Moumita Chakraborty
Geocycle India, the in-house waste management arm of Ambuja and ACC, has harnessed a non-invasive, zero-waste technology to clean the Yamuna River of plastic waste. Used in India for the first time, Bubble Barrier technology channelises plastic waste towards the banks of rivers, from where it can be collected for further treatment. The Bubble Barrier has been installed in Agra’s Mantola Canal, which carries 40% of the city’s stormwater and wastewater, and empties into the Yamuna.
In an interview with Clean India Journal, Moumita Chakraborty, Head, Geocycle Asia explained how the barrier works, what happens to the collected plastic and why this is a scalable solution.
The principle
The canal contains plastic waste that drifts along with its current; some of it is also dragged along the bed of the canal. Ordinarily, this plastic would flow into the Yamuna and ultimately into the sea.
The Bubble Barrier is produced by introducing perforated air tubes under the surface of the water body and across its breadth; these can be placed at a depth or even on the floor of the water body, depending upon water quality analysis. The tubes are connected to a source of compressed air, which is powered by solar or any other form of renewable energy. This air forms a vertical sheet of bubbles, or a ‘bubble barrier’, which forces plastic to the surface of the water body.
Since the air tubes are arranged diagonally across the canal, the plastic waste which is made afloat is pushed by the current of the river to its banks, where it collects.
What happens to the collected plastic?
In Agra, this material is lifted by a front-end loader and taken to a material recovery facility, where it is segregated by Geocycle’s partners. Recyclable material is sent to an authorised recycler, while other material is taken to the nearest Ambuja ACC plant where it is co-processed to generate alternative fuels which are fed into cement kilns, replacing traditional fuels like coal, reducing the plant’s carbon footprint. “Nothing we collect goes back into the environment; this is a zero-residue technology,” said Chakraborty.
The bubble barrier has been used by the oil industry to clear up spillage from the ocean and other water bodies. Recently, it has been adapted to curb marine pollution.
“Nothing we collect goes back into the environment; this is a zero-residue technology”
Why the Bubble Barrier is an apt solution
The technology is non-invasive; there is no net, mesh or electrical pulse. Marine fauna does not get caught by the barrier; ships too are undisturbed.
By using combinations of 3-5 barriers, the plastic entrapment efficiency increases. The pilot project at Agra uses three barriers, and operates at over 90% efficiency.
The collected plastic is deposited along the banks of the canal over 3-5km. In the future, Geocycle plans to use a suction mechanism to collect it. In the first year of operations, 2,400-3,000 tonnes of plastic waste are expected to be collected.
Under the aegis of United Nations Environment Programme (UNEP) India’s ‘Air Pollution Control Action Plan’, Geocycle has partnered with Agra Municipal Corporation and GIZ India with Canadian Pond as technology provider. Once successful, this technology will be replicated in other countries.
According to Chakraborty, the overall aim of the project is making the environmental footprint of companies more positive. “We are partnering with people who are already in the value chain and integrating our system with it,” she said. “That’s why it is so scalable.”
