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Thursday, May 19, 2022

Explained: Mumbai’s sewage disposal project, and why it’s important for the city

What is the sewage disposal project, and why is it important for the city? Why has it been delayed repeatedly since it was first planned in 2002?

Written by Laxman Singh , Edited by Explained Desk | Mumbai |
Updated: May 4, 2022 11:20:52 am
A sewage treatment plant in Mumbai.(Express Photo: Prashant Nadkar, File)

The Brihanmumbai Municipal Corporation (BMC) has finalised seven contractors to execute work on its ambitious Mumbai Sewage Disposal Project-II (MSDP-II). The long-pending project will be undertaken at a cost of nearly Rs 30,000 crore.

What is the sewage disposal project, and why is it important for the city? Why has it been delayed repeatedly since it was first planned in 2002? The Indian Express explains.

Sewage generation in Mumbai

With a population of 12.5 million, Mumbai generates around 2,400 million litres of sewage every day. The city currently has a sewer line network of 2,025 km. However, the existing lines do not cover the entire city, and the BMC is in the process of laying new lines.

The sewage generated across the city is collected at seven Sewage Treatment Plants (STP) sewage zones — Colaba, Worli, Bandra, Versova, Malad, Ghatkopar and Bhandup.

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Except for Colaba, the other STPs can only do primary treatment of sewage before discharging it into the Arabian Sea. This contributes to high-level pollution in the sea and impacts coastal biodiversity.

A study had previously found that coastal water around Juhu, Girgaum Chowpatty and Haji Ali was the dirtiest. The 17.6 km Mithi river that flows into Mahim Creek and the Arabian Sea was also found to have very high levels of pollution due to the discharge of sewage as well as industrial waste.

Besides this, in the absence of a 100 per cent sewerage network, about 25 per cent of the city’s sewage enters water bodies without any treatment, thus polluting the coast.

What is the sewage disposal project?

Initially, the BMC had planned to upgrade the existing primary STPs at the seven locations. However, in an updated plan, the civic body proposed to construct new STPs to treat the sewage as per the latest norms set by Central Pollution Control Board.

Of the seven STPs, work at the Colaba STP was completed in 2020.

The BMC now wants to complete construction at the remaining locations, as well as build a new plant in Dharavi. The cost for these seven plants is estimated to be Rs 29,653 crore.

So, why has there been a delay in the project?

Technical difficulties in construction, space constraints, change in discharge norms, and political fights are some of the reasons for the delay.

Further, the tenders for the project have been cancelled four times so far. For instance, in 2019 when the National Green Tribunal ordered the BMC to follow the stringent discharge norms for the proposed STPs, the tenders were cancelled.

In February this year, the tenders for appointing contractors were once again cancelled. This time, tenders were scrapped due to high bids from contractors and allegations of cartelisation.

Why is there a cost escalation in the project?

The cost of the MSDP-II has been hiked three fold from its initial proposed cost of Rs 5,500 crore in 2009. The BMC has said the cost of the project has increased due to delays and changes in discharge and stringent treatment norms.

As per the estimates prepared in August 2020, the contract for the six STPs was to cost Rs 16,412 crore. The tenders, however, were scrapped after contractors quoted 30-70 per cent above the BMC’s estimate.

Now, as per fresh estimates prepared for the STPs, the cost for the initial six STPs has gone up to Rs 23,247 crore. With the inclusion of Malad, the cost has risen to Rs 29,653 crore.

Officials from the BMC said that in the last 20 months, change in inflation rates, technical challenges and the Russia-Ukraine war have contributed to cost escalation.

What is the current status of the project?

The BMC has finalised seven contractors for each of the seven STPs. They have agreed to execute the work for Rs 25,963 crore.

The civic body will now submit a detailed affidavit with the finalised contractors to the Supreme Court seeking further direction on the project.

On February 1, the apex court while hearing a petition on coastal pollution due to the discharge of untreated sewage into the sea, had criticised the Mumbai civic body. Expressing anger over the delay in the project, the top court had said it would monitor the process of awarding the contracts, and directed the BMC to submit a report after contractors are finalised. The hearing before the court is likely to be held on Wednesday.

BMC officials said once contractors are appointed, it will take 48-72 months to complete the work. Apart from design and construction, contractors will also be responsible for operation and maintenance of STPs for the next 15 years.

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