City Matters | Puducherry

Polluted Thengaithittu lagoon an environmental hazard

Beyond redemption: Thengaithittu fishing harbour has now become a cesspool posing a serious health hazard with the untreated sewage flowing into it from Uppar and the Grand Canal (right).

Beyond redemption: Thengaithittu fishing harbour has now become a cesspool posing a serious health hazard with the untreated sewage flowing into it from Uppar and the Grand Canal (right).   | Photo Credit: T.Singaravelou

Indiscriminate discharge of untreated sewage has made the waterbody an eyesore; Grand Canal, built in 1765, has turned into an open drain

Poor waste management systems coupled with discharge of raw sewage from the city’s drains into the Thengaithittu lagoon is posing a serious environmental and health hazard.

The policy makers and bureaucrats often make tall claims about solid waste management and the need to recycle water these words are never put into action. The poor management of wastewater and sewage stands testimony to this.

The Thengaithittu lagoon, where the fishing harbour is located, continues to bear the brunt of neglect over the years. At the confluence point of the Uppar drain and the Grand Canal that carries the city’s sewage, untreated wastewater is illegally released into the lagoon that directly flows into the sea.

According to Probir Banerjee of PondyCan, a non-governmental organisation, “A Coastal Regulatory Zone (CRZ) notification in 2011 mandated that untreated sewage should never be let into the sea as it would damage the marine ecosystem. But the Puducherry government has not taken any initiative to put a mechanism in place to address this issue. The situation is extremely serious as the discharge of sewage has not only compounded the groundwater pollution but also increased pollution of the coast endangering the mangroves and the marine life.”

Originally, water from Aayikulam, Murungampakkam and Kanagan Lake from the city’s north flowed through the Marappalam canal, which was earlier a rainwater canal that drained into the Thengaithittu lagoon.

Several houses in Thengaithittu illegally discharge their household sewage into the canals that drain into the sea.

“All the major canals that originally carried rainwater are now choked with sewage and solid waste. There has been no proper inspection or monitoring by the authorities and the Sewage Treatment Plant (STP) at Dubrayapet, which has a capacity of 17 million litres a day, is not operated properly. This has to be brought to the notice of the people as to why after spending so much of money, STPs are not functional. There should be some system for the public to know whether these huge assets are functioning or not,” Mr. Banerjee added.

Toxic waste

M. Selvamanikandan, president, Puducherry Environment and Mangrove Forest Development and Protection Society, said the discharge of raw sewage mixed with toxic waste into the lagoon infiltrated the mangrove forests, posing a serious threat to mangroves and marine life.

For decades, sewage coming from places such as Nellithope, Boomiyanpet, Reddiyarpalayam, Mudaliarpet, Anna Nagar, Engineer Colony (Velrampet), Olandhakeerapalayam, Uppalam, Vambakeerapalayam has been directly running into sea in and around Thengaithittu.

An official, on condition of anonymity, said successive governments adopted a shortsighted approach to the problem that resulted in mismanagement of sewage treatment.

An underground drainage system was built in 1979 and designed for a population of 1,17,000 as per the City Development Plan.

The Public Works Department was directed to set up grit chambers at a few locations in the Thengaithittu lagoon to reduce the quantity of solid waste entering the sea. But these grit chambers are also not working now, the official added.

A classic example is the Grand Canal that was built as a stormwater drain by the French around 1765.

It was designed to regulate the flow of rainwater towards the north-end into the Uppar drain and to the south into the sea near the new Light House. Over a period of time, the Grand Canal has turned into drain in the heart of the town.

A long stretch of the Grand Canal was covered about 15 years ago. Now it is being used as a dump yard, a parking lot and as a space for local market, he said.

A survey by the Indian National Trust for Art and Cultural Heritage (INTACH) revealed that around 250 houses were let their wastewater into the drains.

Dirty beaches

According to Aurofilio Schiavina of PondyCan, “a lot of sludge has now settled in the Thengaithittu lagoon. During dredging, the sludge, which is highly contaminated with heavy metals, is disturbed resulting in secondary pollution. The lagoon has now turned in to a stinking cesspool located right in the middle of the city. This raises serious concern as all the raw sewage and plastic waste draining into the sea have been polluting the beaches on the southern side.”

During summer, the ocean currents move from the fishing harbour towards the city bringing along with it all the sewage that has accumulated in the lagoon. The sludge again flows towards the beaches on the southern side when the ocean current changes its flow during the northeast monsoon, Mr. Schiavina said.

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Printable version | Mar 29, 2020 12:02:50 AM | https://www.thehindu.com/news/cities/puducherry/polluted-thengaithittu-lagoon-an-environmental-hazard/article28236868.ece

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