In India, climate change, population growth and urbanisation will amplify the challenges and increase the necessity to strengthen governance capacity. The demand for water is expected to rise by over 70 per cent by 2025, leading to a massive gap between supply and demand.

Ahmedabad is one of the cities where water scarcity will plumb even greater depths. The Sabarmati river is a key source of Ahmedabad's drinking water supply.

Sabarmati's Dirty Secret

At a recent hearing of a suo motu PIL over pollution in the Sabarmati River, the Gujarat High Court directed the Gujarat Pollution Control Board (GPCB) and other authorities to work out reutilisation of industrial wastewater released by common effluent treatment plants (CETPs) after treatment. 

The Court noted that while industries were getting pure groundwater or river water, the wastewater remained impure even after treatment and was not meeting prescribed norms. And this wastewater was being released into the Sabarmati, further polluting the river.

The wastewater after treatment  by CETPs doesn't meet prescribed norms for TDS and water colour, it noted.

The Court proceedings have made it public that Ahmedabad's sewage treatment plants (STPs) are not functioning at capacity, and the Ahmedabad Municipal Corporation (AMC) has been evading proper calibration of the needs of the city despite several orders by the High Court.

“The present 6 CETPs are not working at capacity and sewage is not being recycled. Eighty per cent of it is mandated by the Water Act to be reused and supplied back to the industries.

"There are no open spaces for rainwater and other surface water runoff to percolate; storm water flows over our roads entering our drains and causing logging and clogging, and getting wasted,” Mahesh Pandya, Environment Engineer from Paryavaran Mitra, Ahmedabad, told The Secretariat.

“Simply providing freshwater won’t do if we are not able to give back to the source," he added.

The High Court has been trying hard to find out exact data from AMC about the current capacity and efficiency of the existing STPs, and to determine the correct capacity for the future. 

Though final numbers are not out, it is reported that 16 STPs presently functioning with the capacity to treat 1,693 million litres of sewage are only treating 1,252 million litres and, that too at substandard levels.

The remaining sewage is disposed into the Sabarmati, one of the country's most polluted rivers. 

Surat's Success Can Be Inspiring

The AMC's inability to find a fix for this is surprising given that a role model is not far away: The Surat Municipal Corporation (SMC) is a pioneer in establishing the sewage sludge-based power plant in India. 

“Sewage gas generated during sewage sludge treatment is utilised as a fuel to run gas engines to produce electrical energy that replaces grid electricity required to run the sewerage system” making them self-sufficient, says research on the STPs by the School of Planning and Architecture, Bhopal and the Inter-Graduate School Program for Sustainable Development and Survivable Societies, Kyoto University, Japan. 

Wastewater is conventionally treated in four ways. Preliminary Treatment removes material that will either float or settle. Secondary Treatment addresses soluble organic matter that escapes primary treatment. Meanwhile, Tertiary Treatment which can purify water to such an extent that make it safe for reuse in water-intensive processes or even as drinking water.

Tertiary treatment is more effective than primary or secondary treatment at removing unwanted colour from wastewater, and thus it is essential in industrial pulp and paper applications and textiles manufacturing. 

“On successful operation of the first Tertiary Treatment Plant at Bamroli in the last 5 years, the user industries have come forward to get more treated water from SMC,” the research says.

To create tertiary water treatment facilities in Surat, SMC invested Rs 280 crore in it and charged industrial units Rs 23 per 1,000 litres.

Though AMC is said to have begun work to build a tertiary sewage treatment plant and supply textile industries with treated water, this can only work when existing STPs work at capacity.

Ahmedabad is projected to generate 915 million litres per day (MLD) of sewage by 2041, and it would cross a billion litres per day before 2051, says a 2021 case study of Ahmedabad sewage management in the International Journal of Research in Engineering and Science (IJRES).  

At the moment, Ahmedabad uses only 48 MLD of treated wastewater. Of the 774 MLD of sewage treated, only 281 MLD is of reusable quality, reveals the National Inventory of Sewage Treatment Plants of the CPCB in 2021. 

It gets worse. The World Research Institute's Water Risk Atlas places Ahmedabad at 75 per cent with extremely high water depletion. This is measured on the ratio of total water consumption to available renewable water supplies.

Groundwater Depletion, Untreated Wastewater Strain City’s Resources

While the urban set-up suffers from unregulated extraction of groundwater and insufficient supply of freshwater, agricultural lands around the city are forced to make do with supply of untreated wastewater for irrigation.

Uncontrolled urbanisation and building projects on the outskirts of the city are bound to put pressure on the scarce freshwater resources in Ahmedabad, a city with growing heat wave temperatures and related stresses. 

With digging of private borewells for increased industrial and urban usage in the city, groundwater levels have declined by the year, both in quantity or quality.  

The volumes of wastewater generated are so large that managing these quantities becomes a problem. Therefore, besides treating the wastewater, one should explore strategies for reducing the amount of wastewater generated.

“If STPs worked properly, not only will they be able to run themselves sustainably, but also eventually become providers of energy, and earn themselves some money, a domino effect that can then percolate in other areas where Ahmedabad is failing,” notes Pandya. 

Ahmedabad is a good enough stand-in for the countrywide trend across India which has caused nearly irreversible damage: depleted groundwater, its substandard quality, deteriorated and stunted rivers.

This is a first in a two-part series on Gujarat's water management challenges and the growing crisis of pollution, urbanisation, and resource depletion.