Not rain, drain water harvesting is the need of the day for growing cities
- India’s cities produce nearly 62,000 million litres per day (MLD) of sewage.
- The current capacity for sewage treatment stands at 23,277 MLD.
- Only 18,883 MLD sewage is treated in India.
- Currently, only 30% of sewage water is treated for purification in India. The rest of the untreated sewage flows directly into water sources like rivers and ponds.
- The untreated sewage is severely polluting the natural water sources, owing to mismanagement.
- Technology is available to turn sewage into safe drinking water.
For a country with ambitious plans like the Swachh Bharat Abhiyan and the Smart Cities Project, figures about India's sewage don't make for very good reading.
India’s cities produce nearly 62,000 million litres per day (MLD) of sewage, while the current capacity for sewage treatment stands at 23,277 MLD. Of this, only 18,883 MLD sewage is treated in India.
Beneath the tall claims of a surging economy lies a grim reality – ruining of nearly 75% of India’s water resources are wasted. Domestic sewage – flowing untreated into drains – accounts for 75-80% of contamination of natural water bodies.
According to a 2016 report published by the data journalism portal indiaspend.com, no more than 30% of sewage generated by 377 million people in urban areas flows through treatment plants. The rest finds its way to rivers, seas, lakes and wells without any treatment.
The case of Bhopal and Indore
Bhopal and Indore – two of Madhya Pradesh’s biggest cities – epitomise this problem like few other Indian urban centres. The government has spent thousands of crores to supply drinking water to these cities from the Narmada River, which flows at a distance of around 70 kilometres. However, water resources lying nearer to the population have been rendered useless, only because of the lack of sewage treatment.
State capital Bhopal gets around 266 million litres a day of water (MLD). The city generates 285 MLD of sewage, of which only 39 MLD is treated. Nearly 246 MLD of untreated sewage is discharged into drains, a large part of which ultimately finds its way to major ponds and lakes. Every day, water is lifted from the Narmada River to fulfil the requirements of a rapidly growing city. To bring water from a distance of nearly 67 km costs around Rs 50-70/litre.
Senior journalist Devendra Sharma has closely monitored development-related issues in Bhopal for years. He laments: “Nearly Rs 1,500 crore was spent in Bhopal on drinking water and solving the sewage problem during the past decade. Besides Project Uday, lavish funding was also provided under the Jawaharlal Nehru National Urban Renewal Mission (JNNURM) to sort out these issues. However, there was a little tangible impact on the ground. No plan could take effect, due to the lack of coordination among the various government agencies, and non-availability of proper expertise.”
Likewise, Indore receives approximately 200 million litres of water every day (MLD). The city produces 240 MLD of sewage, of which only 25% is treated. The rest is dumped into the Kahn River (now known as Kahn nullah), which ultimately merges into the Kshipra River. An overwhelming majority of sewage produced by Madhya Pradesh’s financial capital mixes with the Kshipra, the same river that provides drinking water to Ujjain.
Like Bhopal, water is lifted 70 km from the Narmada River at a considerable cost. Yet, it falls short of quenching the thirst of Indore’s citizens. A large population still relies on groundwater for daily requirements in both the cities.
Need for a new solution
“The sources supplying water to our urban centres are limited. We urgently need to start water management to ensure continuous supply to rapidly-developing cities,” warns Megha Shenoy, Adjunct Fellow at the Ashoka Trust for Research in Ecology and the Environment (ATREE) in Bengaluru.
She adds: “All states are focusing on rainwater harvesting. However, most cities get rainfall only for a few days. Whereas, millions of litres of water is wasted every day in the form of sewage. An effective utilisation of this water can solve the water crisis of our cities to a great extent.”
Drain water harvesting
An increasing number of experts can see the point in Shenoy's argument. This is the reason country’s IT capital, Bengaluru, has taken its first steps towards ‘drain water harvesting’.
The Karnataka government has made it necessary for every building in the city with 20 or more flats to have a sewage treatment plant of its own. The rule also applies to every commercial complex over the size of 2,000 square metres, and educational institutes spread in an area of 5,000 square kilometres or more.
Every such sewage treatment plant costs around Rs 10-15 lakh. The average cost of treatment of sewage water in these plants comes to nearly Rs 40-60 per litre.
The concept of treating sewage water for drinking purposes in still taking root in India. But, it is already successful in Singapore, a country that imports drinking water from Malaysia. The city-state now fulfils 30%of its drinking water requirements through such sewage treatment plants.
Singapore is among the countries that face the most acute water crisis. It is the country that started the innovation of making sewage water fit for drinking. Now, Singapore-based companies are giving consultancies to other nations on sewage treatment.
It's probably the way India needs to go, sooner than later.