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Wednesday, July 08, 2020

By the side of a dirty Delhi drain, an Indo-Dutch hunt for a cleaning solution

Why a novel project holds out hope for cleaner drains and rivers, free also of ‘contaminants of emerging concern’.

Written by Harikrishnan Nair | New Delhi | Updated: July 24, 2018 2:11:05 pm
Barapullah flyover

Next to Delhi’s foul Barapullah drain, under the flyover that bears the name of the nullah, a unique project is under way — one that has the potential to change how sewage is treated in India.

LOTUS HR — Local Treatment of Urban Sewage Streams for Healthy Reuse — is a joint effort by top Indian and Dutch institutions to test technologies that target, apart from conventional contaminant parameters like biochemical oxygen demand (BOD), pH value, etc., “contaminants of emerging concern” such as pharmaceutical and personal care products (PPCPs), the effects of which were until recently only poorly understood.

LOTUS HR is funded by the Department of Biotechnology and NWO, the Dutch science agency. The foundation stone for the project was laid a year ago by Science and Technology Minister Harsh Vardhan and the then Foreign Minister of the Netherlands, Bert Koenders.

Personal care, general fallout

The US Environment Protection Agency defines PPCPs as “any product used by individuals for personal health or cosmetic reasons or used by agribusiness to enhance growth or health of livestock”. Untreated sewage and improper disposal of leftover medication are its prime sources, besides poor sanitation.

“Things that you use every day contribute to this, and its effects are not very apparent. There are around 3 lakh chemical compounds that fall under this category,” said Shaikh Z Ahammad, assistant professor, IIT-Delhi, which is leading the Indian team that includes The Energy and Resources Institute (TERI) and the National Environmental Engineering Research Institute (NEERI).

Even a few nanogrammes of PPCPs per litre can disrupt the endocrine systems of animals and plants. It can also increase resistance of certain microbes, and could even be carcinogenic. “A UK study showed oestrogen in rivers that could have come from birth control pills, could have contributed to the feminisation of certain aquatic animals,” Prof Ahammad said.

India does not currently have protocols and treatment standards for emerging contaminants.

The Barapullah experiment

An on-site lab and pilot plant has been set up on a 200 sq m plot by the drain, close to the Sun Dial park. “This is one of the most polluted canals, containing waste from both urban and rural areas, and industrial effluents as well,” Dr Pushap Chawla, senior project coordinator, IIT-Delhi, said. “We believe that if we can successfully treat the water here, we can replicate it according to need in other areas too.”

Biomechanical filters

The lab has six sets of biomechanical filters, with the water passing through agitated algae, a soil of sponge-like cubical blocks, and a sealed section in which microbes worked anaerobically (in the absence oxygen). The lab is currently able to treat only around 100 litres a day, but the aim is to build, within two years, a viable treatment plant that could process 10,000 litres daily, before offering it to industry to be scaled up.

“We have chosen bio-mechanical methods to keep the cost down, keeping in mind Indian requirements,” said Prof Ahammad. “Much of the sewage in India is untreated. The new systems will be modular, and once tested and proven, can be put in place as a cheaper alternative to retrofitting and upgrading existing systems.” A government release last year had underlined the potential of the project to “produce clean water that can be reused… while simultaneously recovering nutrients and energy from the urban waste water, thus converting drains into profitable mines”.

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