Flourishing seaside Chennai with water woes

Location: Chennai, India
Project: Minjur Seawater Desalination Plant
Capacity: 100,000 m³/ day
Energy Savings: 95,484,000 kWh/year* (energy savings estimates based on India’s power cost of $0.1/kWh)

The Challenge: A Flourishing Seaside Metropolis with Water Woes

With a growing metropolitan population of over 8 million people, Chennai is the fourth biggest population center in India after Mumbai, Delhi, and Kolkata. Historically dependent upon limited water resources, the people of Chennai must pay high costs to transport water. Meanwhile, the lakes that supply the city’s water have been rapidly depleting over the last decade due to a rapidly growing population and dwindling seasonal rains. Chennai’s population was in desperate need to find a fresh water alternative.

The Innovation Solution: Increasing Seawater Reverse Osmosis Capacity in Region

In 2007, the water governing body of Chennai—Metropolitan Water Supply and Sewerage Board (CMWSSB)—contracted Befesa Construcción y Tecnología Ambiental (Befesa CTA) to build Chennai’s largest desalination plant. Under the agreement Befesa would design, build, own, and operate the $140 million Minjur plant for 25 years. The plant, located near Minjur just north of Chennai, would produce 237 million liters of sea water per day, supplying 100,000 m3/day (100 MLD) of desalinated water to the region. In order to produce economically viable water and uphold environmental standards, Befesa selected Energy Recovery’s advanced PX® technology as the plant’s energy recovery device (ERD) of choice. The decision was based on the PX device’s high efficiency, low overall life cycle cost, and reliability, as well as for Energy Recovery’s industry credibility and exceptional aftermarket service expertise.

The Result: Environmentally Sustainable Drinking Water at Low Cost

The Chennai plant was built with five trains containing 23 PX devices each and has since been upgraded to a permanent intake system, running four trains and reserving the remaining train for backup. The plant is currently supplying 100,000 m3/day (100 MLD) of desalinated water to the region. To ensure that the brine from desalination is disposed of in an environmentally friendly manner, it is diluted with pure treated water before being discharged back into the sea, so the salinity does not disrupt natural habitats.

This fresh water currently reaches approximately 2 million people at a cost of just over $1 per 1,000 liters.

“Energy Recovery’s energy-saving technology makes it possible for our city’s population to receive clean, reliable water at a much more competitive cost, enabling our people to live without the fear of insufficient water.“– Natarajan Ganesan, Joint General Manager, Chennai Water Desalination Company

“We use Energy Recovery’s PX technology in many of our plants because the technology gives us a competitive advantage.” – Carlos Cosin, International Director, Befesa

Chennai’s second 100 MLD desalination plant, constructed by VA Tech / IDE Consortium, has been commissioned.