With major water projects in three cities, L&T is helping Maharashtra attain a crucial Sustainable Development Goal, writes Bappaditya Paul
The use of gravitational force for water distribution is nothing new. We use this to distribute water from the terrace tanks in our houses. In treatment plants at small villages, water is distributed from tall tanks by exploiting the same mechanism as it does not require electricity.
But ever imagined water being distributed as far as 88 km from a treatment plant by only using gravitational force? Well, this is what L&T is making possible in Mumbai!
The Water & Effluent Treatment (WET) vertical of L&T is close to completing a major project – Surya Regional Water Supply Scheme – to distribute a whopping 403 MLD (million litre per day) water to Mira-Bhayandar and Vasai- Virar – the two ever-growing urban hubs that are part of the Mumbai Metropolitan Region. Prime Minister Mr Narendra Modi dedicated Phase-I of this project to the nation during his visit to Mumbai this 12 January.
Mira-Bhayandar and Vasai-Virar are, in every sense of the term, an extension of Mumbai city to the north. These localities are witnessing a huge surge in population with every passing day: as per the 2011 census Vasai-Virar had 12.22 lakh and Mira-Bhayandar had 8.09 lakh people. In the past 12 years, the population has gone up manifold, and with it, the thirst for water.
To address this growing thirst, the Mumbai Metropolitan Region Development Authority (MMRDA) conceived the Surya Regional Water Supply Scheme at Suryanagar village in Palghar district – about 122 km from Mumbai. Treated water from there is to traverse about 60 km through hilly and forested areas to the master balancing reservoir (MBR) at Kashidkopar for distribution in Vasai-Virar and another 28 km to the MBR at Chene for distribution in Mira- Bhayandar.
L&T started working on this project in August 2017, with the initial commissioning deadline being April 2023. The project was delayed as the forest department’s clearances, etc. came only in 2020, and then there was the COVID pandemic. The revised completion deadline now is May 2024.
But in between, in June 2023, L&T has commissioned Phase-I of the project involving 185 MLD capacity and the water supply to Vasai-Virar commenced in November 2023.
“With over 96% of the work been completed, we are confident of homing in the remaining 218 MLD portion for Mira-Bhayandar by coming May,” says Mr Colin Nithin Nonis, a young L&T-ite heading the project as Project Director.
WEAVING A WONDER
River Surya is the source for this ambitious water supply scheme. As in any water project, here too raw water is first pumped up in an intake facility, treated at a plant, channelised to a reservoir and then to the designated distribution system.
The bi-storied intake facility for the project has been constructed at Kawadas, a rocky forested village downstream of Dhamani Dam on Surya river in Palghar district.
“The intake facility where we are standing right now was once an 85-metre-high rocky hill. We had to excavate some 30 metres to construct this facility, and that was easier said than done,” reveals Mr R Ratnaparkhi (Section In- charge – Intake & WTP), looking towards the Dhamani Dam located some seven km away.
As against the requirement of 403 MLD water, the intake facility’s built-in capacity is 707 MLD. The additional capacity is for future expansion. Right now, the intake has six pumps of 560 kW each – four for regular operations and two on standby.
Raw water from the intake facility traverses through an underground pipeline to the treatment plant located two-km away at Suryanagar, another tribal village in the vicinity.
The plant has been constructed on a 40-acre plot surrounded by forests on three sides and a school on one side.
One of the largest water treatment plants in Maharashtra, it is equipped with state-of-the-art infrastructure and technologies – fume channels, flash mixers, sludge blanket clarifiers, rapid sand gravity filters, chlorine contact tanks, clear water reservoir, a 1 MLD break pressure tank (BPT), modern testing lab and a 24x7 SCADA control room.
Adding to the plant’s sustainability quotient is a sludge treatment plant that converts the sludge separated from water and turns it into ‘cakes’ for disposal as per pollution control norms. “This makes the plant a zero-discharge one as against the minimum 2% discharge by conventional water treatment plants,” points out Mr Nonis.
But the most interesting part of the Surya Regional Water Supply Scheme is not the plant per se. Rather, it is how the treated water flows from the BPT to the distribution points and finally to households located up to about 100 km away!
The outlay from the BPT to the reservoirs involves an underground pipeline and four tunnels of 7.4 km cumulative length starting as deep as 55 metres below the surface and negotiating a peak overburden of 185 metres. The pipeline runs below National Highway No 8, Tansa and Vaitarna rivers, Vandri lake, several hills and finally the Vasai creek.
Of the four tunnels, the longest is the one running through Tungareshwar. It runs for 4.6 km and has an internal finish of 2.85 m diameter – meaning, an individual can easily stand inside. “This is India’s first RCC pressurised tunnel and, so far, the longest single-drive tunnel that L&T has constructed using a tunnel boring machine,” says the Project Director.
The three other tunnels are Medhwankhind (1.7 km), Kaman creek (250 metres) and Vasai creek (900 metres). While the first two are complete, work on the one under the Vasai creek is in progress.
“The biggest challenge in this project, apart from boring the tunnels under rocky forested hills, was the laying of underground pipeline along the ever-busy Mumbai-Surat national highway. We achieved this through controlled blasting without hindering the traffic at all,” beams Mr Nonis.
ADVANCING A SUSTAINABILITY GOAL
Once the Surya project is fully commissioned, Mumbai will be a step closer to attaining the United Nation’s crucial Sustainable Development Goal of ensuring clean water for all, and L&T can take pride in the role it has played towards this noble endeavour.
Apart from the construction, L&T will operate and maintain the project for eight years. The treated water supplied from it will cater to about 30 lakh people of Mira-Bhayandar, Vasai-Virar and the adjoining 27 villages.
This is no mean a feat, because as per NITI Aayog’s Composite Water Management Index report 2018, about two lakh people die in India every year due to inadequate access to safe water.
“Apart from Surya, our association with the state of Maharashtra extends to the Nashik Water Supply project (137 MLD) which was commissioned in 2019, and an ongoing first-of- its-kind 24x7 water management project in the city of Pune split over five packages to cater to 59-lakh people,” says Mr G Balasubramanian (Head – Urban Water & Water Management, WET).
The Nashik water treatment plant is no less than a benchmark when it comes to constructing and operating a drinking water scheme. Located at Vilholi, on the outskirts of Nashik, it caters to a population of around six lakhs.
The plant draws raw water from the Mukane dam, located some 15 km away, and treats it before channelising to the Pathardi distribution point of Nashik Municipal Corporation (NMC).
“Apart from catering to NMC areas, the plant also supplies drinking water to three other locations closer to the city,” says Mr Sandeep More (Project Manager – O&M).
L&T was supposed to operate and maintain the plant for three years until July 2022, but the NMC authorities are so pleased with the service that it has so far extended the tenure by an-year-and-a-half. Further extension is likely.
“The quality of construction is very good, and the operations & maintenance are extremely transparent. We haven’t encountered any major issue in the past four years and for this we thank L&T,” says Mr Avinash Dhanait (Superintendent Engineer – Mechanical & Electrical, NMC), who looks after water sourcing for the city.
This candid appreciation is a testimony to L&T’s commitment to bring about a sustainable change to people’s lives through the Company’s many and varied business offerings.
FACTS THAT MATTER
- The earth possesses only 3% fresh water as against the total water cover of 70%.
- World Bank classifies water scarcity as when people receive less than 1,000 cubic metres of fresh water per person a year.
- Globally, over one billion people lack access to water and another 2.7 billion receive limited water supply for at least one month a year.
- According to NITI Aayog, about two lakh people die in India annually due to inadequate access to safe water.
- According to UN-endorsed projections, the global demand for fresh water will exceed supply by 40% in 2030.
