a billion dollars on projects to clean up the Ganges, but it is still largely unfit for drinking, bathing, household use, or irrigation. For almost 80% of the population that lives within the Ganges’ catchment, water taken from the river fails sewage standards for agricultural irrigation; 85% live near water that is unsafe for bathing.
The prime minster has stressed improved sanitation, and in 2014 he launched the Swachh Bharat Abhiyan (Clean India Mission) campaign to end the widespread practice of open defecation before Mohandas Gandhi’s 150th birthday on October 2, 2019. The campaign has the slogan, “toilets before temples.” Gandhi himself once said, “Sanitation is more important than independence.”
Problems With Sewers
But recent research suggests that new sewer systems are even worse for the Ganges than no sewers at all. A team of researchers looked at 10 years of water data and found concentrations of fecal coliform (a pollution-indicating bacterium found in human feces) increased when upstream population density increased, which was not surprising. But the surprise was that Indians living in densely populated areas contributed 100 times more sewage to the river per capita than rural residents or residents of comparably populated areas in other countries.
Of course, the residents do not each produce more sewage. Metropolitan sewers in India often simply flush the sewage quickly out into the river without treatment, leading to the higher per-person discharge levels. In rural areas, by contrast, sewage is usually deposited in open pits and latrines, so microbes are more likely to break it down before it reaches the river.
Decentralized WWT for the Developing World
The efficient sewage removal provided by sewers is necessary for public health, but without wastewater treatment, sewers simply move the problem of waterborne diseases to the river and, hence, to downstream residents. Newcastle University research fellow David Milledge and Joshua Bunce, an environmental engineering researcher, concluded that decentralized treatment is a possible answer to the dilemma:
The urgency to invest, not only in sewers, but in the treatment of sewage has never been greater — especially in the most densely populated areas. However, the Western approach of taking all waste to a central treatment plant is expensive and so may not be the best solution.
Onsite treatment technologies such as off-grid toilets or decentralised treatment plants are rapidly developing and may help improve river water quality sooner, enabling more and more people to celebrate Kumbh Mela safely.